Abstract:

Objective Fabric bending is an important attribute that affects the style and appearance of fabrics and directly reflects the magnitude of fabric draping ability, therefore fabric bending evaluation has attracted the attention of many researchers. The fabric is soft and prone to deformation that even test results in the same direction witness considerable variation. It has been necessary to conduct multiple tests to reduce experimental errors. The current bending test standard is to test the warp and weft directions of the fabric for 5 times each, the average of which is taken to characterize the overall bending performance of the fabric, which is cumbersome and time-consuming. Facing this situation, this paper proposes a fast and simple testing method capable of simultaneously obtaining multiple sets of results, which is referred as the sunflower method.

Method In this research, 14 types of woven fabrics were selected as the research objects, and 2 samples were cut from each fabric in two directions, 0° and 90°. Four characteristic indexes were extracted by the new method, which are unfolding area S, unfolding perimeter Z, unfolding length L and sagging height H. The relationship between the new method and the conventional testing methods was explored by analyzing the relationship between four new indicators and bending length C and bending stiffness B. Correlation analysis was adopted to explore the correlation between various indicators. Coefficient of variation was introduced to study the testing stability of the two methods through one-way analysis of variance, such as CV of different directions, fabrics, and textures.

Results Comparing the correlation coefficient values of S, Z, L and H with the bending length and bending stiffness in four directions, it was found that all Pearson coefficient values are above 0.78, except for H at 90°. The negative correlation with conventional indexes was H, and the positive correlation was S, Z and L. Pearson coefficient between Z and L in all four directions was greater than 0.85. All the four new indicators showed good correlation with the bending length and bending stiffness in convenitional methods, proving feasibility of the method proposed in this paper. The CVs of Z of the new method and the bending length of the inclined plane method were both less than 0.1. Single factor analysis of variance is adopted to compare the CVs of the four directions in the new method, and no obvious difference was found. Comparing the CV of the new method for testing the bending properties of cotton and chemical fiber fabrics through single factor analysis showed no significant difference, and there was no significant difference in the CVs of the bending test results of plain and twill fabrics. In other words, the stability of the new method for testing the bending properties of fabrics in different directions was the same. The stability of the bending test results for cotton and chemical fiber fabrics, as well as the stability of the bending test results for plain or twill fabrics, are the same as well.

Conclusion The new method proposed in this paper, named as the sunflower method, showed satisfactory agreement with the conventional bending test method. It can test the bending stability of fabrics in two directions, which can simultaneously obtain 10 test values and 4 characteristic indicators, without the need for multiple cutting and repeated testing. Compared with conventional methods, it has higher efficiency and saved testing time. The data obtained from using the new method can also be adopted to visualize the stability of fabric bending, providing a clear understanding of the differences in fabric bending, which is conducive to material selection in fashion design.

Key words: fabric, bending property, bending length, bending stiffness, unfolding area, unfolding perimeter, unfolding length, sagging height