In previous chapters you explored the basics of explicit dynamics procedures; in this chapter you will examine this topic in greater detail. The explicit dynamics procedure can be an effective tool for solving a wide variety of nonlinear solid and structural mechanics problems. It is often complementary to an implicit solver such as Abaqus/Standard. From a user standpoint, the distinguishing characteristics of the explicit and implicit methods are:
Explicit methods require a small time increment size that depends solely on the highest natural frequencies of the model and is independent of the type and duration of loading. Simulations generally take on the order of 10,000 to 1,000,000 increments, but the computational cost per increment is relatively small.
Implicit methods do not place an inherent limitation on the time increment size; increment size is generally determined from accuracy and convergence considerations. Implicit simulations typically take orders of magnitude fewer increments than explicit simulations. However, since a global set of equations must be solved in each increment, the cost per increment of an implicit method is far greater than that of an explicit method.