ASTM D3787

ASTM D3787 is a widely used test method that measures the bursting strength of textiles using a ball burst procedure. This test is especially useful for materials like woven fabrics, nonwovens, coated textiles, and geotextiles that are often subjected to multi-directional stress in real-world applications.

Unlike tensile tests that apply force in one direction, the ball burst test mimics real-life conditions more closely by applying pressure in all directions simultaneously. It helps manufacturers ensure materials can withstand puncture, pressure, and bulging forces.

1. Purpose and Scope

The main purpose of ASTM D3787 is to determine the force required to rupture a fabric by pushing a steel ball through it. The test is applicable to a wide range of textile products, including:

• Industrial fabrics

• Upholstery and home furnishings

• Protective clothing

• Coated fabrics

• Geotextiles and tarpaulins

It is particularly useful for fabrics that experience bulging, doming, or pressurized loads during use.

2. Test Specimen

Test specimens are typically cut into square or circular pieces large enough to be securely clamped in the test fixture.

Standard Specimen Dimensions:

• Recommended size: 100 mm x 100 mm (4 in x 4 in) minimum

• The specimen must be free of wrinkles, folds, or creases

Specimens should be conditioned in standard atmospheric conditions (usually 21°C and 65% RH) for at least 4 hours before testing. Multiple replicates (usually at least 5) are tested to ensure statistical reliability.

3. Test Equipment

• Universal Testing Machine (UTM) or similar testing frame

• Ball Burst Fixture: Includes a clamping ring with a circular opening and a steel ball (typically 1 inch in diameter)

• The test apparatus features a ball with a 1-inch diameter, and an inner circle with a diameter of 1.75 inches (approximately 44.45mm). Square samples measuring 2 inches on each side are affixed securely using screws on the fixture's ring. A standard size adapter of 5/8" is employed, and additional details can be found in the accompanying literature.

• Grips: Upper grip holds the steel ball, lower fixture clamps the fabric

• Test Speed: Standard crosshead speed is 305 mm/min (12 in/min)

Optional:

• Environmental chamber for testing at high or low temperatures

• Data acquisition software for force-displacement curves

4. Test Procedure

1. Condition the specimens as required by the standard.

2. Mount the specimen in the clamping ring so the fabric is taut and secure.

3. Align the steel ball above the center of the opening.

4. Begin the test: the steel ball is driven downward at a constant speed.

5. Record the maximum force required to rupture the fabric.

6. Optionally, measure the displacement at rupture for additional insights into fabric elasticity.

The test ends when the fabric bursts or when a significant drop in force indicates failure.

5. Calculations (Plain Text)

The bursting strength is calculated as:

Bursting Strength = Pmax

Where:
Pmax = Maximum load recorded during the test (in Newtons or pounds-force)

There are no complex equations in ASTM D3787 — the key result is simply the maximum force applied to burst the fabric with the steel ball.

Optionally, if displacement data is collected, it can be used to assess the fabric’s resistance to deformation before failure.

6. Reporting Requirements

A complete ASTM D3787 report should include:

• Fabric identification (type, weave, weight, coatings, etc.)

• Specimen dimensions and number of replicates

• Test speed and environmental conditions

• Type and size of ball used

• Maximum bursting force for each specimen

• Average bursting strength (mean of all replicates)

• Displacement at rupture (if recorded)

• Observations of failure mode (e.g., radial tear, puncture, delamination)

7. Applications

ASTM D3787 is particularly relevant in industries where fabrics must resist pressure, flexing, or multidirectional loads:

• Medical textiles: Hospital gowns, mattress covers, sterile wraps

• Upholstery and furniture: Seat and back coverings, cushion materials

• Automotive: Headliners, interior panel fabrics

• Industrial and protective gear: Coated tarps, flexible barriers, inflatable products

• Geotextiles: Used in soil stabilization, drainage, and erosion control

The ball burst method is a reliable way to evaluate performance in non-tensile loading conditions, which are common in real-world use.

8. Related Standards

Here are ASTM and ISO standards often used alongside ASTM D3787:

• ASTM D3786 – Hydraulic diaphragm bursting strength (similar purpose, different method)

• ASTM D5034 – Grab tensile strength of fabrics

• ASTM D6241 – CBR puncture resistance of geotextiles

• ASTM D6797 - Bursting Strength of Textile Fabrics

• ASTM D1683 – Failure in sewn seams of woven fabrics

• ISO 13938-2 – Ball burst test equivalent under ISO methods

9. Conclusion

ASTM D3787 is a valuable test for measuring the bursting strength of textiles using a realistic, multi-directional force application. It is especially useful for coated fabrics, nonwovens, and technical textiles that are subject to puncture, pressure, or stretching during use.

By evaluating the fabric’s resistance to rupture under stress, ASTM D3787 helps manufacturers ensure quality, performance, and durability for products used in demanding environments.