FZ/T 01034-2008Textiles - Test methods of the tensile elasticity for woven fabrics (English PDF)

8.1 Instrument settings

8.1.1 The zero position and full force of the instrument and recording device shall be calibrated before the test.

8.1.2 Correct the gap length to 200mm, and make the clamps aligned and parallel to each other.

8.1.3 Setting the stretching speed

--- Constant elongation: When the elongation is <=8%, the stretching speed is 20mm/min;

when the elongation is >8%, the stretching speed is 100mm/min.

--- Constant force: According to the pre-test, when the elongation reaching the specified

L1 – length of specimen when it is stretched to constant force, in mm;

deltaL - elongation at pretension when specimen is clamped loosely, in mm. deltaL is 0 when performing pretension clamping.

8.3.2 Determination of constant elongation force

8.3.2.1 The constant elongation shall be determined according to product requirements or mutual agreement. If there is no agreement, it is recommended to use 3%, 5% or 10%.

8.3.2.2 Start the instrument (when the sample is loosely clamped, the elongation shall be measured from the time when the pretension is reached), stretch the specimen to a constant elongation value; and read the corresponding stress, in Newton (N).

8.3.2.3 The measurement results are expressed by the average of three specimens, rounded off to 0.1N.

8.3.3 Determination of elastic recovery rate and plastic deformation rate at constant force

8.3.3.1 Select the constant force value according to product requirements or mutual agreement.

If there is no agreement, it is recommended to use 20N, 25N or 30N.

8.3.3.2 The stretching holding time and recovery time shall be determined according to the agreement between the two parties. If there is no agreement, it is recommended to use a stretching holding time of 1 min and a recovery time of 3 min.

8.3.3.3 Start the instrument, stretch the specimen to a constant force; and read the specimen length L1 after maintaining the constant force for 1 min. Then return the clamp to the zero position at the same speed and stop for 3 min.

8.3.3.4 Then stretch the specimen at the same speed to the pretension specified in 8.2.1; and read the specimen length L2.

8.3.3.5 Calculate the elastic recovery rate and plastic deformation rate (%) of each specimen according to formulas (2) and (3). The measurement results are expressed by the average of the three specimens, rounded off to 0.1%.

Where:

L0 – gauge length, in mm.

L1 - the length of the specimen after being stretched to a constant force for 1 min; in mm;

Recovery rate of elasticity at constant force

Deformation rate of plastics at constant force

L2 - the length of the specimen when it returns to the zero position and rests for 3 min before applying pretension, in mm;

deltaL - Elongation at pretension when specimen is clamped loosely, in mm. deltaL is 0 when clamping at pretension.

8.3.4 Determination of elastic recovery rate and plastic deformation rate under repeated

stretching at constant force

8.3.4.1 Select the number of cycles based on product requirements or mutual agreement. If there is no agreement, it is recommended to use 3 times, 5 times or 10 times.

8.3.4.2 Stretch repeatedly according to 8.3.3.1~8.3.3.3. After reaching the predetermined

number of cycles, measure the length L1.

8.3.4.3 Then measure the length L2 according to the method in 8.3.3.4.

8.3.4.4 Calculate the elastic recovery rate and plastic deformation rate of each specimen under repeated stretching at constant force according to Formulas (2) and (3). The measurement results are expressed by the average of the three specimens, rounded off to 0.1%.

8.3.5 Determination of elastic recovery rate and plastic deformation rate at constant

elongation

8.3.5.1 Select a constant elongation according to product requirements or mutual agreement. If

there is no agreement, it is recommended to use 3%, 5% or 10%.

8.3.5.2 The stretching dwell time and recovery time are determined according to product requirements or mutual agreement. If there is no agreement, it is recommended to use a stretching dwell time of 1 min and a recovery time of 3 min.

8.3.5.3 Start the instrument (when the specimen is loosely clamped, the elongation shall be measured from the time when the pretension is reached), stretch the specimen to a certain elongation L3, and stop for 1 min. Then return the clamp to the zero position at the same speed and stop for 3 min.

8.3.5.4 Then stretch the specimen at the same speed to the constant elongation L3.

8.3.5.5 Read the specimen length L2 corresponding to the pretension in 8.2.1.

8.3.5.6 Calculate the elastic recovery rate at constant elongation and plastic deformation rate

(%) of each specimen according to Formulas (4) and (5). The measurement results are expressed by the average of the three specimens, rounded off to 0.1%.

Recovery rate of elasticity at constant elongation

Deformation rate of plastics at constant elongation

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