Using objects to handle complexity in finite element software

Engineering software is becoming ever more complex. Finite element programs have sophisticated graphical input and output facilities, and are increasingly required to be linked to other software such as CAD or. databases. The paper shows how an object oriented approach to finite element programming can be used to handle this complexity. This requires an approach that is very different from that adopted in more traditional programming. A foundation finite element class system is developed. This represents the essential data structure of the main finite element classes. It is then shown how this system can be used in a graphical model of two dimensional structures. The finite element system imposed no constraints on the development of the graphical model, yet could still be used easily. An important feature is that the nodes and elements are distributed around the graphical model, rather than being held centrally. For instance nodes may belong to points or lines of the graphical model. This means that the data structure used in the program more closely matches the way that the user of the program is likely to think.