Study on universal testing machine

Introduction:  A universal testing machine (UTM), also known as a universal tester, materials testing machine or materials test frame, is used to test the tensile strength and compressive strength of materials. An earlier name for a tensile testing machine is a tensometer. The "universal" part of the name reflects that it can perform many standard tensile and compression tests on materials, components, and structures.

Objectives: 

1. To test the mechanical properties.
2. To conduct axial load testing.
3. To know about the UTM
4. To determine strength of textile materials.

Description:  The main purpose of textile testing is to determine the strength of fiber/ fabrics. Before doing the tensile test by UTM some terms need to acquianted.

Load: The application of a load to a specimen in its axial direction causes a tension to be developed in the specimen. The loads are usually expressed in grams weight or pounds weight.

Breaking Load: This is the load at which the specimen breaks. Usually expressed in grams weight or pound weight.

Stress: This is the ratio between the force applied and the cross section of specimen.

                                    Stress =  Force applied / cross sectional area

Tenecity or specific strength: The tenecity of a specimen is mass the stress at break.

Breaking length: the maximum length of a fabric  (assuming a fixed cross-section) that could suspend its own weight when supported only at the top.

Breaking extension: The breaking extension is the extension of the specimen at the breaking point. 

Work of Rupture: This is the measure of the toughness of the material. It is the energy of work required to break the specimen.

UTM : A universal testing machine is used to test the tensile stress and compressive strength of materials. It is named after the fact that it can perform many standard tensile and compression tests on materials, components, and structures.

It consists of two main parts, called:

1. Loading Unit
2. Control Unit

Loading unit

In this unit actual loading of the specimen takes place - consists of three cross heads namely upper head, middle head and lower head. Using appropriate cross heads tensile, compressive, shear, bending load with the help of different attachment can be applied. Loading unit of a UTM consists of:

1. Upper cross head - To clamp testing specimen from top
2. Lower cross head - To clamp testing specimen from below
3. Table - to place the specimen, used for compression test.

Control Unit

The load is applied and recorded by this unit. The load is applied with control valve and released by release valve. The load is applied with the help of hydraulic pressure.

Fig: Universal Testing Machine

Working Procedure:

1. The specimen is placed in the machine between the two clamp jaws.
2. Then we started the machine for applying tension.
3. The fabric was in tension and at 841 N the specimen broke.
4. The graph from the machine provided us further results.

Results:

           

Test No	Force Peak (N)	Elong. Peak (mm)	Elong. Break (mm)	Strain Peak (%)	Strain Break (%)
1.	841.5	76.063	76.682	38.032	38.341

Conclusion:

           In this experiment, we learnt about the universal testing machine and the tensile properties of fabric. We can use this method in lab for testing the strength of  textile product. As we know for better quality of products we need to maintain strength in industrial production. That’s why we think this experiment will help us to achieve our goal in the long run.