IMPACT RESPONSE OF SINGLE-LAP COMPOSITE JOINTS

The low-velocity impact of adhesive-bonded single-lap composite joints has been studied using a spring-mass model. In this quasi-static mode l, the impact response is represented by a time-dependent force, and t he target joint is represented by an equivalent mass with equivalent s tiffness. An analytical model has been developed to determine the equi valent mass and stiffness of the joint. The laminated anisotropic plat e theory was used in the derivation of the governing equations of the two bonded laminates. The entire coupled system, as well as the assume d peel stress, were solved using both the joint kinematics and suitabl e boundary conditions. With the combination of a spring-mass equilibri um system and the developed joint model, a relationship between the im pact force and the duration has been established. Adhesive stresses, w hich are believed to be the cause of failure, were predicted from the impact force. Impact tests of single-lap composite joints with differe nt sample thicknesses and overlay lengths have been conducted to verif y the proposed model.