Elastic-plastic beam-on-foundation subjected to mass impact or impulsive loading

A mass-spring model is developed to analyze elastic-plastic beam-on-foundations (BoFs) under mass impact or impulsive loading. A general analytical procedure is proposed and it is shown that three phases, i.e. a transient phase, an elastic unloading phase and a final elastic vibration phase, exist in an elastic-plastic BoF after the dynamic loading. Similar to the quasi-static analysis given by Chen and Yu [Int. J. Mech. Sci. 42 (2000) 2261], an elastic-plastic BoF under dynamic loading may undergo various deformation scenarios, depending merely on some dimensionless parameters. Both its own characteristics and the external loading parameters govern the dynamic behavior of an elastic-plastic BoF. The "plastic hinge migration" and the propagation of plastic deformation in the foundation occur in both quasi-static and dynamic cases; however, the failure modes of elastic-plastic BoFs are different under those two loading conditions.