Study On The Braided Process Optimization And Properties Of 3D Five-Direction Tubular Braided Materials

The 3D braided composites which have high performance are widely used in aerospace, transportation fields and so on. Making high-performance spacecraft parts need 3D five-direction tubular braided composites, research of these composites are very important. The braided process of 3D five-direction tubular braided materials is very complicated and the braided structure is difficult to understand, there have been few researches to these kinds of composites.Based on symmetry of the braided structure and repeatability of the unit-cell, the new simplified unit-cell geometric model is established, which describes geometric properties of braided materials. According to cells shape and distribution methods of braided structure, built mathematical relationship between unit-cell geometric properties and braided process parameters, deduced count formulae of fiber volume percentage content. According to theory of braided process parameter optimization, researched optimized braided array and braided yarn section parameter.Predicted fiber volume percentage content compared with experiment results, the count data agree with the experiment data and have the same trend, proved the unit-cell which has agreement with actual braided structure is logical, provided condition for depth research these kinds of composites in the future.Using VC++6.0 language compiled special program which include formulae of braided process parameter optimization and counting fiber volume percentage content, developed the software which can optimize process parameter and predict fiber volume percentage content, this software supplied basis for researching of the class composites braided process and mechanical properties.