ASTM D3787:2020

A specimen is securely clamped without tension between the circular slotted plates of the ball break fixture secured to the (movable) traction jaw for the constant velocity travel testing (CRT) machine. A force is exerted against the specimen by a hardened and polished steel ball that is attached to the pendulum (fixed) jaw of the machine, until rupture occurs.

• Constant Velocity Travel (CRT) Tensile Testing Machine (CRT) with a ball burst fixture that replaces the clamp assembly.
• Ball Drill Attachment.
• The polished steel ball shall have a diameter of 25.400 ± 0.005 mm (1.0000 ± 0.0002 in.) and shall be spherical. The ring clamp shall have a diameter of 44.450 ± 0.025 mm (1.750 ± 0.001 in.).

1. Take a sample from the lot as indicated in the applicable material specification.
2. Cut at least one lab sample the full width of the fabric and at least 1m (1yd) along the selvage.
3. take five test tubes
4. Each specimen shall be at least a 125 mm (5 in.) square or a 125 mm (5 in.) diameter circle.

• According to Standard D1776
• Place the sample without tension in the clamping ring and clamp securely by means of the screw or lever device. Start the CRT tensile testing machine, using a tensile clamp speed of 305 ± 13 mm/min (12 ± 0.5 in/min), and continue at that speed until the specimen bursts.
• Record to the nearest 0.5 N (0.1 lb) the resistance to bursting of the sample ball.

Calculate the average burst force to the nearest 0.5 N (0.1 lb) for each laboratory sample and for the lot.

List specimens tested as outlined in ASTM D3787 test method.

Describe the material or product.

Report the burst strength of each specimen and the average burst strength to the nearest 0.5 N (0.1 lbf).