The Experiment And Numerical Simulation Of Crack Propagation Path In Cracked And V-notched Structures

The complex engineering structure is generally composed of simplecomponents, such as connectors, beams, rods. In some advanced materials andstructures, there often exist stress concentration caused by the discontinuity ofthe material or geometry mutation, such as interface and interface end, gap, inwhich the structure damage initiates. Because the degree of stress concentrationis very high, it can lead to crack initiation and propagation, which greatlyreduces the carrying capacity of material or component. Therefore, research onthe reliability of crack and propagation behavior will has positive effects toevaluate product.In this thesis, some plane cracked steel specimens with crack/V-notch werestudied by the experimental method under tensile and shear, and finite elementmethod is used to simulate crack expansion of the specimens.The theory of linear elastic fracture mechanics and elastic-plastic fracturemechanics and the crack tip stress singularity are first introduced. Then thefracture mechanics test methods and test specimens are introduced. A test deviceis designed for the experiments of crack propagation of V-notch. The crackpropagation process of some V-notch and crack specimens are tesed by thedevice.The extended finite element method (XFEM) for fracture mechanics studies,which is very effective, is introduced. Then the XFEM of Abaqus software isused to simulate the process of crack propagation of the plane steel specimenscontaining V-notch and crack under various load combinations. By using theXFEM method, the specimen crack propagation is modeled under a given loadform. The test results are compared with ones of the finite element method, so asto predict the crack extension path under the load pattern.