Research On Double-sided Stitching Technology Of Carbon/carbon Composite Preform

C/C composite material is a typical representative of advanced composite materials.It has the advantages of high temperature resistance,high fatigue strength,high specific strength and specific modulus,low thermal expansion coefficient and excellent shock absorption.It is considered to be an ideal thermal structure and Thermal protection material.The composite material stitching technology is to introduce fibers in the thickness direction of the sewing material to connect the multilayer fabric into a three-dimensional fabric,which greatly improves the mechanical properties of the composite material,and has low cost and good quality consistency.It is widely used in aerospace,Automobiles,ships and other fields.In order to realize the automatic stitching of large-thickness carbon/carbon composite preforms,this paper improves the stitching prototype suitable for stitching large-thickness composite preforms based on the analysis of the current research status of composite material preforms stitching molding equipment at home and abroad.Suture device suture technology to carry out research work,the main research content is as follows:Firstly,a comprehensive analysis of the different stitching process principles and the stitching process requirements of large-thickness composite material preforms is carried out,and the stitching method used is determined to be single-needle chain stitching.In order to realize automatic suture and ensure the success rate of hook hook hooking loops,an experimental platform was built to conduct experimental research on the retreat displacement of the needle when sutured with carbon fiber composite materials of different thicknesses to form the best loops;the stitching mechanism and the crochet mechanism of the suture device Structural design,theoretical derivation of its kinematic coordination and simulation analysis after the establishment of a threedimensional model.Secondly,study the influence of the parameters of the suture device on the quality of stitch forming,analyze the force of the needle of the suture machine during the punching process,and determine the diameter of the needle of the suture machine;improve the design of the needle holding guide block in the punching mechanism to ensure The needle can only move in the direction perpendicular to the carbon cloth;in order to verify that the stitching needle meets the requirements of strength and rigidity,a finite element analysis is performed on it.In order to ensure the quality and efficiency of suture stitches,the amount of thread required in each stage of the suture process was studied,and the influence of different suture parameters on the amount of thread required during the suture process was analyzed.Design the thread passage of the suture device and analyze the pre-tightening force and suture tension of the tension regulator in the thread passage.Finally,building a suture prototype experimental platform to verify the stability of the needle constrained by the improved needle holding guide block;conduct an experimental study on the coordination of the double needle movement when the suture parameters are different and examine the continuous operation of the suture device and the quality of suture stitches authenticating.