Types of Tests
Shear
What is a shear test?
The ASM Handbook®, Volume 8, Mechanical Testing and Evaluation states: shear testing is commonly performed as part of routine quality control procedures during manufacturing and as part of the final inspection of, for example, precision fasteners. Shear testing is also a critical step in determining fastener strength during research and development of new fasteners.. The degree and complexity of the shear testing of the shear test is usually dictated by the fastener standard or the service/end-use conditions of the part.
Shear testing of fasteners is accomplished by exerting pressure (shear force) in the transverse plane of the fastener until shear failure occurs. Shear force causes the two contiguous portions of the fastener to slide in opposite directions parallel to their contact plane. The force that results in the shear failure is called the ultimate load, while the load required to cause permanent deformation is called the yield load.
A single shear test fixture uses two blades with centrally located transverse holes. The single shearing action happens when one blade is kept stationary with the fastener in place, and the second blade is moved in a parallel plane, so shearing the fastener. Typically single shear tests are performed on fasteners that are too short to test using a double shear fixture and whose length is typically less than 2.5 times the diameter.
Double shear testing is similar except that it uses and second stationary blade behind the moving / shearing blade. |
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