Rivets play an important role in the aerospace industry. These heavy-duty fasteners are used to create permanent joints in airplanes and other types of aircraft. A typical Boeing 737, for instance, has roughly 200,000 rivets. When shopping for aerospace rivets, however, you should consider their shear strength.
What Is Shear Strength?
Shear strength is a measurement of how strong a rivet it. More specifically, it represents a rivet’s ability to resist sliding forces. The higher a rivet’s shear strength, the better protected it will be from sliding forces.
Why Shear Strength Is Important
You can’t ignore shear strength when shopping for aerospace rivets. Like with most fasteners, rivets are used to hold two or more parts together. Some of these parts are exposed to significant shear forces, such as wing roots.
A shear force may push one part held together with rivets in one direction and another part held together with the same rivets in the opposite direction. If the rivets’ shear strength is too low, they may fail by sliding apart.
Shear strength is closely related to fatigue resistance. Rivets with a high shear strength can typically withstand repeated stress for more hours than those with a low shear strength.
Another reason shear strength is important is for safety. Aircraft parts like rivets have strict safety specifications. They must be designed and manufactured to meet these specifications, including shear strength for certain rivets.
Shear Strength vs Tensile Strength: What’s the Difference?
Contrary to common belief, shear strength and tensile strength aren’t the same. They are both strength-based metrics, but they represent different characteristics of rivets or materials.
Shear strength represents a rivet’s ability to resist sliding forces, whereas tensile strength represents a rivet’s ability to resist being pulled apart. Tensile strength is essentially a measurement of how much force it takes to pull apart a rivet. If a rivet is exposed to a force greater than the tensile strength for which it’s rated, it may be pulled apart.
The key difference between shear strength and tensile strength is that the former represents a rivet’s resistance to sliding apart, whereas the latter represents a rivet’s ability to resist being pulled apart.
In Conclusion
Understanding shear strength is essential when selecting rivets for aerospace applications. It directly impacts how well a rivet can handle sliding forces and contributes to the structural integrity, fatigue resistance and overall safety of an aircraft. While tensile strength also plays a role, it’s the shear strength that often determines whether a rivet can endure the stresses found in flight-critical areas like wing assemblies and fuselage joints.
