Tensile Testing || Strip test || Grab Test || Tearing test of Fabric

Tensile Testing of Fabric 

Jay Trivedi

Department of Textile Manufactures

Government Polytechnic, Nagpur, India

What is tensile strength testing?

It is referred to as a strength test where the load is applied along the direction of the test sample.

What is tensile strength of Fabric?

The tensile strength of the fabric is defined as the maximum amount of tensile stress and 

tension that fabric can take before breaking.

Why we carried out Tensile Strength Test?

The test is generally carried out to determine breaking strength and elongation of most fabrics.

Methods use to measure tensile strength of Fabric:

Two types of test are done:- Strip Test

                                              Grab Test

Strip Test:

Fig- Strip Test

Method:

• Five fabric samples are taken in parallel to warp and five samples parallel to weft direction
• Then cut the specimen of 2.5 inch in width and removing the threads from both the edges until the width has been reduced to 2 inch.
• Test length should be 8 inch  clamped between the jaws, take enough test length so that the sample if properly gripped in the jaws.
• Then mount the specimen centrally and security gripped along the full width of he fabric which prevent slippage of sample.
• Then tensile force is applied uniformly till the specimen tear out.

Grab Test:

Fig-Grab Test

Method:

• Take a specimen size 4”x6”        
• Marked the specimen at 1.5” from the edge of the fabric to assist in clamping it so that the same set of threads are clamped in jaws.
• From 1” edge two jaws are fixed on both sides of the specimen so that 1” of fabric  are  stressed.
• Use gauge length of  3” and the speed is adjusted so then the sample is broken in 20 + - 3 second.                                                                                                           

The relation was approximately:-

Grab Strength= 1+ breaking extension %

                                                40

Tearing Strength of Fabric:-

Types of tear Test:

• Tongue Tear Test
• Trapezoid Tear Test
• Elmendorf  Tear Tester

Elmendorf  Tear Tester :

Fig-Elmendrof Tearing Tester

• Sample size: (100x75) mm sq.
• Atmospheric Condition: Temperature 21-30° C RH% 65
• Apparatus used: Scissor, mm scale, Elmendorf Tearing Strength Tester

Procedure:

• The apparatus consist of moving clamp and fixed clamp.
• Prepare the sample with the help of template warp and weft.
• The specimen is transferred between the two clamps, it is well centered with the bottom edge set tightened the clamp.
• Give a slit cut to the specimen by knife fixed near the sample holder, the tear is started between the clamps.
• Release the pendulum by pressing the latch and let the specimen to be torn.
• After the tear is completed hold the pendulum on its return swing by hand without disturbing the position of pointer.
• Pointer read the tearing force directly.
• Read the scale to the nearest whole scale division.

References:

Principles of Textile Testing by J.E. Booth