When choosing sheet metal for your next project, you may want to consider more than just the size and shape of your sheet. There are several factors that can affect the final strength and durability of the sheet once it’s been cut and formed into its final product shape. 

Bending stiffness plays an important role in determining how flat your part will turn out to be after bending, as well as other factors like how long the material takes to bend, how many times it can be bent before becoming permanently deformed, and how strong it will be when put under pressure or stress.

What Is Flexural Rigidity?

To better understand the importance of bending stiffness, it is important to first define what flexural rigidity is. Flexural rigidity is a measure of how much a material resists being bent or deformed. 

A material with high flexural rigidity will resist bending more than a material with low flexural rigidity. The resistance to bending is also based on the thickness of the sheet metal and its mass per unit area.

 The bending stiffness is also influenced by elasticity. Elasticity refers to how much a material will deform when force is applied and then removed. The more elastic a material is, the more it will return to its original shape after an applied force has been removed. 

The combination of flexural rigidity and elasticity influences how easily a sheet metal part can be bent with different tools or methods. Flexural rigidity determines how hard it will be to bend whereas elasticity determines how far it can be bent before returning back to its original position.

How to Calculate Flexural Rigidity

When sheet metal is bent, the curvature of the sheet can be calculated as a function of its flexural stiffness. The higher the flexural stiffness, the more resistant it is to bending. It’s important to consider not just bending stiffness when designing a product but also how it will affect other parts of the design. 

For example, a car bumper needs to have sufficient flexural stiffness to absorb high energy impacts without compromising other parts of the car like the engine or fuel tank.

Flexural rigidity can be calculated using the following formula:

Flexural rigidity (EI) = Young’s Modulus (E) x (width of material) x (thickness of material)

This formula can help you determine how much force will be required to bend your sheet metal as well as what its maximum load bearing capacity will be under certain circumstances.

How Flexural Rigidity Differs from Yield Strength

Flexural Rigidity is the stiffness of a beam under bending. Flexural Rigidity is calculated by dividing the load applied to the beam into the deflection of the beam. In sheet metal, it is important to consider how thick your sheet metal product is and what type of material you are using. 

If you were bending a thin sheet of steel, then your flexural rigidity would be high because there isn’t much resistance as it bends, but if you were bending a piece of rubber, then your flexural rigidity would be low because there is plenty of resistance from the material itself. 

Yield Strength (also known as ultimate tensile strength) refers to how much stress or load a material can take before it breaks or fails.  The general rule for yield strength is that any point on a material will break when more than 50% of its yield strength has been exceeded. 

More on Stiffness and Plasticity

Another factor that affects the stiffness of sheet metal is its plasticity, or how much it stretches when force is applied. Plasticity is measured using the term strain, which can be thought of as a percentage. 

In order to calculate the strain for a given material, you need to know its original length and final length after it has been bent. For example, if your metal starts at one meter long and is bent into a 90° angle with a radius of 0.5 meters, then your strain would be 45%.

If your sheet metal is too stiff, it can be difficult to bend. If it’s not stiff enough, however, you’ll struggle to get a tight seal. So it’s important to know how much strain your material is capable of handling before you start working with it.