# Mechanics of Material Lab Manual

Table of Contents

Introduction to the lab equipment and safety precautions

1. Compression of a spring

a. To obtain the relationship between the forces applied to a compression spring and its change in length.

b. To determine the stiffness of the test spring (s).

2. Extension of a spring

a. To obtain the relationship between the forces applied to an extension spring and its change in length.

b. To determine the stiffness of the test spring (s).

3. Rubber in Shear

a. To determine the variation of deflection with applied load.

b. To investigate how shear strain varies with shear stress.

c. To determine the Modulus of Rigidity of the rubber block.

4. Hooke’s Law for Wires

a. To determine the Young's Modulus of Elasticity of the specimen wire. b. To verify Hooke's Law by experiment.

5. Strain in Compound Wires

a. To determine the modulus of elasticity of two wires and hence evaluate the equivalent Young’s Modulus of Elasticity of the combination b. To position the single applied load on the slotted link in order that both wires are subjected to common strain and hence to establish the load in each wire

6. Deflection of a simply supported beam

To find the slope and deflection of a simply supported beam with point load at the center and to prove the results mathematically

7. Deflection of a cantilever beam

To verify the slope and deflection of a cantilever beam experimentally and theoretically.

8. Deflection of a overhanging beam

To find the central deflection of overhanging arm beam and confirm the results theoretically

9. Shear center for a channel

Find Shear center for a channel section cantilever.

10. Unsymmetrical Deflections

To determine the deflections for symmetrical bending of an angle section beam

11. Shear Forces and Bending Moment in Beams

To measure the bending moment at a normal section of a loaded beam and to check its agreement with theory

12. Study and Application of experimental photoelasticty techniques on linear crack propagation analysis

13. Direction and magnitude of principal stresses

To use the Photo-elasticity as an experimental technique for stress analysis and to understand construction and operation of transmission polariscope.

14. Calculation of stress intensity factor

Interpretation of Fringe Data and calculation of stress intensity factor (k) at different loading conditions

15. Micro Hardness Testing

16. Thin Cylinder

Experiment No. 1Compression of a spring

1. OBJECTIVES

a) To obtain the relation among the force applied to an extension spring and its change in length.

b) To determine the stiffness of the test spring (s).

2. PROCEDURE

a) Setup the apparatus vertically to the wall at a convenient height.

b) Add increasing loads to the load hanger recording to the corresponding deflection for each load.

c) Continue loading until at least 30 mm of extension has been achieved.

3. RESULTS

Tabulate the results obtained and draw a graph of load (y-axis) against extension (x-axis). Note the following data for each spring used:-

a. Outside diameter,

b. Effective length,

c. Wire diameter,

d. Number of turns.

The stiffness to the spring is the force required to produce a nominal extension of 1 mm.

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If Kg masses are used: The force applied to the spring in Newtons = Mass in Kg x 9.81.

4. POINTS TO PONDER

a. What relationship exists between the applied force and compression?

b....

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