The shock response spectrum is defined as a ratio of the maximum responses of a structural system to the input shock excitations as a function of the ratio of the shock duration to the natural period of the system. Estimation and evaluation of such a shock response spectrum is necessary in the design and test procedure for products exposed to the shocks and vibrations.
Often a part(or parts) of such products is isolated somehow so that the level of the shock directly delivered to the part may not exceed a given allowance. Then the qualification of the isolation system is decided typically by performing shock tests on a dedicated test machine by which the duration and magnitude of the input shock can be controlled. In some cases, however, one finds difficulties particularly in reducing the shock duration due to the limited properties of the programmers provided together with the test machine while the information in the short contact time region is critically required.
A method of extrapolation is adopted in this paper to overcome such difficulties. By modeling the underlying system with a single degree of freedom, the shock response spectrum in the region where the shock duration cannot be realized are estimated by curvefitting of the results obtained in the region where the shock duration can be manipulated. The extrapolated estimations are compared with the actual measurements to check the applicability of the proposed technique.
