# Bending Moment Exp

Topics: Force, Beam, Bending Pages: 7 (1686 words) Published: December 12, 2010
DEPARTMENT OF CIVIL ENGINEERING
COLLEGE OF ENGINEERING

CEMB 121 MECHANICS OF MATERIALS LABORATORY
LABORATORY EXPERIMENT NO. 3
BENDING OF BEAMS - (a) Bending Moment I
(b) Bending Moment II

SECTION 1
GROUP NUMBER 3

GROUP MEMBERS
1. YEOW SU LEE( CE085335 )
2. JOUDI J. MOOSOM( CE085338 )
3. NINI EZLIN ROSLI( CE086340 )
4. MOHD AFIQ AFIFE BIN ABAS( CE085310 )

DATE OF LABORATORY SESSION6 DECEMBER 2010
DATE OF REPORT SUBMISSION13 DECEMBER 2010
LAB INSTRUCTORMISS SITI ALIYYAH MASJUKI

LAB REPORT MARKING|

CRITERIA| Scale|
| Poor| | Acceptable| | Excellent|
A. Appearance, formatting and grammar/spelling| 1| 2| 3| 4| 5| B. Introduction and objective| 1| 2| 3| 4| 5|
C. Procedure| 1| 2| 3| 4| 5|
D. Results: data, figures, graphs, table, etc.| 1| 2| 3| 4| 5| E. Discussion| 1| 2| 3| 4| 5|
F. Conclusions| 1| 2| 3| 4| 5|
TABLE OF CONTENT

Section| Page|
Summary| |
Objective| |
Apparatus| |
Procedure| |
Results| |
Discussion| |
Conclusions| |

SUMMARY

When applied loads act along a beam, an internal bending moment which varies from point to point along the axis of the beam is developed. A bending moment is an internal force that is induced in a restrained structural element when external forces are applied. Failure by bending will occur when loading is sufficient to introduce a bending stress greater than the yield stress of the material. Bending stress increases proportionally with bending moment. It is possible that failure by shear will occur before this, although while there is a strong relationship between bending moment and shear forces, the mechanics of failure are different. A bending moment may be defined as “the sum of turning forces about that section of all external forces acting to one side of that section”. The forces on either side of the section must be equal in order to counter-act each other and maintain a state of equilibrium. For systems allowed to rotate, then the equivalent force would be referred to as torque.

OBJECTIVE

To show that the bending moment at a cut section of a beam is equal to the algebraic sum of the moments acting to the left or right of the section.

APPARATUS

1. A pair of simple supports.
2. Special beam with a cut section.
3. A set of weights with several load hangers.

PROCEDURE

1. The load cell is connected to the digital indicator.
2. The indicator is switched on. For stability of the reading the indicator is switched on 10 minutes before taking readings. 3. The two simple supports is fixed to the aluminium base at a distance equal to the span of the beam to be tested. The supports are screwed tightly to the base. 4. The load hanger is hung to the beam.

5. The beam is placed on the support.
6. The load hanger is placed at the desired location.
7. The indicator reading is noted. The tare button on the indicator is pressed to make sure the reading is zero. 8. A load is placed on each load hanger.
9. The indicator reading is recorded. This represents the force at the cut section. 10. All loads are removed from the load hangers and a different set of loading is applied and at different locations. 11. Step 6 to 11 is repeated for another 5 sets of readings.

RESULTS

Beam span= 800 mm
Distance of the cut section from the right support= 300 mm
Distance of the load cell from centre of the beam cross section= 175 mm

Table 1
Load Case| Load And Its Distance From The Left Support| Load Cell ReadingF (N)| | W1(N)| L1(mm)| W2(N)| L2(mm)| W3(N)| L3(mm)| | Case 1| 2| 100| 5| 250| 7| 350| 8.23|

Case 2| 5| 100| 7| 250| 10| 350| 12.14|
Case 3| 7| 200| 10| 300| 15| 700| 15.30|
Case 4|...