ASTM D1002, ASTM D5868, ASTM D3163 for Lap Shear Tests Scope:

Lap Shear value determined by ASTM D1002, ASTM D3163, ASTM D5868 is useful in ascertaining the shear strength of adhesives for bonding materials such as metals, plastics when tested on a standard single-lap-joint specimen. A sliding failure that happens along a flat surface is termed as shear.

This test is used to determine adhesive strengths, surface preparation criteria, comparative shear strength data, and adhesive environment durability. ASTM single-lap-joint shear testing covers ASTM D1002 that specifies the apparent shear strength for bonding metals, ASTM D3163 for rigid plastic adherends, and ASTM D5868 for fibre-reinforced plastic (FRP) adherends.

Test Procedure:

For ASTM D1002, ASTM D3163, ASTM D5868 tests, each end of the sample is loaded in the tensile grips. A force is adjusted at a fixed rate to the sample until it fractures and the maximum force and the kind of joint failure are recorded. The test procedures for three different ASTM are: (a) ASTM D1002 specifies a load control rate of 1,200 to 1,400 psi/minute. A crosshead control rate of 0.05 inch/minute approximates the loading rate and also is an acceptable mode of control; (b) Two samples are bonded along with an adhesive and cured as needed for ASTM D3163 for rigid, adhesively bonded plastic. The test samples are put in a universal test machine and pulled up to failure at a speed of 1.3 mm/min; and (c) ASTM D5868 recommends a loading rate of 13 mm/min (0.5 in/min) for fibre reinforced plastic.

Although adhesives used to attach polymers can also be tested for their lap shear strength, ASTM D1002 testing is normally done with metals like aluminium. Testing plastic substrates can be very helpful as well because plastics are widely utilised in the aerospace, electronics, medical, oil & gas, and other industries.

A material’s capacity to bear stresses placed on a plane, when the applied shear force is moving the two substrates in opposition, is measured by lap shear strength testing. It is among the most typical stresses that a bonded joint may experience while in use, particularly in structural bonding applications. One measure of an adhesive’s long-term viability in a given application is its lap shear strength. When tested on a single-lap-joint specimen, lap shear determines the shear strength of adhesives for bonding materials. The test can be used to figure out adhesive strengths, surface preparation specifications, and environmental durability. 

Video 01: Adhesive lap joint shear testing