Prediction And Implementation For Circluar Braiding Tow Orientation On Complex Constant Section Mandrel

Because of the decisive role of tow orientation in braided fabric on mechanical performance of the final composite part,accurate tow orientation prediction method for a specific shape mandrel is a premise in applying circular braiding technology.The research in this paper is the prediction and visualization of tow orientation for circle braiding.Introduction in chapter one presents mainly the background,meaning and status of this research in domestic and overseas,which lead to the main research contents in this work.The chapter two introduces firstly the theory and composition,simplifies the process of circluar braiding.Then this work introduces disadvantages of traditonal method for circle braiding.And this work presents a numerical method that can predict the tow orientation on a complex constant mandrel based on some theoretical equations.In this numerical method,the surface of mandrel is meshed by a mount of tiny meshes,and gets all initial point position information using the initial setting algorithm.A single tow path can be solved based on a numerical discrete model using a time step algorithm.At last,the preform of composite which consists of all tows can be acquired.The next introduces mainly how to realize the algorithm using computer virtual tool in chapter two.The numerical simulation and visualization for circle braiding is realized based on.net framework with OpenTK graphics library and the design scheme of.dll dynamic lib modularization as input and output interface that can give some convenience for latter maintenance,even more module transplantation and secondary utilization.This chapter also explains detailedly the design thought and codes implement of all module,such as STL format file and so on.The chapter four introduces mainly comparison and analysis between experiment and simulation.The comparison between experimental data and numerical results shows the numerical method can effectively predict the tow orientation for irregular constant cross-section mandrel.In the braiding experiments,the angle of braiding tow of complex constant mandrels was measured to compare with numerical results in the same condition.And the mandrel is manufactured by widely used 3D printer.The influence of translation speed,the shape of cross section and initial convergence region length on the braiding angle of tow were analyzed by comparison simulation results and experimental data.The depositing quantity,releasing quantity and instant convergence length was extracted from the numerical method to explain the influence of translation speed of take-up device,the cross-section of mandrel and length of convergence region on the variation of braiding angle of tow.In the end,there are some conclusions about the influence of different translation speed and initial convergence region length on braiding angle that are helpful in the production and processing.The last part summarizes all main point and innovative points of this research.And this paper also presents some prospects for the scholars who research similar work.