碳纤维复合材料单边缝合机构运动轨迹设计

Motive trajectory design of one-sided stitching mechanism for carbon fiber composite

单边缝合技术具有不需要在织物底部安装缝合台的优点,被广泛应用于复合材料曲面预制件及大型结构件中,也为碳纤维复合材料三维增强方面做出了重要的贡献。为了使单边缝合技术在碳纤维预制体中获得预期的线迹,避免线迹稳定成环中出现跳针、线迹过紧或过松的问题,对单边缝合设备原理进行分析,对原有的OSS线迹缝合中引线、钩线、挑线机构的动作配合关系和时间配合关系进行重新设计与规划,并增加滑槽式杠杆拨线机构拨取线环,使线环被钩线针穿入。使增加的拨线机构不产生任何线程损耗且具有一定挑线功能,在有效避免成环失败问题的基础上,降低挑线机构设计难度。提出一种在机构各个瞬时时刻缝线消耗量思想,分析在各个时间点的配和关系,建立改良OSS线迹需线量模型。利用运动循环图对各机构的变化规律进行直观表达,最后对不同厚度的样本进行缝合验证。实验结果表明各个机构配合优良,样本线迹成型稳定,改进的机构配合关系未出现跳针的问题,验证了单边缝合机构运动轨迹的可靠性。

The single-sided stitching technology is widely used in composite curved surface preforms and largescale structural parts because it does not require a stitching table to be installed at the bottom of the fabric,and it also makes an important contribution to the three-dimensional reinforcement of carbon fiber composites.In order to obtain the desired stitches in the carbon fiber preform with the unilateral stitching technology,and avoid the prob-lems of skipped stitches,over-tight or too loose stitches in the stable loop of the stitches,the principle of the unilat-eral stitching equipment is analyzed and the original in some OSS stitch stitching,the action and time coordination relationship of the lead,hook thread and thread take-up mechanism are redesigned and planned,and the chute type lever thread pulling mechanism is added to the thread loop to be penetrated by the hook thread needle.The added thread take-up mechanism does not cause any thread loss and has a certain thread take-up function.On the basis of effectively avoiding the loop failure problem,the difficulty of designing the thread take-up mechanism is reduced.This paper proposes an idea of suture consumption at each instant of the mechanism,analyzes the matching relation-ship at each time point,and establishes an improved OSS stitch demand model.The motion cycle diagram is used to visually express the changing laws of each mechanism,and finally verify by stitching samples of different thicknesses.The experimental results show that the various mechanisms are well matched,the sample stitches are formed stably,and the improved mechanism coordination relationship does not have the problem of skipping stitches,which verifies the reliability of the movement trajectory of the unilateral stitching mechanism.