ROBUST PROJECT Norwegian Public Roads Administration/Force ... · WP5 - Computational Mechanics. Summary Report MAIN REPORT The group “Computational Mechanics – Europe” (CME)

ROBUST PROJECT Norwegian Public Roads Administration/Force Technology Norway AS WP5 - Computational Mechanics Summary Report MAIN REPORT Volume 1 of 1 Deliverable 5.3.1

April 2006 Doc. No.: ROBUST-05-025 / TR-2005-0056 - Rev. 1

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Main Report

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Report title: WP5 - Computational Mechanics Summary Report Client: Norwegian Public Roads Administration/Force Technology Norway AS

Doc. no.: ROBUST-05-025 / TR-2005-0056

Project no.: 14081

Reporter(s): R. Gladsø K. Johannessen O. Kleppe

Abstract: This document is issued as a deliverable 5.3.1 to the WP 5 of the Robust project. The document summarises all work performed during WP5, and concludes on findings. Keywords:

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Free distribution Ref. allowed

Rev. no. Date Prepared by Checked by Approved by Reason for revision

1

28.04.2006

K. Johannessen

O.Kleppe

O. KLeppe

Comments included and errors corrected.

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31.01.2006

K. Johannessen

O. Kleppe

O. Kleppe

Issued as deliverable 5.3.1 to WP5

A

23.09.2005

R. Gladsø

K. Johannessen

O. Kleppe

Issued for Comment

ROBUST project Page i Norwegian Public Roads Administration/Force Technology Norway AS ROBUST-05-025 / TR-2005-0056 - Rev. 1WP5 - Computational Mechanics. Summary Report MAIN REPORT

CONTENTS 1 INTRODUCTION ...................................................................................................1 2 SUMMARY, FINDINGS AND RECOMMENDATIONS...........................................2

2.1 Summary................................................................................................................2 2.2 Findings .................................................................................................................3 2.3 Recommendations .................................................................................................4 2.3.1 Criteria and procedures .........................................................................................4 2.3.2 Recommendations for further work........................................................................5

3 WORK PACKAGE DESCRIPTION – WP5 ............................................................7 3.1 Partners involved ...................................................................................................7 3.2 Description of tasks................................................................................................7 3.3 Deliverables ...........................................................................................................7

4 DOCUMENTS ISSUED BY WP5...........................................................................8 5 ANALYSIS OF FULL SCALE TESTS ....................................................................9

5.1 General ..................................................................................................................9 5.2 Software.................................................................................................................9 5.3 Vehicle models.....................................................................................................10 5.4 Post-processing of results....................................................................................11 5.5 Barrier B1 – Steel N2 ...........................................................................................12 5.5.1 General ................................................................................................................12 5.5.2 Comments on input data......................................................................................12 5.6 Barrier B5 – Concrete ..........................................................................................20 5.6.1 General ................................................................................................................20 5.6.2 Comments on input data......................................................................................20 5.7 Barrier B2 – Steel H3 (Superrail) .........................................................................27 5.7.1 General ................................................................................................................27 5.7.2 Comments on input data......................................................................................27 5.8 Barrier B3 – Steel H2 (Varioguard) ......................................................................31 5.8.1 General ................................................................................................................31 5.8.2 Comments on input data......................................................................................31

6 PARAMETRIC STUDY ........................................................................................37 6.1 General ................................................................................................................37 6.2 Studies on input parameters ................................................................................37 6.3 Acceleration transducers .....................................................................................40

7 COMPARISON AND VALIDATION......................................................................41 7.1 Comparison between simulations ........................................................................41 7.1.1 Barrier B1 – Steel N2 ...........................................................................................41 7.1.2 Barrier B5 – Concrete ..........................................................................................47 7.1.3 Barrier B2 – Steel H3 ...........................................................................................49 7.1.4 Barrier B3 – Steel H2 ...........................................................................................50 7.2 Comparison between simulations and full scale tests..........................................52 7.2.1 Barrier B1 – Steel N2 ...........................................................................................52 7.2.2 Barrier B5 – Concrete ..........................................................................................53 7.2.3 Barrier B2 – Steel H3 ...........................................................................................54 7.2.4 Barrier B3 – Steel H2 ...........................................................................................56

8 REFERENCES ....................................................................................................58 APPENDIX A – TRL PARAMETRIC STUDY .......................................................................... A

ROBUST project Page 1Norwegian Public Roads Administration/Force Technology Norway AS ROBUST-05-025 / TR-2005-0056 - Rev. 1WP5 - Computational Mechanics. Summary Report MAIN REPORT

1 INTRODUCTION

The Robust Project aims to improve scientific and technical knowledge on the main issues still open in the new European standards on road restraint system EN 1317.

The knowledge acquired will form the basis of updated standards for EN1317 and lead to more advanced road restraint systems and improve road-users safety.

This report is the main deliverable from Work Package 5 - Computational Mechanics. Additional documents have been produced, and these are listed in Section 3.

The objective of WP5 is:

• Evaluation and enhancement of the use of computational mechanics to complement experimental activity

• Criteria and procedures for the validation of computational mechanics results through comparison with test results

• Reconstruction of real life accidents

• Identification of the activity needed for further enhancement of the use of computational mechanics.


2 SUMMARY, FINDINGS AND RECOMMENDATIONS

2.1 Summary This report presents the summary of the work performed within Work Package 5 - Computational Mechanics of the ROBUST project.

The tasks defined for ROBUST WP 5 was:

Analysis of full-scale tests in Task 4 with different models and codes

Reconstruction of real life accidents to obtain correlation with real injuries

Comparison and validation of computations made with different codes

Five institutes have participated in the work within WP5:

Politecnico di Milano (POMI) - Italy

Centre for Automotive (CIDAUT) – Spain

Norwegian Public Roads administration (NPRA) – Norway

TRL Limited (TRL) – England

A total of three vehicle types have been used; small car (900kg), bus (13t) and heavy vehicle (10t). The small car has been improved during the project. The heavy vehicle has been developed during the project, and the bus has been developed prior to the project (restricted for use).

A total of five barriers have been investigated. The simulation matrix, ref below was based on the full-scale test performed by the partners in WP4.

Task Test Vehicle Barrier Partner – performing simulations

TRL CIDAUT POMI NPRA/ FORCE

4.1 TB11 LV1 B1 (ESP-N2) X X X X

4.2 TB11 LV1 B5 (concrete) X X X X

4.3 Reconstruction (Task 5.2)note 1 X X X

4.4 TB11 LV2 B1 (steel N2 - - -

4.4 TB11 LV1 B2 (steel H3) X X

4.5 TB42 HV1 B3 (steel H2) X X

4.5 TB51 Bus B3 (steel H2) X X Note 1 :This task is not performed – Please refer to ROBUST deliverable D.1.2.1 for an explanation.

In addition to the predefined simulations (ref. matrix above), an extensive parametric study has been carried out, i.e. all of the partners have performed several numbers of simulations in addition to the 3-6 simulations predefined.


Task 4.3 has not been carried out, ref. deliverable from Task 2.1 stating: “After an extensive analysis of the accidents received, it was decided by the Consortium that none of the accidents were suitable for this Task. This was due to the information relating to the accident being restricted, unavailable and/or incomplete”

CIDAUT has performed simulation work for Task 4.1 and 4.2, ref table above. Some results have been presented in partner meetings, but not formally reported in a technical report. Due to lack of reporting partners have not been able to quality check and evaluate results from CIDAUT. Further documentation of CIDAUT’s results is therefore not presented in this report.

2.2 Findings During the Robust project and the work performed within Work Package 5 (WP5) several studies and investigations have been carried out. From these studies and simulations findings and conclusions have been made and documented in various reports. The below list of “findings” are a summarised list from WP5.

• There are - good correlation between the results from different institutes and between the full scale test and simulation when the boundary conditions are the same. This is valid for the two types of barrier that have been extensively tested.

• Using of full scale test as acceptance criteria for simulation is difficult since the scatter is too big for that purpose.

• The acceleration data should be sampled with a frequency of minimum 100 kHz. The study is documented in report ROBUST-05-007.

• The ends of soft guardrails need to be restrained for avoiding collapse of the post in simulations (Ref ESP-N2).

• Post-processing of results from simulations to be compared with full-scale data has been a challenge. Findings in the ROBUST project show that the raw data should be filtered with CFC60 filter before using procedure as described in 1317, or before using the TRAP program with CFC 180 filter. The study is documented in the report ROBUST-05-007.

• Inclusion of dummy and seat in the small car seems to stiffen the floor of the vehicle. The Z acceleration is lowered and corresponds better with the Z-acceleration obtained in full-scale test. However it seems also that inclusion of dummy and seatbelt may cause some instability in the vehicle for some cases, ref ROBUST-05-016a for details.

• Modification of spinning wheel, wheel suspension and the steering of the small car seem to have improved the vehicle trajectory compared to full scale tests.

• The small car, improved in this project (GeoMetro), is comparable to the small car normally used in full scale test. The vehicle model will be made available to everybody that intends to use it.

• The friction coefficient between vehicle and barrier and between wheel and roadway must be determined.

• For steel barrier the friction coefficient between the vehicle and the barrier should be relatively low (0-0,1). The Robust project has shown that such friction coefficient gives the best results compared to the full-scale tests.


• For concrete barrier the friction between barrier and vehicle is of great importance to the results. Robust has used coefficient between 0,1-0,3, which is based on experience.

• For some barriers the friction between roadway and barrier (sliding barriers) need to be focused. In the Robust project a coefficient of 0,6-0,7 has been used.

• Further studies on the importance of friction coefficients should be performed to make more final conclusions.

• It is important that the vehicle model do not penetrate the barrier model during the crash scenario (ref. contact definition). The Robust project has shown that this may be a problem for some models.

• Using of bolts modelled by spot welds with plastic failure criteria function well. The same for bolts modelled by deformable beams. It should be noted that the failure criteria must be determined based on the mesh size. The failure criteria should be investigated more thoroughly.

The findings from the parametric study were (based on one barrier type only):

• Mass-scaling in the model does affect results. Mass scaling should be used moderate, and is useful to save computational time. Further studies on the effects should be investigated.

