Evaluation of Single-Lap and Block Shear Test Methods in Adhesively Bonded Composite Joints

Adhesive bonding is increasingly being used for composite structures, especially in aerospace and automotive industries. One common joint configuration to test adhesive strength the single-lap shear joint, which has been widely studied shown produce significant normal (peeling) stresses. When stresses are capable of causing delamination before bond fails, providing inconclusive engineering data regarding strength. An alternative block uses a shorter sample geometry compressive-shear loading reduce Analytical models proposed by Goland Reissner Hart-Smith compare edge-bending moment two configurations. The stress distributions along bondline also compared using finite element analysis. Experimental tests conducted evaluate these analyses failure modes each recorded. Block samples demonstrate over 100% higher than specimen bonded with same material. lower measured found be potentially misleading due adherend.