Modal Expressions for Relative Displacements Underlying Pseudo-velocity Shock-Response Spectra, for Idealized Remote Shock Loadings: Derivation and Verification
Dr. R. David Hampton, U.S. Military Academy

Abstract:

Recently, exact expressions were presented for the time-domain response of a mass-spring-damper (MSD) system to a seismic input comprising exponentially decaying sinusoids.  Such an input could result from a remote shock consisting of an ideal impulse, as filtered through the eigensystem comprising the linear model of a structure.  Using these results the analytical time responses were found, of the (hypothetical) MSD system used for shock-response-spectrum (SRS) determination, for remote shock inputs of three forms: (1) an ideal impulse, (2) a rectangular pulse, and (3) a saw-tooth pulse.  These responses permit exact SRS determination without necessitating numerical evaluation of a convolution integral.  This paper first repeats in detail the earlier derivations of the responses to these remote shocks, and then describes their verification via a combination of algebraic-manipulation software, dimensional analysis, numerical checks, and a 2DOF test case.

 

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