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What is Tensile Test? How Tensile Strength Tester Works?

Tensile Test

This Tensile test done to measure the Tensile strength tester property of any  material. The equipment is called tensile strenght tester. Take a strip of 12” x 1” from testing material and aligned it properly between two iron rods. Before moving further, make sure that t.s. Tensile tester scale needle is on zero. Press the start button and both iron rods move into reverse direction. Where this strip breaks, take the reading of meter scale. This reading comes in k.g. So for lbs multiply it with 2.2. So derive figure will be Tensile strength tester for testing material. This strength requirement varies from buyer to buyer.

Purpose of Tensile Strength Tester:

This Tensile test covers the grab test procedures for determining the breaking strength and elongation of most textile fabrics. This test is not recommended for knitted fabrics or other textile fabric which have high stretch.  To determine the maximum force required to rupture (break) a woven fabric. This machine is also used for Bra hook and Bra Rings

Method we use:   for usa / canada: astmd 5034

Principle of Tensile Tester

The centre part of the test specimen is held by grips of a specific dimension and extended at a constant rate until it ruptures (breaks).  The force at which this occurs is then recorded. The correct number of test specimens are to be prepared and tested as specified within this test method in order to achieve a performance assessment of the product/fabric as described within the scope. Nb: a 2.5mm seam opening is used where the warp and weft threads are contrasting colours. A blank dyeing is prepared in the presence of uv-screening agents.  The improvement in extensibility and Tensile strength tester is determined  following exposure to light (fakra 3x)

Equipment

Cnstant rate of extension tensile testing instrument with the following:

Tensile Strength Tester
Tensile Strength Tester
  • Load cell with a maximum of 1,000n capacity
  • 50mm/minute constant rate of extension
  • Distance between upper and lower sets of grips is 100 mm
  • Pneumatic rubber faced grips  (rear 75 x 25mm and 25 x 25mm front)
  • For pc operated machines, appropriate software (to  bs en iso 13934 part 2;1999 )
  • Printer capability
  • Calibrated metal ruler
  • Template

Equipment 1:

  • Constant rate of extension tensile testing instrument with a minimum load capacity of 500n (50kg).
  • 50mm ruler
  • Lockstitch sewing machine
  • Ticket 75 or 80 100% polyester sewing thread
  • Size 90 metric needle.

Equipment 2:

  • Machine name: Lea strength tester.
  • Model number:
  • Machine origin: England
  • Brand name: GOODBRAND & CO. LTD
  • Function: To measure the lea strength and C.S.P of textiles.

Description: The special features include:

  • Double screw rod mechanism to ensure uniform and parallel movement of lower jaw to test lea strength accurately
  • Instrument is floor mounted with rugged steel body
  • Self aligned upper and lower jaws for precision measurement of breaking strength without any parallax errors. Auto return of lower jaw after completion of test
  • Testing range 0 to 500lbs (0 to250kgs), traverse speed 300mm/min
  • Provision to interface with Statex yarn count balance to get CSP value directly in display and printout

Equipment 3:

Machine name: Single yarn strength tester.

Brand name: BRANCA IAEALAIR

Function: To determine the tensile properties of single yarn.

Description: Tensile strength and elongation are the two prime characteristics of most of the raw materials, whether they are metals, or non metals such as foam, rubber, leather, textiles, plastic, paper or finished products such as rods, ropes, yarns, belts etc.  This  two  properties  often   play amajor role in determining the suitability of any raw materials for specified application. It is therefore, of utmost importance to determine these characteristics accuratel

Specimen preparation

  • Prepare specimens, randomly selected from the fabric so that they do not contain the same warp and weft threads.
  • Cut 3 rectangular specimens parallel to the warp direction and 3 rectangular specimens parallel to the weft direction.
  • Each specimen should measure 150mm in length and 100mm in width
  • Place a direction line parallel to the warp on each specimen prior to removing from the fabric

Note: the un seamed sample from Tensile test method 4.13 can be used for this test (this sample measures 100mm x 180).on each specimen, carefully draw a guide line at a distance of 38mm from one of the long edges running the full length of the specimen.

Conditioning: condition the specimens for a minimum of 4 hours in a conditioned atmosphere of 20 ± 2°c and 65 ± 2% rh before testing. Carry out the test in this atmosphere. The test specimens are to be conditioned in the standard atmosphere of 65% relative humidity (rh) +/- 2% and 20°c +/- 2°c for a minimum of 4 hours. All tests should also be carried out in this atmosphere.

Tensile Test procedure

Using an automatic constant rate of extension tensile tester

  • The programme is automatic. The test speed is 50mm per minute.
  • Use the 75mm x 25mm rubber faced grip on the rear and 25mm x 25mmm grip on the front.
  • With the correct grips in place set  the distance between upper and lower sets of  grips  to 100mm, this should be checked using a calibrated metal ruler
  • Select the correct programme and input the appropriate machine settings and fabric details etc.
  • Fix the Tensile test specimen centrally in the upper grips, so that the 38mm line drawn on the specimen coincides with one edge of the grips.
  • Close the upper grips.
  • Avoiding any pretension, adjust the specimen along the guide line into the lower grips.
  • Close the lower grips
  • Set the cross head in motion.
  • The maximum force at which the fabric ruptures (breaks) will be recorded
  • Repeat the above procedure for the remaining specimens.

Note: any break which occurs within 5mm of the clamping line of the grips should be reported as a grip break . If the grip break falls below the lowest normal break results then it should be disregarded and further samples tested. If it falls above the lowest normal break result, then it can be included

Tensile Test Procedure 1     

Substrate Pa 66 yarn (the yarn should not be too fine and may therefore have to be plied).