• Variations found when using different revisions of the same software.

• Rotational velocity data output at 1kHz and 100kHz produced the same results

• Variations in impact conditions such as speed and angle cause variations in model predictions/severity indexes, ref. discussion in chapter 6.

• Variations in material properties cause variations in model predictions/severity indexes, ref. discussion in chapter 6.

2.3 Recommendations

2.3.1 Criteria and procedures One of the objectives of the ROBUST project was to develop: criteria and procedures for the validation of computational mechanics results through comparison with test results.

During the Robust project a lot of simulations have been performed. Studies on several parameters and issues have been focused.

Based on the work performed it can be concluded that simulations and full-scale test compare quite good, bearing in mind the condition for the simulation and test. However the Robust project is not comprehensive enough to give a complete set of criteria and procedures for validation of computational mechanics.

The Robust project should however form basis for the criteria’s and procedures that need to be established for the use of Computational Mechanics in validation and acceptance to road restraint systems.


The group “Computational Mechanics – Europe” (CME) is currently working with validation criteria towards the EN 1317 system. It is anticipated that this group will propose criteria’s and procedures in a short time. Work performed in CME, is partly based on work performed in the ROBUST project together with work performed in other joint industrial projects.

The Robust project has shown that using of full scale test as acceptance criteria for simulation is not recommendable since the scatter for the full scale test is too spacious for that purpose. More reliable results will be gained by study the CM itself.

The documentation from a CM analysis has to be more comprehensive than the documentation from a full scale crash test, especially related to input data (coefficients, boundary conditions, material data, software description, FE-model description etc.).

Documentation for a CM-analysis should contain (in addition to demands set forth in EN1317):

• A complete list of all input parameters and values incl. presumption. Especially focus on simulation parameters influencing the results.

• Which program (and version, revision) is used and the experience for the operator

• Description in how the program is used (which part of the program is used, the use of mass scaling, where is the data taken from, contact definition etc)

• Description of the barrier model; no. of posts, spacing, total length, element formulation/type, connection/joints, foundation, end anchoring, soil, material data etc.

• Description of the vehicle model with relevant testing/validation

• Analysis data; time step, precision, friction between all parts (vehicle/barrier, vehicle/road), sampling rate, weight of vehicle, impact speed and angle etc.

Follows it is mentioned some check points. The list is based on the experiments from ROBUST and it is limited to use of LS-DYNA, Concrete and soft steel barrier (the list is not completed):

• Timestep should not be greater than 3,0 E-6 (valid for small vehicle)

• Samling rates should not be greater than 100 kHz

The lists should be further developed and possible extended, and must be seen as a first proposal from ROBUST.

2.3.2 Recommendations for further work Another objective of the ROBUST project was to: Evaluation and enhancement of the use of computational mechanics to complement experimental activity.

There are some important criteria that should have been investigated more for further enhancement.


The Computational Mechanics group in the Robust project have concentrated the studies on a concrete barrier and a soft steel barrier. For other barriers, as stiff barriers or movable barriers more investigations/studies should be performed.

The following list identifies some of the activities needed for further enhancement of the use of CM:

• The influence of soil/asphalt to the results should be investigated more. Topics like where to fix the post, and how to do it (springs, fixation, modelling the soil) should be focused.

• Failure criteria in bolts modelled by spot welds and for bolts modelled by deformable beams should be investigated more.

• Influence of different parameters should be investigated for different types of barriers (concrete, soft barrier, stiff barrier, sliding barrier). Computational Mechanics is a very good tool to perform such parametric studies, and reliable results will be gained. Proposed parameters are:

– Friction coefficients (barrier/vehicle, vehicle/road surface)

– Material data (fraction criteria, yield, young’s modulus, material model etc.)

– Impact speed and angle

– Mass scaling

– Boundary conditions (fixing of posts, fixing of ends, anchoring)

– Etc


3 WORK PACKAGE DESCRIPTION – WP5

3.1 Partners involved

Partner involved R&D Task/Activity

Politecnico di Milano (POMI)

Perform computational mechanics on identified conditions, including parametric studies and model development.

Centre for Automotive (CIDAUT) Perform computational mechanics on identified conditions.

Norwegian Public Roads Administration (NPRA)

Work Package Leader

Perform computational mechanics on identified conditions, including parametric studies.

Collect results from other partners.

TRL Limited (TRL) Perform computational mechanics on identified conditions, including parametric studies.

3.2 Description of tasks The following tasks are defined:

Task 5.1 Analysis of full scale tests in Task 4 with different models and codes

Task 5.2 Reconstruction of real life accidents to obtain correlation with real injuries

Task 5.3 Comparison and validation of computations made with different codes

3.3 Deliverables The following deliverables are defined:

D.5.1.1 Analysis of full scale tests to identify computational mechanics priority

D.5.2.1 Reconstruction of real life accidents with numerical tools

D.5.3.1 Comparison and validation of computations – Recommendations for computational mechanics future


4 DOCUMENTS ISSUED BY WP5

A number of documents have been issued within the WP5, see Table 1 List of documents WP5below.

Table 1 List of documents WP5

Doc number Title Performed by

Date

Robust 5-002 WP5 - Computational Mechanics NPRA/Force 19/04/2004 Robust 5-005 WP5 - Computational Mechanics NPRA/Force 20/12/2004 Robust 5-006 Geo-Metro Finit Element model

(GM_R3) POMI 28/01/2005

Robust 5-007 Acceleration transducers on Finite Element vehicles models for crash simulations with Ls-Dyna

POMI 17/01/2005

Robust 5-009 WP5 - Computational Mechanics NPRA/Force 01/04/2005 Robust 5-010a B5 – Temporary Vertical Concrete

Safety Barrier TRL 29/11/2005

Robust 5-010b B5 – Temporary Vertical Concrete Safety Barrier

TRL 29/11/2005

Robust 5-010c B5 – Temporary Vertical Concrete Safety Barrier

TRL 08/12/2005

Robust 5-011 VOID Robust 5-012 B5 – Round Robin Concrete Barrier POMI 11/10/2005 Robust 5-013 Barrier B5 – Concrete barrier NPRA/Force 13/11/2005 Robust 5-014a B1 (ESP-N2) Barrier – Steel N2 TRL 29/11/2005 Robust 5-014b B1 (ESP-N2) Barrier – Steel N2 TRL 25/11/2005 Robust 5-014c B1 (ESP-N2) Barrier – Steel N2 TRL 08/12/2005 Robust 5-015 VOID Robust 5-016a B1 Barrier (ESP-N2) POMI 01/06/2005 Robust 5-016b Modelling of posts for the ESP-N2

barrier POMI 04/11/2005

Robust 5-016c Modelling of bolt connections for the ESP-N2 barrier

POMI 30/11/2005

Robust 5-017 B1 Barrier – Steel N2 NPRA/Force 08/11/2005 Robust 5-018 B3 barrier - Varioguard POMI 25/01/2006

Robust 5-019 B3 barrier - Varioguard NPRA/Force 16/01/2006

Robust 5-020 VOID

Robust 5-021 VOID

Robust 5-022 VOID

Robust 5-023 B2 barrier - Super-Rail®plus POMI 20/12/2005

Robust 5-024 B2 barrier - Super-Rail® plus NPRA/Force 08/11/2005


5 ANALYSIS OF FULL SCALE TESTS

5.1 General There are performed a number of full scale tests in the Robust project, ref. WP4. These tests are reconstructed by use of Computational Mechanics. In Table 2 the test matrix is presented together with the partners and the simulations each partner has performed.

Table 2 Test matrix

Task Test Vehicle Barrier Partner – performing simulations

TRL CIDAUT POMI NPRA/ FORCE

4.1 TB11 LV1 B1 (ESP-N2) X X X X

4.2 TB11 LV1 B5 (concrete) X X X X

4.3 Reconstruction (Task 5.2)note 1 X X X

4.4 TB11 LV2 B1 (steel N2 - - -

4.4 TB11 LV1 B2 (steel H3) X X

4.5 TB42 HV1 B3 (steel H2) X X

4.5 TB51 Bus B3 (steel H2) X X Note 1 :This task is not performed – Please refer to ROBUST deliverable D.1.2.1 for an explanation.

CIDAUT has performed work for Task 4.1 and 4.2, ref table above. Some results have been presented in partner meetings, but not formally reported in a technical report. Due to lack of reporting partners have not been able to quality check and evaluate results from CIDAUT. Further documentation of CIDAUT’s results is therefore not presented in this report.

5.2 Software

For the simulations referenced in this document the software LS-DYNA have been used.

LS-DYNA LS-DYNA is a general-purpose, explicit finite element program used to analyze the nonlinear dynamic response of three-dimensional inelastic structures. Its fully automated contact analysis capability and error-checking features enables the user to solve a full range of complex problems. Typical problems are:

• Large Deformation Dynamics and Contact • Crashworthiness Simulation • Occupant Safety Systems • Multi-physics Coupling


• Failure Analyses

The program take full account of both material and geometric non-linearities. Material non-linearities include effects of yield strength and strain hardening of the steel material. Geometric non-linearities include effects of large deformations, large rotations and local and global instability/buckling.

The program is developed by Livermore Software Technology Corp. (LSTC). (www.lstc.com)

5.3 Vehicle models The following vehicle models have been made available to and developed within the Robust project:

– Small car 900kg: GeoMetro, developed by NPRA/FORCE and made available to public in year 2000. The model has been modified by POMI and NPRA/FORCE partly as part of the Robust project. For documentation see document list, Table 1. The following versions are available:

• GM_R0: The model was delivered by National Crash Analysis Centre (NCAC) and was originally developed for the simulation of frontal impact into a rigid wall. The model was developed under year 1999-2000. A detailed description of the model is given in Ref. 3. The following model modifications were made by Safetec (now FORCE):

o The mass of the vehicle was modified in accordance with 1317 specifications, Ref. 1.

o The thickness of the outer fender on both sides was increased to avoid considerably damage to individual elements, with subsequent element failure.

o The original model included spinning wheels. This effect was removed.

o Accelerometer included on the car floor near the centre of gravity.

