Bursting strength test

Bursting Strength Test

1. Bursting Strength Analysis Dr.R.Sunitha Assistant Professor Department of Textiles and Clothing

2. Introduction Tensile strength tests are generally used for woven fabrics where there are definite warp and weft directions in which the strength can be measured Bursting strength analysis is unidirectional It is done for the fabrics such as knitted materials, lace or non- wovens do not have definite alignment of yarns/ fibres and multidirectional froce is required In the Bursting strength test the material is stressed in all directions at the same time and is therefore more suitable for such materials. There are fabrics which are simultaneously stressed in all directions during service, such as parachute fabrics, filters, sacks and nets, where it may be important to stress them in a realistic manner. A fabric is more likely to fail by bursting in service than it is to break by a straight tensile fracture as this is the type of stress that is present at the elbows and knees of clothing

3. Introduction Cont… In the Bursting strength test the material is stressed in all directions at the same time and is therefore more suitable for such materials. There are fabrics which are simultaneously stressed in all directions during service, such as parachute fabrics, filters, sacks and nets, where it may be important to stress them in a realistic manner A fabric is more likely to fail by bursting in service than it is to break by a straight tensile fracture as this is the type of stress that is present at the elbows and knees of clothing, parachute, sacks and nets

4. What happens when fabric breaks in bursting strength analysis? When a fabric fails during a bursting strength test it means that it has the lowest breaking extension This is because when the fabric is stressed in all the directions it undergoes the same extension so that the fabric direction with the lowest extension breaks first

5. Principle The pressure in a liquid is exerted in all directions and this phenomenon of a liquid is used for testing bursting strength in hydraulic bursting strength tester

6. Hydraulic Bursting Tester

7. Sample Size The specimen for this test should be cut so that the sample is ½ inch greater in diameter of the clamp ring Ten specimens are chosen The instrument used for testing bursting strength should have a constant rate of speed and must be capable of giving a uniform displacement of 6 ± 0.25 cubic inches per minute The clamp ring should have an internal diameter of 1.20 inches For proper operation, the machine must be stopped at the instant of rupture in order to avoid additional application of pressure and load on the specimen

8. Working Procedure The specimen – circular shape is clamped by a ring over a thin flexible rubber diaphragm which itself is clamped over a circular hole in the upper face of a reservoir The liquid used may be water or glycerine The pressure in the liquid is increased, by values or screw-driven position Due to increase in the pressure, the diaphragm bulges, taking with it the specimen At some point the fabric bursts within 20-23 seconds, the pressure at that point is indicated by the pressure gauge which is recorded

9. Working Procedure Cont… Since the rubber diaphragm requires a certain pressure to stretch it, corrections are made by doing a blank test In the test specimen, if cuts by chisel for ½ inch are made if a ¼ inch hole is punched and then the same test is carried out, then it is called as wounded bursting strength test  

10. Types of Burst Test ASTM D 3786 ASTM D 6797 It is Mullen Burst Test, Fabric is clamped across a 1.22 inch ring and rubber diaphragm underneath is inflated to push against the fabric until it bursts It is Ball Burst Test, Fabric is probed with a1-inch ball-shaped end id pushed through the fabric until it bursts

11. Steps of Fabric Bursting

12. Reference https://textileapex.blogspot.com/2014/08/hydraulic-bursting-tester.html http://acadiantextiles.com/news/burst-strength / Apurba Das, Evaluation of Textile Materials Department of Textile Technology, Indian Institute of Technology-Delhi.

13. Thank You