Is the maximum acceleration an adequate criterion of the dynamic strength of a structural element in an electronic product?

The dynamic strength of structural elements of micro- and portable electronic products is often evaluated on the basis of the measured maximum acceleration which these elements experience during shock or drop tests. It is well known, however, that it is the dynamic stress, not the acceleration, which is a true criterion of the dynamic strength. Using examples of structural elements that can be idealized as a simply supported beam or a cantilever beam with a concentrated mass at the end, we show that for elements of the given geometry and weight, the level of the maximum stress can be indeed judged upon on the basis of the measured acceleration. However, the application of the measured acceleration as a criterion of the dynamic strength can be misleading if applied to elements of different dimensions, weight and materials. We conclude that although the maximum acceleration is substantially easier to measure, it is the maximum dynamic stress that should be evaluated experimentally or theoretically when there is a need to establish the level of the dynamic strength of a structural element of an electronic product and the role of different factors affecting this strength. The obtained information can be helpful when evaluating the results of, or designing drop tests for electronic products.