• GM R1: POMI has performed extended upgrading of the steering system, suspension etc. The model is not further documented.

• GM R2: Dummy, seats and seat belt were included in the GM R1 model. Detailed description of the model is given in “Robust 5-002”.

• GM R3: Further improvements to the steering system and suspension system have been performed by POMI. No further documentation is available.

• GM R4: Dummy, seats and seat belt were included in the GM R3 model. The same procedures as used for establish the GM R2 model was used. No further documentation is available.

• GM_R4.2: Redefinition of parameters related to dummy, seatbelt, glass material and contact between dummy and vehicle. For further documentation se “ROBUST 5-016”

– 10t vehicle (truck): developed by POMI as part of the ROBUST project. Finite element model of a 10 t Heavy Goods truck with a fully working steering system and front& rear suspension. A test and coarse verification is documented in ROBUST-009. The test is performed by NPRA/FORCE.

http://www.lstc.com/


– Bus: developed by NPRA/FORCE and made available to the Robust partners for use in this project only. The model is restricted for use as requested by Scania.

All models presented above are developed on LS-DYNA format only.

In addition TRL has used a generic model of a Fiesta for some of the simulations. The model is fairly simple and no further documentation is available.

5.4 Post-processing of results The method for calculating the ASI, THIV and PHD values are given in EN1317. However, when it comes to simulations, the output data normally needs to be subjected to filtering before the calculation according to EN1317 can be performed. The different approaches used for filtering data are given below:

o Local accelerations are extracted from the simulation with a sampling rate of 100 kHz. The data are subjected to a CFC60 filter before the calculation according to EN1317 is performed. This method is used by POMI and NPRA/FORCE. The method is named TRAP (CFC180 filter included in TRAP)

o Local velocities are extracted from the simulation with a sampling rate of 100 kHz. The local accelerations are calculated by derivation of the velocities (dv/1e-5). The calculated accelerations are subjected to a CFC60 filter before the calculation according to EN1317 is performed. This method is used by NPRA/FORCE. The method is named in-house.

o Local velocities are extracted from the simulation with a sampling rate of 100 kHz. The data is regularised and converted into the required SI units. It is then inputted directly into the DIADEM program where it is filtered at CFC180 and then used to calculate ASI, THIV and PHD. The autosequence used to calculate severity indices was written by TRL and validated against VISA software. The PHD data was compared with the calculations make in DIADEM 9. This method was used by TRL.


5.5 Barrier B1 – Steel N2

5.5.1 General Several simulations have been carried out for the Steel N2 barrier, for illustration see Figure 1 The different partners have used slightly different input parameters, see Table 3.

The results from the simulations are presented in Table 4.

To allow a visual comparison of the crash scenario a table of figures containing snap shots at discrete time intervals has been included. This is illustrated in Table 5.

Detailed documentation is given in reports from each partner, ref. document list Table 1.

Figure 1 Barrier B1 – Steel N2, illustration (picture from TRL). The barrier is

delivered by Volkmann & Rossback, a ROBUST partner

5.5.2 Comments on input data When performing simulations input data is of crucial importance. The first issue to be discussed when comparing simulations, later simulations and full-scale tests are therefore the input data, the differences and the possible influence on the results.

The nature of the different barrier parameters will have different influences on the result.

All institutes have performed several simulations with different input parameters for this barrier. This will allow for comparison of different parameters and their influence. Table 3 gives an overview of the input data, with the basis from one case from each institute. In the bottom of this table the different additional simulations are presented and comments are given on the data changed.

When evaluating the input parameters it is important to focus on the following, see Table 3:


– The car model; the car model should be as alike as possible. At least the same behaviour should be expected based on the level of detail of the model. All institutes have used a GeoMetro as basis for the analysis. The three institutes (POMI, TRL and NPRA/FORCE) are using the same model but different versions of it. The GM_R3 model is refined with respect to suspension, steering etc. which clearly will influence the trajectory and maybe the severity indexes for the car during an impact.

– Impact energy will influence the results. From Table 3 it can be observed that different impact speeds and vehicle mass have been used. This leads to differences in the impact energy which will clearly also influence the simulation results.

– The barrier itself is based on the same geometry, but each institute has developed the FE-model themselves. The main differences in the barrier models are the material data. POMI has used slightly lower yielding point for the steel than TRL NPRA/POMI. For a barrier which will utilise the material data into a non-linear range during an impact the material data will have some influence on the results.

– The method of modelling the barrier rail and post connections differed between institutes. If breaking/disconnection of the rail form the post is experienced during impact such modelling differences may contribute to different results between the partners.

– Friction between vehicle and barrier and tyre and asphalt will influence the simulations results to some extent. For the N2 barrier the friction coefficients are more or less the same, so no uncertainty due to this factor is expected.

For further discussion of the results please see Section 7.1.


Table 3 Barrier B1 – Steel N2. Input parameters. Description POMI TRL NPRA/FORCE

Case 1 Vehicle version GM_R3 GM_R2 GM_R2 Impact point (m) 28 26 29 Impact speed (Km/h) 102,5 100 103,5 Impact angle (Deg.) 20 20 20 Vehicle test mass (Kg) 928 855 944 VRS-length incl. (m) 69 76 64

Connection/joints Spotwelds with failure Spotwelds with failure Spotwelds with failure

Foundation Fixed -190mm Fixed -200mm Fixed -200mm End anchoring W-profile fixed W-profile fixed W-profile fixed Element type Shell Shell Shell Accelerometer pos. 111 Longitudinal 111 Longitudinal 120 Longitudinal from COG (mm) 32 Lateral 27 Lateral 20 Lateral 138 Vertical 140 Vertical 142 Vertical Material data Non-linear Non-linear Non-linear - Elastic module (GPa) 207 210 210 - Density (Kg/m3) 7800 7850 7850 - Yielding point (MPa) 235 300 300 - USL (MPa) 450 450 450 Friction(Static/Dynamic) - Steel – Steel NA/NA NA/NA NA/NA - Tire – Asphalt 0,6/NA 0,7/NA 0,7/NA

Time step 1,18E-06 - 1,25E-06 2,03E-06 3,10E-06

Sampling rate 100 KHz 100 KHz 100 KHz

Case 2 End anchoring: W-profile fixed As case 1 End anchoring: W-

profile free

(Changes w.r.t base case) Impact point: 29 m LS-DYNA version-970 revision 3858.1 instead of 5434a Partial data output at 1 kHz

Post fixed 30mm above ground level

Case 3 End anchoring: W-profile free Vehicle type: Generic fiesta End anchoring: W-

profile free

(Changes w.r.t base case) Impact point: 29 m Mass of vehicle 940kg Reduced complexity of vehicle model

Vehicle material properties

Post fixed -200 m below ground level

Case 4 Vehicle type: Generic fiesta End anchoring: W-profile free (elastic BC)

(Changes w.r.t base case)

LS-DYNA version-970 revision 3858.1 instead of 5434a Partial data output at 1 kHz Mass of vehicle 940kg Reduced complexity of vehicle model

Vehicle material properties

Foundation: Soft springs

Case 5 Vehicle type: GeoMetro version R4 Same as case 4

(Changes w.r.t base case)

Updated vehicle model Dummy included

Mass 893 kg incl. dummy Mass-scaling lowered

Timestep 1.29E-6

Increased stiffness in the springs.

Case 6 Same as case 5

(Changes w.r.t base case) Increase in yield of 50 MPa

Case 7 Same as case 4

(Changes w.r.t base case) Vehicle version GM_R4, Velocity: 102,5 Km/h

Case 8 Same as case 1 (changes w.r.t. base case Vehicle model GM_R4


Table 4 Barrier B1 – Steel N2. Results.

Analysis performed by ASI THIV PHD D W Exit speed

Exit angle

[km/h] [g] [mm] [mm] [km/h] [deg]POMI Case 1: Posts fixed -190mm, Free rail ends, GM_R3 0,77 20,40 17,40 1320 1390 72,00 17,50

Case 2: Posts fixed -190mm, Fixed rail ends,GM_R3 0,85 23,60 15,10 628 818 82,00 18,00

Case 3: As above, but the impact point is moved, GM_R3 0,83 23,30 12,10 671 765 85,00 13,50

Case 4: As case2, but with vehicle type GM_R4 0,84 21,8 11,9 735 807 83,9 12,9

NPRA/FORCE Case 1: Posts fixed -200mm, Posts non-linear, fixed rail ends,GM_R2

0,72 25,90 11,30 730 825 56,00 13,50

Case 2: Posts fixed +30mm, End posts elastic and free,GM_R2 0,81 27,40 14,60 674 766 54,00 13,50

Case 3: Posts fixed -200mm, End posts elastic and free,GM_R2 0,67 25,10 9,70 772 869 58,00 13,30

Case 4: Soil w/soft springs, End posts elastic and free,GM_R2 0,70 23,70 10,80 840 933 57,00 13,70

Case 5: Case 4 but with an increased spring stiffness 0,69 23,70 12,10 830 926 58,00 13,3 Case 6: Case 4 but with an increase in post yield of 50 MPa 0,70 23,80 8,90 780 878 56,00 13,2 Case 7: Case 4 but with vehicle type GM_R4 0,63 21,20 8,10 812 905 65,70 13,90 Case 8: Case 1 but with vehicle type GM_R4 0,63 22,40 7,00 737 824 68,40 12,80 TRL Case 1: Post fixed -200mm, Fixed ends,GM_R2 0,86 24,60 12,89 636 774 67,9 8,9 Case 2: As above but LS-DYNA version, partial output 1kHz

1,08 29,33 15,97 622 773 69,7 9,1

Case 3: As above but Generic vehicle model 0,69 23,80 8,8 639 836 68,4 2,3 Case 4: As above but Generic vehicle model, LS_DYNA version and partial output 1kHz

0,69 27,6 8,8 651

837 67,8 2,2

Case 5: As above but GM_R4 vehicle model 0,80 23,70 12,86 666 748 81,5 7,6


Table 5 Barrier B1 – Steel N2. Pictures related to early vehicle.

