The effect of pre-impact waves on the coefficient of restitution (COR) in longitudinal impact of a uniform elastic rod on a linear elastic or bilinear inelastic spring supported by a fix rigid wall is studied. The spring models may represent the quasi-static response of, e.g., a small elastic cylinder or the inelastic bit-rock interaction in percussive drilling. The rod is accelerated to its impact momentum either by a force of relatively short duration which generates significant pre-impact waves in the rod (pre-impact wave case) or by a force of long duration which does not generate such waves (reference case). Analytical and numerical results based on the 1D wave equation are presented in dimensionless form. It is shown that the work performed by the accelerating force is much larger in the pre-impact wave case than in the reference case, and that the COR generally depends on spring stiffness, elasticity parameter, initial rod-spring separation, and wave transit time. In the pre-impact wave case, the COR may be significantly larger or smaller than in the reference case. It may also be significantly larger or smaller than unity. A pre-impact wave mechanism leading to super rebounds with COR up to 1.4261 is described.

研究了均匀弹性杆在固定刚性壁支承的线性弹性或双线性非弹性弹簧的纵向冲击中，预冲击波对恢复系数（COR）的影响。弹簧模型可以表示例如小的弹性圆柱体的准静态响应或冲击钻探中的非弹性钻头-岩石相互作用。杆通过持续时间相对较短的力（在杆中产生明显的预冲击波）被加速至其冲撞动量（预冲击波情况）或不产生此类波的持续时间较长的力（参考情况） 。基于一维波动方程的分析和数值结果以无量纲形式呈现。结果表明，在预冲击波情况下，由加速力执行的功要比参考情况下大得多，并且COR通常取决于弹簧刚度，弹性参数，杆-弹簧初始分离和波渡时间。在冲击前波的情况下，COR可能比参考情况下的显着更大或更小。它也可能远大于或小于1。描述了导致COR高达1.4261的超反弹的预冲击波机制。