Shear testing applies a force parallel to the plane we are interested in finding the shear strength for, which is the stress required to fracture the material. The difference between shear and tension/compression test, is that the force is applied parallel to the surface instead of perpendicular.
Why Use Shear Testing
The main purpose to use shear test is to determine the shear strength, which is essential information for fasteners like bolts.
If bolts are used to secure plates from moving in parallel to each other, and the total shear stress is higher than the total shear strength of all bolt used in a construction, it can have catastrophic consequences.
Shear Test Setup
The shear test can be set up in two different ways
- Double Shear: The sample is setup with a three or four point fixture, where a midsection of a sample is removed during test. In this test the part will end up in three pieces, as the plastic deformation until failure happens in two locations as seen on the picture to the right.
- Single Shear: Here each end is placed in a grip fixture and pulled in opposite direction. In this test the sample will end up in 2 pieces, as it will only brake in one location. The principle is illustrated in the picture on the right hand side.
When to use Shear Testing
As mentioned earlier, the shear tests is often used to validate fasteners commonly made from metal. Two other examples where it is used is when testing adhesives and composites, where you in both cases are pulling two layers in opposite direction to test the bond between them. This could be done as part of developing a new product, where a few potential types of adhesives are compared with each other.
Alternatively you can continue to our quality training page to see our available courses.Go to Quality Training