POMI (Case 3) GM_R3 TRL (Case 1) GM_R2 NPRA/Force (Case 1) GM_R2

Time = 0,11 sec Time = 0,12 sec Time = 0,11 sec




NOTE: The time given in the table is the analysis time for each simulation and will not reflect the actual time of the crash scenario, i.e. the pictures are not directly comparable.


Table 6 Barrier B1 – Steel N2. Pictures GM_R4

POMI (Case 4) GM_R4.2 TRL (Case 5) GM_R4 NPRA/Force (Case 8) GM_R4


Time = 0,16 sec Time = 0,16 sec NA





5.6 Barrier B5 – Concrete

5.6.1 General Several simulations have been carried out for this barrier, for illustration see Figure 2.

Additional simulations have been performed with the GeoMetro version R4 as an activity replacing the reconstruction case. The different partners have used slightly different input parameters, see

Table 7.

The results from the simulations are presented in Table 8.

To allow a visual comparison of the crash scenario to be made, a table of figures containing snap shots at discrete time intervals has been included. This is illustrated in Table 9 for the early version of the GeoMetro and in Table 10 for GM_R4.


Figure 2 Barrier B5 – Concrete, illustration (picture from LIER).

5.6.2 Comments on input data Several scenarios have been performed also for this barrier. Emphasis has been on vehicle models/versions and on friction coefficients.

Evaluating the input parameters it is important to focus on the following, see

Table 7:

– For a concrete barrier the friction coefficient between the barrier and the vehicle is of great importance. It was therefore early in the project agreed to start with a friction coefficient around 0,3. The simulations performed have friction coefficients varying from 0,1 to 0,3 (static). The institutes have also used different definitions when giving the friction parameter, i.e. some have used a


combination of static and dynamic friction while others have used only static. This will influence the results.

– The institutes have used different vehicle mass in the simulations, and therefore the impact energy will differ. This may influence the results.

– Different vehicle versions are used, see section 5.5.2 for further comments.

For further discussion of the results please see Section 7.1.

Table 7 Barrier B5 – Concrete. Input parameters

Description POMI TRL NPRA/FORCE Case 1 Vehicle version GM_R2 Geometro (260804) GM_0 Impact point (m) 4,5 4,8 NA Impact speed (Km/h) 100 100 100 Impact angle (Deg.) 20 20 20 Vehicle test mass (Kg) 860 862,5 900 VRS-length incl. (m) 15 18 NA Connection/joints NA NA NA

Foundation Fixed to ground Fixed to ground Fixed to ground

End anchoring NA NA NA Element type Rigid wall Solid Solid

Accelerometer position 111 Longitudinal 120 Longitudinal

from COG (mm) 32 Lateral As supplied with vehicle 21,5 Lateral 138 Vertical 144 Vertical Material data Elastic Elastic Elastic - Elastic module (GPa) 15 40 40 - Density (Kg/m3) 1400 2700 2700 - Yielding point (MPa) - USL (MPa) Friction (Static/Dynamic) - Steel – Concrete 0,1/0,05 0,3/0,1 0,3/NA - Tire – Asphalt 08/NA 0,3/0,3 0,6/0,6

Time step Max 1,18E-06 Min 1,25E-06 2,03E-06 3,00E-06

Sampling rate 100 KHz 100 KHz 100 KHz

Case 2 As case 1 As case 1 Vehicle type: GM_R1

(Changes w.r.t case 1)

Vehicle GM_R4, Tire-asphalt friction 0,6

LS-DYNA version-970 revision 3858.1 instead of 5434a Partial data output at 1 kHz

Case 3 Vehicle type: Generic TRL Vehicle type: GM_R2

(Changes w.r.t case 1) Friction (tire-asphalt) 0,8/0,8

Case 4 Vehicle type: Generic fiesta Vehicle type: GM_R4


LS-DYNA version-970 revision 3858.1 instead of 5434a Partial data output at 1 kHz

Initial velocity: 100 Km/h, Steel – concrete friction: 0,3/0,3


Mass of vehicle 940kg Reduced complexity of vehicle model Vehicle material properties

Tire-asphalt friction: 0,7/0,7

Case 5 NA Vehicle type: GM_R4 NA

(Changes w.r.t case 1) Steel – concrete friction 0/0 Tire-Asphalt friction 0,7

Table 8 Barrier B5 – Concrete. Results.

Analysis performed by ASI THIV PHD W Exit

speed Exit

angle [km/h] [g] [mm] [km/h] [deg]

POMI GM_R0 1,86 31,70 17,90 NA 81,00 2,50 GM_R4 1,78 26,6 17,2 NA 88,00 0,00 NPRA/FORCE Case 1: Fixed to ground,GM_0 (post-proc: in-house)

1,86 33,60 16,73 NA 81,40 4,10

Case 2: Fixed to ground,GM_R1 (post-proc: in-house)

1,73 33,90 7,10 NA 73,10 4,20

Case 3: Fixed to ground,GM_R2 (post-proc: TRAP)

1,95 35,20 12,40 NA 75,50 5,60

Case 4: Fixed to ground,GM_R4 (post-proc: TRAP)

1,98 34,3 12,1 NA 78,00 4,60

TRL Case 1: Barrier fixed to ground, GM_R0 1,93 39,5 11,09 450 71,38 6,33

Case 2: Case 1 but with different software version and output rate (partial)

1,92 36,0 9,46 450 71,3 6,3

Case 3: Generic TRL 1,40 24,50 34,70 450 83,12 2,28 Case 4: Generic TRL but with different software version and output rate (partial)

1,38 24,23 34,6 450 83,06 2,31

Case 5: GeoMetro version R4 1.75 29.13 - 450 91.07 4.12

Note: No displacement are registered for the concrete barrier in the simulations, therefore the working width is equal to the width of the barrier.


Table 9 Barrier B5 – Concrete. Pictures; early version of GeoMetro.









Table 10 Barrier B5 – Concrete. Pictures of GM_R4



Time = 0,10 sec NA Time = 0,10 sec






5.7 Barrier B2 – Steel H3 (Superrail)

5.7.1 General A total of three simulations have been carried out for the Steel H3 Superrail, for illustration see Figure 3.

The input parameters for the simulations are given in Table 11, the results are presented in Table 12, and a visual comparison of the crash scenario in Table 13.


Figure 3 Barrier B2 – Steel H3 Superrail (picture from TRL). The barrier is delivered by

Volkmann & Rossback, a ROBUST partner.

5.7.2 Comments on input data The four simulations are performed by POMI and NPRA/FORCE. POMI has performed three simulations with different end anchoring.

Evaluating the input parameters it is important to focus on the following, see Table 11:

– Different version of the GeoMetro has been used. The differences are mainly the inclusion of the dummy and seat, which will influence the strength of the car floor and the weight of the vehicle model. For further discussion see section 5.5.2.

– Fixation to the ground is also different. POMI model is fixed -180mm wilt NPRA/FORCE is fixed at ground level. It may influence the stiffness of the post and the ability to move.

– Slightly difference in material data. POMI used lower yield point than NPRA/FORCE. This may influence the damage and behaviour of the rail/post system. If collapse of impact element/tube is experienced such difference may give different results from partner to partner.


– Ends of barrier free or fixed will give different results and behaviour of barrier and vehicle.

Table 11 Barrier B2 – Steel H3; Input parameters

Description POMI NPRA/FORCE Case 1 Vehicle version GM_R3 GM_R4 Impact point (m) 13,3 13,3 Impact speed (Km/h) 102,5 102,5 Impact angle (Deg.) 20 20 Vehicle test mass (Kg) 928 897 VRS-length incl. (m) 40 40 Connection/joints Deformable beams (PSFAIL=0.1) Spotwelds Foundation Fixed -180mm Not modeled End anchoring Barrier ends fixed Barrier ends fixed Element type Shell+Beams Shell Accelerometer position 111 Longitudinal 120 Longitudinal from COG (mm) 32 Lateral 20 Lateral 138 Vertical 141 Vertical Material data Non-linear Non-linear - Elastic module (GPa) 207 210 - Density (Kg/m3) 7800 7850 - Yielding point (MPa) 235 300 - USL (MPa) 450 450 Friction (Static/Dynamic) - Steel – Steel NA/NA NA/NA - Tire – Asphalt 0,6/NA 0,7/NA Time step 1,12-1,14E-06 2,50E-06 Sampling rate 100 KHz 100 KHz Case 2 End anchoring: (Changes w.r.t case 1) Barrier ends free Case 3 As case 2


Bolts modelled by deformable beams (PSFAIL=0.085). Posts fixed 292.5 mm below ground level. Defo-Tube steel properties modified (Yield stress=300Mpa)


Table 12 Barrier B2 – Steel H3; Results

Analysis performed by ASI THIV PHD D W Exit

speed Exit

angle [km/h] [g] [mm] [mm] [km/h] [deg]

POMI Case 1: Posts fixed -180mm, Fixed rail ends,GM_R3

1,63 30,70 12,10 280 709 87,5 16,0

Case 2: Posts fixed -180mm, Free rail ends,GM_R3

1,55 30,30 18,00 460 715 86,0 15,0

Case 3: Posts fixed -292.5 mm, Defo-Tube steel properties modified (Yield stress=300Mpa)

1,41 29,20 11,90 373 736 87,2 14,6

NPRA/FORCE Case 1: All non-linear, Fixed rail ends,GM_R4

1,36 32,80 11,70 332 648 67,00 15,30


Table 13 Barrier B2 – Steel H3; Pictures.

NPRA/Force GM_R4 POMI GM_R3

Time = 0,10 sec Time = 0,07 sec





5.8 Barrier B3 – Steel H2 (Varioguard)

5.8.1 General Several simulations have been carried out for the Steel H2 barrier, for illustration see Figure 4.

The focus has been on testing different vehicle types against the barrier, ref WP4 (full-scale tests).

The input parameters for the simulations are given in Table 14, the results are presented in Table 15, and a visual comparison of the crash scenario in Table 16 and Table 17.


Figure 4 Barrier B3 – Steel H2 Varioguard, illustration (picture from www.volkmann-

rossbach.de).

