Improvement and validation of a vehicle numerical model for crash test simulations

Abstract

The subject of this master thesis is the improvement of a numerical model of a bus used by GDTech for the simulation of crash tests against safety barriers. These tests are requested by customers wishing to verify the containment level of their safety barrier before proceeding with the experimental tests necessary for their validation. The objective is on the one hand to make modifications to an already existing numerical model of a bus in order to successfully pass a series of the so-called CME (Computational Mechanic Europe) tests, and on the other hand, to carry out crash test simulations against a deformable safety barrier. Firstly, the different European standards used are presented in order to understand the various tests and verifications to carry out. These standards include the dimensions that the vehicle must respect to be into the category considered (namely the 13 tons bus), the compulsory tests to be carried out for the validation of the vehicle model and the performance criteria to classify the safety barrier. Then, numerical simulations related to each compulsory test are performed. These tests involve verification of stability and behavior of the numerical model, including not only the behavior of the suspensions and the steering system, but also behavior during several kinematic tests. The tests are performed iteratively to make sure that a modification done to solve a particular problem in a test does not become the source of error in another test. During these tests, parameters such as the accelerometer connection, the suspension properties, the initial velocity and the friction coefficients are analyzed and modified in order to validate all the CME tests. Finally, a simulation of crash test against a deformable safety barrier model is performed to compare the behavior of the model with a real one based on a crash test report. At the end of this work, the numerical vehicle model is valid according to European Standards and ready to be used for crash test simulations.