shear force.doc
DESCRIPTION
lab bahanTRANSCRIPT
1.0 OBJECTIVE
1.1 To determine how shear force varies with an increasing point load.
1.2 To examine how shear force varies at the cut position of the beam for various
loading condition.
2.0 LEARNING OUTCOME
2.1 To Application the engineering knowledge in practical application.
2.2 To enhance technical competency in structural engineering through laboratory
application.
2.3 To communicate effectively in group.
2.4 To identify problem, solving and finding out appropriate solution through
laboratory application.
3.0 INTRODUCTION
Beams are defined as a slender members and support loadings that are applied
perpendicular to their longitudinal axis. Generally, beams are long, straight bars and having a
constant cross sectional area. It can be classified as one of the most structural members.
Shear force is the force that acting perpendicular to its longitudinal x-axis in the
beam. The important factor in designing beam is the ability of beam to resist shear force. This
ability is more important than to resist axial force, the force that acting parallel to the
longitudinal axis.
4.0 THEORY
Part 1:
Part 2:
Use the statement:
“The shear force at cut is equal to the algebraic sum of the force acting to the left or right of the cut”
5.0 APPARATUS
Apparatus for Shear Force Experiment
Digital Force Display The Loader (1 = 100gm)
6.0 PROCEDURE
Part 1
1. The Digital Force Display meter is checked to ensure the reading is zero with no
load.
2. A hanger with load of 100g mass is placed to the left of the ‘cut’.
3. The Digital Force Display’s reading is recorded in table 1. This step is repeated by
using different masses between 200g and 500g.
4. The unit for the reading is converted from mass into a load in Newton (by
multiplied with 9.81) and the force reading into bending moment (Nm). The
following expression is used:
Shear Force at cut (Nm) = Displayed Force
5. The theoretical value of shear force is calculated and Table 1 is completed.
Part 2
1. The Digital Force Display meter is checked to ensure the reading is zero with no
load.
2. The hangers are loaded on the beam in any position carefully and the loads
exampled as in Figure 2, Figure 3 and Figure 4. Table 2 is completed.
3. The force reading is converted into bending moment (Nm) by using:
Shear Force at cut (Nm) = Displayed Force
4. The support reaction at RA and RB and the theoretical value of shear force are
calculated.
Figure 2
7.0 RESUTS
Table 1:
Mass (g) Load (N) Force (N) Experimental Bending
Moment (Nm)
Theoritical Bending
Moment (Nm)
0 0 0 0 0
100 0.9810 -0.4 0.4 0.312
200 2.9430 -0.7 0.7 0.6248
300 3.4335 -1.0 1.0 1.092
400 3.9240 -1.3 1.3 1.255
500 4.4145 -1.6 1.6 1.415
Table 2:
No
.
W1
(N)
W2
(N)
Force
(N)
Experimental
Bending Moment
(Nm)
RA (N) RB (N) Theoritical
Bending
Moment (Nm)
2 3.924 0 -1.3 -1.3 - 3.920 -5.172 1.248
3 1.962 2.943 1.7 1.7 2.720 2.177 -2.728
4 1.962 2.943 0.3 0.3 1.338 1.247 -0.624
8.0 ANALYSIS DATA
Calculation for Theoritical Shear Force value.
