What’s The Difference Among Strength, Stiffness And Hardness

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What’s The Difference Among Strength, Stiffness And Hardness

When buying hoses or other rubber products, the seller may ask if you have any require on strength, stiffness and hardness. But what’s the difference and how to identify them?

Strength, stiffness and hardness are the mechanical property index. To know them, we should first know the elastic deformation and plastic deformation. Elastic deformation is that it can return to its original shape and size when the external force is removed, while plastic deformation is that it can’t return to its original shape and size when the external force is removed. Knowing the elastic and plastic deformation, it’s easy to understand the strength, stiffness and hardness.

Strength
Strength means the plastic deformation and fracture resistance under the external force. It’s an important index to measure the bearing capacity and also the basic requirement that the hose and rubber products should meet. The strength can be divided into static strength, fatigue strength, breaking strength, impact strength, high and low temperature strength, corrosion strength, bonding strength and creep strength.

Stiffness
The elastic deformation resistance under the force. The stiffness of a part is usually expressed by the force or moment required for unit deformation, and the stiffness depends on the geometry of the part and the type of material (the elastic modulus of the material). The rigidity requirement is particularly important for some parts that will affect the working quality of the machine when the amount of elastic deformation exceeds a certain value, such as the spindle, guide rail, and screw of the machine tool.

Hardness
The capacity to resist harder object press in. Hardness is an important index to measure the hardness and softness degree of materials. It can be understood as the capacity to resist elastic deformation, plastic deformation and breaking. Hardness is an aggregative indicator of elasticity, plasticity, strength, toughness and other mechanical properties.

After reading this article, do you have a brief knowledge of strength, stiffness and hardness? If you want to learn more, follow OrientFlex.