Williams Element And Its Engineering Applicationgs For Structural Fracture Analysis

Most structures are containing cracks or defects in engineering practice, application of traditional strength theory is no longer sufficient to analyze the type of these problems, it is necessary to introduce the fracture mechanics theory to the analysis of the structure with cracks. The primary task of linear elastic fracture mechanics analysis is to solve the stress intensity factor, using traditional finite element or singular element calculation of stress intensity factor need large amount of calculation and can not directly obtain SIR Based on these, Williams element about the mode III and I-II mixed mode crack problems has been established and applied to solve practical engineering problems, the stress intensity factor can be obtained directly by the corresponding undetermined parameters in the model of Williams element.The main research work and contribution of this thesis are as show below:1. Based on the linear elastic fracture mechanics and finite element method of the generalized coefficients, Williams element on the structural fracture analysis has been established, through the programming of Fortran90procedure to analyzed and calculated the mode III and I-II mixed mode crack problems, the influence of the three important parameters on the stress intensity factor calcualation accuracy is mainly discussed, and their recommended values are gived.2. The plane strain model has been established to simulate the semi-rigid asphalt pavement, stress intensity factor of reflective crack is calculated by Williams element method. And then, the impact of aspalt pavement material parameters on the stress intensity factor is analysed, the measures to suppress reflective crack further expansion is proposed finally.3. Williams element is introduced into the analysis of the type III fracture problem in piezoelectric materials, the relationship between section geometry and stress intensity factor is discussed.