IMPACT Phase II – 9/13/00 Activity Report Slide 1/20 University of Louisville IMPACT Architecture Team Glen Prater, Jr., Associate Professor Ellen G. Brehob,

Slide 1/20IMPACT Phase II – 9/13/00 Activity Report

University of Louisville IMPACT Architecture Team

Glen Prater, Jr., Associate ProfessorEllen G. Brehob, Assistant Professor

Michael L. Day, Professor

J.B. Speed Scientific SchoolUniversity of Louisville

Louisville, KY 40292

September 13, 2000

External Architecture Group Activity Report

June 27, 2000 – September 12, 2000


• Make transition to Phase III work plan.

• Establish University of Louisville Dearborn office.

• Complete SimMod training.

• Assess various cab floor architectures.

• Develop benchmark SimMod model; SimMod models for high-priority concept assessment.

• Develop additional detail for integrated cab/box concept.

Work Planned, 6/27/00 - 9/12/00


Work Completed, 6/27/00 - 9/12/00

• Completed Phase III work plan; currently making preparations to move focus of modeling work to F-350 platform.

• G. Prater and A. Shahhosseini spent the week of 6/26 ad Beech Daly. Visa problems experienced by new team member have prevented long-term stays.

• SimMod training is ongoing.

• Performed static and modal analyses on six cab floor architectures.

• Used SimMod model to develop F-150 pickup box model, MSC NASTRAN to perform linear analysis.

• Integrated cab/box concept is not a priority in the Phase III work plan.


Cab Floorpan Studies

• Formulated six architecture concepts that have the potential to significantly reduce component weight without adversely affecting cab structural characteristics or functionality.

• Prepared solid models for an existing floorpan/cross member assembly to be used as a benchmark.

• Prepared corresponding solid models for the architecture concepts.

• Used the benchmark and concept models for a series of finite element analyses.


Floorpan Finite Element Analyses

• SDRC I-DEAS used for modeling and analysis.

• Evaluated relative nominal stress distributions for simulated vehicle loading conditions. Vehicle loads included 450 lb at each front seat support, 400 lb along the transmission tunnel, 100 lb on each rear seat mounting area, 100 lb along the rear shelf, and 100 lb on the front footwell area. Traction loads were used on the sides of the floorpan to simulate the weight of the cab; 150 lb loads were placed on the front and rear, with 250 lb loads used on the driver and passenger sides.

• Applied bending and torsional loads to permit stiffness calculations.

• Performed modal analysis under varied loading conditions.


Benchmark Floorpan Design

• Four transverse cross members.• Longitudinal bending stiffness

comes primarily from the tunnel.

Bottom View


Floorpan Architecture Concepts (1)

• Two longitudinal members.• One transverse split-end cross member.• Small transverse member in transmission

tunnel.• Rear transverse member similar to original.• Reduced sheet thickness in cross members.

• Two longitudinal members.• Straight transverse cross member.• Small transverse member in transmission

tunnel.• Rear transverse member similar to original• Reduced sheet thickness in cross members.

Concept 1

Concept 2


Floorpan Architecture Concepts (2)

• Longitudinal and straight transverse cross members are integrated.

• Otherwise identical to Concept 2.

• Longitudinal and split transverse cross members are integrated.

• Otherwise identical to Concept 1.

Concept 3

Concept 4


Floorpan - Architecture Concepts (3)

• Longitudinal transverse cross members near rocker.

• Longitudinal cross members along tunnel.• Rear transverse member similar to original.• Reduced sheet thickness in cross

members.

• Two integrated, split transverse cross members.

• Rear transverse member similar to original.

• Reduced sheet thickness in cross members.

Concept 5

Concept 6


Concept 1 Concept 2

Concept 3 Concept 4

Concept 5 Concept 6

Benchmark Architecture

Von-Mises Stress Distribution and Deformations


Fundamental Bending Modes

Concept 1(b1 = 30.2 Hz)






Benchmark Architecture(b1 = 26.9 Hz)

Increasing Deformation

No Displacement Boundary Conditions at the Rear Shelf Edge and the Front Edge of the Floorpan.


Fundamental Torsion Modes

Concept 1(t1 = 34.0 Hz)






Benchmark Architecture(t1 = 31.1 Hz)

Increasing Deformation

No Displacement Boundary Conditions at the Rear Shelf Edge and the Front Edge of the Floorpan.