5.8.2 Comments on input data Simulations have been performed with different vehicle models. 10t lorry, 13t Bus and small car have been simulated for this barrier.

The model of the 10t lorry has been developed by POMI, and NPRA/FORCE has not performed any changes to the received model. From pictures it can be seen that there are some changes in the model after it has been distributed, and the weight is also slightly different. Modifications to the model may influence the results.

For the small car simulation again two different versions of the GeoMetro has been used, see section 5.5.2 for further discussion.


Table 14 Barrier B3 – Steel H2; Input parameters

Description POMI NPRA/FORCE Case 1

Vehicle version Heavy Goods Vehicle (10t) Heavy Goods Vehicle (10t) (Lorry_version R1)

Impact point (m) 28 24 Impact speed (Km/h) 70 70 Impact angle (Deg.) 15 15 Vehicle test mass (Kg) 10000 10248 VRS-length incl. (m) 68 68

Connection/joints Merging coinc. nodes at bolt spots Contact (friction coefficient of 0.25)

Foundation Barrier lay on the road surface Not modeled End anchoring Barrier terminals jointed to ground Model fixed at spikes locationElement type Shell Shell Accelerometer position NA NA from COG (mm) NA NA NA NA Material data Non-linear Non-linear - Elastic module (GPa) 207 210 - Density (Kg/m3) 7800 7990 - Yielding point (MPa) 235 300 - USL (MPa) 450 450 Friction (Static/Dynamic) - Steel – Steel NA/NA NA/NA - Tire – Asphalt 0,6/NA 0,6/0,6 Time step 1,19-1,22E-06 2,70E-06 Sampling rate 100 KHz 100 KHz Case 2 Vehicle type: GM_R3 Vehicle type: Bus (13 ton)

(Changes w.r.t case 1) Impact point: 20 m Friction (Steel-Steel): 0,2/0,3

Angle: 20 deg. Impact point: 23 m

Case 3 Same as case 2 Vehicle: GM_R4 (Changes w.r.t case 1) Friction (steel-steel):0/0 Friction (steel-steel): 0/0


Table 15 Barrier B3 – Steel H2; Results.

Analysis performed by ASI THIV PHD D W Exit

speed Exit

angle [km/h] [g] [mm] [mm] [km/h] [deg]

POMI Case 1: Heavy goods vehicle (10t)

NA NA NA 1592 1850 66 4,5

Case 2: GM_R3; Friction vehicle-barrier: 0,2/0,2

1,25 25,30 9,80 1320 1422 78 1,5

Case 3: GM_R3; Friction vehicle-barrier: 0/0

1,13 19,40 10,60 1020 1564 90 0

NPRA/FORCE Case 1: Heavy goods vehicle (10t)

NA NA NA 1386 2086 64 5,4

Case 2: Bus (13t) 0,21 6,30 4,20 1584 2284 63 1,5 Case 3: GM_R4; Friction vehicle-barrier: 0/0

1,24 22,5 10,8 870 1570 87 NA


Table 16 Barrier B3 – Steel H2; Pictures of 10t and Bus.

NPRA/Force – 10t POMI – 10t NPRA/FORCE - Bus






Table 17 Barrier B3 – Steel H3; Pictures of small car

NPRA/Force GM_R4 POMI (Case 2) GM_R3






6 PARAMETRIC STUDY

6.1 General Parametric studies have been performed by TRL, POMI and NPRA/FORCE. Several parameters have been studied, and reported as part of deliverable 5.1.1 (see the reports of the different barriers from the different institutes)

TRL have performed an extensive parametric study in addition. This study is reported in Appendix A, and summarised in section 6.2.

POMI have performed a study on acceleration transducers (ref. ROBUST-05-007). The study is commented in section 6.3.

It should be noted that just a selection of simulations have been performed. To make final conclusions more studies (several of) should be performed. However the studies performed within ROBUST project gives an indication on which parameter influence the results and the deviation in the results.

Several more parameters will influence the results, as discussed both in chapter 5 and 7. Parameters such as friction, accelerometer location, mass scaling, versions of software, types of software, no. of CPU’s etc. are partly studied as part of ROBUST. Based on the simulations performed it is not possible to draw any clear conclusions (only an indication), mainly due to just a small amount of simulations performed.

The parameters used in the simulations, as reported in section 5 and 7, are based on experience and engineering judgement, and should form a good basis for results. It is shown in chapter 7 that despite the differences in parameters the variation in the results is within the variation in the results from the full-scale tests.

6.2 Studies on input parameters The parametric study from TRL had two main areas of focus and was carried out using the model of the GeoMetro version R4 (GM_R4) vehicle impacting a ESP-N2 barrier. The areas under consideration were impact conditions such as speed and angle and material properties such as steel yield, ultimate tensile strength (UTS) and thickness.

The figures below, Figure 5 and Figure 6 shows that percentage change in impact energy caused by change in angle is more important than when caused by change in speed. It can be observed that both for ASI and for dynamic deflection this is true.

The dynamic deflection seem very little influenced by change in the material parameter. However the dynamic deflection decreases when increasing the yield stress, ref. Figure 7.

Change in thickness (profile and post) influences the dynamic deflection more than change in yield stress, ref also Figure 7.

Change in yield stress and young’s modulus influence the ASI more than changes in thickness, ref. Figure 8.

Se also comments made by TRL in Appendix A.


Impact condition - ASI

0,74

0,76

0,78

0,80

0,82

0,84

0,86

0,88

0,90

0,92

-5,00 0,00 5,00 10,00 15,00 20,00

% change of Impact energy

ASI

Speed-100/107 Angle-20/21.5 S+A-100-20/105-21.5 S+A 100-20/102-19Linear (S+A-100-20/105-21.5) Linear (Angle-20/21.5) Linear (Speed-100/107) Linear (S+A 100-20/102-19)

Figure 5 Parametric study – Impact condition vs. ASI

Impact condition - Dynamic deflection

400

450

500

550

600

650

700

750

800

850

-5,00 0,00 5,00 10,00 15,00 20,00

% change of Impact Energy

Dyn

amic

def

lect

ion

Speed 100-107 Angle 20-21,5 S+A 100;20-105;21.5S+A 100;20-102;19 Linear (Speed 100-107) Linear (Angle 20-21,5)Linear (S+A 100;20-105;21.5) Linear (S+A 100;20-102;19)

Figure 6 Parametric study. Impact condition vs. dynamic deflection


Figure 7 Parametric study. Material properties vs. dynamic deflection

Material properties - ASI

0,68

0,70

0,72

0,74

0,76

0,78

0,80

0,82

0,84

-25% -20% -15% -10% -5% 0% 5% 10% 15% 20%

Changes of material properties

ASI

E.mod-+/-2%YieldS-+13/-22%Tickn-+5/-5%YS(NPRA)_0/17%BasispointLinear (YieldS-+13/-22%)Linear (E.mod-+/-2%)Linear (YS(NPRA)_0/17%)

Figure 8 Parametric study. Material properties vs. ASI.

Material properties - Dynamic Deflection

500

550

600

650

700

750

800

850

900

-25% -20% -15% -10% -5% 0% 5% 10% 15% 20%

Changes of material properties

Dynamic Deflection

E_+2%/-2% YS_+13/-22% YS(NPRA)_0/17% Basispoint Tickn_+5/-5

Linear (YS_+13/-22%) Linear (E_+2%/-2%) Linear (YS(NPRA)_0/17%) Linear (Tickn_+5/-5)


6.3 Acceleration transducers Crash test of a 900kg small car, the GeoMoetro, striking the rigid barrier (RoundRobin) forms the basis for this study.

The study showed that the sampling rate must be 100kHz or more to give reliable severity indexes from simulations ref. ROBUST-05-007.


7 COMPARISON AND VALIDATION

One of the main tasks of the Robust project is to evaluate and compare the simulations performed. Further, a comparison with full-scale tests should be performed.

Section 7.1 presents comments and comparison between the simulations performed.

Section 7.2 presents the comparison between simulations and full-scale tests.

7.1 Comparison between simulations Several issues can be compared and evaluated between the different simulations. It is important to compare simulations with same basis data when evaluating the conformity and accuracy between simulations.

For each barrier there are commented on the differences and the simulations comparable is compared and commented on.

7.1.1 Barrier B1 – Steel N2 Comparing simulations (or full-scale tests) it is natural to start with the impact severity indexes. The ASI values for all simulations performed are shown in Figure 9.

Based on comments given in Section 5.5.2, it is necessary to look at the simulations that are similar (based on input data) and make further evaluations.

Early in the project it was decided that all partners should perform simulations with post fixed 200mm below ground. These simulations are defined as “base case”. The ASI values for these simulations are presented in Figure 10. In Table 18 the results from these simulations, mean values and std. deviations are given.

The differences in the ASI values are present, both between simulations performed by one institute and also between institutes.

A standard deviation of 0,07 or the ASI values is quite good given that there are some differences in the input data. Based on this it is possible to conclude that there is good correlation between ASI values for the LS-DYNA simulations.

Working Width (W) and Dynamic Deflection (D) are two important parameters when evaluating a barrier. In Figure 11 the parameters are presented for each partner for the selected base cases. Standard deviation is for W 32,4 and for D 47,5, which shows good correlation between the simulation results given that there are some difference in the impact energy, ref Table 18.

Impact energy is different for the different car models and institutes. Plotting impact energy versus ASI it can be observed that for increasing impact energy the ASI value is decreasing, nearly linear, ref. Figure 12. The working width increase nearly linear to the impact enegy, ref. Figure 13.

Table 5 shows the vehicle trajectory for three cases, one from each institute. Case 3 from POMI is performed with the vehicle GM_R3 which is improved much compared with the GM_R2 which is used by TRL and NPRA. Several issues can be observed studying these pictures:

– The posts are deformed in different ways. This may be due to different ways of defining the roadway or the way of defining the contact between the post and roadway.


– Damage to the vehicle is different. Possible explanation may be impact energy, impact point or contact definition. It is also obvious that the GM_R3 is less damaged than the GM_R2, and also following the roadway in a better way, the GM_R2 is bouncing more.

