Optimization by the Finite Element Method of a Commercial Sedan Automobile Monocoque for Best Response to an Impact Collision

Abstract

From the beginning of rational man, there was a need for faster mobility and efficient transportation. However, when men apply transportation by vehicles it means, safety issues that arise and had to be addressed. Safety matters increase with the evolution and development of the automobile, but this was not possible without the substantial technology implementations. Nevertheless, it is estimated worldwide that there are approximately one million road accident fatalities and ten million people injured annually. In this sense, resources have been directed to evaluate vehicle crash sceneries and to reduce resources by numerical modelling of vehicles during an impact incident, as well as considering safe car body design. During an impact vehicle accident, the determination of the energy absorbed during the event in an extremely difficult task. Nonetheless, by the application of results of crash testing and displacement data in the car body, software computer methods directed to produce a solution can be derived and safety for both the diver and occupants can be guarantee. In this research it is implemented and applied a programed deformation concept to redefine the monocoque of a commercial vehicle. Also the research work has been developed by applying the conditions under which a crash test must be carried (IIHS and Latin NCAP protocols). Nevertheless, the investigation was established in a static manner, so the forces developed in the impact were calculated and applied into the evaluation to consider the maximum effect into the impact incident, against a concrete barrier. Two cases of study were developed; initially the actual steel monocoque of a commercial sedan vehicle was analysed to obtained the actual response data, lastly from the results acquired, a proposal of an optimized composed monocoque for the same type of commercial sedan vehicle was developed and numerically evaluated. It was decided, to carry out two numerical evaluations for each case of analysis, in one the monocoque was under the effect of a general load effect and in a second one, the monocoque is under effects from the implementation of a global displacement consequences from the impact. Both numerical simulation provides results that can estimate the total displacement of the vehicle structure when a collision occurs, consequences into the cabin of the vehicle and effects to the driver and occupants. The proposed optimization of the monocoque, provides a better ductility behaviour into the vehicle and dissipation of the energy that could eventually harm the occupants. Numerical impact simulation can be effective only if it is developed under the combination of actual and real impact crash test.