ASTM D6797
Fabrics - Ball Burst Test Fixture
Standard Test Method for Bursting Strength of Fabrics Constant-Rate-of-Extension (CRE) Ball Burst Test
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Theory
ASTM D6797 describes a method for determining the bursting strength of textile fabrics using a spherical steel ball as the loading element. Unlike traditional puncture testing that relies on a sharp probe, this method distributes the load across a wider contact area, creating a multi-axial stress condition within the fabric. This more closely replicates real-world scenarios where materials experience localized deformation rather than cutting or piercing.
The test is performed on a Constant-Rate-of-Extension (CRE) universal testing machine, where the crosshead drives the ball into the specimen until rupture occurs. Because the load is applied centrally and expands radially, the test captures both tensile and shear interactions within the material structure, making it highly relevant for nonwovens, geotextiles, and industrial fabrics.
Virtually any modern universal testing machine can perform ASTM D6797 when equipped with the proper ball burst fixture.
Geometry
Proper specimen preparation is essential for repeatability. Fabric samples are typically taken from a production roll, with material selected from the center of the bolt to avoid inconsistencies found near edges or ends.
Each specimen is cut into a 5 × 5 inch square, providing sufficient area for secure clamping and uniform deformation during testing.
The fixture geometry is designed to standardize stress distribution:
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A 1-inch diameter hardened steel ball applies the load
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The lower fixture includes a 1.75-inch diameter opening, allowing the fabric to deform prior to rupture
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Precision-machined grooved clamping plates secure the specimen and prevent slippage
These dimensions ensure that failure occurs within the unsupported test region, not at the edges or clamping surfaces.
Solution
ASTM D6797 can be performed on most universal testing machines at a crosshead speed of 12 inches per minute (305 mm/min). Because most fabrics fail under 500 lbf (≈2.2 kN), a single-column load frame is typically sufficient for this application.
The key to consistent and repeatable results is the fixture itself.
Universal Grip Co. offers a precision-engineered ball burst fixture designed specifically for ASTM D6797 and similar standards. The fixture ensures:
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Accurate alignment of the spherical indenter
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Uniform clamping pressure across the specimen
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Minimal compliance during loading
The fixture mounts to the testing machine using a clevis-style adapter, with a standard connection size of 15.9 mm (5/8 inch), making it compatible with a wide range of load frames and load cells.
As with all Universal Grip solutions, the focus is on repeatability, durability, and ease of integration into existing test systems.
Analysis
The primary result from ASTM D6797 is the bursting strength, defined as the maximum force recorded at the point of rupture. A valid test requires complete specimen failure.
In most quality control environments, multiple specimens—commonly five samples per lot—are tested and averaged to provide a representative value of material performance.
In addition to peak load, many labs also evaluate:
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Displacement at rupture
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Energy absorption (area under the force-displacement curve)
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Failure characteristics (fiber breakage vs. pull-out or tearing)
These additional data points provide deeper insight into how the material behaves under multi-directional stress conditions.
Software & Automation
Modern universal testing systems allow ASTM D6797 to be performed with full automation. Software platforms such as Graphworks 6 enable:
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Pre-programmed test methods
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Automatic peak load detection
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Real-time data acquisition
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Standardized reporting
This reduces operator variability and ensures consistency across test runs.
Similar Specifications
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ASTM F1342 – Puncture Resistance (sharp probe comparison, A, B, & C)
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ISO 13938-2 – Pneumatic Bursting Strength of Textiles