– The POMI simulations show detachment of parts of the barrier. This is not observed in the other simulations looking at the pictures. It may not be visible.

Simulations against N2 barrier have been performed with different versions of the GeoMetro. From Figure 14 it can be seen that the ASI value is decreasing when using a more detailed vehicle model. In general it can be observed that the severity indexes are decreasing when refining the vehicle models. Later models are modelled with more correct suspension, etc. which will probably lead to a more correct trajectory of the vehicle.

To further study the behaviour of the GM_R4 pictures from three of the institutes are enclosed in Table 6. The following can be commented:

– Still the posts are deformed in different ways. It has not been any changes to the barrier models documented by any of the partners.

– It seems that the simulation from POMI and NPRA/FORCE show much of the same behaviour, partly detachment of the front bumper, damage to the hood (most for NPRA/FORCE).

– The guardrail in the POMI case in bending downwards, while in the NPRA/FORCE case the profile is bending upwards. This is probably the largest difference to be observed by the pictures.

– The GM_R4 is following the roadway in a better way, not bouncing as much as the GM_R2. This is probably due to the improvements in the steering system and in the suspension.

For the B1 barrier (N2) it can be concluded that the simulations compare very well in all aspects. It is important to be aware of the fact that when comparing results one must focus on comparing simulations with the same input data and conditions.


ASI

0,00

0,10

0,20

0,30

0,40

0,50

0,60

0,70

0,80

0,90

POMI (LS-DYNA) TRL (LS-DYNA) NPRA (LS-DYNA)

Figure 9 Barrier B1- Steel N2; ASI values, all simulations with different input

data/parameters

ASI

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9


Figure 10 Barrier B1 – Steel N2; ASI values, simulations with comparable conditions


Table 18 Barrier B1 – Steel N2; Values, simulations with comparable conditions

Analysis performed by ASI THIV PHD W D

[km/h] [g] [mm] [mm] POMI : (Case 3: Posts fixed -190mm, Fixed rail ends,GM_R3)

0,83 23,30 12,10 765 671

NPRA/FORCE: (Case 1: Posts fixed -200mm, Fixed rail ends,GM_R2)

0,72 25,90 11,30 825 730

TRL: (Case 1: Post fixed -200mm, Fixed ends,GM_R2) 0,86 24,6 12,89 774 636

Mean values 0,8 24,6 12,10 788 679

Standard deviation 0,07 1,3 0,8 33 48

Working Width and Deflection

0

100

200

300

400

500

600

700

800

900


Figure 11 Barrier B1 – Steel N2; Working Width and Dynamic Deflection; simulations

with comparable conditions


0,5

0,55

0,6

0,65

0,7

0,75

0,8

0,85

0,9

40 42 44 46 48 50

Impact Energy [kJ]

ASI

Figure 12 Barrier B1 – Steel N2; Impact Energy vs. ASI, simulations with comparable

conditions

600

650

700

750

800

850

900

950

1000

40 42 44 46 48 50

Impact Energy [kJ]

Wor

king

Wid

th [m

m]

Figure 13 Barrier B1 – Steel N2; Impact energy vs. Working Width, simulations with

comparable condition


Table 19 Barrier B1 – Steel N2; GM_R2 vs. GM_R4

Analysis performed by ASI THIV PHD W D [km/h] [g] [mm] [mm]

POMI: GM_R3 (case 2) 0,85 23,60 15,10 818 628 POMI: GM_R4 (case 4) 0,84 21,80 11,90 807 735 TRL: GM_R2 (case 1) 0,86 24,60 12,89 774 636 TRL: GM_R4 (case 1, scenario 5) 0,80 23,70 12,86 748 666 NPRA: GM_R2 (case 1) 0,72 25,90 11,30 825 730 NPRA_GM_R4 (case 8) 0,63 22,40 7,00 824 737 NPRA: GM_R2 (case 4, soft springs) 0,70 23,70 10,80 933 840 NPRA: GM_R4 (case 7,soft springs) 0,63 21,20 8,10 905 812

ASI

0,00

0,10

0,20

0,30

0,40

0,50

0,60

0,70

0,80

0,90

TRL - Case 1 NPRA - Case4

NPRA - Case1

POMI - Case 2

GM_R2GM_R4

Figure 14 Barrier B1 – Steel N2; ASI for GM_R2 and GM_R4


7.1.2 Barrier B5 – Concrete Figure 15 shows the ASI values from all performed simulations for the Concrete barrier.

The simulations of the Concrete barrier were started early in the project. Therefore the institutes have used early versions of the vehicle model. Comparing these results a good correlation can be observed between the ASI values, but THIV and PHD show too different values, se results in Table 20.

In addition the institutes have also performed simulations with the GM_R4 version of the small vehicle. The results are presented in Table 21. Figure 16 shows the ASI values for the early vehicle model compared to the GM_R4.

Results from POMI and TRL show that the ASI value decrease when using a newer version of the car model. This corresponds to the findings from the N2 barrier. The data from NPRA/FORCE show opposite results i.e. increase in ASI. Friction may have influence on the results. All institutes have altered the friction coefficients from the first to the last simulation case. It is therefore no possible to conclude finally on these results.

In Table 9 and Table 10 pictures of the simulations are presented. The behaviour of the early version of the GeoMetro is comparable between the three institutes. There are some more damage to the car used by NPRA/FORCE and TRL, but still all simulations show impact quite similar and the car leaving the barrier.

Looking at the behaviour of the GM_R4 the picture show slightly more differences. The impact seems quite similar; all simulations show detachment of the front bumper and damage to the hood. Later in the simulation the car from POMI is following the barrier while the car from TRL and NPRA/FORCE is leaving the barrier. Clearly there are differences in the behaviour between the three institutes. The reason is not clear, but friction and impact energy may explain some of the differences, se Figure 17.

Figure 15 Barrier B5 – Concrete; ASI from all simulations with different input

data/parameters

ASI

0,00

0,50

1,00

1,50

2,00

2,50



Table 20. Barrier B5 – Concrete; results for early simulation.

Analysis performed by ASI THIV PHD [km/h] [g]

POMI - Case 1: GM_R2 1,86 31,7 17,9 NPRA/FORCE - Case 3: GM_R2 1,95 35,20 12,40 TRL - Case 1: GM_R2 1,92 36,01 9,46 Mean values 1,91 34,30 13,25 Standard deviation 0,05 2,29 4,29

Table 21 Barrier B5 – Concrete: results from GM-R4 simulations


POMI 1,78 26,6 17,2 NPRA/FORCE 1,98 34,3 12,1 TRL 1,75 29,13 NA Mean values 1,84 30,01 NA Standard deviation 0,13 3,92 NA

ASI

0

0,5

1

1,5

2

2,5

POMI (LS-DYNA) NPRA (LS-DYNA) TRL (LS-DYNA)

GM_R0

GM_R4

Figure 16 Barrier B5 – Concrete; ASI for early model and GM_R4


ASI - Energy for B5-Concrete

1

1,2

1,4

1,6

1,8

2

2,2

40 41 42 43 44 45

Energy (J)

ASI Early GeoMetro

GM_R4

Figure 17 Barrier B5 – Concrete; Impact Energy vs. ASI

7.1.3 Barrier B2 – Steel H3 A total of four simulations have been performed. Results from the simulations with ends of the barrier fixed are presented in Table 22. Comparing the simulations with fixed ends:

– ASI values slightly different

– Working width and dynamic deflection is comparable

– Behaviour of vehicle quite different, ref Table 13.

Only two simulations have been performed with same base condition (fixation of barrier etc), but with different input parameters. It is obvious that the input influence the results quite much. Some parametric studies have been performed for this barrier but it is not possible to evaluate fully which parameter that is governing for the results.

Table 22 Barrier B2 – Steel H3

Analysis performed by ASI THIV PHD W D [km/h] [g] [mm] [mm]

POMI GM_R3 (Case 1) 1,63 30,70 12,10 736 373 NPRA/FORCE GM_R4 1,36 32,80 11,70 648 332 Mean values 1,39 31,00 11,80 692 352,5 Standard deviation 0,04 2,55 0,14 62,23 28,99


7.1.4 Barrier B3 – Steel H2 Simulations results from the Barrier B3 are presented in Table 23 and Table 24.

Figure 18 shows Energy vs. ASI for the small car. Slightly lower impact energy used by NPRA/FORCE than POMI, also different friction coefficient between tyre and asphalt. For the varioguard the friction between the barrier and asphalt will affect the results, se the two different simulations from POMI. Correct friction coefficient is not evaluated in this project, and should be based on studies or literature. Based on the partners experience a friction coefficient around 0,35 should be fairly correct. For the simulations performed it seems that the partners have used from 0,3 to 0,7 for friction coefficient.

Table 16 presents pictures of the large vehicles. Comparing the 10t Lorry it can be seen that the behaviour is slightly different. The model used by NPRA/FORCE is bumping more that the model used by POMI. The front wheel of the POMI model is turning in toward the barrier, while the front wheel of the NPRA/FORCE model is more in direction forward. The Working width calculated by NPRA/FORCE is higher than calculated by POMI. The reason for the differences may be due to different friction coefficients between barrier and asphalt, between barrier and lorry and/or weight of vehicle model (slightly higher in NPRA/FORCE than in POMI model).

Table 17 Shows pictures of the GeoMetro in impact condition against the Vario-Guard. In the start of the sequence the vehicle behave quite similar; climbing slightly up the barrier both with front wheel and rear wheel. Late in the sequence the vehicle is partly leaving the barrier and hitting the roadway again. The NPRA/FORCE model is hitting the roadway with the front wheels while the POMI model is more stable hitting the roadway. Again several issued may case this difference as mentioned in above paragraph. The working width between these two simulations is quite similar, ref Table 15.

