The value of shear testing
Shear testing can be used to:- determine a material’s static and dynamic shear modulus
- understand the rupture or failure forces of a material in shear
- look at how a material responds during creep or stress relaxation
- or quantify coefficients of friction between two material surfaces.
Shear testing is typically selected as the test method for one of two reasons:
1) Shear is how the material will be excited in the component or structure so properties measured in shear best represent the material properties needed to design a solution
2) Shear is used to excite soft or highly viscous materials that are difficult to grip in tension or compression modes.
As an example, single or double lap shear tests are quite often utilized to characterize adhesives and the shear forces required to cause failure. ASTM standard D3528 - Standard Test Method for Strength Properties of Double Lap Shear Adhesive Joints by Tension Loading describes the test method for determining the shear properties, such as yield or fracture force, of adhesives during a static shear test.
Some shear tests utilize a rotational actuator to characterize shear properties. A specific example of a rotational shear test is the positioning of two cartilage plugs in opposition to each other to look at lubrication and surface effects during loading.
ElectroForce® test instruments are capable of performing many of the traditional linear and rotary shear tests. The optional DMA software package is useful when determining the linear dynamic shear modulus of materials or components as a function of frequency, amplitude, temperature or many other test parameters. ElectroForce systems are available in an axial or axial-torsion configuration, if rotational shear is of interest.
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