A study of the vibration of delaminated beams using a nonlinear anti-interpenetration constraint model

In this paper, the vibration of a beam with an embedded delamination is studied within the formalism of Timoshenko beam theory. As the free-body model results in dramatic interpenetration of the delaminated sublaminates that is physically impossible, a novel nonlinear constraint model is introduced to prevent the interpenetration. Unlike the previous model in the literature, the present constraint model automatically produces the zero or a proper contact traction following any given contact law without specifying whether the sublaminates are in contact or not before solving the problem. The resulted nonlinear partial differential equations are solved numerically. It is found that the predicted vibration of the beam with the constraint model is remarkably different from that without it. Moreover, the vibration mode of the beam depends upon the type of the contact function. ? 2002 Published by Elsevier Science Ltd.EI1483-4885