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