经纱张力调节机构的拓扑优化设计与疲劳分析

Topology optimization designand fatigue analysis of the warp tension regulating mechanism

为提升经纱张力调节机构的动态补偿能力,适应三维间隔织物剑杆织机的高速化织造需要,引入可吸收应力的变刚度气动肌腱作为原动件,设计了一种新型经纱张力调节机构。采用有限元技术对该机构进行了静力学分析和模态分析,得到其静态特性及前六阶固有频率阵型,在此基础上采用变密度法对机构进行拓扑优化,随后根据优化结果在SW中进行结构优化并采用有限元仿真实验进行验证。结果表明:拓扑优化后的机构可以减重13.32%,同时应力、应变和固有频率等静动态性能均有较大提升,其最小疲劳寿命可达17.91年,满足织机使用年限的需要。最后在VSI系列样机上进行了对比实验,分析优化前后的张力采样曲线。实验结果表明优化后的织机经纱张力波动更加平稳,机构动态特性有效提升。

The main function of the warp feeding system of a three-dimensional weaving machine is to feed the yarn required for weaving according to the weft density requirements of the fabric structure and to keep the warp tension stable during the weaving process by using its own regulating movements.The three-dimensional weaving machine has two ground warps for weaving ply yarns and a pile warp for"standing"of the fabric,which are coupled to form the warp feeding system of the entire interval fabric weaving machine.Each warp feeding system consists of three parts,namely,the warp feeding shaft parts,the warp tension regulator and the tension detection device.The warp tension regulator is the key part of the warp feeding system for dynamic compensation and is the core of the warp feeding function.With the development of high-speed and intelligent weaving machines,the dynamic compensation capability of the warp feeding system has become more demanding for interval fabric weaving machines.In order to improve the dynamic compensation capability of the warp tension adjustment mechanism and to adapt to the high-speed weaving needs of the three-dimensional spacer fabric rapier weaving machine,a new warp tension adjustment mechanism is designed from the functional principle by introducing a variable stiffness pneumatic tendon as the prime mover that can absorb stress.The static stress and strain characteristics as well as the first six orders of inherent frequency pattern were obtained by using finite element technique.On this basis,the improved variable density method was used to optimize the topology of the mechanism,and then the structure was optimized in Solidworks according to the optimization results,and the finite element simulation experiment was used to verify the static and modal characteristics of the optimized mechanism.The fatigue life prediction based on linear cumulative damage theory was then performed on the core part of the mechanism,the swing arm,to confirm whether it meets the weaving needs after optimization.The results show that the topologically optimized mechanism has a weight reduction of 13.32%,while the static and dynamic properties such as stress,strain and inherent frequency are greatly improved,and its minimum fatigue life can reach 17.91 years,which meets the needs of the service life of the three-dimensional loom.Finally,a comparative experiment was conducted on a VSI series prototype to analyze the tension sampling curves corresponding to the optimized warp tension adjustment mechanism before and after the optimization.The experimental results show that the warp tension fluctuation in the optimized weaving machine is smoother and more accurate,and the dynamic characteristics of the mechanism are effectively improved.The perfect design and optimization process of the warp tension adjustment mechanism can help to promote the improvement of the weaving quality of the three-dimensional loom,and the corresponding design optimization and experimental verification of other key components of the three-dimensional loom can be carried out according to the idea of this scheme,in order to meet the development requirements of high-speed and intelligent three-dimensional loom for spacer fabrics.At the same time,knowledge of dynamics can be introduced to study the various influencing factors in the weaving motion of the mechanism and to promote the joint improvement of the warp feeding system and other systems in the weaving machine.