Chain reaction from impact on aggregate of elasto-plastic ‘rigid’ bodies

In a mechanism or system of ‘rigid’ bodies that are pressed together at elasto-plastic 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 displacement constraints. For each pair of bodies and their compliant connection, there is a local wave speed that depends on contact compliance and mass of the adjacent bodies. If the local wave speed decreases with ‘distance’ from the external impact, the reaction impulses at neighboring contacts occur sequentially whereas if there is a large gradient of local wave speed, the impulses at neighboring contacts occur simultaneously. Between these limits, the dynamics of impact on multi-body systems with compliant contacts depend on coupling between time-dependent contact forces rather than some assumed timing of the resultant impulses.