Table 23 Barrier B3 – Steel H2: 10t Lorry

Analysis performed by W D [mm] [mm]

POMI - 1850 1592 NPRA/FORCE 2086 1386 Mean values 1968 1489 Standard deviation 167 146

Table 24 Barrier B3 – Steel H2; Small car 900 kg


POMI GM_R3 (road tyre friction 0,3) 1,25 25,3 9,8 POMI GM_R3 (road tyre friction 0,6) 1,13 19,4 10,6 NPRA/FORCE GM_R4 (wheel ground friction 0,7) 1,24 22,5 10,8 Mean values 1,21 22,4 10,4 Standard deviation 0,07 2,95 0,53


1,12

1,14

1,16

1,18

1,2

1,22

1,24

1,26

44,50 45,00 45,50 46,00 46,50

Impact Energy [kJ]

ASI POMI

NPRA/FORCE

Figure 18 Barrier B3 – Steel H2. Small Car ASI vs. Energy


7.2 Comparison between simulations and full scale tests The results from simulations and full-scale tests are compared in the following sections.

Only simulations where conditions comparable to the full-scale tests are presented and compared.

7.2.1 Barrier B1 – Steel N2 The ESP-N2 barrier was tested with different ground conditions, stabilised soil, asphalt, and socket in concrete. When comparing results and draw conclusions the same initial conditions must be in place.

Two of the test houses has performed test with stabilised soil condition. Simulations with soft springs (as performed by NPRA/FORCE) may be comparable to a stabilised soil condition.

One of the test houses has performed test with asphalt surface. Simulations with posts fixed near the surface may be compared to the asphalt condition.

The last test house has used sockets in concrete as foundation for the posts. The simulation with fixed posts near the ground should compare relatively good to this condition.

The simulations with fixed posts -200 under ground level are not directly comparable to any of the full-scale tests performed. However the simulations may be comparable to the full-scale test with stabilised soil.

Figure 19 shows the ASI vs. the Working Width for simulations and full-scale tests. Simulations show less scatter that full-scale test related to WW. Looking at the ASI it is opposite; the full-scale test shows less scatter than the simulations.

The figure is also a good illustration of the scatter in the results both for full-scale tests and for simulations. It shows that it is important to evaluate the results bearing in mind the input and test condition. Full scale test with ground condition of asphalt will not compare good with ex. Soil condition. There are also differences dependent on the vehicle used (vehicle make), and/or the impact condition (speed, angle etc.). The same will be found when comparing simulations. The ground condition, i.e. fixation of the barrier, different input parameters as speed, weight of vehicle, impact angle, material data etc. will clearly influence the results as have been illustrated earlier in this document.

In Table 25 Mean values and standard deviation for simulation and full-scale is shown. Disregarding the condition it can be seen that the simulations and full scale tests compare very good looking at severity indexes. For the Working Width and Dynamic deflection there are some larger differences, but still within acceptable limits.

If several tests are available (both from full-scale tests and simulations) it is possible to compare and draw conclusions based on the available data and averaged data. Comparing one to one (either simulation to simulation, full-scale to full-scale) it is important to focus on the impact conditions and the basis for the test. Discussion and conclusions related to results must be based on such data.

Comparing simulation to full-scale test (one to one) will most probably give difference in the results. The more close the impact condition and the basis for the test and simulation are, the more reliable the results are, and it is possible to compare it.


Bearing in mind the discussion above the results produced for the N2 barrier compare very good. Despite the different conditions it can be seen that the deviation between the results are within acceptable limits.

It is demonstrated that when both simulations and full-scale test are carried out in qualified and safe manner with near comparable impact conditions the results are comparable.

ASI - Working width

0,50,55

0,60,65

0,70,75

0,80,85

0,90,95

600 700 800 900 1000Working width

ASI

Full scale_Soil Simulation_spring Full scale_Asph-Bet

Simulation_+30 Simulation_-200

Figure 19 Barrier B1 – Steel N2. ASI vs. working width for full-scale and simulations

Table 25 Barrier B1 – Steel N2. Mean values for full-scale and simulations

Description ASI THIV

[km/h] W

[mm] D

[mm] SIMULATION 1 Mean value 0,75 23,8 834 732 Standard deviation 0,08 1,65 63 63 FULL-SCALE TEST Mean value 0,79 23,21 758 683 Standard deviation 0,08 1,47 83 78

Note 1: values without TRL generic and POMI free ends.

7.2.2 Barrier B5 – Concrete The concrete barrier is a quite simple barrier with respect to impact and absorbing energy. The barrier will at least for the small car not move, and the damage and energy absorption will be dependent on the vehicle model.

The concrete barrier was also used in the Round Robin project. In this project it was demonstrated that the friction between the barrier and the vehicle was of great importance to the results from the simulations. So even if this is a simple barrier it seems that the results vary even more than for a more complex barrier. This is illustrated in Figure 20.


The simulations show minor differences in the ASI values. There are larger scatter in the results from the full-scale tests, ref also Table 26.

For more discussion of the full-scale results it is referred to the documentation from WP4.

It is demonstrated that when both simulations and full-scale test are carried out in qualified and safe manner with near comparable impact conditions the results are comparable.

ASI - Energy

1,4

1,5

1,6

1,7

1,8

1,9

2

2,1

40 41 42 43 44 45 46 47 48

Energy (J)

ASI Simulation

Full scale

Figure 20 Barrier B5-Concrete. ASI vs. impact energy for simulation and full-scale test

Table 26 Barrier B5-Concrete. Mean values for simulation and full-scale test


[km/h] SIMULATION Mean value 1,87 32,16 Standard deviation 0,09 3,71 FULL-SCALE TEST Mean value 1,73 31,05 Standard deviation 0,15 1,31

7.2.3 Barrier B2 – Steel H3 For the steel H3 barrier (Super Rail) only a few full-scale test (2 of) and simulations (4 of) have been performed. All cases are TB11 test (small car 900kg).

It is not possible to draw full conclusions based on such marginal data. What can be observed is that the scatter within full-scale is rather small as also for the simulations, se Table 27 and Figure 21.

However is can be seen that the simulations show higher ASI values and lower working width than the full-scale test. The reason is not easy to explain without performing any


parametric studies, but issues as material data may influence results to an extent. Delivery of steel from a supplier is dependent on the batch of production, and the material strength will vary from batch to batch. The simulation will use either minimum values or recommended values. Correlation between full-scale data and simulation is for the Robust data not possible to fully investigate. Se also section 6 for discussion related to material properties.

ASI - Working Width

1,00

1,10

1,20

1,30

1,40

1,50

1,60

1,70

500 600 700 800 900 1000

Working Width

ASI Simulation

Full scale

Figure 21 Barrier B2 – Steel H3. Working width vs. ASI, full-scale test and simulation

Table 27 Barrier B2 – Steel H3. Mean values for simulation and full-scale test


[km/h] W

[mm] D

[mm] SIMULATION Mean value 1,49 30,75 702 361 Standard deviation 0,12 1,51 38 76 FULL-SCALE TEST Mean value 1,25 27,65 877 414 Standard deviation 0,14 5,16 88 65


7.2.4 Barrier B3 – Steel H2 Full-scale tests have been performed with the Heavy Goods Vehicle of 10t (3 of) and the Bus (2 of). One simulation has been performed with the bus and two with the 10t. It is a small amount of data and not easy to make comparison and conclusions.

It can be observed from Figure 22 and Table 28 that the simulation in general presents lower values for the Working width compared to the full-scale. ASI values have not been measured for simulations.

The Steel H2 (Varioguard) barrier is highly dependent on the ground friction as it is free-standing. This effect has not been studied. Friction coefficients used in the simulations have been based on experience.

The full-scale tests have also in general used higher Impact energy. The tests do also have a more spreading in the impact energy compared to the simulations. However all cases are within the requirement in EN 1317.

Working Width - Impact Energy

200,00220,00240,00260,00280,00300,00320,00340,00360,00

1800 1900 2000 2100 2200 2300 2400 2500

Working Width

Ener

gy

Simulation - Lorry 10t Full scale - Lorry 10t

Simulation - Bus Full-scale - bus

Figure 22 Barrier B3 – Steel H2. Working Width vs. Impact Energy for full-scale test and simulation


Table 28 Barrier B3 – Steel H2. Mean values for full-scale test and simulation

Description ASI W

[mm] D

[mm] Heavy Goods Vehicle 10t (Lorry) SIMULATION Mean value NA 1968 1489 Standard deviation NA 167 146 FULL-SCALE TEST Mean value 0,3 2267 1567 Standard deviation 0,1 58 58 Bus SIMULATION (only one case) Mean value NA 2284 1584 Standard deviation NA NA NA FULL-SCALE TEST Mean value 0,25 2380 2200 Standard deviation 0,07 99 28


8 REFERENCES

Ref. 1 EN 1317-1: Road restraint systems – Part 1: Terminology and general criteria for test methods. European Committee for Standardization, April 1998.

Ref. 2 EN 1317-2: Road restraint systems – Part 2: Performance classes, impact test acceptance criteria and test methods for safety barriers. European Committee for Standardization, April 1998

Ref. 3 OD-2000-0024: Crash Analysis of Road Restraint System – Validated finite element models, Main Report, January 2001

ROBUST project Page A.1Norwegian Public Roads Administration/Force Technology Norway AS ROBUST-05-025 / TR-2005-0056 - Rev. 1WP5 - Computational Mechanics. Summary Report MAIN REPORT

APPENDIX A – TRL PARAMETRIC STUDY

Three tables have been included for this part of the study. Table 29 and Table 30 below are sub-studies to the main parametric study. A number of queries were raised during the simulation runs that required extra model runs to be undertaken to better understand the influences of each modification. The baseline run in Table 29 simulated an impact between the ESP-N2 barrier and the GeoMetro version R2 (GM_R2) vehicle model.

The results are presented below.


