What is Tensile Strength and How is It Measured?

At some point, we’ve all felt as though we’re under enough stress to snap. If you wanted to quantify how close you are to snapping (in a flexible material sense), this would be tensile strength. 

If your application undergoes pressure, you may already know that a part component needs to possess a specific tensile strength (resistance to pull breakage). 

At Strouse, we recognize that the mechanical aspects of your chosen material should align with your end goals. Product development can be a complicated process that requires selecting the right material, adhesive, format, elongation at break percentage, and many other factors.  

Understanding tensile strength will allow you to choose the most suitable material for your application and design. Let’s explore what it is and how to prepare for it when choosing a material. 

What Does Tensile Strength Mean?

Tensile strength is the maximum force or stress a material can withstand while being pulled apart from both ends before failing. It’s typically measured in pounds per square inch, and is also called “breaking strength.”

High tensile strength means that a material can withstand a lot of stretching before it snaps. Copper, for example, has a relatively high tensile strength due to its resistance to breaking.

Tensile strength is measured in a test in which a universal testing machine (UTM) pulls material until it breaks and marks the tension. 

Why is Knowing Tensile Strength Important?

Tensile strength—which is key data when selecting adhesives to determine the strength and durability of the material—is often expressed in pounds per inch of width (lbs./in. width) or N/100mm. For example, 3M VHB can have 55 to 160 lbs/in2 tensile strength.

As long as the load applied via stretching is below the material's tensile strength, the material will not fail. The elastic behavior of materials extends to a “yield point,” which denotes when the deformations are entirely recoverable. Some products have a high breaking point but a lower yield point, while others have a lower breaking point but a higher yield point. Nonetheless, the yield point will always be below the breaking point. 

Pressure sensitive adhesive tape has the added benefit of having a yield point very close to its normal tensile strength, so the material can withstand tension repeatedly.

Tensile strength is important to note when using adhesive to bond materials. Bonded joints will face stresses of all sorts, including tension (tensile), compression, shear, cleavage, and peel strength. 

Applying an adhesive that cannot withstand the necessary stresses will result in failure of the adhesive and potentially failure from the parts you’re bonding or the entire application.

Selecting a Material with Tensile Strength in Mind

Selecting a material is like juggling price, durability, and function. While it can be tricky and confusing, it becomes much easier when you have the right expertise. That’s why it’s best to partner with a converter that understands the adhesive's and the entire product's intended use.

Your tensile strength can be a key piece of information when it comes to material durability and performance.