ASTM D6797

Theory:

ASTM D6797 describes a procedure for testing the bursting strength of fabrics. The test is similar to a puncture test, except a steel ball is used instead of a sharp puncture plunger. The ASTM D6797 puncture fixture is attached to the end of a Constant-Rate-of-Extension (CRE) machine. Virtually any modern universal testing machine can be used to perform this test. 

Geometry:

The fabric samples should be cut from a bolt or roll. Samples from the middle of the bolt of fabric should be used. Each square sample measures 5x5 inches. 

The ball on the fixture has a diameter of 1 inch and is spherical. The internal diameter of the bottom fixture hole should measure 1.75 inches in diameter. There are special grooves in the fixture plates which help to restrain the sample.

Solution:

This test can be performed with a Galdabini tensile tester at a speed of 12 inches per minute. Most fabrics will burst at forces under 500 lbs. so a single column testing is usually strong enough to handle the task. 

The ball burst fixture is part of Universal Grip's line of premium puncture testing fixtures. The fixtures attach to the testing machine by use of a clevis style adapter. The standard adapter size for this fixture is 15.9mm or 5/8". 

Analysis:

The bursting strength is given by the maximum peak load seen during the test. The specimen must rupture for a positive test result. Many quality control departments will take a sample lot of 5 and average the results. 

This test can be performed automatically on the Galdabini Graphworks 6 software program and is included in the standard test library.