The ASTM D3528 test method specifies how to determine the tensile shear strengths of adhesives for bonding metals in an essentially peel-free standard specimen. This leads to an adhesive stress distribution similar to that found in a typical low-peel production-type structural junction. Conformance to specified preparation and testing conditions is closely connected to the reproducibility of the strengths produced in this ASTM D3528 test method.
This test method is intended to generate shear property data for use in adhesive process control and specification. This test could also potentially be effective in adhesive research and development.
Metal plates are bonded together with the adhesive in one of the configurations and cured for the ASTM D3528 test process. After that, the assembly is subsequently sliced into double-lap sheared specimens of uniform width. The test specimens are then cut from bigger assemblies to reduce the possibility of edge effects in the specimens. The test specimens are held in the grips of a universal testing machine and pulled at a rate of 1.27 mm/min until they fail. Glue failure, cohesive failure, or a break in one of the substrates are all three possible failures that occur during the test procedure.
Video 01: Shear strength testing of adhesives
Lap shear specimens should be 25.4 mm wide with a 12.7 mm overlap at each bond as per the ASTM D3528 test method.
The parameters of lap shear vary depending on the specimen configuration, testing speed, and testing environment. As a result, these variables must be carefully controlled and reported when exact comparative results are sought.
The ASTM D3528 test method specifies how to determine the tensile shear strengths of adhesives for bonding metals in an essentially peel-free standard specimen.