# Determine the tensile properties of yarn by single thread strength tester

Introduction: The tensile properties of yarn are important parameters in the textile industry as they directly affect the quality and performance of finished textile products. The single thread strength tester is a common instrument used to determine the tensile properties of yarn. In this lab experiment, we will use a single thread strength tester to determine the tensile properties of various yarn samples.

Objective: The objective of this lab experiment is to determine the tensile properties of various yarn samples using a single thread strength tester.

Materials:

• Various yarn samples
• Weights
• Scissors
• Ruler
• Graph paper

Procedure:

1. Obtain a set of yarn samples to be tested.
2. Cut a length of yarn from each sample, approximately 30 cm long.
3. Determine the linear density (count) of each yarn sample using a balance and ruler.
4. Record the linear density (count) of each yarn sample.
5. Attach one end of the yarn to the single thread strength tester.
6. Adjust the tension of the tester to the standard value for the yarn being tested.
7. Place a weight on the other end of the yarn to apply a constant load.
9. Record the maximum load (breaking strength) applied to the yarn in grams.
10. Record the elongation (stretch) of the yarn at the point of maximum load in millimeters.
11. Repeat steps 5-10 for each yarn sample.
12. Calculate the tensile strength (TS) of each yarn sample using the formula:

TS = maximum load (g) / linear density (g/m)

1. Record the tensile strength (TS) of each yarn sample in units of g/denier or g/tex.
2. Calculate the elongation at break (EAB) of each yarn sample using the formula:

EAB = elongation at maximum load (mm) / original gauge length (mm) x 100

1. Record the elongation at break (EAB) of each yarn sample as a percentage.
2. Plot a stress-strain curve for each yarn sample using the recorded data.
3. Compare the tensile strength and elongation at break of each yarn sample and note any differences or deviations.

Results: Record the linear density, maximum load, elongation at maximum load, tensile strength, and elongation at break for each yarn sample tested. Plot a stress-strain curve for each yarn sample. Compare the tensile strength and elongation at break of each yarn sample and note any differences or deviations.

Discussion: Discuss the importance of tensile properties in the textile industry and how they affect the quality and performance of finished textile products. Analyze the results obtained from the experiment and discuss any trends observed in the tensile strength and elongation at break values. Compare the tensile properties of the various yarn samples tested and evaluate their quality. Discuss the strengths and limitations of the single thread strength tester as a tool for measuring tensile properties and suggest alternative methods for measuring tensile properties. Suggest further experiments that could be conducted to investigate the strength and quality properties of yarns in more detail.