TABLE OF CONTENTS Many situations are encountered where treatment of the entire system as deformable bodies is neither necessary nor practical. For example, the frontal impact of a vehicle against a barrier requires a detailed modelling of the front part of the vehicle but the primary function of the engine and the rear part is to provide inertia, deformation being negligible for purposes of modelling the frontal impact. A second example, from geotechnical engineering, is the modelling of rock mass landslides or interaction between rocks on a conveyor belt where deformation of individual blocks is secondary. In this chapter we consider briefly the study of the first class of problems and in the next chapter the second type in much more detail.
The above problem classes divide themselves into two further subclasses: one where it is necessary to include some simple mechanisms of deformation in each body (e.g. an individual rock piece) and the second in which the individual bodies have no deformation at all. The first class is called pseudo-rigid body deformation1 and the second rigid body behaviour.2 Here we wish to illustrate how such behaviour can be described and combined in a finite element system. For the modelling of pseudo-rigid body analyses we follow closely the work of Cohen and Muncaster1 and the numerical implementation proposed by Solberg and Papadopoulos.3 The literature on rigid body analysis is extensive, and here we refer the reader to papers for additional details on methods and formulations beyond those covered here.
