ECE Regulation №66 allows to use computer simulation to determine the durability and passive safety of buses in the rollover conditions for approval. The most common method of computer simulation is currently the finite element method (FEM). Simulation of contact interaction using FEM has several assumptions that are shown in the article. Since the bus is contacted with the rotating platform during rollover, assumptions in contact interaction modeling can lead to errors in load conditions determining and, as a consequence, inaccurate values of the bus body deformations can be obtained. Therefore, authors developed a mathematical model of bus motion, which occurs before the impact with the ditch surface. To confirm the accuracy of the systems of differential equations, the comparison of the results of mathematical modeling, FEM simulation and experiment using separate bus section are provided in the article.

Keywords: mathematical model, finite element method, passive safety, bus body, deformations, rollover, ECE R66, planar motion, experiment, load conditions