Citation

Ambrosio JAC. Int. J. Crashworthiness 2003; 8(1): 73-86.

Copyright

(Copyright © 2003, Informa - Taylor and Francis Group)

DOI

unavailable

PMID

unavailable

Abstract

The use of multibody or finite element vehicle models in impact scenarios requires appropriate descriptions of the contact forces. A continuous contact force model based on Hertzian contact, including energy dissipation, is shown to be suitable to handle both rigid and flexible body contact. The energy dissipation characteristics of this model are well suited to represent the local deformation effects during contact, when a flexible model for the vehicle is used, or to characterize the energy associated with large deformations, when a rigid body model is used to describe the vehicle. Furthermore, it is shown that the continuous force model also contributes for a stable integration of the system equations of motion, adding to the numerical efficiency of the methodologies that use the formulation. An alternative description of contact, based in the addition and deletion of kinematic constraints between flexible body nodes and contacting surfaces, is presented to model flexible body impact. This second model has the advantage of not requiring that any contact parameter be established, besides the explicit definition of the geometries of the contacting surfaces. The drawback of the model concerns with the high frequency contents of the system response resulting from the change of topology of the system when the contact constraints are introduced. The representation of the friction forces, accounting for slipping and stiction conditions, is done for both contact models. The influence of the different contact and structural models in the system response is discussed through the application to the impact of a flexible beam in a rigid surface. Finally, the suitability of the proposed approach is demonstrated in the design of complex vehicle systems, under impact conditions. For the purpose, the crashworthy behavior of the front crash-box of a sports vehicle and the rollover of an all-terrain truck are studied in different crash scenarios that involve all the major features of the methodology.

Language: en