变截面三维编织预型件的净形制备工艺与细观结构

Near-net shape braiding techniques and microstructures of tapered 3D braided preforms

介绍变截面三维编织预型件的减纱与添纱净形制备工艺,以行单元减纱预型件为代表,观察截面缩减区域的外观形态,并建立表面与内部减纱单元的几何模型,最后讨论了减纱对纱线交织规律的影响。结果表明,保证减纱或添纱后纱线的编织规律不变是净形编织工艺应遵循的原则,预型件在减纱区域呈现平滑的梯形过渡,表面与内部减纱单元中纱线的编织角增大,长度增加,且减纱截面处的纱线交织点位于减纱前两相邻交织点的中心。

Near-net shape braiding techniques of tapered 3D braided preforms including yarn reduction and yarn addition are introduced. Preform microstructures near the yarn-reduction cross-sections are observed. Geometrical models of the surface or interior yarn-reduction units are built and the influences of yarn reduction on interlacing patterns are discussed. Results indicate that braiding rules should not be disturbed after yarn reduction or yarn addition. Smoothly trapezoidal profiles are formed near the yarn-reduction cross-sections and all braiding angles and terlacing points in the yarn-reduction cross-sections move to yarn lengths in the surface or interior reduction units increase. In the center of the two adjacent points before yarn reduction.