Computer Shape Finding of Form Structures

Abstract

This paper presents a non-linear finite element procedure for shape finding of form structures and studies an approach wherein the engineer recognises formable curved surfaces focusing on the engineer's own imagination and creativity before turning to numerical analysis to assist in the design. With the investigation of a simple numerical method of locating geodesic lines, a convenient shape finding approach is presented. Another purpose of this paper is to present a method by which compression shell shapes can be obtained by inverting the loads on the tension shape obtained by loading a cable net system. This work parallels the physical models used by H. Isler for his work on thin concrete shells. The paper gives examples of the mesh shapes generated and the computer visualisation of several examples. It demonstrates that the computer modelling is a suitable alternative to the physical modelling process. The numerical results given show that the computer software is reliable, and provides the designer with a useful tool for membrane design.