Abstract
This thesis presents a computational analysis of the fatigue strength of add-on parts of a truck body, with a particular focus on the cross members, which exhibited cracks during real endurance tests. The objective of this thesis is to develop a workflow for the simulation of dynamic loads using the finite element method (FEM) and response spectrum analysis. The objective of this method is to provide a viable alternative to physical testing.The issue arises from damage that was identified during real load tests and that cannot be sufficiently predicted using static calculations. A crucial element of the present study is the analysis of dynamic and random loads, such as those generated by uneven road surfaces. To address this issue, a workflow based on the finite element method (FEM) has been developed and validated using experimental data.
The procedure comprises two principal elements: modal analysis, harmonic-responseanalysis and random vibration analysis. The former concerns the determination of the natural frequencies and vibration modes of the components, while the latter encompasses the assessment of random vibrations. The results of the aforementioned analyses are incorporated into the assessment of the fatigue strength, which is carried out with the aid of the FEMFAT software. The service life of the components is calculated taking dynamic and stochastic stresses into account.
The results obtained demonstrate that the workflow developed can predict the real service life of the components with sufficient accuracy. The simulations show a high level of agreement with the experimental data, indicating that the workflow can be regarded as a complementary method to physical tests. This enables the early detection of potential weak points in the components and their optimisation, which contributes to a reduction in product development costs in the long term.
| Date of Award | Sept 2024 |
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| Original language | German (Austria) |
| Supervisor | Wolfgang Witteveen (Supervisor) |