9 – Numerical Modeling of Discontinua

Publisher Summary This chapter focuses on numerical modeling of discontinua. It discusses the important aspects in the modeling of systems of discrete bodies—both physical and numerical aspects— and explains the diversity of applications. A discontinuous medium is distinguished from a continuous one by the existence of contacts or interfaces between the discrete bodies that comprise the system. An important component of any discrete element method is the formulation for representing contacts. In the direct method of introducing deformability, the body is divided into internal elements or boundary elements to increase the number of degrees of freedom. The possible complexity of deformation depends on the number of elements into which the body is divided. A complex deformation pattern can also be achieved in a body by the superposition of several mode shapes for the whole body. In the naive approach, each body is checked against every other body to determine if contact can occur. Many finite element, boundary element and Lagrangian finite difference programs have interface elements or slide lines that enable them to model a discontinuous material to some extent.