Laboratory Investigation of Hooke’s Law

By: Haseeb Jamal / On: May 08, 2017 / Lab-Notes, Experiments, Theories, Mechanics Lab

Apparatus:

UTM , test specimen, divider, vernier caliper, scale.

Prepare the test specimen that is steel bar and find its diameter at tree different places and find its man value.
Mark two points 8" a part of 2 ft long steel bar.
Insert the bar in jaws for gripping the steel bar and select suitable bar on UTM. Place the steel bar and fix it.
Start t machine and start applying load.
There will be gradual increase in length which will be directly proportional to applied load.
During this load application measure change in length at different load, till the steel bar breaks.
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