# Internal Shear Stress Question

• rat4x4
In summary, The conversation discusses a figure commonly found in statics books and the confusion surrounding the delta V added to the shear force on the right side of the figure. The question arises as to whether this addition would take the segment out of equilibrium, but it is ultimately determined that the delta V may be a negative quantity rather than a positive one.
rat4x4
Something has been bugging me for a long time, since I took my first statics class a few years ago. I have a problem with a common figure found in many statics books. I have attached the figure to my post.

My question deals with the delta V added to the shear force on the right side of the figure. According to the textbooks, both the shear force and moment acting on the right-hand face must be increased by a small, finite amount in order to keep the segment in equilibrium. But wouldn't this take the segment out of equilibrium? I mean, you have the resultant loading acting downwards, and then you have a shear force on the right-hand face acting downwards which itself is greater than the shear force on the left hand side. Summing the forces in the y direction, wouldn't there be a net force downwards?

What am I missing here? Why does this not make sense to me and why is this figure so common in statics books?

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OK, I believe that I have figured it out. Perhaps the delta V is negative and I have always taken it to be a positive quantity.

Wow, what a stupid question. Sorry guys.

## 1. What is internal shear stress?

Internal shear stress is the stress that occurs within a material when it is subjected to forces or loads that cause it to deform or break apart. It is the result of shear forces acting on a material, causing it to undergo shearing or sliding deformation.

## 2. How is internal shear stress calculated?

Internal shear stress can be calculated by dividing the shear force by the cross-sectional area of the material. The shear force is the force applied parallel to the cross-sectional area, and the cross-sectional area is the area perpendicular to the direction of the force.

## 3. What are the factors that affect internal shear stress?

The factors that affect internal shear stress include the magnitude and direction of the applied forces, the material's cross-sectional area and shape, and the material's properties such as strength and elasticity.

## 4. What is the difference between internal shear stress and normal stress?

Internal shear stress is the stress that occurs within a material due to shear forces, while normal stress is the stress that occurs perpendicular to the cross-sectional area of a material due to normal forces. In other words, internal shear stress acts parallel to the surface, while normal stress acts perpendicular to the surface.

## 5. How does internal shear stress affect the stability of a structure?

Internal shear stress can affect the stability of a structure by causing it to deform or break apart. If the internal shear stress exceeds the material's strength, it can lead to failure of the structure. Therefore, it is important to consider internal shear stress in the design and construction of structures to ensure their stability.

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