# Twisting at shear center / centroid

• fonseh
In summary, the author discusses the bending and twisting of a channel when a force is applied through its centroid. However, it is also mentioned that the shear center, which is located on the axis of symmetry, can prevent twisting. This raises confusion about whether the member will twist when the force is applied through the centroid or shear center. The author also explains why the shear center is located outside the C channel. Further, the notes mention that to prevent twisting, the force should be applied at both the centroid and the shear center simultaneously. The meaning of the force applied along the once vertical, unsymmetrical axis that passes through the centroid is also questioned.
fonseh

## Homework Statement

In the notes , the author stated that when the force is applied through the centorid of cross section , the channel will bend and twist.
but , on the second page , the author stated that the shear center lies on an axis of symmetry of member's cross sectional area...
So, i am confused whether the member will twist or not when the force P is applied thru the centroid or shear center ...

Why the shear center is located at O , which is located outside of the C channel ?

## The Attempt at a Solution

Is there anything wrong with the notes ? [/B]

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In the notes , it's also stated that to prevent twisting , the P should be applied at O , does it mean we have to apply the force thru the centoid and also at the O at the same time to prevent twisting ? I'm confused

Bump

what is the meaning of the force is applied along the once vertical , unsymmetrical axis that passes thru centroid ? Since the applied force already passing thru centroid , it's already the symmertical axis , right ?

## 1. What is the difference between twisting at shear center and centroid?

The shear center is the point on a beam or structure where the applied load creates only shear stress and no twisting moment. The centroid, on the other hand, is the point where the entire weight of the object can be considered to act, resulting in no net force or torque.

## 2. How do I determine the shear center and centroid of a structure?

The shear center and centroid can be determined through mathematical calculations using the properties and dimensions of the structure, such as the moment of inertia and cross-sectional area. Alternatively, experimental testing can also be conducted to determine these points.

## 3. Why is it important to consider the twisting at shear center and centroid in structural analysis?

Ignoring the effects of twisting at these points can result in incorrect predictions of the structural behavior and lead to potential failure or instability. It is crucial to accurately determine and consider the shear center and centroid in order to ensure the structural integrity and safety of a design.

## 4. Can the shear center and centroid be at the same location?

No, the shear center and centroid are typically located at different points on a structure. However, in some symmetrical structures, these points may coincide.

## 5. How does twisting at shear center affect the structural behavior of a beam?

Twisting at shear center can result in a warping deformation of the beam, which can lead to changes in the distribution of stresses and potentially affect the overall stability and strength of the structure. It is important to accurately account for this effect in structural analysis and design.

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