Design And Implementation Of Soil Nonlinear FEM Program Based On Object-Oriented Programming

The FEM (Finite Element Method) is a widely used numerical tool in engineering application. As the programs of FEM become bigger and bigger, the classical structured programming, the Process-Oriented Programming, exposures the low reusability and maintainability. The emergence of the Object-Oriented Programming made the program design refrain from those disadvantages. It exhibits advantages in functional modularization, integration, reuse and flexible programming extension.The Object-Oriented Programming has been applied to the field of FEM programming. However, it can hardly been seen in the aspect of soil nonlinear FEM analysis. Because of the complexity of soil character, it is essential to research its nonlinear performance. So, the research of soil nonlinear FEM program has the prospect of its wide application and the practical signification.Used VC++6.0 as the development tool, this thesis applies the Object-Oriented Programming to the nonlinear FEM,and completes to simulate soil nonlinear performance. The main researches in this thesis are as follows:⑴The four nonlinear constitutive models are introduced. They are Duncan-Chang Model, Drucker-Prager Model, modified Cambrige Model and Lade Model. And their advantages, disadvantages and applicability are analyzed.⑵Two calculational methods for nonlinear analysis are adopted, that is, the improved Euler method and the Newton iteration method.⑶The storage of unsymmetrical matrix is completed. The program can calculate and analyze with the constitutive model adopted the non-associated flow rule.⑷It is completed that the program in this thesis stimulates soil nonlinear elastic and plastic performance. The calculation of the examples proves that the result of the nonlinear FEM program is consistent with that of ANSYS. The nonlinear FEM program obtains satisfactory result, which indicates the validity.