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What is Shock Testing?

It often seems that dynamic testing within the environmental test laboratory is concerned primarily with steady state vibration conditions. Simulation of the shock environment often plays a less significant role. And yet, our inherent physical understanding of everyday dynamic situations suggests that shock is of critical importance to product survival. If we drop our mobile telephone, drive our car over a pothole in the road, or our new television set is "dropped-off" the delivery vehicle, we are concerned that damage may have been inflicted.

Perhaps steady state vibration is easier to measure, analyse and quantify for a given product, and therefore it becomes more convenient to only incorporate this form of data into procurement specifications. Perhaps the measured shock is so dissimilar from the classical (and mathematically simple) shock pulses which appear in published references that the test appears inappropriate and any resulting test data would be mistrusted. Perhaps there is a fundamental lack of understanding of the real world environment relating to the product, or a lack of understanding of the basic concepts of shock testing. Whatever the reasons, if a shock test is not called for, then commercial pressures may mean that the test is not performed.

A reluctance to consider shock testing may be exacerbated by the need to make a number of assumptions. For classical shock, which type of pulse is most appropriate, should filtering be applied, and if so, how much? For Shock Response Spectrum, how valid are the assumptions concerning single degree of freedom systems and damping?