OBJECT: To Determine the Bending Stress and Deflection of Simply Supported Beams

APPARATUS:

• Beam (Simply Supported Beams)
• Measuring Tape
• Weight, Gravity Gauge

THEORY:

BENDING STRESS

1. DEFLECTION
   

BEAM

METHODOLOGY:

OBSERVATIONS:

• Span of Beam (L) = _______________________ mm
  
• Width of the Beam (B) = _________________ mm
  
• Thickness of the Beam (t)= ____________________ N
  

RESULTS:
𝒀𝒐𝒖𝒏𝒈^′𝒔 𝑴𝒐𝒅𝒖𝒍𝒖𝒔 _____________________ N/mm²

or

DEFLECTION TEST ON SIMPLY SUPPORTED BEAM

AIM: Determine the deflection and bending stress of simply supported subjected to concentrated load at the center.

APPARATUS:

Beam apparatus, Bending fixture, vernier caliper, meter rod, test piece & dial gauge.

DIAGRAM:

THEORY:

The bending test is performed on the beam by using the three-point loading system. The bending fixture is supported on the platform of the hydraulic cylinder of the UTM. The loading is held in the middle crosshead. At a particular load, the deflection at the center of the beam is determined by using a dial gauge. The deflection at the beam center is given by:

𝜹 = 𝑾𝑳^𝟑/ 𝟒𝟖𝑬𝑰

PROCEDURE:

1. Measure the length, width, and thickness of the test piece, by the vernier caliper.
   
2. Place the bending fixture on the lower crosshead of the testing machine.
   
3. Place the test piece on the rollers of the bending fixture.
   
4. By loading the dial gauge in a stand, make its spindle knob the test piece.
   
5. Start the m/c and note down the load and dial gauge readings.
   
6. Plot the graph between load and deflection.
   

OBSERVATIONS:

1. Least count of vernier caliper = —–
   
2. Length of beam (L) = ——
   
3. Width of the beam (b) = ——
   
4. Thickness of beam (t) = ——
   

TABLE:

CALCULATIONS:

1. I= 𝒃 𝒕𝟑 / 𝟏𝟐
2. 𝜹 = 𝑾𝑳𝟑 / 𝟒𝟖𝑬𝑰

PRECAUTIONS:

1. The length of the simply supported should be measured properly.
   
2. The dial gauge spindle knob should always touch the beam at the bottom of the loading point.
   
3. The loading hanger should be placed at a known distance.
   
4. All the errors should be eliminated while taking readings.
   
5. The beam should be positioned horizontally.
   

RESULT:

The bending strength of the given specimen = —— N/mm2

VIVA QUESTIONS

1. Types of beams.
   
2. What is deflection?
   
3. Write the equation for the Slope for a cantilever beam with a point load.
   
4. Write the deflection equation for the simply supported beam with a point load at the center.
   
5. How many types of bending are there?

APPLICATIONS:

1. for the construction of bridges.