Study on the Distribution of Frictional Forces on Z-yarn Continuous Implanted Preforms and Their Applications

To improve the quality and efciency of Z-directional 3D preform forming,the Z-yarn frictional force distribution model of the preform and its wear mechanism were investigated.In this study,a tensile force measuring device was designed to measure the force required to replace the guide sleeve,which is equivalent to the Z-yarn frictional forces.The frictional force is proportional to the number of preform layers and is applied to the preform decreased from the corner,edge,sub-edge,and middle in order.A back propagation neural network model was established to predict the friction at diferent positions of the preform with diferent layers,and the error was within 1.9%.The wear of Z-yarn was studied at diferent frictional positions and after diferent times of successive implantation into the preform.The results showed that with an increase in the number of Z-yarn implantations and frictional forces,the amount of carbon fber bundle hairiness gradually increased,and the tensile fracture strength damage of the fber was increasingly afected by the frictional forces.In the corner position of the preform,when the number of implantations was 25,the fber fracture strength decreased non-linearly and substantially;in order to avoid fber fracturing in the implantation process,the Z-yarn needs to be replaced in time after 20–25 cycles of continuous implantation.This study solves the problem of difculty in measuring the force required for individual replacements owing to the excessive number of guide sleeves,puts forward the relationship between fber wear,preform position,and implantation times,solves the phenomenon of fracture in the preform during Z-direction fber implantation,and realizes the continuous implantation of fbers.