How Do You Determine Displacement and Rotation at Point A in a Beam?

In summary, The conversation discusses how to show that there is no displacement or rotation at point A in a beam with constant EI and a deformation described by u(x). The solution is to replace x with 0 in the u(x)-equation to show no displacement, and to use the first derivative du(x)/dx to show no rotation, which is equivalent to slope for small angles.
  • #1
kasse
384
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A beam AB has constant EI and u(x) describes the deformation:

http://www.badongo.com/pic/625051

The first task here is to show that there's no displacement or rotation at A. For the case of the displacement, I guess I can do that simply by replacing x with 0 in the u(x)-equation?

But how about the rotation? What is meant by that? Is it the same as slope?
 
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  • #2
kasse said:
A beam AB has constant EI and u(x) describes the deformation:

http://www.badongo.com/pic/625051

The first task here is to show that there's no displacement or rotation at A. For the case of the displacement, I guess I can do that simply by replacing x with 0 in the u(x)-equation?

But how about the rotation? What is meant by that? Is it the same as slope?


Yes and yes the first derivative du(x)/dx is the rotation or slope (Remember that for small angles [itex] \tan \theta \approx \theta [/itex])
 
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  • #3



I can provide a response to the topic of displacement and rotation in the context of a beam with constant EI and a deformation described by u(x). Firstly, displacement refers to the change in position of a point on the beam from its original position. In this case, since the beam has a constant EI, the displacement at point A can be determined by substituting x=0 into the u(x) equation. This will give us the displacement at point A, which is zero, indicating that there is no change in position at this point.

Rotation, on the other hand, refers to the change in orientation or angle of the beam at a particular point. It is not the same as slope, which refers to the change in elevation or height of the beam at a point. To determine the rotation at point A, we can use the slope of the beam at that point. This can be calculated by taking the derivative of the u(x) equation and substituting x=0. If the slope is zero, then the rotation at point A is also zero, indicating that there is no change in orientation at this point.

In summary, for a beam with constant EI and a deformation described by u(x), the displacement and rotation at point A can be determined by substituting x=0 into the u(x) equation and taking the derivative, respectively. This information is important in understanding the behavior and stability of the beam under different loading conditions.
 

FAQ: How Do You Determine Displacement and Rotation at Point A in a Beam?

What is displacement?

Displacement is the change in position of an object from its initial to final location. It is a vector quantity, meaning it has both magnitude and direction.

What is rotation?

Rotation is the movement of an object around a fixed point, also known as the axis of rotation. It is typically described in terms of angular displacement, velocity, and acceleration.

How do you calculate displacement?

Displacement can be calculated by subtracting the initial position from the final position. This can be represented mathematically as Δx = xf - xi, where Δx is the displacement, xf is the final position, and xi is the initial position.

What is the difference between displacement and distance?

Distance is the total length traveled by an object, while displacement is the shortest distance between the initial and final positions. Distance is a scalar quantity, meaning it only has magnitude, while displacement is a vector quantity.

What factors affect the rotation of an object?

The rotation of an object can be affected by its mass, shape, and distribution of mass. Additionally, external forces such as torque and friction can also impact an object's rotation.

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