Experiment # 8

Title:
To investigate the relationship between stress and strain and determine the tensile strength & Modulus of Elasticity
of a given specimen.

Abstract:
___________________________________________________________________________________________
___________________________________________________________________________________________
___________________________________________________________________________________________
___________________________________________________________________________________________
___________________________________________________________________________________________

Objective:

To determine the Tensile strength, strain &Modulus of Elasticity of a plain Mild steel bar.

Equipment & Material:

Universal Testing Machine, Test Specimen in Mild Steel, Vernier caliper, Steel rule
 Universal Testing Machine

Procedure:
1) Measure the specimen and punch marks 50 mm up two end points in test specimen.
2) Measure the initial length between the punch marks on the test specimen and measure the
initial diameter of the test specimen and record.
3) Select the mode tensile test in machine software.
4) After break stop the machine from software.
5) After break stop the machine from software.
6) Find the Mid-Point specimen by measure its Length.
7) Mark two points on specimen by punch, such that one is 50 mm above the Mid-Points or other
 50 mm below Mid-Point. In this way, distance b/w these two points will be 100 mm, which is
the gauge length of specimen.
8) Turn on the computer & come into operation of software state.

9) Select tensile test mode in the software.

10) Find the related tensile test information from M/c Software.

11) Press “Power On” on the top of control console & press the button “Pump On” .at once.

12) Starting hydraulic oil pump power set.

13) In tensile test, the specimen should be clamped from both ends such that both punch marks are
free from jaws.

14) Adjust the test load zero & re-set peak value.

15) Start the test and note the load &elongation.

16) Keep on increase load or note the increasing elongation until the test specimen suddenly breaks.

17) At breaking stop the machine by software.

18) Now take out the two pieces of test specimen.

19) Measure the final diameter and the final length between the punch marks.

20) Draw the graphs between, Load-deformation, Load-time, Load-Displacement, Stress-Strain, Time-
Stress, Time-Strain, Deformation-Time, and Displacement-Time.

Observations and Calculations:

𝐿𝑖 = initial length of test specimen

𝐿𝑓 = final length of test specimen

𝑑𝑖 = initial diameter of the test specimen

𝑑𝑓 = final diameter of the test specimen

𝜋𝑑2
𝑓
cross section area at breaking place = 𝐴𝑓 =
4

𝐹 = applied force

𝐹
tensile stress = 𝜎 =
𝐴

𝐿𝑓 − 𝐿𝑖
Δ𝐿
tensile strain = 𝜖 = =
𝐿𝑖
𝐿𝑖
𝜎
modulus of elasticity = 𝐸 =
𝜖
 𝑳𝒊 𝒅𝒊 𝑨𝒊 𝑭 𝑳𝒇 𝒅𝒇 𝑨𝒇 𝝈 𝝐 𝑬
Obs.
(𝒎𝒎) (𝒎𝒎) (𝒎𝒎𝟐) (𝒌𝑵) (𝒎𝒎) (𝒎𝒎) (𝒎𝒎𝟐) (𝑵⁄𝒎𝒎𝟐) (𝑵⁄𝒎𝒎𝟐)
1
2
3
4
5
6
7
8
9
10

Conclusion:
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________

Question # 1
Enlist modifications or improvements in this experimental set up.
___________________________________________________________________________________________________
___________________________________________________________________________________________________
___________________________________________________________________________________________________
___________________________________________________________________________________________________
___________________________________________________________________________________________________
___________________________________________________________________________________________________
___________________________________________________________________________________________________
___________________________________________________________________________________________________
________________________________________________________________________________________________