Object-Oriented Structure Finite Element Software Exploitation

The traditional finite element software is procedure-oriented. These codes contain many complicated data structures and are visited through procedure, which greatly constrains the program's maintainability. However, the object-oriented method successfully solves the problem. At the same time, we shouldn't exploit the software at will like writing a small paragraph of program because of the complexity of the structural finite element software, adversely, we should follow the method of software engineering. During the exploitation, the primary content and result of the study include:The necessity of object-oriented method and software engineering method is expounded, also, we should combine the two tightly in each procedure of software exploitation. On the basis of analyzing the object-oriented method, how to solve the problem fundamentally of maintainability (contains expandability) of large complicated software is discussed. The three basic characteristics, which are class of object-oriented method, inheritance hierarchy, polymorph, are deeply taken apart.In allusion to the linear static finite element computing of planar beam and plate structure, standard requirement analysis is carried out and normative requirement documents are written.The Object-Oriented Analysis is carried out toward structural finite element software system, the static model is built through class diagram, which constructs a core frame for the finite element program. In the model, 7 base classes and their association, each class's attribute, generalization hierarchy of element class and material class, each base class's operation are ascertained.The Object-Oriented Design is carried out toward structural finite element software system, by means of improved sequence diagram, each dynamic step of structural finite element static analysis, such as initializing of each object in the system, the formation of each object, the formation of element stiffness matrix, the solution of linear equations by LDLT method, is clearly described. Also, more careful analysis is carried out on the two complicated steps, which are computing the total stiffness matrix and getting the displacement vector as well as the load vector.On the basis of the above work, the expression of stiffness matrix of beam element whose computing axis is away from centroid , is deduced, the structural finite element static analysis program, which contains truss element, beam element, plate element as well as linear material class, is written, its correctness is validated by numerical examples. The well maintainability of the software is showed through the case that class of beam element and class of material of concrete can be easily added to the program.