Scope:

The ASTM D5656 is a standard test method for determining the stress-strain behavior of adhesives in thick-adherent metal lap-shear joints. The data reduction and analysis of stress-strain curves acquired with thick-adherent lap-shear samples are covered by this test procedure. This test method can also be used to establish the proportional limit of the stress-strain relationship and to assess the stress-strain properties of an adhesive under shear. This information could be valuable in the design and study of adhesively bonded structures.

Test procedure:

The ASTM D5656 test technique involves applying a tensile force to thick-adherent lap-shear samples while simultaneously placing the adhesive in shear. The adherends employed in this standard test method are thick and robust, minimizing peel forces while obtaining the adhesive’s shear stress-strain properties. A finite element study of the thick adherent metal lap-shear specimen is presented in the referenced data, which calculates the effect of altering the adherent and adhesive stiffness. Because the stress is not completely uniform across the specimen’s overlap, factors like adhesive stiffness, adherent stiffness, and the location of shear strain measurement along the bond’s length can impact the experimentally measured load-displacement curve.

Video 01: Explanation of the stress-strain curve through tensile tests

Specimen size:

The ASTM D5656 test process uses a thick adherend lap shear test specimen.

Data:

An average value for shear stress, corrected strain, and modulus for each group of specimens tested is calculated and reported according to the ASTM D5656.

Conclusion:

The ASTM D5656 is a standard test method for determining the stress-strain behavior of adhesives in thick-adherent metal lap-shear joints.