In the textile industry, tensile testing cannot be implemented everywhere. You can test woven fabric as their directions of warp and weft are known. This is more important to know the strength of the fabric. But what about non-woven fabrics? You cannot test them, as the tension applied to them will not be concentrated on a certain point. In this scenario, bursting strength tester is used to determine the strength of the fabric. Certain fabrics like sacks, nets, parachute fabrics experience consistent stress from all directions. These types of fabrics cannot be successfully tested on a tensile tester.
During the test, we cannot assume that the direction of the breaking extension has the weakest strength. When a pressure is applied uniformly in all directions the fabric will undergo same pressure in all directions. When fabric fails due to continuous bursting strength, the material gets burst from the place where there are lowest breaking extensions. This happens when the stress is applied to the fabrics in all the directions, the material with low strength get burst first.
According to the British standards, the pressure cannot be directly applied to the specimen cloth. As this will not apply uniform pressure on the fabric. Therefore, the fabric is clamped over rubber diaphragm using annular clamping. Usually, glycerine is used as a medium to apply the pneumatic pressure. The sample is clamped over diaphragm and pressure is exerted on it until it bursts.
The specimen that is to be tested is of two sizes, either 30mm or 113 mm in diameter. While both the samples will behave differently but are observed that sample with bigger diameter burst at lower pressure. According to the testing standard, 10 specimens are to be tested to get the accurate test results. To begin the test, the sample is clamped on the rubber diaphragm. The hydraulic pressure is applied to the sample until it ruptures. Or creep test can also be performed to estimate the capability of the fabric to hold the pressure for the certain time limit. The test will be carried for 20 to 23 seconds.
With this test, following observations are recorded:
- Bursting dilation in mm
- The medium is glycerine
- Mean bursting strength in kN/m2
Testing Procedure to Determine the Bursting Strength of Fabrics
Bursting test assessment is the perfect way to determine the quality of the fabric. Not only strength, an idea about the tear resistance can also be derived from this test. In real working conditions, you cannot guess from which direction the fabric will experience more pressure. So, a uniform omnidirectional pressure is applied on the specimen. The fabrics tested in this test are usually used for the high-performance application. So, no chance can be taken.
To perform the test, first of all, a sample is prepared first. The sample is usually circular in shape. The sachet is clamped through annular clamping. This can be done by either pneumatic mechanism or manually. It has to be made sure that sample is gripped appropriately. Neither too tight as this may lead to inaccurate reading, nor too loose as this may lead to slippage as pressure is applied. This test can be performed in two ways. Creep test or apply the pressure until sample ruptures. The pressure at which sample ruptures is considered as a standard for the sachet.
Presto offers 6 models to test the bursting strength of the fabric, viz;
- Analog model with manual clamping
- Digital model with manual clamping
- Digital model with pneumatic clamping
- Digital computerised model with manual clamping
- Digital computerised with pneumatic clamping
- Digital model of pneumatic clamping and printer
What is a computerised model?
Computerised model is a high-end model of bursting strength tester. It allows the operator to connect the machine to a computer for data logging. Using a software, the report can be generated on the computer. The report can be modified as per the requirements. This is one of the most effective methods of generating credible reports for auditing. For more information about the computerised model, you may contact our experts.
Formulae to derive other valuesBurst Index = Bursting Strength (KPa) x 0.10197 / Grammage (g/m2)
Bursting Factor = Bursting Strength (Kg/cm2) x 1000 / Grammage(g/m2)
Where, Grammage is the base weight.
1 KPa = 101.97162 Kgf/m2