Tensile testing is one of the simplest and most widely used mechanical tests that allows us to determine an epoxy's material properties and predict performance out in the field.
Today we’re looking at tensile testing, which as its name indicates, determines the tensile strength of a material. Tensile strength is defined as the maximum stress that a material can be subjected to in tension (i.e. stretched or pulled) before failing.
In addition to tensile testing and depending on the specific product and its intended application, a combination of other mechanical, chemical, and thermal tests can also be performed. Mechanical properties describe a material’s reaction to an applied load, which is relevant to all pipe support products. Thermal properties indicate how a material functions when subjected to extreme temperature, which is especially relevant to products in cryogenic or high temperature applications.
Tensile testing is one of the simplest and most widely used mechanical tests. It is an automated test that measures the amount of force required to elongate a specimen to a breaking point. The results of a tensile test are presented in a stress and strain curve where stress is on the Y-Axis and strain is on the X-Axis. The stress-strain curve includes many point of interest such as: yield strength, ultimate tensile strength, breaking strength, modulus of elasticity, and elongation.
Tensile Strength of Epoxy
One of the applications of tensile testing is to measure bond strength, which is particularly relevant to epoxies. Tensile testing of epoxy allows us to determine its material properties which enables us to predict performance out in the field. A high tensile strength indicates an epoxy’s capability to withstand large tensile loads without losing adhesion integrity.
For example, the elongation property of an epoxy is an important number to look at because it indicates how effectively the material will flex with the piping system as opposed to failing upon loading and pipe expansion and contraction.
Ending with an applied example, we’ll now look at the force needed to remove a ProTek Composite Wear Pad from its piping. The epoxy used to bond the wear pad to the piping fails at 2750 PSI. The inside surface area of a standard 4” wear pad is 84.84 in2. Therefore, it would require more than 230,000 pounds of force to remove the wear pad from its piping. That’s almost half the mass of a blue whale!