Deriving the equation for Shear Stress for Different cross-sections

In summary, the equations for shear stress in beams can be derived using the concept of shear flow. Different cross sections (I-beam, T-beam, rectangular, hollow rectangular, circular, and hollow circular) have different equations for shear stress, which involve the second moment of area, the width or radius of the beam, and the applied force. The integration is taken over the area of the beam.
  • #1
Nexus305
13
0
Hi I know the general equation for shear stress in beams is this:
Shear Stress τ = F/Ib ∫y dA

Depending on the shape of the cross section (ie. If its an I beam, T-beam, hollow square/circle) , after integration we will end up with a different equation. I want to know the exact procedure to do the integration for specific cross sections.
I want to know the derivations for the following cross sections: I-beam, T-beam, rectangular, hollow rectangular,circular and hollow circular).

I really need some help with this because I don't understand this derivation at all
Thank you so much!
 
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  • #2
The derivation of the shear stress in beams is based on the concept of shear flow. We can use this concept to derive the equations for shear stress in different cross sections. For an I-beam, we can use the equation: τ = F/2Ib ∫y2 dA where I is the second moment of area of the cross section, b is the width of the beam, and F is the applied force. The integral is then taken over the area of the beam. For a T-beam, we can use the equation: τ = F/2Ib ∫(y2 + x2) dA where I is the second moment of area of the cross section, b is the width of the beam, and F is the applied force. The integral is then taken over the area of the beam. For a rectangular beam, we can use the equation: τ = F/4Ib ∫(y2 + x2) dA where I is the second moment of area of the cross section, b is the width of the beam, and F is the applied force. The integral is then taken over the area of the beam. For a hollow rectangular beam, we can use the equation: τ = F/8Ib ∫(y2 + x2) dA where I is the second moment of area of the cross section, b is the width of the beam, and F is the applied force. The integral is then taken over the area of the beam. For a circular beam, we can use the equation: τ = F/2πIb ∫(y2 + x2) dA where I is the second moment of area of the cross section, b is the radius of the beam, and F is the applied force. The integral is then taken over the area of the beam. For a hollow circular beam, we can use the equation: τ = F/4πIb ∫(y2 + x2) dA where I is the second moment of area of the cross section, b is the radius of the beam, and F is the applied force. The integral is then taken over the area of the beam.
 

1. What is shear stress and why is it important?

Shear stress is the force applied parallel to an object's surface, causing it to deform or slide. It is important in engineering and material science as it helps determine the stability and strength of structures and materials.

2. How is shear stress calculated for different cross-sections?

Shear stress is calculated using the equation τ = F/A, where τ is the shear stress, F is the force applied, and A is the cross-sectional area of the object. The cross-sectional area varies depending on the shape of the object, so different equations are used for different cross-sections.

3. What is the equation for shear stress in a rectangular cross-section?

The equation for shear stress in a rectangular cross-section is τ = (F x L)/(t x h), where F is the force applied, L is the length of the object, t is the thickness, and h is the height of the cross-section.

4. How do you derive the equation for shear stress in a circular cross-section?

The equation for shear stress in a circular cross-section is τ = (F x r)/(π x r^2), where F is the force applied, r is the radius of the cross-section, and π is the mathematical constant pi. This equation is derived from the definition of shear stress and the formula for the cross-sectional area of a circle.

5. Can the equation for shear stress be applied to any cross-sectional shape?

No, the equation for shear stress varies depending on the shape of the cross-section. For example, the equation for a triangular cross-section would be different from that of a rectangular or circular cross-section. It is important to use the correct equation for the specific shape in order to accurately calculate shear stress.

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