DYNAMICS OF STRUCTURES UNDERGOING GROSS MOTION AND NONLINEAR DEFORMATIONS - A MULTIBODY APPROACH

The formulation and application of a flexible multibody dynamic formul ation to the study structural systems experiencing geometric and mater ial nonlinear deformations, while its components undergo large relativ e rotations and displacements, are presented in this paper. The descri ption of a flexible structure able to undergo a large rigid body motio n is based on the finite element description of its geometric and mate rial nonlinear deformations. The choice of the generalized coordinates used to describe the body flexibility with emphasis on their influenc e over the explicit nonlinearity of the numerical model of a structure is discussed. Subsequently, the relative motion between different str uctural and rigid system components is described using a multibody for malism based on joint coordinates and velocity transformations. The ca pability of this methodology to describe nonlinear geometric effects i s illustrated with an example of a rotating beam. Finally the procedur e is applied to the crashworthiness and structural impact of a train c arbody the results being compared with those obtained by the use of a commercial nonlinear finite element code. Furthermore, the results obt ained in an experimental test of a full scale model of the train carbo dy are used to validate the application of this method to large scale multibody systems. Copyright (C) 1996 Elsevier Science Ltd.