GLOBAL AND LOCAL INFLUENCE OF STACKING SEQUENCE ON THE STRENGTH OF ADHESIVELY BONDED JOINTS OF CFRP LAMINATES

摘要

Although adhesive bonding of composite materials has undeniable advantages compared to other joining techniques, the difficulties encountered in predicting the failure of such joints prevent the generalization of their use. In the case of CFRP laminates, the failure strength can be affected by the ply orientation near the adhesive layer. But the assessment of the influence of this local parameter is difficult because changing local ply orientations results often in changing also the global elastic properties of the laminates. Matthews and Tester [1] studied the influence of the stacking sequence on the failure of single lap joints (SLJ) of laminates with different configurations of 0°, 45° and -45° layers. The highest strengths were obtained when the 0° layers were placed on the outer surfaces of the laminates. In this case, the bending stiffness was also increased, making it difficult to attribute the strength to the local orientation or to the global stiffness. Johnson and Mall [2] studied 0/0, 45/45 and 90/90 interfaces in SLJ of composite laminates. The higher strength was attained with 45/45, followed by 0/0 and 90/90 was the worst case. Kairouz and Matthews [3] investigated the behavior of cross ply adherends with 0° or 90° surface layer. They noticed that the joint strength increased when the bending stiffness increased in the first case and increased when the bending stiffness decreased in the second case. The failure mechanisms were also different. Song et al. [4], in a more recent study, compared the behavior of SLJ made from laminates with three different sequences and concluded that the larger in plane moduli led to higher strength.