AN INSTRUMENT TO MEASURE TEMPORAL STABILITY OF SPRING COMPRESSION FORCE

摘要

Mechanisms incorporating loaded springs to provide a known force over long periods of time must account for the potential of stress relaxation leading to a change in spring force and concomitant change in mechanism performance. If the intended period of operation is many years, it is impractical to test springs for a period equal to the lifetime of the mechanism in order to determine the adequacy of the design. Instead, the force of the spring at a precisely known deflection must be measured over a shorter period of time but to a much higher degree of precision than that required by the mechanism, and the results combined with an appropriate constitutive model to predict performance of the spring over the mechanism lifetime.