Laboratory Investigation of Hooke’s Law
Apparatus:
UTM , test specimen, divider, vernier caliper, scale.
Procedure:
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Prepare the test specimen that is steel bar and find its diameter at tree different places and find its man value.
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Mark two points 8" a part of 2 ft long steel bar.
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Insert the bar in jaws for gripping the steel bar and select suitable bar on UTM. Place the steel bar and fix it.
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Start t machine and start applying load.
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There will be gradual increase in length which will be directly proportional to applied load.
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During this load application measure change in length at different load, till the steel bar breaks.
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Find the stress and strain at those points and investigate the law by drawing the graph between stress and strain
S No | Dia of Bar | Load(Tons) | Elongation | Area of Bar | Stress = Load/Area | Strain= Elongation/Gauge Length |
01 | ¾ in | 3.68 | 0 in | 0. 441 in2 | 8.34 Psi | 0 |
02 | ¾in | 6.84 | 0 in | 0. 441 in2 | 15.51Psi | 0 |
03 | ¾ in | 10.28 | 0 in | 0. 441 in2 | 23.31 Psi | 0 |
04 | ¾ in | 10.72 | 1/8 in | 0. 441 in2 | 24.30 Psi | 0.0156 |
05 | ¾in | 11.82 | 3/16 in | 0. 441 in2 | 26.80 Psi | 0.0234 |
06 | ¾in | 12.04 | ¼ in | 0. 441 in2 | 27.30 Psi | 0.031 |
07 | ¾in | 13.04 | 5/16 in | 0. 441 in2 | 29.56 Psi | 0.039 |
08 | ¾in | 13.78 | 7/16 in | 0. 441 in2 | 31.24 Psi | 0.054 |
09 | ¾in | 14.34 | 9/16 in | 0. 441 in2 | 32.51 Psi | 0.070 |
10 | ¾in | 14.88 | 11/16 in | 0. 441 in2 | 33.74 Psi | 0.085 |
11 | ½ in | 12.6 (Rupture) | -------------- | 0. 196 in2 | 64.28 Psi | --------------------- |
12 | ½ in | 15.86 (Ultimate) | 2 ¼ in | 0. 196 in2 | 80.91 Psi | 0.218 |