gb/t 7689.2-2013 is the second part of the Chinese national standard on the test methods for reinforcing materials and woven fabrics, which mainly covers the determination of warp and weft density. This part of the standard is of great significance for understanding the structure, properties and application of woven fabrics in the preparation of fiber-reinforced composites. Warp and weft density are two key parameters in woven fabrics, which represent the number of yarns per unit length or unit width, respectively, and are critical for material properties, manufacturing processes, and quality control. The following is a response to GB T 76892-2013 detailed introduction of longitude and weft density detection.
1.Scope of application of the standard.
gb/t 7689.2-2013 is suitable for the warp and weft density determination of woven fabrics of carbon fiber, glass fiber, organic synthetic fiber and other reinforcing materials. These materials are often used in the preparation of fiber-reinforced composites and are therefore essential for understanding parameters such as fiber distribution, fabric structure, etc. This standard specifies the methods and requirements for determining the density of warp and weft to ensure the accuracy and repeatability of the test.
2.Methods for determining warp and weft density.
2.1 Density determination:
Warp density refers to the number of yarns per unit length. The specific measurement steps are as follows:
Prepare a sample of woven fabric of a certain length.
Use appropriate tools (e.g. microscopes, warp meters) to measure the number of yarns over a range of lengths.
The warp density is calculated based on the measured quantity and length.
2.2 Latitude density determination:
Weft density refers to the number of yarns per unit width. The steps of the assay include:
Similarly, prepare a sample of the woven fabric of a certain length.
Use the appropriate tool to measure the number of yarns within a certain width.
The weft density is calculated from the measured quantity and width.
When performing the measurement, it is necessary to select the appropriate tools and methods according to the actual situation and ensure the accuracy of the measurement.
3.Instruments and equipment.
In GB T 7689In the 2-2013 standard, it does not specify which specific instruments and equipment to use, but mentions the tools that may be used, such as microscopes, warp meters, weft meters, etc. In actual operation, according to the characteristics of the sample and the equipment of the laboratory, the appropriate instrument and equipment can be flexibly selected.
4.Precautions for measurements.
When determining the density of warp and weft, the following aspects need to be noted:
Sample selection: The selection of samples should be representative and reflect the structural characteristics of the entire woven fabric.
Measuring range: Select the appropriate measuring range according to the standard to ensure that the measurement results are reliable and practical.
Use of instruments: When using tools such as microscopes, warp meters, and weft meters, it is necessary to operate them correctly according to their instructions to ensure the accuracy of measurement.
Environmental conditions: Appropriate environmental conditions, including temperature, humidity, etc., need to be maintained during the measurement process to avoid the influence of external factors on the measurement results.
5.Data logging and reporting.
After the density determination is completed, the tools, methods, environmental conditions and other information used in the measurement should be recorded in detail, and the data should be processed and reported in accordance with the requirements of the standard. This facilitates subsequent data analysis, validation of results, and reproducibility of experiments.
By following GB T 7689The test methods and requirements specified in the 2-2013 standard can ensure the accurate and reliable determination of the warp and weft density of the reinforcing material woven fabric, and provide a scientific basis for product design, manufacturing and quality control.