Analytical modeling of ASTM lap shear adhesive specimens. FInal report

Abstract

An analytical model was developed to predict the stress distribution within the specimen specified in ASTM D 3165 Strength Properties of Adhesives in Shear by Tension Loading of Single-Lap-Joint Laminated Assemblies. In the developed model, the composite adherends were assumed elastic orthotropic, and the adhesive was assumed elastic-perfectly plastic. Experimental joint strength data was used in conjunction with the developed model to define the failure criterion for cohesive failure mode. Finite element analyses were conducted to simulate the behavior of both ASTM D 5656 Standard Test Method for ThickAdherend Metal Lap-Shear Joints for Determination of the Stress-Strain Behavior of Adhesives in Shear by Tension Loading and ASTM D 3165 test specimens for deformation, stress distribution, and failure. In the finite element models, aluminum adherends were assumed elastic-perfectly plastic, and the adhesive stress-strain relation was determined by trial calculations of ASTM D 5656 specimens and comparison to experimental results. Both the equivalent plastic strain criterion and the fracture mechanics approach with J-integral were used as failure criteria. Predicted joint strengths were compared with experimental data.