IMPERFECTLY CONSTRAINED PLANER IMPACTS - A COEFFICIENT-OF-RESTITUTIONMODEL

A simple coefficient-of-restitution model is proposed for the impact o f a rigid body, constrained by an imperfect pin support, with a rigid barrier The collision process is represented by two phases. In the fir st phase, the rigid body impacts the barrier with negligible influence from the support. The next phase is characterized by an impact betwee n the rigid body and the imperfect pin support. This second phase comm ences when the impact with the barrier ceases. Both moving and station ary barriers are considered. For a moving barrier, energy can be added to the rigid body due to the work done by the friction force exerted by the moving barrier. Such a result is not predicted with the usual c onstrained impact formulation. Impact with a stationary barrier is cha racterized by continuous slip, slip reversal, or slip followed by stic k. A 'constrained' coefficient of restitution is presented for these p artially-constrained impacts. (C) 1997 Elsevier Science Ltd.