What Is Stiffness Of Material?

Stiffness of material is the measure of a material’s ability to return to its original form after being acted on by an external force. It refers to the material’s ability to resist external forces and still return to its original form. These forces include bending, stretching, and other forms of strain. It can also be referred to as the rigidity of a material. This is its ability to resist deformation. Stiffness is closely related to elastic or flexible materials. The more flexible a material is, the lesser the stiffness.

In general, stiffness is the total measure of the amount of deflection caused by the load on the material. Engineers often associate a value known as Young Modulus “E” for Stiffness. Knowing the properties of materials is important for your part design. 

Relationship Between Stiffness and Strength

When it comes to stiffness vs. strength, it is easy to confuse things. It often appears to logic that if a material is stiff, it is strong enough to withstand force and support load without breaking. However, this is not the case as “stronger” does not necessarily mean “stiffer.”

A material’s strength and its stiffness properties are not directly related. This is evident when these materials of varying stiffness and strength properties are exposed to external forces. The properties of the stiff material may allow it to return to its original shape after taking on several forms to take on the force.

On the other hand, a strong material does not change its form. It either resists the force, or it deforms permanently if the force is greater than its tensile strength. This can be confusing to mere logic because resistance to physical deformation is a key part of defining both strength and stiffness. However, the material can break easily if it has low strength. If it has low stiffness, it can deflect a high load.

What Is the Difference Between Strength and Stiffness of Material?

Strength and stiffness are two physical properties of a material. One major difference between them is that stiffness is the ability of an object to withstand stress without breaking. On the other hand, strength is the ability of an object to resist deformation when stress is applied.

Strength measures the stress or force applied to a material before it breaks (tensile strength) or permanently deforms (yield strength). However, stiffness of material defines how a material bends to resist exerted force while returning to its original form upon removing the force. A strong material with less stiffness will break if the exerted force exceeds its tensile strength. The strong material does not change its form. If the exerted force exceeds its strength, it simply breaks, completely losing its original shape.

However, stiff material with less strength will deflect. The deflection helps it to accommodate the force exerted on it. Therefore, it can return to its original shape once the force is removed.

It is important to understand the individual roles of strength and stiffness of material in foundational decision-making. They are highly essential factors in the production of high-end products. This is because the production depends on the materials’ response to applied force or load.  Source