The Effect Of Laving Process Parameters On Tensile And Bending Behavior Of Carbon Fiber Composites

As a new type of composites manufacturing technology, automated fiber placement has many advantages, such as high production quality, high production efficiency and low labor costs and so on. At present, the research work on the laying process of carbon fiber composites is mainly focused on two aspects. On the one hand, it is the research on the laying trajectory of composites and the other is the optimization of automated fiber placement process parameters.Therefore,this paper starts from the two main research area,and explores the effect of the main stress distribution path on the mechanical properties of the open-hole composite laminates and the effect of the laying process parameters on the interlaminar performance of composite laminates. The relevant numerical simulation and experimental verification is carried out, which lays the foundation for further explore the carbon fiber composites laying process.Firstly, the technology of resin matrix composites and automated fiber placement are briefly introduced. The design methods of variable stiffness composites,the optimization of composite laying process parameters, the progressive failure analysis of open-hole composite laminates and the research status at home and abroad are introduced. Combined with the design of the maximum principal stress trajectory and the optimization of the parameters of the automatic placement process, the background and significance of the research are put forward.Finally, the research content and structure frame of this paper are given.Secondly, the basic theory of composite material mechanics is discussed, and the stress-strain relationship of single angle laying is briefly summarized. The stress-strain relationship of variable angle fiber laminates is deduced based on the stress - strain relationship of single angle. Finally, the constitutive relations of several common cohesive forces models are briefly introduced, which lays the foundation for the design of the subsequent variable stiffness laminates and the analysis of the damage failure and the performance of the short beam shear test.Based on the B-spline interpolation, the maximum principal stress locating trajectory of the open-hole composite laminates is obtained and the variable stiffness open-hole composite laminates model is established by the discrete mesh method. By introducing Tsai-Wu damage failure criterion and normal stiffness degradation criterion, the tensile failure numerical simulation and damage failure analysis are carried out, and two sets of rigid and variable stiffness open-hole composite laminates are laid respectively, and the tensile contrast test is carried out.Using the combination of experiment and numerical simulation, the relationship between different laying pressure and the interlayer performance of composite laminates was explored.The damage evolution process and mechanism of short beam shear test under different pressure conditions are studied by using Linde’s damage failure criterion. At the same time, the short beam shear test is carried out by using autoclave, the composite laying platform and universal material testing machine. The experiment results are compared with the simulation results.Finally, the content of this paper is summarized, and the content of further research is prospected.