Numerical Simulation Of Dynamic Fracture Behavior Of Nonhomogeneous Materials

Along with the development of high and new technology industry that is represented by aerospace, the traditional isotropic homogeneous material is very difficult to satisfy the harsh request proposed by extreme environment such as ultrahigh temperature, ultralow temperature, ultrahigh pressure. The functionally graded materials appeared at this time. However, in the serving process of FGMs all kinds of cracks will appear inevitably and these cracks will lead to the failure of the whole structure. Especially under dynamical loads the effect is more evident. Hence, studying the fracture behavior of FGMs under dynamical loads has very important theoretical meaning and engineering value.The present thesis investigated the dynamic fracture behavior of FGMs using XFEM. There are four chapters in this thesis. The First Chapter introduces the state-of-art of the dynamic fracture behavior of FGMs and the XFEM. The Second Chapter elaborates the fundamental theory that is needed in computing the dynamic stress intensity factors (DSIFs). including the generalized J integral, the dynamical equilibrium equation of linear elastic mechanics, Newmark method and so on. At the same time it also introduces the XFEM implementation of the simulation of dynamic fracture behavior. The Third Chapter confirms the accuracy and the astringency of the theory of this thesis. The Fourth Chapter researches the dynamic fracture behavior of FGMs and analyzes the ingredients that affect the DSIFs of FGMs.