ASTM D6775 Test Standard for Breaking Strength and Elongation of Textile Webbing

Introduction to ASTM D6775 Test Standard

ASTM International, headquartered in the United States, is renowned for establishing global standards for materials, products, systems, and services. One of the most widely adopted standards is ASTM D6775, specifically designed to measure the breaking strength and elongation of textile webbing and braided materials. This standard plays a critical role in evaluating materials used in high-stakes applications like seatbelts, tie-downs, and other essential transportation equipment.

What is ASTM D6775?

ASTM D6775 is a test method for determining the breaking force and elongation of textile webbing and similar braided materials. It is extensively used across industries such as textiles and automotive manufacturing, where both strength and elasticity are paramount for safety and reliability. It is particularly valuable for testing materials found in seatbelts, cargo tie-downs, and restraint systems.

This method is limited to materials with a maximum width of 90 mm (3.5 inches) and a breaking strength of no more than 89,000 N (20,000 lb). ASTM D6775 is similar to Federal Test Method 191A, Section 4108, with specific grip requirements, such as the webbing capstan grip.

Properties Measured by ASTM D6775

The test evaluates key properties, including:

• Breaking Force
• Elongation

These properties are crucial in assessing the strength and elasticity of materials used in safety-critical applications like seatbelts and cargo straps.

Specimens for ASTM D6775 Testing

This standard applies to webbing and braided textiles, which are commonly used in the production of seatbelts and tie-downs. The test is suitable for materials with:

• A maximum width of 90 mm (3.5 in.)
• A maximum breaking strength of 89,000 N (20,000 lb)

Grips for ASTM D6775 Testing

The webbing capstan grip is recommended for testing webbing and textile materials. It ensures secure holding during testing, minimizing damage and slippage.

Recommended Universal Testing Machines (UTM)

For ASTM D6775 testing, Universal Testing Machines (UTM) with load capacities ranging from 50 kN to 100 kN are ideal, depending on the material’s strength. Dual-column floor-type machines are preferred for their stability and precision.

Recommended UTM Model:

• VEW 2302 – A computer servo-type UTM offering high accuracy and sensitivity in load and displacement measurements. It is suitable for testing both metallic and non-metallic materials, including plastics, rubber, and composite materials.

ASTM D6775 Test Procedure

To perform the ASTM D6775 test, follow these steps:

1. Prepare the Specimens
   Ensure the sample is prepared using the full width of the webbing to be tested.
2. Clamp the Specimen
   Load the specimen into the webbing capstan grips, securing it in both the top and bottom grips. Ensure proper alignment to avoid skewed results.
3. Zero the Testing Machine
   Zero the testing machine before beginning the test to ensure accurate measurements.
4. Preload (Optional)
   Apply a slight preload to remove slack and ensure proper alignment.
5. Measure Elongation (Optional)
   If required, apply provisions for measuring elongation as described in the standard.
6. Start the Test
   Perform the test with a constant rate of extension until the specimen breaks.
7. Record the Results
   Document the breaking force and elongation at failure.

Conclusion

The ASTM D6775 test standard is vital for determining the breaking strength and elongation of textile webbing and braided materials. Widely used in automotive and transportation industries, this test ensures that safety-critical materials like seatbelts and tie-downs meet stringent strength and durability requirements. By adopting ASTM D6775, manufacturers can guarantee the safety and reliability of their products.