A procedure for the virtual evaluation of the stress state of mechanical systems and components for automotive industry: development and experimental validation

Abstract: This paper is part of the research activity led by the Machine Design Group of the University of Perugia, whose main objective was to set up and develop modelling criteria and methods for dynamic simulation of mechanical systems including flexible components. The activity was finalized to the design of systems using virtual prototyping, driving the modelling accuracy to simulate real functioning conditions of the system. It was therefore possible to extract realistic and directly usable information for fatigue component design using any fatigue damage evaluation criterion. In particular, the present work was developed with the cooperation of the research centre Elasis S.C.p.a. and con- cerns the set-up of methods and criteria for the development of the virtual prototype of an auto- vehicle, with the aim of simulating the conditions of sign-off tests. This aspect of virtual prototyping has a relevant importance. The sign-off tests of the vehicle, in fact, are standardized and the results obtained constitute one of the main sources of information for product development using physical prototypes. The industry is interested in reducing, as much as possible, the tests on prototypes by developing predictive virtual prototyping methods. The results obtained in this paper show an optimum correspondence between numerical and experi- mental simulations and demonstrate that time-domain stress/strain numerical recovery in critical points of the chassis is not only feasible but leads to quantitative information directly usable by fatigue damage evaluation methods. Keywords: flexible body, mode component synthesis, modal stress recovery, multibody simulation