The Finite Element Realization Of Cracking In Concrete By Object-oriented Method

At tensile,concrete performance for a quasi brittle material, and the concrete structure crack is a widespread problem and it’s also a difficuclt engineering problem. For concrete structure, crack is the most common diseases. Therefore, the cracking analysis was the one of the hot issues of academia and engineering. At the same time, along with the concrete application to continue,the innovation of concrete varieties and concrete application scope expanded, the concrete cracks theory and research will also unceasingly thorough and development.At present the finite element method that the more application of numerical simulation about the cracking of concrete structure,but the early finite element software basically all used the structured programming language (such as:FORTRAN).This paper leaded the object-oriented programming technology based on C++in the cracking analysis. Relative to the other programming languages, object-oriented programming technology has the unique superiority, can greatly increase the finite element software modular, code reusability and expansibility.According to the calculating requirement of finite element problems,it designed the basic data-type class, including vector class, the matrix kind, stress and strain class,and the mechanics state class;and Secondly according to the finite element model data information abstracted the basic information kind:such as node class, material class, and unit class.Then designed the structure analysis class about the calculation method, including the various calculation methods based on the sparse matrix.Based on the choice of concrete constitutive relation and cracking algorithm,this used LDLT resolve the total stiffness matrix,and juded the stiffness matrix in the rise section or down section according to the diagonal element is positive or negative.On the rise section uesd the Newton-Raphson interation method,at the down sention applied the Arc method. Numerical examples verify the correctness of the program code, the algorithm can realize the concrete structure nonlinear analysis including the whole process of the cracking of concrete.Because of the complexity of the concrete constitutive relation and the cracking problem, as opposed to the concrete cracking problem, this paper merely programed the concrete cracking program and analysised the simple cracking problems, just did some basic work and attepmt, there are many problems to further research.