Local crush rigidity of pipes and elbows

Engineering evaluations of postulated pipe ruptures sometimes require a knowledge of the local cruch rigidity of straight pipes and elbows. However, little data is available, so an experimental and theoretical study was conducted to determine the quasi-static local crush stiffness of piping. Applications include the evaluation of displacement limiting bumpers, low velocity impacts and a novel energy absorbing restraint. The experiments provided force-deflection curves and scaling laws for several configurations. The scaling law for the simplest geometry, a ring, was compared to computer evaluations and proved acceptable well beyond the range of experiment. This comparison also justifies analytical techniques for investigating varibility due to material, temperature, internal pressure, and loading geometry. (Auth.)