Chain Reaction From Impact on Coaxial Multibody Systems

Abstract

In a mechanism or system of “rigid” bodies that are joined or connected by compliant points of contact, an external impact at one point in the system generates a pulse of reaction force that propagates outward successively through neighboring joints or connections. At each point of contact between adjacent bodies, this wave of reaction force is just sufficient to change the relative velocities so that interpenetration of the bodies is prevented; i.e., the reactions enforce the displacement constraints. Each connection has a local wave speed that depends on the contact compliance and the mass of the adjacent bodies. Where the local wave speed is decreasing with “distance” from the external impact, the reaction impulses at neighboring contacts occur sequentially whereas if the local wave speed is increasing substantially with distance, the impulses at neighboring contacts occur simultaneously. Between these limits, the dynamics of impact of multibody systems with compliant contacts depends on coupling between time-dependent contact forces rather than some assumed timing of the resultant impulses. [S0021-8936(00)00903-X]