The Longitudinal Impact of Coil Springs

Abstract

The impact problems of an elastic body treated by Saint Venant, Bousinessq and Donnel are only about the transient state in the shocked surface of the body. Pipes transformed a shocked system into the equivalent electric circuit and solved it with the operative method. In this paper the authors introduce Dirac's δ (t)-function into the boundary condition in the parallel system of a coil spring and a damper, and solved it with the method of Laplace transformation. The results are summarized as follows : (1) The condition that a falling body separates from a spring after impact is obtained. (2) The maximum stress at the fixed end of a spring and the approximate equation for it are found. (3) The effects of a damping coefficient of the restitution coefficient are made clear. (4) The behavior that a damping coefficient affects the spring stress due to impact and the transmission force at the fixed end of the spring is known.