Impact testing was one of the first practical applications of the
fast-Fourier transform (FFT) technique in the late 1960s. Prior to
developing the FFT, measuring the frequency response function
(FRF) was limited to sinusoidal testing procedures. The sine testing
methods were slow, and required elaborate fixtures for excitation
(electro-mechanical or hydraulic exciters). Impact testing pro-
vided an order of magnitude faster test time and minimal fixtures.
As a result, it became a very good field-testing and troubleshooting
method, as well as a pretesting method for controlled laboratory
testing. This article is a general review of the evolution of impact
testing from its development in the 1960s and ’70s to the present
time, with a more extensive review of recent developments in test-
ing procedures and parameter estimation for multiple-reference
impact testing (MRIT).