Table 29 B1 – Steel N2. Barrier Results RUN

# SIMULATIONS CPUs LS-DYNA

Version Added Mass

(T) OUTPUT VEHICLE

MASS kg W mm D mm ASI THIV

km/h PHD g Exit

Speed Exit

Angle TEST 698 558 km/h degrees

1 GM_R2 into ESP-N2 as reported in Final_Revision_ESP-

N2_Barrier_Final_Report.doc

4 V970 rev.3858.1

0.33673 1E-5 THF, RBDOUT

1E-3

855 773 622 1.08 29.33 15.97 69.73 9.06

2 RERUN 4 CPU GM_R2 into ESP-N2 barrier

4 V970 rev.3858.1


1E-3

855 773 618 1.08 23.60 15.97 69.73 9.06

3 RERUN 4 CPU GM_R2 into ESP-N2 barrier -Version change

4 V970 rev.5434a 0.33624 1E-5 THF, RBDOUT

1E-3

855 774 636 0.86 24.60 12.89 67.85 9.06

4 RERUN 4 CPU GM_R2 into ESP-N2 barrier Version and Output change- as

reported in Final_Revision_ESP-N2_Barrier_Final_Report_A.doc

4 V970 rev.5434a 0.33624 1E-5 THF, NODOUT

1E-5

855 774 636 0.86 24.60 12.89 67.85 8.90

5 RERUN 4 CPU GM_R2 into ESP-N2 barrier - Timestep size for mass scaled

solutions was halved from 2.9E-6 to 1.45E-6


1E-5

855 729 592 1.23 26.10 23.72 67.44 4.30

6 RERUN 4 CPU GM_R2 into ESP-N2 barrier (Node attached to RB208)


1E-5

855 744 639 0.85 24.20 11.23 78.24 8.96

7 RERUN 4 CPU GM_R2 into ESP-N2 barrier (Node attached to RB208)-

Timestep size for mass scaled solutions was halved from 2.9E-6 to 1.45E-6


1E-5

855 732 605 1.04 26.50 12.59 75.36 8.74



1E-5

855 N/A N/A 0.86 24.20 11.23 N/A N/A



1E-5

855 744 623 0.86 24.20 11.23 78.25 8.96

10 Generic Vehicle into ESP-N2 as reported

in Final_Revision_ESP-N2_Barrier_Final_Report.doc

2 V970 rev.3858.1


1E-3

940 837 651 0.69 27.60 8.80 67.83 2.19

11 RERUN 2 CPU Generic into ESP-N2 barrier - Version and Output change - as

reported in Final_Revision_ESP-N2_Barrier_Final_Report_A.doc


1E-5

940 836 639 0.69 23.80 8.80 68.35 2.25


The main findings from Table 29 were:

• LS-DYNA software updates caused differences in model results- LS-DYNA 970 revisions 3858.1 versus 5434a. With the same model run the severity indices and exit speed varied due to this change (ref. runs 2 & 3)

• Rotational velocity in Z output at 100kHz and 1kHz did not influence the predicted results (ref. runs 3 & 4)

• Reduced mass-scaling significantly affected all results. In the model the bolt connections between the barrier rail and posts were the areas that would have gained mass. This area is considered influential to the impact outcome and has affected the results. Mass-scaling is useful for reducing run times provided the areas adding mass are away from the areas of focus and the mass gained is acceptable.

Table 30 shows the predictions for the B5 barrier runs using a generic, GeoMetro version R2 (GM_R2) and a GeoMetro version R4 (GM_R4) vehicle. Presented also are the differences in the predicted results due to changes in software version and output data.

Table 30: B5 Barrier Results RUN

# SIMULATIONS CPUs LS-DYNA

Version Added Mass

(T) OUTPUT VEHICLE

MASS kg W mm D mm ASI THIV

km/h PHD g Exit

Speed Exit

Angle TEST 698 558 km/h degrees 1 Generic Vehicle into B5 barrier as

reported in Final_Revision_Concrete_Barrier_Re

port.doc

2 V970 rev.3858.1

- 1E-5 THF, RBDOUT

1E-3

900 450 0 1.385 Visa

1.384Diadem

24.227 V

24.23D

34.741 V

34.591D

83.06 2.31

2 RERUN Generic into B5 barrier -Version and Output change - as reported in

Final_Revision_Concrete_Barrier_Report_A.doc

2 V970 rev.5434a - 1E-5 THF, NODOUT

1E-5

900 450 0 1.40 24.50 34.70 83.11 2.28

3 GM_R2 into B5 barrier as reported in

Final_Revision_Concrete_Barrier_Report.doc

2 V970 rev.3858.1


1E-3

863 450 0 1.917 V 1.916D

36.189 V 36.01

D

38.479 V

9.456D

71.30 6.30

4 RERUN GM_R2 into B5 barrier - Version and Output change - as reported in

Final_Revision_Concrete_Barrier_Report_A.doc


1E-5

863 450 0 1.93 39.50 11.09 71.38 6.33

5 GM_R4 into B5 barrier to be reported in RevA_GM_R4-

Concrete_Barrier_Report.doc. (Timestep size for mass scaled solutions was defined at 1.85E-6, the same as in

the parametric study)


1E-5

893 450 0 1.75 [VISA]

29.13 [VISA]

- 91.07 4.12



• The combination of LS-DYNA revisions and output rates for rotational velocity in Z cause differences in model results. LS-DYNA 970 revisions 3858.1 versus 5434a and rotational velocity in Z output at 100kHz and 1kHz. Using the same model run the results varied due to these changes but not significantly (ref. runs 2 & 3 and 3 & 4). Based on Table 30, the LS-DYNA software revision is likely to be the main cause of the predicted differences.

The B5 barrier and vehicle models varied from those in Table 29. The reduced complexity of the model run may be the reason the variances in results are not as significant as found in Table 29.


Table 31: Parametric Study RUN

S RUNS CPUs LS-DYNA

Version Added Mass

(T) OUTPUT VEHICLE MASS

kg W mm D mm Severity Indices Exit

Speed Exit

Angle ASI THIV

km/h PHD g km/h degrees

Basel

ine GM_R4 vehicle into ESP-N2 barrier (Mass

Scaling was set to -1.85E-6) 4 V970

rev.5434a 0.004279 1E-5 THF,

NODOUT 1E-5

893 748 666 0.80 23.70 12.86 81.49 7.57

Version

GM_R4 vehicle into ESP-N2 barrier (Mass Scaling was set to -1.85E-6) - Version

difference

4 V970 rev.3858.1

Results not available

1E-5 THF, NODOUT

1E-5

893 748 660 0.81 23.30 11.36 76.26 5.93

10 Impact Conditions: 107km/h 4 V970 rev.5434a

0.0044872 1E-5 THF, NODOUT

1E-5

893 813 719 0.89 23.12 13.04 84.60 6.29

9 Impact Conditions: 21.5 degrees impact angle 4 V970 rev.5434a

0.0046034 1E-5 THF, NODOUT

1E-5

893 807 723 0.90 25.18 12.00 78.23 8.22

1 Impact Conditions: 105km/h - 21.5 degree impact angle

4 V970 rev.5434a

0.0042639 1E-5 THF, NODOUT

1E-5

893 894 812 0.88 24.30 10.54 82.79 5.98

2 Impact Conditions: 102km/h - 19 degree impact angle

4 V970 rev.5434a

0.0041726 1E-5 THF, NODOUT

1E-5

893 740 649 0.76 21.60 12.16 81.34 6.08

+19.52% +21.92% +12.5% +6.24% +1.40% +3.82% +8.59%

-1.07% -2.55% -5% -8.86% -18.04% -6.42%

3 Material Properties: E = +2% 4 V970 rev.5434a

0.0042218 1E-5 THF, NODOUT

1E-5

893 765 678 0.79 23.60 12.58 78.59 6.06

4 Material Properties: E = -2% 4 V970 rev.5434a

0.0044751 1E-5 THF, NODOUT

1E-5

893 744 658 0.78 23.90 14.01 79.73 8.13

5 Material Properties: Yield Stress = 235 Mpa 4 V970 rev.5434a

0.004115 1E-5 THF, NODOUT

1E-5

893 852 763 0.76 22.60 10.68 78.29 7.50

6 Material Properties: UTS =340 Mpa 4 V970 rev.5434a

0.0042582 1E-5 THF, NODOUT

1E-5

893 766 682 0.82 23.40 12.72 80.25 7.67

7 Steel thickness (Rail and Posts only) +5% 4 V970 rev.5434a

0.0041568 1E-5 THF, NODOUT

1E-5

893 712 615 0.82 23.50 10.57 79.16 9.06

8 Steel thickness (Rail and Posts only) -5% 4 V970 rev.5434a


1E-5

893 782 695 0.82 24.00 9.83 75.92 1.47

+13.90% +4.57% +2.5% +1.27% +8.94% - +19.68%

-4.81% -7.66% -5% -4.64% -23.56% -6.84%

17 AMM: RUN 4 BASELINE RUN - 1 CPU (GM-R4) (Node attached to RB208)

1 V970 rev.5434a


1E-5

893 783 685 0.78 22.90 9.70 72.92 10.41

18 AMM: RUN 4 BASELINE RUN - 2 CPU (GM-R4) (Node attached to RB208)

2 V970 rev.5434a


1E-5

893 783 687 0.78 22.90 9.70 72.92 10.41


The parametric study had two main areas of focus and was carried out using the model of the GeoMetro version R4 (GM_R4) vehicle impacting a ESP-N2 barrier. The areas under consideration were impact conditions such as speed and angle and material properties such as steel yield, ultimate tensile strength (UTS) and thickness. Mass added to the model by mass-scaling was minimised to under 5kg over the whole model run.


• Significant deviations from the baseline results were predicted. The percentage deviation for each output is shown on Table 31

• For impact conditions, angle and speed seem equally significant in influencing the model predictions.

• For material properties, yield stress and steel thickness variations most influenced the model’s predictions

• Exit angle predictions varied widely and most significantly for both impact conditions and material properties

• Some of the model runs experienced early termination due to excess mass being added to the belt system of the vehicle.

• The animation that predicted a major change in behaviour of the vehicle coming off the barrier was seen in run 8 where the steel thickness for the rails and posts was reduced by 5%.

• With this model run, a change in software version for the baseline gave different predictions most notable for exit angle and speed (ref. baseline and version in Table 31).

Documents

ROBUST PROJECT Norwegian Public Roads Administration/Force ... · WP5 - Computational Mechanics. Summary Report MAIN REPORT The group “Computational Mechanics – Europe” (CME)