Study On Iterative Coupling Between Time Domain Boundary Element Method And Finite Element Method

Finite element method is very suitable for non-homogeneous,anisotropic materials and non-linear processing materials.The boundary element method can deal directly with infinite and semi-infinite problems without applying artificial boundaries.In this paper,the combination of the two methods,give full play to the advantages of the two methods,learn from each other,the sub-domain coupling principle used in semi-infinite domain coupling problem.The specific work of this paper includes the following parts:In the partition algorithm of static problem,the factors influencing the convergence of iterative method are discussed,and the suitable relaxation parameter range is applied to the coupling algorithm of dynamic problem.On the common boundary,the force conversion between the two subdomains is carried out by the displacement coordination condition.In the coupling algorithm of dynamic problem,the time domain boundary element method and the Newmark fine direct integration method are used to transform the surface force in the time domain boundary element method with the linear element in time.For singular integral processing,separation method to get the integral non-singular and singular parts,singular part of the complete use of finite integration method for processing.In the finite element method,the traditional direct integration method is changed to Newmark fine direct integration method.By using the finite element dynamic equation to construct the relationship between adjacent time step displacements,the time-domain boundary element control equation is used to construct the relation of the same time step displacement and force.The unknown quantity is updated on the common interface,Displacement and force as the real displacement and force of the nodes on the public interface,thus completing the coupling of the time domain boundary element method and the finite element method.Taking the cantilever bar under shearing force as an example,the factors influencing the convergence of the partitioned iterative method are discussed.The cantilever bar under the sudden load is used as an example to verify the correctness of coupling method about the dynamic problem.On the basis of this,the results of the semi-infinite domain coupling example are compared with those obtained by solving the time domain boundary element alone.