The Coupled Computation And Contact Impact Algorithm

This thesis mainly includes two parts: fluid-solid coupling computation with impact load, and contact impact computation. In this paper, TVD format is used to calculate the fluid field's Euler equations, and finite element method with three dimension elements is used to solve the virtual work function in Lagrange coordinate. To realize the contact impact algorithm in the solid computation program, Pinball Method is employed to decide the interface force generated by the contact of master and slave elements. Based on the already existing program, modules about new types of constitutive relationship of materials are added, which are soil and crushable foam material, and viscoelastic material. After the explosion of compound propellant bullet, the combustion filed of the powder and its propagation in the water is computed. With the impact load from the fluid field, the dynamic response of rock material is calculated. The results of the distribution of the damage zone, and its relation with the parameters of the load is analyzed in detail. The dynamic response of laminate embedded with different angles of cracks is calculated under impact load. The generation and propagation of new cracks in the plate and the distribution of the stress field around the crack corners are discussed. Pinball Method is used to realize the contact impact algorithm. Three groups of cases are used to verify the accuracy of the algorithm result, which are one dimension elastic contact impact case, three dimension low contact speed case and three dimension high contact speed case. Other cases about fluid-solid coupling computation and contact impact are carried out and some results are given.The this paper is summarized as follows:1. In chapter one, the background of the research topic is given, together with the progress of the research relevant to the topic around the world. Also the summary of the whole paper is illustrated.2. In chapter two, the theoretical background and basis is discussed concerning solid computation, fluid computation and contact impact algorithm. Emphasis is put on the foundation, discretization, boundary condition and numerical solution of finite element method and contact impact algorithm. 3. In chapter three, the constitutive relation of two kinds of materials is discussed at the first part. At the second part, there are two different cases. The first case is about the combustion field of the powder, the pressurization of rock under impact load of exhausted gas, and the dynamic fracture generation and propagation of the rock. The second case is about the dynamic response of laminates which are embedded with different angles of cracks, the evolution principles of the crack and the stress field.4. In chapter four, the realization of contact impact algorithm is discussed thoroughly. Pinball Method is used to decide the contact of master and slave elements, two different ways of calculating the interface forces are employed, which should be used in different circumstances. Three groups of cases are carried out to demonstrate the precise of the method.5. In chapter five, two cases about fluid-solid coupling and contact impact problem are given.6. In chapter six, the conclusion of this paper is given, together with some suggestion about the research of next step.