Virtual Crack Closure Technique Fracture Element

As a branch of solid mechanics, fracture mechanics is widely practiced in many engineering areas, such as mechanical engineering, structural engineering, aerospace engineering, naval architecture and ocean engineering, rock and soil engineering, nuclear power engineering, oil and gas pipelines. However, only few fracture problems have analytical solutions, many engineering problems should be solved by numerical methods.The most used numerical method is finite element method. In the present work, some numerical techniques based on FEA in fracture mechanics are reviewed first, such as extrapolation technique for stress intensity factors, equivalent domain integral technique for J-Integrals, virtual crack extension technique and virtual crack closure technique (VCCT) for strain energy release rates. Then, virtual crack closure technique, which is simple and straightforward, and is not sensitive to the FEA mesh size, was discussed in detail. Based on virtual crack closure technique, a fracture element, named as VCCT fracture element, was developed in conjunction with commercial FEA software ABAQUS by its user-defined element (UEL) feature. The VCCT fracture element was validated to be accurate in calculating fracture parameters by comparing to the analytical solution of finite width center cracked plate. And virtual crack closure technique was validated to be the simplest method in calculating fracture parameters by comparing to other methods.The results of this dissertation provide a simple and efficient method for engineers to study the fracture problems in engineering structures.