Pick-up and impact of flexible bodies

摘要: Picking up, laying down, colliding, rolling, and peeling are partial-contact interactions involving moving discontinuities. We examine the balances of momentum energy across a discontinuity in string, with allowance for injection or dissipation by singular supplies. split according to its invariance properties, discuss analogies systems particles connections literature on shocks phase transition fronts various bodies, derive compatibility relation between supplies translation-invariant energy. For contact string smooth rigid plane presence gravity, we find surprising asymmetry processes picking up such that steady-state kinks geometry associated jumps tension not admissible during pick-up. This prediction is consistent experimental observations. briefly related problems including falling folded chain, an adhesive tape, “chain fountain”. Our approach applicable study impact locomotion, as moored floating structures some musical instruments feature vibrating cable elements interacting surface.