ASTM D5034:2021

A 100 mm (4.0 in.) wide specimen is mounted in the center of the clamps of a tensile testing machine and a force is applied until the specimen breaks. Values ​​for the breaking force and elongation of the test specimen are obtained from machine scales, dials, autographic register charts, or a computer connected to the testing machine.

This test method describes the procedures for carrying out fabric grab tensile tests using two types of specimens and three alternative types of testing machines.

The grip test procedure in this test method for determination of breaking strength and elongation is considered satisfactory for commercial shipment acceptance testing of most woven or nonwoven textile fabrics.

This test method is not recommended for knitted fabrics due to their high elasticity.

Some modification of the technique may be necessary for any fabric that has a strength greater than 200 N/cm (1140 lb/in.) in width.

Comparison of results from tensile testing machines operating on different principles is not recommended.

The grab test procedure is applicable to the determination of the effective strength of the fabric, that is, the strength of the yarns in a specified width together with the help of the weaving of the adjacent yarns. The breaking force determined by the gripping procedure is not a reflection of the strength of the wires actually gripped between the clamps and cannot be used for direct comparison with wire force determinations.

• Tensile testing machine according to D76:
  • CRE: Constant rate of extension
  • CRL: constant upload rate
  • CRT: Constant travel speed
• Clamps
• Jaws

Batch Sample – Take a batch sample as indicated in the applicable material specification. In the absence of such a specification, take at random the rolls or pieces that constitute the sample lot.

Cut at least one lab swatch the full width of the fabric and 1 m (1 yd) along the selvage.

Test Specimens: From each laboratory sample, take five warp (machine) direction and eight weft (transverse) direction specimens (if tested) for each test condition.

Note: (It is recognized that in practice, materials are often not weighed to determine when moisture equilibrium has been reached. While conditioning for a fixed time cannot be accepted in disputed cases, it may suffice in testing. routinely expose material to the standard atmosphere for testing textiles for a reasonable period of time before testing samples.)

Cut each test piece 100 6 1 mm (4 6 0.05 in.) wide by at least 150 mm (6 in.) long (Note 7) with the long dimension parallel to the direction of testing and application of the force.

Draw a line on the test piece that is parallel to the long direction (and along a piece of woven cloth) and located 37 ± 1 mm (1.5 ± 0.02 in.) from the edge of one side of the test piece.

• Mount the specimen in the clamping jaws with the parallel line previously drawn adjacent to the side of the upper and lower front jaws, or top, that is closest to this edge, and with approximately the same length of fabric extending beyond clamp at each end. The parallel line serves as a guide to ensure that the same longitudinal yarns of woven fabrics are gripped in both clamps and that the application of force does not form an appreciable angle with respect to the testing direction of non-woven fabrics. The stress on the sample should be uniform across the entire width of the clamp.
• For stretch or high-strength fabrics where the sample cannot be satisfactorily clamped, place each sample around the pins and between the jaws, using jaw pads if necessary.
• The elongation depends on the initial length of the specimen which is affected by any prestress applied when mounting the specimen in the testing machine. If measurement of specimen elongation is required, mount the specimen in the upper clamp of the machine and apply a uniform pretension, not to exceed 0.5% of the full scale load, to the bottom end of the specimen before clamping. the sample in the lower clamp.
• Mark the specimen on the front inner edge of each jaw to check if the specimen slips. When slippage occurs, the mark will move away from the edge of the jaw.
• Read the breaking force, and elongation if required
• Record the warp and weft direction results separately.
• If a test tube slips in the jaws, or breaks at the edge or in the jaws, or if for any reason the result falls markedly below the average of the set of test tubes, discard the result and take another test tube.

Breaking Force: For each laboratory sample and test condition, calculate the average of the observed breaking force for all acceptable specimens, that is, the maximum force exerted on the specimen as read directly from the indicating mechanism of the testing machine. Test.

Measurement of apparent elongation. Unless some other force is specified, measure the apparent elongation of samples acceptable at the breaking force. Measure the increase in length from the start of the force-extension curve to a point corresponding to the breaking force or other specified force, as shown on the autographic record.

Calculate the apparent elongation as the percentage increase in length based on the gage length (initial nominal test length of the specimen).

• Indicate that the specimens were tested as directed in Test Method D5034.
• Describe the material or product sampled and the sampling method used.
• Report the following information for each laboratory sample:
• The average breaking force per specimen giving acceptable breaks, for each test condition,
• The average percent elongation at break apparent of the acceptable specimens for each test condition, if requested.
• of specimens
• Sample type and testing machine
• maximum obtainable force
• Pretension if used