Why does pure axial loading cause shear stress?

As the normal force is applied, the shear stress is also generated due to the deformation of the rod. This relationship is explained by Mohr's Circle, which shows the distribution of stress components in different planes. Therefore, in summary, the application of an axial load on a ductile rod leads to both normal and shear stress, with the maximum in-plane shear stress being half of the applied axial load. This is due to the orientation of the plane at 45 degrees and can be understood through Mohr's Circle.
  • #1
zachdr1
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I just found that applying an axial load of magnitude σ on both sides of a ductile rod will produce a max in plane shear stress of magnitude σ/2. Why is this? How can there be shear stress if only a normal force is applied?
 
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  • #2
Do you know about Mohr's Circle? If so, there is the answer. The state of stress at a point consists of all the stress components at that point. Which component you see depends upon the plane in which you look at the stresses. You see the pure axial stress only when you look at a section aligned normal to the load direction.
 
  • #3
zachdr1 said:
I just found that applying an axial load of magnitude σ on both sides of a ductile rod will produce a max in plane shear stress of magnitude σ/2. Why is this? How can there be shear stress if only a normal force is applied?
For a plane oriented at an angle of 45 degrees to the rod axis, the stress vector acting on the plane has components in both the normal direction and the tangential (shear) direction (of the plane).
 

FAQ: Why does pure axial loading cause shear stress?

Why is shear stress caused by pure axial loading?

Pure axial loading causes shear stress because it involves applying a force along one axis, causing the material to deform and experience a shearing force perpendicular to the applied force. This shearing force results in shear stress, which is a measure of the internal resistance of the material to the applied force.

How does pure axial loading differ from other types of loading?

Pure axial loading is a type of loading that involves applying a force along one axis, while other types of loading, such as bending or torsion, involve applying a force that causes the material to deform in more than one direction. This difference in the direction of deformation results in different types of stresses, including shear stress.

What factors affect the amount of shear stress caused by pure axial loading?

The amount of shear stress caused by pure axial loading depends on several factors, including the magnitude of the applied force, the cross-sectional area of the material, and the material's shear modulus. Additionally, the length of the material and the type of support at the ends can also affect the amount of shear stress.

Can pure axial loading cause failure in a material?

Yes, pure axial loading can cause failure in a material if the applied force exceeds the material's shear strength. This can result in the material shearing or breaking apart, which can be dangerous in certain applications. It is important to consider the maximum shear stress that a material can withstand when designing structures and components.

How is shear stress calculated in a material under pure axial loading?

The shear stress in a material under pure axial loading can be calculated by dividing the applied force by the cross-sectional area of the material. This results in a shear stress value in units of force per area, such as pounds per square inch (psi) or newtons per square meter (Pa). The shear stress can also be calculated using the formula tau = F/A, where tau is the shear stress, F is the applied force, and A is the cross-sectional area of the material.

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