Substructuring using impulse response functions for impact analysis

In the present paper we outline the basic theory of assembling substructures for which the dynamics is described as impulse response functions. The assembly procedure computes the time response of a system by evaluating per substructure the convolution product between the impulse response functions and the applied forces, including the interface forces that are computed to satisfy the interface compatibility. We call this approach the Impulse Based Substructuring method since it transposes to the time domain the Frequency Based Substructuring approach. In the Impulse Based Substructuring technique the impulse response functions of the substructures can be gathered either from experimental test using a hammer impact or from time-integration of numerical submodels. In this paper the implementation of the method is outlined for the case when the impulse responses of the substructures are computed numerically. A simple bar example is shown in order to illustrate the concept. Future work will concentrate on including in the assembly measured substructure impulse responses. The Impulse Based Substructuring allows fast evaluation of impact response of a structure when the impulse response of its components are known. It can thus be used to efficiently optimize designs of consumer products by including impact behavior at the early stage of the design.