Design and Automation of Miniature Tensile Testing Machine

A tensile test, also known as tension test, is probably the most fundamental type of mechanical test you can perform on material. By measuring the force required to elongate a specimen to breaking point, material properties can be determined that will allow designers and quality managers to predict

Project Title

Design and Automation of Miniature Tensile Testing Machine

Project Area of Specialization

Robotics

Project Summary

Project Summary

A tensile test, also known as tension test, is probably the most fundamental type of mechanical test you can perform on material. By measuring the force required to elongate a specimen to breaking point, material properties can be determined that will allow designers and quality managers to predict how materials and products will behave in their intended applications. Many performance parameters can be measured by well executed tensile testing.  The resulting data - a curve of force vs extension - shows the tensile profile of the test up to the point where the specimen breaks. Along this tensile profile there are many points of interest, such as the ultimate tensile strength, yield strength, elongation and elastic modulus and these factors are very important for engineering designs.

 It had been observed that conducting tensile tests of small specimens on manual ultimate tensile testing machines have many uncertainties in results and properties cannot be directly predicted due to usage of manual setups (hydraulic pneumatic) and low control on loading and unloading processes. Also these manual setups are not user friendly and have costs usually in millions. In our work, a small and handy low cost automatic tensile testing machine was designed that will help the designers and engineers to conduct tensile tests of small specimens using this automated machine. The miniature automatic tensile testing machine consists of mechanical setup that contain jaws to hold the specimen, plates and rails as a guide for linear movement of specimen, mechanisms like chain and sprocket for transmitting force to extended distance and lead screw mechanisms for transforming the circular motion of motor to linear motion necessary for stretching of specimen. The electrical setup consists of single phase AC motor as an actuator, a load-cell, a load-cell amplifier for measuring force, a potentiometer for measuring linear displacement a control system consisting of Arduino and a displaying unit that uses LCD and excel interface for displaying and plotting the stress-strain graph. The detected load signal is amplified by the amplifier and is sent to the control system. The potentiometric knob of linear potentiometer sends the signals of voltage change to Arduino. Arduino UNO receives the signals from the load-cell and displacement gauge and sends these signals to LCD and excel. LCD displays the real time data and excel records that data. At the end when specimen will break a graph of stress-strain is displayed showing the response of material under intended conditions. Using this testing machine, it is possible to conduct tensile tests of small specimens of varying cross sectional area provided that the force required to break the specimen shall not exceed than 200N.

Project Objectives

Project Objectives

• Design an automatic miniature tensile testing machine for testing mechanical properties of small specimens.

• Design an automatic tensile testing machine that uses electrical systems to have a control over loading and unloading processes and to reduce mechanical error chances.
• Design a low cost miniature automatic tensile testing machine that is purchasable for small industrial unit.
• Design an apparatus that will be an ease for the designers to study real time stress strain diagram of concerned material.
• Design an automatic tensile testing apparatus that is user friendly and easy to operate able by normal person.
• Design an automatic machine that reduces man effort in tensile testing.

Project Implementation Method

Project Implementation Method

The project implementation method consists of the following steps

• Literature review and Survey.
• Selection of material for project fabrication.
• Selection of specimen for testing.
• Finite Element Analysis of specimen.
• Mathematical Modeling of the project.
• Selection of limits (mechanical and electrical parts)
• Designing of mechanical parts on solid works.

• Mechanical parts include base, plates, rails, mechanisms, jaws.

• Fabrication of mechanical parts
• Assembly of mechanical parts
• Electrical Components Purchasing

• Electrical Components include purchasing of motor.

• Transducer Purchasing

• Transducers include load cell, load cell amplifier, potentiometer, Arduino, LCD.

• Testing of electrical and electronic components.
• Simulation of electronic components on Proteus
• Installation of electronic components on hardware.
• Testing and troubleshooting of whole setup.
• Experiment Conduction (of different specimens), graph plotting and results verification.
• Comparing results with manual setup.

Benefits of the Project

Benefits of the Project

• Miniature automatic tensile testing machine give the correct estimation of mechanical properties of materials.
• It is very accurate and error chances in results are very low due to use of electrical components.
• It is economically beneficial for small industrial unit.

• It has low cost as compared to conventional UTS that have costs in millions.
• An ease for designers and quality managers to predict mechanical properties of materials.
• It is a user friendly apparatus and ease to operate able by students
• It requires no initial training to operate
• It can be installed in a small area i.e. in a small lab.
• It is a gift from engineers to society.
• No man force is required to perform the testing operations.
• This machine has a control on loading and unloading processes.

Technical Details of Final Deliverable

Technical Details of Final Deliverable 

In engineering design and analysis, tensile stress-strain relationships are frequently needed. From this relationships various mechanical properties, such as the ultimate tensile and yield strengths, Young’s modulus, Poisson’s ratio, the elongation, and reductions in area can be obtained. Also, the true stress-strain properties, strain hardening and tensile toughness can be calculated by means of conversion using special equations from the stress-strain curve. 

Modules Used:

HX-717

Mechanical Parts:

 Base of Mild steel, Plates and rods of steel, Chain and sprocket mechanism, lead screw mechanism,nuts and bolts, bearings,spring.

Processes Performed while fabricating hardware

knurling on jaws,drilling,boring,molding,streching. 

Electrical Parts

Single phase AC Motor, load cell, variable potentiometer, HX-717 amplifier, LCD (16x2), Arduino UNO.

 Overview of the tensile testing process performed on our automatic tensile testing machine is shown below:

To accomplish the process following steps should be taken.

 After the selection of specimen, we perform mathematical modeling and Simulation. We perform Finite element Analysis on the specimen and conclude the results.From these results we select the limits of mechanical and electrical parts and then we fabricate/purchase them. We install integrate and assemble them.

The following methodology is adopted.

Force Detection Unit

In this unit we use the load cell which detects the tension force acting on the specimen. Load cell converts this force into electrical signals. These signals are in millivolts which are being amplified by amplifier and then sent to controller.

We use Load Cell (20kg) with HX-717 amplifier.

Deformation Detecting Unit

Variable Potentiometer is used as a deformation detecting unit as it is used to detect the deformation in the specimen and to measure the change in length of the specimen during its deformation

Max Displacement (1.6 inch)

Deformation Producing Unit

A single phase AC motor with gear box will be used as a deformation producing unit along with the chain and sprocket and lead screw mechanisms to increase the force on the specimen, and to measure that stress on the load cell.

Motor torque should be 80Nm. (from calculations)

Controlling Unit

The microcontroller takes the signals from force detection unit and deformation detecting units as analog inputs and sends these signals to LCD (16x2) and excel.

In plotting unit, the recorded values of stress vs strain in excel are plotted in the form of curve that are taken continuously and are solved using equations as shown given below.:

                                                 ? =F/A                            

                                                ?=?L/L 

Hardware Limitations:

This machine has the following limitaion.

The specimens for which the force required to break them are greater than 200N cannot be tested on this machine.

Final Deliverable of the Project

HW/SW integrated system

Type of Industry

Manufacturing

Technologies

Robotics, Others

Sustainable Development Goals

Decent Work and Economic Growth, Industry, Innovation and Infrastructure

Required Resources

If you need this project, please contact me on contact@adikhanofficial.com