The Dynamic Shock analysis technique was developed in the days of hand calculations to calculate or estimate the maximum response of a structure to a shock or transient input load such as an earthquake, explosion or transportation shock.
The input to this type of analysis is a Response Spectral curve. The curve represents the response at different frequencies for a damped single degree-of-freedom (DOF) structure tuned to each frequency resulting from some applied transient load. In the days of hand calculations one would calculate the natural frequency of the structure with the assumption that it had a single DOF. You would the look at the amplitude of the curve at that frequency and use that as a static load on the structure to estimate the maximum response. Generally there are different curves provided for different damping levels. The big assumption is that your structure behaves as a single DOF and that the static response will look like the mode shape of the first mode. As computer solutions became available and the ability to calculate multiple modal frequencies became more common, this technique was extrapolated to estimate the combined effects of these multi-DOF systems. Some of these combination methods are included in the Creo Simulate implementation of this Dynamic Shock technique.
It is important to remember that this technique in its pure form is only valid for single DOF models, however, the multi DOF methods are still used extensively in the building, military and transportation industries. Many times load specifications are provided as Response Spectrum curves.