Second-Contact Analysis of Elastic Bar Impacted by a Rigid Body

摘要

Dynamic finite element explicit method is employed to trace the impact procedure of elastic bar with one end fixed axially impacted by a rigid body in this paper. Impact load and contact time from the calculation results were obtained and nondimensionalized. The non-dimensional impact load time-history curves are achieved as well. The calculation results agree to the theoretical solutions very well, which demonstrates the feasibility of this method. Based on the numerical model, the second contact during impact procedure is investigated as the key issue here. The impact load curves indicate the end of bar would chase up the rigid body after the rigid body separates from the end of bar first time. By comparing non-dimensional impact load time-history curves and the velocity time-history curves, the mechanism is illustrated that the reflection of stress wave from the fixed end causes the second contact. Finally a large number of non-dimensional impact load and contact time are drawn from Finite element analyses examples. The characteristics of secondary contact are presented. By searching the mass ratio, the critical mass ratio of second contact can be gained. The durations of second contact in different stress wave cycles are gotten.