Research On The Compression Properties Of3D Warp-knitted Space Fabric

The double needle bed raschel warp-knitted machine is used to produce thewarp-knitted space fabric. They are composed of two surface layers and the middlelayer that is the space yarns. The space yarns contact and support the two surfacelayers, and the thickness can be up to65mm. The unique structure makes the fabricsuperior compression performance and climate regulation function. It can be used forclothing, sporting goods, automotive textiles and medical textiles. This paper studiedthe compression performance and the distribution of transfer load under the sphericalcompression model.At first, based on the compression test, the compressive rate, compressive workelastic rate and stress relaxation rate were obtained in this dissertation. Then therelationship between compressive properties’ indexes and structure of warp-knittedspacer fabric were analyzed by the linear regression analysis. The main results showas follow:Compressive rate has the linear relationship with thickness and the linear densityof spacer yarn. Besides, the thickness has a greater effect on the compressive rate thanthe linear density of the spacer yarn.Compressive work elastic rate has the linear relationship with the density ofcourse, linear density of yarn in the surface layer and fabric weave, and the lineardensity of yarn in the surface layer has the greatest effect on compressive work elasticrate, the fabric weave is the third followed by the density of course.Stress relaxation rate has significant linear relationship with the thickness, withthe increase of the thickness; the stress relation rate will decrease.Secondly, paper first proposed that the transfer load through the warp-knittedspace fabric can be characterized the compression performance. The experiment developed the8-channel pressure test device to test the transfer load of thewarp-knitted space fabric. The device has smart design and it is easy to use. Besides,the pressure sensors have the high accuracy.The paper tested a group of different kinds of warp-knitted space fabric under thespherical compression model. The distribution of transfer load along the vertical,horizontal and45°direction of the warp-knitted spacer fabric were tested. Based onthe origin software and the first-order exponential decay function, the distributions oftransfer load of the warp-knitted space fabric in three directions were discussed. Thecoefficient of determination of fitting equation is greater than99%, so the fittingresults are perfect.The multiple linear regression analysis from SPSS statistical software was alsoused to analyze the transfer load decay indexes of the warp-knitted space fabric. Theresults show that the transfer load decay indexes of the warp-knitted space fabric haverelation with the density of wale and courses, fabric weave, and the weight ofspherical pressure model. Besides under the spherical compression model, there is astrong positive linear correlation between the decay indexes of vertical, horizontal and45°direction.At last, in order to understand the compression performance of the warp-knittedspace fabric furthermore, some suggestions were listed in this dissertation. The textilematerials and the details of the weave structure in experimental samples will beconsidered. The spherical compression model must be optimized and the method ofnumerical simulation can also be explored to study the compression performance ofthe warp-knitted space fabrics.