Impacting of Pipes on Elastic Supports

Abstract

Piping systems are often provided with supports and restraints with gaps to reduce the thermal stresses and to limit the motion caused by other loads, e.g., due to pipe rupture or seismic effects. However, the presence of the gap causes the pipe to impact on the support under dynamic loading. In this paper the impacting effects have been studied using a simple model. The effect of support rigidity on the impact force, bending moment and deflection of the pipe has been evaluated. The bending moment at the impact loading is found to decrease up to a certain value of the support stiffness beyond which it increases. However, the impact force increases and the overall deflection at the impact location decreases continuously as the support stiffness is increased. The results are presented in nondimensional form as ratios of the appropriate quantities for the simply supported pipe with no elastic restraint. Thus, they provide useful information for design considering impact effects.