bursting strength (sheet rupture)
Bursting strength is the capacity of a material or product to maintain in continuity when subjected to pressure. Typically, the object is subjected to internal pressure and must resist rupturing in order to contain its contents or remain intact under loads in service. Clothing textiles, paper and other film packaging (such as medical supplies), plastic covers and metal piping are some examples of applications where burst strength testing is required for measuring functional performance.
Standards
In burst strength testing, a force is applied to the test sample to measure the conditions that will cause the material to rupture. For thin material specimens, such as textiles, paper, films and foils several international test standards define methods which use fluid pressure (pnuematic or hydraulic) to inflate a diaphragm which exerts consistent tension loading to the sample. Many manufacturers of these types of products's own internal standards are based in this principle.
As a result of this controlled distending force, applied at right angles to the plane of the specimen, under specified conditions, the sample will rupture. The Bursting Strength is then calculated and reported as:
(Pressure to rupture sample) - (Pressure to inflate diaphragm)
in the units of pressure, kPa (psi).
Equipment
A Diaphragm Bursting Tester capable of performing these tests requires a secure clamping mechanism, a diaphragm of a precise specification in terms of size and material properties, and a system to create the pressure. Additionally, to ensure optimum accuracy of results, verification foils are required to calibrate the instrument to known burst strength attributes.
The James Heal TruBurst Pneumatic Bursting Strength Tester meets all of the prerequisites for these tests. It's TestWise software also enables the instrument to perform cyclic fatigue testing on fabrics, for a complete solution to measuring the performance of these materials. The instrument also features non-contact laser distension measurement for accuracy and repeatability of test results, as the 'diaphragm correction' is an integral part of the bursting strength calculation, and is used in cyclic testing.