"Shock" refers to a physical effect of a high-level external force pulse applied to the product in a very short time (instantaneous), including the free fall, flip, throw, slap, and slap of the product during transportation and use. Various environmental phenomena such as mechanical shock, ballistic shock, and explosive shock. The time of impact is called "pulse width" or "pulse period", and the unit is milliseconds (ms). The "peak acceleration" is used to measure the magnitude of external force, and the unit (m/s²) is often used (G) in the industry.

Due to the short duration of the impact, such as the duration of mechanical impact does not exceed 1.0s, usually in the range of several milliseconds to tens of milliseconds, the time of ballistic impact and explosive impact is shorter. However, the force generated by the impact is very large, and the peak acceleration of the impact is very high. For example, the peak acceleration of a general mechanical impact is tens of G to hundreds of G, and the peak acceleration of ballistic impact and explosive impact may be as high as tens of thousands to hundreds of thousands G.Labtone High Speed Shock Test System acceleration can reach 350000G.

The time-domain function of impact action is a pulse function with very high amplitude and extremely fast attenuation. In environmental tests, the upper limit evaluation rate of the spectrum of most mechanical impact sources does not exceed (2~5)*10³Hz. The time-domain response characteristics of general products subjected to shock can be enveloped by an exponential function that decreases with time, and the upper limit frequency of the shock response spectrum usually does not exceed 2^5.