OPTIMUM DESIGN OF AN URBAN BUS CHASSIS BASED ON GENETIC ALGORITHM AND FINITE ELEMENT METHOD SIMULATIONS

Resumo

A very important part of the vehicles design is related to the chassis, on which several
mechanical components are mounted. An important feature to the chassis is to provide the highest
service reliability for as long as possible in a cost effective way. During its service life, the chassis is
subjected to several static and dynamic loadings. This way, this research work aims to obtain an
optimum design of an urban bus chassis manufactured based on current steel rectangular and “C”
section structural elements and subjected to deterministic loads. The optimization problem considers
the dimensions of the structural elements sections of the investigated chassis as its design variables,
which are established based on commercial standard dimensions. The lengths of these structural steel
elements are fixed in 9.75 m and 2.46 m, respectively. Throughout this investigation, the numerical
model of the analysed chassis was developed, based on the use of the Finite Element Method (FEM),
utilising usual discretization techniques implemented in the ANSYS computational program. The
optimization problem was resolved using Genetic Algorithms (GA), utilising the MATLAB software.
A properly interface between this two software ANSYS and MATLAB was developed in this
investigation to work in synergy considering the FEM and the GA. The results of this study show that
it is possible to obtain lower cost designs to the chassis, based on the application of optimization
techniques as the Genetic Algorithms in structural analysis.