OBJECT ORIENTED PROGRAMMING FOR FINITE ELEMENT ANALYSIS OF PLANE STRESS, PLANE STRAIN AND AXISYMMETRIC PROBLEMS

Abstract

The Finite Element Method is very modular by its nature. Object-Oriented Programming (OOP) enables full advantage to be taken of this modularity. Object-Oriented Programming characteristics such as Encapsulation, Inheritance, Polymorphism, Abstraction and Modularity support three desirable features of modularity, reusability and ease of maintenance in the development of complicated engineering software system. This allows safer and easier programming resulting into a reliable software. Extending or modifying object oriented programs is very straightforward. In this dissertation, an Object-Oriented extension for the PSPSAS program (written in FORTRAN) is done using the C++ as an OOP language. The program can solve the plane stress, plane strain and axisymmetric problems. The program uses the 2D linear, quadratic and cubic serendipity elements. The program uses a new concept known as Generalised Modulus and Generalised Stresses which involves the local derivatives of shape functions at subelement level. The advantage of using the local derivatives of shape function is that it does not vary from element to element. They are to be calculated for subelements.of one parent element once for all. This results in lesser computations as compared to the traditional FE computations. The general conclusion is that Object-Oriented Programming can be used to significantly improve finite element analysis programs. Implementation of an Object-Oriented program requires less time, results in smaller programs, and provides better management of data and procedures than that of the equivalent procedural program.