Comparison of Floorpan Concept FEM Results

Parameter Benchmark Concept 1 Concept 2 Concept 3 Concept 4 Concept 5 Concept 6

Maximum Deflection, Simulated Loads (in)

0.8700.859(-1.3)

0.908(4.4)

0.892 (2.5)

0.843(-3.1)

0.690(-20.7)

0.684(-21.4)

Bending Stiffness, Front Loaded (lb/in)

73.571.1(-3.3)

72.1(-1.9)

73.5(0.0)

80.0(8.8)

75.9(3.2)

92.3 (25.5)

Torsional Stiffness, Front Loaded (lb/in)

121.0111.1(-8.1)

96.2

(-20.5)112.8(-6.8)

137.6 (13.8)

117.2(-3.1)

242.3 (100.3)

Bending Stiffness, Rear Loaded (lb/in)

163.9200.0(22.0)

201.3 (22.8)

241.9 (47.6)

252.1 (53.8)

277.8 (69.5)

193.5 (18.0)

Torsional Stiffness, Rear Loaded (lb/in)

128.2160.4(25.1)

102.7

(-19.9)150.3 (17.2)

196.1 (52.9)

154.3(20.4)

458.7 (257.8)

Fundamental Frequency, Bending (Hz)

26.930.2

(12.3)29.8

(10.8)34.3

(27.5)35.3

(31.2)30.9

(14.9)35.1

(30.5)

Fundamental Frequency, Torsion (Hz)

31.134.0(9.3)

31.6

(1.6)38.7

(24.4)40.1

(28.9)30.9(-0.6)

43.1 (38.6)

Weight (lb) 10987

(-20.2)87

(-20.2) 88

(-19.3)88

(-19.3)88

(-19.3)88

(-19.3)

(Percent Change Relative to Benchmark)


Summary of Floorpan Analysis Results

• Nominal von Mises stresses were decreased by the new designs in many areas, with no major increases.

• Stress in the front footwell area can be decreased by nearly half due to the support of longitudinal cross members.

• Concepts 3 and 4, with integrated cross members, performed better than the corresponding architecture with separate members.

• Concept 6, the architecture with the twin split cross members, exhibits the best overall performance. The torsional rigidity is particularly noteworthy.


Concept Model for F-150 Pickup Bed

Identify BodyStructure Design

Features

Perform FEMAnalysis; View andInterpret Results

Choose FeatureApproximations

Generate BeamElements UsingSimMod Softare

Define Beam Cross-Sections (.mdl

Extension)

Specify Drag Files(.drg Extension)

Drag Cross-Sectionto Complete Beam

Element (.bnasExtension)

Generate ShellElements Using Solid

Modeling Software

AssembleComponents, PayingParticular Attentionto Joint Stiffnesses

Specify Constraintsand Loads to Com-

plete Concept Model

• Based on beam element repre-sentations of the corrugated floor panel, transverse cross members, front and rear corner sections, body-side top section, and front panel top flange.

• Beam elements were developed with SimMod; shell elements have not yet been added

• Used MSC NASTRAN to perform static analysis and eigenvalue analysis similar to I-DEAS floorpan analyses.

Concept Modeling Algorithm


Beam 3 - Vertical Front Corner Section

Beam 4 – Vertical Front Corner Section

Pickup Bed Concept Model - Beam Element Geometry

Beam 1 – Bed Panel Corrugation

Beam 2 - Cross Members

Beam 5 – Body Side Top Section

Beam 6 – Front Panel Top Flange


Pickup Bed Concept Model - Beam Parameters

Parameter Beam 1 Beam 2 Beam 3 Beam 4 Beam 5 Beam 6

Elastic Modulus (MPa) 207 207 207 207 207 207

Poisson’s Ratio 0.29 0.29 0.29 0.29 0.29 0.29

Density (kg/mm3) 7.81E-06 7.81E-06 7.81E-06 7.81E-06 7.81E-06 7.81E-06

Thickness (mm) 1.12 1.12 1.12 1.12 1.12 1.12

Cross-Sectional Area (mm2) 129.66 231.78 628.63 240.24 140.14 80.8

Area Moment of Inertia, I11 (mm4) 1.629E+05 1.937E+05 1.713E+06 3.600E+05 1.834E+05 1.351E+04

Area Moment of Inertia, I22 (mm4) 2.749E+03 1.529E+05 1.612E+06 3.600E+05 4.200E+03 5.540E+03

Polar Moment of Inertia, J (mm4) 4.270E+01 7.738E+01 1.466E+06 7.988E+01 4.662E+01 2.662E+01

Length (m) 1.90 1.48 0.52 0.52 1.90 1.90


Pickup Bed Concept Model – Sample Results (1)

Static Bending Static Torsion


Pickup Bed Concept Model – Sample Results (2)

First Bending Mode First Torsional Mode


• Begin generating component concept models for F-350 cab.

• Convert existing F-150 pickup bed model to F-350.

• Add shell elements to pickup bed components.

• Determine free body natural frequencies and modes for benchmark and concept architectures.

• Recalculate bending and torsional stiffness with constraints applied at front and rear mounting holes.

Work Planned for Next Reporting Period

Documents

IMPACT Phase II – 9/13/00 Activity Report Slide 1/20 University of Louisville IMPACT Architecture Team Glen Prater, Jr., Associate Professor Ellen G. Brehob,