Microstructure Simulation And Mechanical Performance Analysis Of Three-dimensional Braided Composites

In recent years,braiding technology and three-d:imensional braided composites have attracted great attention in engineering field,and three-dimensional braided composites provide new opportunities for the development of composites.Three-dimensional braided composites do not need stitching and mechanical processing,and have good comprehensive performance indicators.Compared with traditional composites,three-dimensional braided composites have multidirectional properties,which not only improve their transverse strength,but also have great potential in damage tolerance and impact resistance.Three-dimensional braided composites are widely used in aerospace,aviation,automobile,ocean and other high-end fields,but these fields require very strict properties of composites.The structure of three-dimensional braided composites is complex and the process cycle is long.Through traditional design methods,not only time-consuming,but also money-consuming.Nowadays,with the development of computer technology,computer aided design technology can be used to simulate and analyze the structure of three-dimensional braided composites,which greatly reduces the time and cost of experiment.At present,two-step method and four-step method are the most commonly used three-dimensional braiding methods,among which four-step method is the most studied method.In this paper,a four-step three-dimensional braided composite material with square cross-section is taken as an example.Based on the existing research on the structure of braided composite material,the motion law of yarn carriers during braiding process is analyzed,the yarn motion model is established and the algorithm is designed.Then the motion simulation of yarn carriers is realized by using MATLAB programming,and the yarn motion is recorded.The space coordinates of the trajectory are used to draw the trajectory of the yarn,and then the trajectory of the yarn is optimized by the cubic B-spline curve.With the secondary development of Visual Studio 2010 and Solid Works,the space coordinates of yarn trajectory are imported into SolidWorks to realize the structure simulation of three-dimensional braided preform.In order to verify the correctness of the simulation structure model,the mechanical properties of the simulated prefabricated structure are tested by using the finite element software ABAQUS.The results of analysis and calculation prove the validity of the structural simulation method.