A finite element computer system and analysis of a bridge structure

Abstract

This paper describes a general purpose finite element computer system ALSA (Accurate Large-order Structural Analysis). It has been created to perform linear elasto-static and dynamic analyses of two and three dimensional structures subjected to different forms of loading. The system's methodology rests on a computationally efficient formulation of hybrid stress finite element technique. The formulation enables the exact analytical construction of stiffness and mass matrices by avoiding the computational burden required for the application of numerical quadrature which renders the hybrid stress method inefficient owing to its dual field property. The hybrid library incorporated in the system is based on an efficient code of a concise algorithmic representation of element matrices. It is noteworthy that, although attention has recently turned to the advantages of element generation without consulting to the costly numerical quadrature, full potential of the computerised analytical integration of the element stiffness and mass matrices is not realised through automatic generation elsewhere. In this paper, the mathematical basis, structure and organisation of the system are presented. Its use and capabilities are illustrated by detailed analysis of a bridge structure.