DYNAMIC STRESSES DURING STRUCTURAL IMPACTS

摘要

Dynamic stresses that occur when an object strikes a structure can be described by considering both vibration theory and conservation of energy principles. An object striking a simple beam is used as one of several examples. The complete stresses are found by adding the stresses obtained from a vibration equation to the stresses found by using a conservation of energy equation. When combined, these two stresses establish the maximum stress in a structure subject to impact. This solution assumes that each point within the beam acts as a linear system, reacting to the dynamic application of a load to the structure. When struck, the surface of the beam is momentarily compressed, and the beam bends. The equations describe both the localized stresses at the point of impact and the bending stresses in the beam following impact. These equations are then extended to an elastoplastic case, using a bilinear model to describe the dual natured linear elastic and linear plastic material behavior. The general solution technique is applicable to cases other than the simple beam.