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FORSCHUNGSGESELLSCHAFTKRAFTFAHRWESEN mbHAACHEN

ANGEWANDTE FORSCHUNG, ENTWICKLUNG UND CONSULT

Durability Analysisika/fka are equipped with an extensive servo-hydraulic

test centre for research and development projects within

the field of durability analysis.

As the test facilities are highly flexible, the entire spec-

trum of possible applications can be considered ranging

from the examination of single components and extensive

multi-axial component tests up to heavy industrial vehicle

testing.

The technical data of the servo hydraulic test facility is

given below:

• 9 linear hydraulic cylinders

• maximum test force: 250 kN

• maximum test frequency: 200 Hz

• maximum capacity per cylinder: 400 mm

• 2 tensioning fields

- 6 m x 15 m with 550 t total weight

- 3 m x 15 m with 16 t total weight

• durability analysis for complete vehicles up to a length

of 13.5 m and up to 35 t total eight

• climatic chamber for component tests in the tempera-

ture range of -40 °C up to +250 °C

• modular test bench system for time- and cost efficient

test configurations

• ITFC or RPC- control

The applied servo-hydraulic testing technology, in con-

trast to corresponding driving tests, provides several

advantages for the durability analysis on complex vehicle

structures and subsystems.

Next to an improved comparability and reproducibility, the

possibility results for example, to reduce the testing time

significantly by time-lapsing test programs.

A ride on a straight track will be simulated by a vertical

excitation with up to nine cylinders for the experimental

investigation of the durability of vehicle bodies on basis of 

vertical damage proportions. The test vehicle is subjected

to a test program during this testing, which is specially

developed for time-lapsing durability test at body struc-

tures.

Generally 80 % of the total damage will be determined by

this simplified test.

Measured load profiles can be represented true to origi-

nal in real time on the test bench by means of the avail-

able test bench software (ITFC or RPC). Thus the possi-

bility is provided, to check modifications at the vehicle

fast and easily in the test laboratory.

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Calculative Durability Analysis 

Next to experimental durability analysis, we also realise

numerical durability simulations. Thus following programs

are used predominantly:

• FALANCS

• FemFat and

• MSC/Fatigue.

The durability simulation provides the opportunity to

simulate and also to evaluate the component behaviour 

under cyclic loading.

On basis of generated or measured load collectives,

load-time at the component are firstly determined with the

help of multi-body simulations (MKS). So-called stan-

dardized load cases are calculated for the acting, time-

variable forces and moments at the component by the

use of the Finite Element Method.

The calculated tension- and expansion data will be read

in the durability program together with the cyclic material

parameters.

Among other things, also weaknesses are identified at

the durability simulation, which prove itself as uncriticalduring the static analysis.

By this means first statements about the service life of 

different construction variants of components or assem-

bly groups can be made very quick in an early develop-

ment stage. Thus the number of prototypes in the devel-

opment process can be reduced.

The application of the durability simulation leads, next to

cost savings also to significantly shortened development

times in the frame of the development process.