ABSTRACT
So far we have discussed steady-state and time-harmonic analysis in acoustics and elasticity. This chapter will deal with the time-dependent equations as applied to boundary element method (BEM). Unlike in finite element method (FEM), the transient problem in BEM requires special treatment of the inertial effects introduced by the transient terms of the governing differential equation. This section will introduce the concept of mass matrix in the context of BEM and as such set the stage for the formulation of algebraic eigenvalue problems in the next chapter. It will become evident that the idea of stiffness and mass matrices does not show up in a straightforward fashion in the BEM. The dynamic equations in acoustics as well as in elasticity will be dealt with in this section.
