Shear Force and Bending Moment
Autor: Joshua • October 3, 2017 • 1,101 Words (5 Pages) • 715 Views
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Lever arm height=180mm
Shear force and bending moment experiment for symmetrical load
Weight
(g)
Force
(N)
Shear
Force
experiment
Shear
Force
calculation
%
error
Bending
moment
experiment
Bending
moment
calculation
%
error
500
4.905
0.000
0.000
Undefined
0.268
0.294
8.80
1000
9.810
0.000
0.000
Undefined
0.554
0.589
5.80
1500
14.715
0.000
0.000
Undefined
0.842
0.883
4.60
2000
19.620
0.000
0.000
Undefined
1.132
1.177
3.85
Lever arm height=180mm
Calculation (Symmetrical Load)
Bending Moment, M
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0.81RB-(0.75*5)-(0.06*5) =0
RB = 5N
∑Fy=0
∑Fup=∑down
RA+RB=5N+5N=10N
RA=5N
Section X (to the right)
Bending Moment, M = (0.75*5)-(0.69*5) =0.3Nm
Shear Force
V=RA-5N-5N+RB=5N-5N-5N+5N=0
Discussion:
Shearing force can be defined as a force that is pushing the part of a body in a direction and different direction from the other side of the body. When these two forces come across each other, they will result in the presence of a force known as the compressive force. Actually shearing force can be applied everywhere in the reality world. For an example, a plane is passed through a body and the force that acts along the plane is known as shearing force. Bending moment of an element can be explained by the moment of applied force that causes the element to be bent. Basically the moment share the same formula with torque which is the production of force applied and the distance which is perpendicular to the direction of force applied. So the unit is in Nm. As we know, shearing force and bending moment can be applied in designing buildings, bridge, cars, planes, boats and other structure that has to resist the force.
While doing this experiment, we used two types of load. The first type of load is a concentrated load. It is a load that only concentrates at 1 fixed point on the beam. The second type of load is a distributed load. It is a load that spread in significant length over the beam. It can be either varies from point to point or in uniform.
In order to calculate the bending force, we must sum up all the moment of the forces to the left or to the right of the beam section. A beam is a horizontal structural element that able to withstand load by resisting bending. In our experiment, we assume the moment which is positive on the left portion is clockwise and anticlockwise on the right hand side. Similarly, we assume that the moment which is negative on the left portion is anticlockwise and clockwise on the right hand side. As we compare the moment with the theoretical and experimental reading for the shear force and bending moment, we found out that there is a difference between these two reading. The bending moment that we calculated is 0.3Nm.
We found out that there are some reasons and causes that resulted in the difference between the experimental value for shear force and bending moment and theoretical reading for shear force and bending force. The applied force had disturbed the load is the first reason that cause the difference between experimental value and theoretical value. This reason causes the inaccuracy of the force. Besides, an accurate answer is difficult to obtain because the reading shown in the shear force dynamometer is keep on changing. The beam shakes during the experiments is also considered as one of the reasons. The beam is not stable as we put the load on it.
To avoid these kinds of error, there are precautions that have to be taken. The first precaution is the method
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