Abstract: The bending property of the fabric is one of the mechanical properties of the fabric to be evaluated. It affects the formability, drapability, and crease recovery of the fabric to some extent. It also plays a key role in determining the stiffness and softness of the fabric, as well as in the performance of the garment shaping. If the fabric bending stiffness is low, clothing will appear easy to arch, easy to wrinkle, and not easy to recover. On the contrary, if bending stiffness is high, the body fit will be poor. So far, traditional fabric bending performance testing mostly relies on repeated labor. In addition, the existing fabric bending test methods can only test the bending properties of a single direction each time, and it is difficult to directly observe the differences in the bending properties of fabrics in each direction.
In view of the above situation, a multi-direction visual bending test method of fabric based on 3D scanning was proposed, and three characteristic indexes representing fabric bending were extracted, namely, the projection perimeter of fabric splines in different directions, the projection area and the overall cross-sectional area of fabric. The projected perimeter and area are measured by the projection formed by the bending shape of the fabric specimen in each direction under gravity conditions. The section area is the area formed by the fitting curve of the point cloud section at 1/4, 1/2, 3/4, and the bottom of the three-dimensional point cloud of the fabric. Using three-dimensional scanning technology can better show the bending shape of fabric. Not only can the whole bending property of the fabric be obtained, but also the fabric samples in different directions can be compared and analyzed. The study shows that the results measured by the new method have better correlation coefficients than the results of the conventional cantilever method. The correlation between the projection circumference and the bending length is higher than the projection area, and the section area of the bottom has the highest correlation with the bending length among the four positions.
Although there are a lot of bending test methods, only the bending result of a single direction of the fabric can be obtained from each test. By contrast, the bending results of three directions of the fabric and the bending indexes of the five specimens in each direction can be obtained. At the same time, the bending differences between different fabrics and different directions of the same fabric can be obtained more intuitively. The research results of this paper can provide a more efficient testing method for the field of textile testing, and the testing efficiency is 15 times that of the existing methods, which has good theoretical significance and practical value.

Key words: fabric, bendability, multi-directional, visualization, 3D scanning, projected area, projected perimeter 

摘要： 目前常用弯曲性测试方法每次只能测试织物一个方向的弯曲性能，不能直接观察到织物不同方向的弯曲形态，且需要多次裁样、重复测试，耗时费力；针对这种情况，提出了一种多方向可视化织物弯曲性测试方法。以20种织物为测试对象，利用三维扫描技术获取织物弯曲形态的点云图像；基于所得图像提取投影周长、投影面积和截面积3个新指标；最后分析新指标与抗弯长度的关系。结果发现：新指标与斜面法中的抗弯长度有较好的相关性；织物底端的截面积能较好地体现织物整体的弯曲性能，这表明提出的方法具有良好的可行性。该方法一次测量可得到织物经纬向、斜向的弯曲指标，且每个方向分别有5个样条，有效提升了测试效率；同时利用三维扫描技术可以更加直观精确地描述织物弯曲形态。

关键词: 织物, 弯曲性, 多方向, 可视化, 三维扫描, 投影面积, 投影周长