 

Uv-screening agent

 

Additives

0,  0.5,  1,  2  %

 

2% ammonium sulphate

1 % albegal sw

 

Dyeing apparatus Labomat, ahiba, zeltex vistacolor or callebaut

 

Liquor ratio 20 : 1,  de-ionized water

 

Method Batchwise exhaustion for 60 min at 98°c
 

 

 

Assessment    

 

Light fastness Tensile test

 

 

 

Fakra 3x          in compliance with din 75202

Determination of extensibility and tensile strength These determinations are  performed in the textile testing physics laboratory.

Test report: using the adidas group standard report format:report the average of the 3 results for each direction tested.

Test standards: minimum requirements

Warp ≥ 250n

Weft ≥ 250n

In-house test: tensile strength, seam slippage & seam strength (5mm opening)

Scop:

This in house test method describes the method of test in order to determine the ability of a woven fabric to resist yarn slippage.

Preparation of test specimens/materials

  • Indicate the face of the fabric. Use an f.
  • Avoid fabric within 50mm of selvedge.
  • The finished specimen size is 100mm x 350mm. Prepare five specimens with the 100mm dimension parallel to the length (warp), this will produce a weft tensile and warp way seam and five specimens with the 100mm dimension parallel to the width (weft), this will produce a warp tensile and a weft way seam.
  • Prepare the specimens so that they do not contain the same set of warp and weft threads.
  • Fray down the 100mm edge on each specimen. Place a direction line parallel to the length on each specimen.
  • Draw a fold line on each specimen on the reverse, 100mm from the frayed side.

Stitching the specimen

  • Use a test piece in the same fabric which must be folded in the same direction as the specimen to check that the number of stitches are 10 per 20mm using a 90 metric needle and ticker 75/80 sewing thread.
  • Check that the stitch is balanced at this stage, this means that the appearance of the stitching is the same on both sides. If the stitch is not balanced re-adjust the tensions.
  • Stitch the specimens 20mm from the fold line.
  • Trim the seam to 12mm exactly, measure from the centre of the stitching line.
  • Cut each specimen in half parallel to the seam to give 2 specimens of equal length. One with and one without a seam.

Test procedure: using an automatic constant rate of extension tensile tester

  • Th programme is automatic. The Tensile test speed is 100mm per minute.
  • Use the 75mm x 25mm rubber faced clamps on the rear jaws and the 25mm x 25mm rubber faced clamps on the front jaws, to give an area of 25mm x 25mm when the jaws are closed.
  • The correct jaws must be in place before going into the programme.
  • Set the gauge length to 75mm using a calibrated ruler. Then go into the appropriate programme.
  • Slack mount the specimens in the jaws, ensuring that they are central and straight, so not apply any tension above 0.1 units. This is shown on the force zero display.
  • Place the un-seamed specimen in the jaws first and then set the cross head in motion. When this has returned to zero, remove the specimen and place the seam specimen in the jaws, the seam should be midway between the jaws.
  • The un-seamed specimen Tensile strength tester will be recorded up to 500n (50kg). This is a 1” grab method tensile strength.
  • The seam opening of 5mm will be recorded at a specific load or if it is stronger than 20kg then this will be recorded. It will also be necessary to report the type of seam failure.

Test procedure: using a constant rate of extension tensile strength tester and chart recorder

  • The test speed is 100mm per minute.
  • Use the 75mm x 25mm rubber faced clamps on the rear jaws and the 25mm x 25mm rubber faced clamps on the front jaws, to give an area of 25mm x 25mm when the jaws are closed.
  • Set the load range to 500n (50kg).
  • Set the gauge length to 75mm using a calibrated ruler.
  • Set the graph to give a chart to cross head ratio of 5:1.
  • Mount the specimens in the jaws, ensuring that they are central and straight, do not apply any tension above 0.1 units.
  • Place the un-seamed specimen in the jaws first and the set of the cross head in motion. When this has returned to zero, remove the specimen and place the seamed specimen in the jaws, the seam should be midway between the jaws.

Assessment/results of tested specimens

  • For each pair of curves, accurately measure the distance between the curves at a load of 50n (0.5kg). This is to compensate for the initial straightening of the seamed test piece.
  • Add this distance to 25mm, (equal to a seam opening of 5mm) or (12.5mm equal to an opening of 2.5mm). This gives the figure for seam opening plus compensation.
  • Moving up the pair of curves, find the point on the horizontal axis, where the separation between the curves is equivalent to this distance, read off the load.

Reporting of results

  • Report the test method number and title.
  • Report the average of the 5 tensile strength results for each direction. If the results exceed 500n (50kg) then state this.
  • Report the average of the 5 seam opening results, by quoting the seam opening, either 2.5mm or 5mm and the load at which this occurred.
  • Also report if this is any seam breakdown, sewing thread breakage, fabric tearing at the jaws or fabric tearing generally.
  • If the results exceed 200n (20kg) report the seam opening of either 2.5mm or 5mm, as exceeds 20kg.
  • If the seam opening results vary by more than 10n (1kg) report the results individually.
  • If seam breakdown occurs at a lower load than the 5mm opening, then this should also be reported.

Conclusion

With elastomeric blends, Tensile test is necessary to record the tensile strength, the seam slippage and seam strength results in both direction.determination of improvement in extensibility and Tensile strength tester obtained with  uv-screening agents

About Engr. Kh. Mashiur Rahman

He is Garment Automation Technologist and Editor in Chief of Autogarment. He is certified Echotech Garment CAD Professional-China, Aptech-India, NCC-UK and B.Sc. in CIS- London Metropolitan University, M.Sc. in ICT-UITS. He is working as a Successful Digital Marketer and Search Engine Specialist in RMG sector during 2005 to till now. Contact him- apparelsoftware@gmail.com

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2 comments

  1. “Single yarn strength tester”. This is very useful post.

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