PART 1:
Example:
Load = 0.981N
MB = 0
RA (0.44) -0.981 (0.14) = 0
0.44 RA = 0.137
RA = 0.3121N
MA = 0
- RB (0.44) + 0.981 (0.3) = 0
0.44 RA = 0.294
RA = 0.669N
FY = 0
RA - W - VC = 0
0.3121 – 0.981 = VC
VC = - 0.669N
Load = 2.9430N
MB = 0
RA (0.44) -2.9430 (0.14) = 0
0.44 RA = 0.137
RA = 0.625N
MA = 0
- RB (0.44) + 2.9430 (0.3) = 0
0.44 RA = 0.294
RA = 2.01N
FY = 0
RA - W - VC = 0
0.3121 – 2.9430 = VC
VC = - 2.01N
Load = 3.4335N
MB = 0
RA (0.44) -3.4335 (0.14) = 0
0.44 RA = 0.481
RA = 1.092N
MA = 0
- RB (0.44) + 3.4335 (0.3) = 0
0.44 RA = 0.294
RA = 2.341N
FY = 0
RA - W - VC = 0
1.092 – 3.4335 = VC
VC = - 2.341N
Load = 3.9240N
MB = 0
RA (0.44) -3.942 (0.14) = 0
0.44 RA = 0552
RA = 1.255N
MA = 0
- RB (0.44) + 3.942 (0.3) = 0
0.44 RA = 1.1826
RA = 2.688N
FY = 0
RA - W - VC = 0
1.255 – 3.942 = VC
VC = - 2.688N
Load = 4.4145N
MB = 0
RA (0.44) -4.4145 (0.14) = 0
0.44 RA = 0.618
RA = 1.415N
MA = 0
- RB (0.44) + 4.4145 (0.3) = 0
0.44 RA = 1.324
RA = 3.0N
FY = 0
RA - W - VC = 0
1.415 – 4.4145 = VC
VC = - 3.0N
Part 2:
Example No. 1 (Figure 2)
FY = 0
RA - W - VC = 0
RA - W = VC
VC = 5.172 – 3.924
VC = - 1.248N
No. 2 (Figure 3)
FY = 0
RA – W1 – W2 – VC = 0
RA – W1 – W2 = VC
VC = 2.72 – 1.962 – 2.943
VC = - 2.728N
No. 3 (Figure 4)
W1 = 1.962N W2 = 2.943N
RA = 2.72N
FY = 0
RA – W1 – VC = 0
RA – W1 = VC
VC = 1.338 – 1.962
VC = - 0.624N
W1 = 1.962N
RA = 1.338N
9.0 DISCUSSION
Part 1
1. Derive equation 1
2. Plot a graph, which compare your experimental result to those you calculated using
theory
Refer to the graph..
3. Comment on the shape of the graph. What does it tell you about how bending
moment varies due to an incresing load?
From the graph, we can see shear force is linearly perpendicular to the increasing
load. When the load increase, the shear force also increase. The experimental value is almost
the same as theoritical value.
4. Does the equation you used accurately predict the behavior of the beam?
Yes, from the graph, we discover the value between experimental shear force and
theoritical shear force value is almost the same as the difference percetage is lower.
Part 2
1. Comment on how the results of the experiments compare with those calculated using
the theory.
the result that obtained from table is different. This is because of the result experimental shear
force were originally taken while doing the experiment compare with theoritical shear force
obtained from the calculation.
Perhaps during the experiment being carried out, there are some errors due to equipment or
enviromental interference.
2. Does the experiment proof that the shear force at the cut is equal to the algebraic sum
of the forces acting to the left or right of the cut. If not, why?
Yes, shear force at the cut is equal to the algebraic sum of the force acting to the left or right
of the cut, the shear force can be calculated based on the data distance. Proof by our
exeriment, distance effects the shear force.
3. Plot the shear force diagram for load casses in figure 2, 3 and 4.
Refer to the diagram in appendix.
4. Comment on the shape of the graph. What does it tell you about how shear forces
varies due due to loading condition?
The value of shear force will be in positive or negative where these values will influenced the
diagram. Either the shear force diagram locatesd at the above or below. The condition of load
also will influenced the value of shear force. From this, it wil help us to draw the diagram.
10.0 CONCLUSION
As a conclusion, after we had done the experiment, we found that the vale of load that
applies on the beam will affect the shear force value. Besides, the distance of the point load
will also affect the result value.
From the data gathered in the experiment, we realise thebeam shear is defined as the
internal shear stress of a beam caused by bending of the beam.
APPENDIX
Graph
0.981 2.943 3.4335 3.924 4.41450
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
Experimental valueTheoritical Value