关键词: 层压板, 综框, 碳纤维, 失效, 有限元, Tsai-Hill准则

Abstract: In the process of weaving production, the heald frame in high-speed reciprocating motion for a long time results in loom vibration, fatigue damage and yarn tension fluctuation, which will not only restrict the loom speed and affect the quality of the fabric, but also easily lead to the failure of the shedding system and shutdown maintenance. This is not conducive to the improvement of the production efficiency and profits of enterprises. In recent years, with the continuous improvement of the automation level of textile machinery, the speed of the new shuttleless loom has reached 1800r/min, and the weft penetration rate has also reached 2000m/s. In this case, the traditional heald frame can no longer meet the development requirements of modern looms. Carbon fiber composites have excellent mechanical and physical properties. Applying them to the design and preparation of new heald frames can effectively improve the working efficiency of the shedding system, and has important practical significance for promoting the high-speed and high-precision development of textile machinery.
In this paper, the negative cam shedding was used to as the application object, and by combining the composite laminate theory with the design and preparation of the new heald frame, the asymmetrical fiber layup scheme was constructed through ANSYS/WorkBench software and its ACP module, and a carbon fiber composite heald frame based on sandwich lamination was designed and developed. According to the equivalent mechanical model of the shedding system, the spring return force, the spring return force, cam lifting force and yarn tension acting on the heald frame were analyzed and calculated. The finite element model of the composite heald frame with asymmetric laminate was set up with epoxy carbon fiber prepreg and honeycomb core, and the reinforcement design of crossbeam was realized with aluminum alloy plates. On the basis of the finite element static analysis, the interlaminar normal stress of each fiber layer of the upper and lower crossbeams was calculated and evaluated. Besides, the Tsai-Hill criterion was used as the failure criterion to analyze and predict the failure hazard zone and failure sequence of the heald frame. Through the sandwich laminated composite laminate design, while the lightweight design of the carbon fiber heald frame was realized, the inertia load and vibration noise of the loom could be substantial reduced, which is helpful to solve the speed matching problem between the traditional heald frame and the modern loom. The results indicate that there is a large stress distribution in the connection area between the crossbeam and side beam. Under the same laying process conditions, the fiber interlaminar normal stress of the upper crossbeam is significantly greater than that of the lower crossbeam. Normal stress S1 and S2 are important factors affecting the fatigue strength of the heald frame. Besides, the failure sequence of the fiber layer on single laminate is:1/5/4/2/8/6/3/7.
The composite heald frame can better adapt to the production requirements of modern high-speed looms, and can meet the development expectations of advanced weaving technology for new heald frames. By vigorously developing, applying and popularizing such high-performance heald frames, the working defects of traditional heald frames can be fundamentally improved, which is conducive to the technical progress of domestic heald frames.

Key words: laminate, heald frame, carbon fiber, failure, finite element, Tsai-Hill criterion