In this project, a portable horizontal tensile testing system involving the use of a specially designed tensile specimen is proposed. The system developed was designed to convert the rotation motion of a ball screw into the linear motion of specimen grips that apply a tensile load to the specimen. The frame contains an aligned linear motion guide for the movement of the specimen grips, ensuring the co-linearity of the travel axes. One side of the specimen is connected to a ball-screw block and the other side is connected to a load-cell (which is static) to detect the load magnitude.

1. CPP301
Core Project-II
Design and development of horizontal tensile testing machine (5kN)
Under the supervision of:
Dr. Dhiraj Kumar Mahajan
A Presentation by
Sajeed Mahaboob (2011ME1111)
Krishanu Sarkar (2012MEB1102)
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2. MOTIVATION
• Tensile tests are performed to achieve material
parameters such as UTS, yield strength, % elongation, %
area reduction and young’s modulus.
• These important parameters obtained are useful for
selection of engineering materials for many applications.
• Need of horizontal tensile machine for testing in different
environment conditions.
• Miniaturized (Horizontal, Max 5kN)
2

3. TENSILE TESTING PRINCIPLE
3
Figure 1 : A typical Engineering Stress-
Strain Diagram for a Ductile Material
𝜎 (Engineering stress)=F/𝐴0
Necking starts (local deformation) : applied
engineering stress is equal to ultimate
tensile stress (i.e 𝜎 = 𝜎 𝑢𝑡𝑠)
Yielding (uniform deformation) : 𝜎 > 𝜎 𝑦𝑖𝑒𝑙𝑑
E: Young’s modulus
Only in elastic region, 𝜎 = 𝐸 ∗ ∈

4. COMPONENTS IN OUR PROJECT
• Lead screw (Trapezoidal)
• Load cell (S-Type)
• Stepper motor
• Strain gauge
• Gripping units
• Base and supporting plates
• Spur gears
• Ball Bearings
• Controllers 4

5. TRAPEZOIDAL LEAD SCREW: SELECTION
• Trapezoidal lead screw is selected over square thread, as it
has higher load carrying capacity.
• Better power transmission
• Parameter selected using criteria,
Tensile and compression D=
4.𝐿𝑜𝑎𝑑
𝜋.𝜎 𝑦𝑖𝑒𝑙𝑑
1
2
Buckling 𝑃𝑐𝑟 =
𝑓𝑠 . 𝜋2.𝐸.𝐼
𝐿2
D =
𝑓𝑠.𝑝 𝑐𝑟.𝐿2
𝜋3.𝐸
1
4
5

6. 6

7. LOAD CELL: SELECTION
• S-BEAM type LOAD CELL
• Less expensive than others
• 500kg capacity available
7
Figure 4: Assembled view of S type Load Cell
(http://www.ipaindia.com/products/double-s-
load-cell/)

8. SPECIFICATION OF LOAD CELL
8

9. TORQUE REQUIREMENT
9

10. 10

11. GEAR DESIGN
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12. • Constraints: Center to center distance is 50 mm
• Torque ratio: 1000/800 (calculated)
• Bore diameter: 19mm for driving and 15mm for driven gear.
• Results based on calculations
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13. STEPPER MOTOR SELECTION
• Lesser price than servo motor
of same size
• Positions are discrete steps in
its revolution cycle
• Degree of rotation need to be as
much as less for accurate results
• More current , the more torque is
generated by the motor
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Figure 5 : typical stepper
motor(https://simple.wikipedia.org/wik
i/Stepper_motor#/media/File:Nema_17
_Stepper_Motor.jpg)

14. STEPPER MOTOR DESCRIPTION
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15. GRIPPING DEVICE SELECTION
• Holds the specimen up to maximum load capacity
• Should minimize both slippage and uneven stress
distribution
• Self-aligning
• Slippage and necking of the specimen into the grip
should be avoided
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Figure 4: 5kN vice grip (http://www.elis.it/lloyd-
pdf/Lloyd_Grips-catalogo.pdf)

16. OLD DESIGN
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17. SCHEMATIC DESIGN
• Components are-
1. Lead screw with nut
2. Load cell
3. Frame
4. Gripping units
5. Spur gears
6. Stepper motor
7. Bearing
8. controllers
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18. 18

19. ASTM E-8M: “Standard Test Methods for
Tension Testing of Metallic Materials.”
19Rectangular tension test specimens (ASTM 370).

20. RESULTS
The functional requirements of the machine are as follows:
•Maximum stroke: 600 mm
• Maximum tensile force: 5kN
• Diameter of trapezoidal lead screw = 20 mm
• Pitch = 4 mm
• Sample size: 1 mm thick, gauge cross-section area of 10 𝑚𝑚2
, and gauge
length 100 mm (Sample: Aluminium alloy 6061-T6 (𝜎 𝑦𝑖𝑒𝑙𝑑 =
241 𝑀𝑃𝑎, 𝜎 𝑢𝑡𝑠 = 300𝑀𝑃𝑎, 𝐸 = 68.9 𝐺𝑃𝑎)
• 5kN vice grip is used
• S-type load cell is used
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21. REFERENCES…
[1] RUSSELL C.HIBBELER, Mechanics of materials, 9th edition.
[2] Woong Lim & Ho-Kyung Kim, Design and development of a miniaturised tensile testing machine, Global Journal of
Engineering Education, Volume 15, Number 1, 2013
[3] Shigley, Mechanical Engineering Design, Richard G. Budynas
[4] Machine Design by V L. Maleev and Hartman
[5] https://en.wikipedia.org/wiki/Tensile_testing
[6] https://en.wikipedia.org/wiki/Linear_encoder
[7] http://www.ipaindia.com/products/double-s-load-cell/
[8] http://www.elis.it/lloyd-pdf/Lloyd_Grips-catalogo.pdf
[9] http://www.motionusa.com.s3-website-us-east-1.amazonaws.com/nook/BallScrews/PowerTrac_Full_Catalog.pdf
[10] http://www.festo.com/net/SupportPortal/Files/10257/Festo_10_Tips_servos_steppers.pdf
[11] https://simple.wikipedia.org/wiki/File:Nema_17_Stepper_Motor.jpg
[12] ASTM E-8M: “Standard Test Methods for Tension Testing of Metallic Materials.”
http://compass.astm.org/EDIT/html_annot.cgi?E8+15a
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22. Thank you!
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