Dynamic analysis of adhesively bonded joint under solid projectile impact

A three-dimensional (3-D) dynamic finite element analysis (FEA) was performed to study the transient stress distribution of adhesively bonded joints under solid projectile impact. The influence of the processing parameters is numerically studied including the thickness of the adhesive layer, the solid projectile size and its velocity, the material properties of the adhesive, and the strain-rate effect on the dynamic stress of the joint. The numerical results show that there exists a complex 3-D stress state in the adhesively-bonded joints under the solid projectile impact. When the solid projectile touches the joint surface, a stress concentration is imparted at the location of contact. The maximum stress of the adhesive layer varies with time as a function of the impinging solid projectile such that the location moves farther from the center of the overlap zone after the solid projectile rebounds from the joint surface. A lower stress is expected at the adhesive layer for low-modulus adhesives with respect to the case for high-modulus adhesives under the same transverse impact load. The numerically-modeled transverse deflection of the single-lap joint for the three impactor sizes with different kinetic energies and three adhesive types was in good agreement with the experimentally observed values. Experiments were performed by using developed equipment for impact testing and a high frame rate videography. The proposed dynamic model is useful in providing a reference for the design of adhesively-bonded structures.