For improving the performance defects of traditional heald frame, the carbon fiber reinforced composites was applied to technical upgrading of the heald frame. On the basis of the theory analysis of composites laminates, the symmetrical ply scheme suitable for manufacturing of the heald frame in overall laminated was constructed, and a type of parametric program for finite element modeling was developed by ANSYS Parametric Design Language (APDL). The optimal mathematical model of the composites heald frame was proposed, and then the thickness parameter ( t) and direction parameters (α, θ) of fiber layer were dynamic optimized by using of Sub-problem method. The work increased the fundamental frequency (ω1) of the heald frame by 10.38%. Besides, the harmonic response frequency was also increased from 48.41 Hz to 53.77 Hz, which conductive to further improve dynamics properties of the composites heald frame. This paper provides technical guidance for innovative design of new heald frame, and is helpful to solve the problem of speed matching between heald frame and high-speed loom.
To explore the actual working characteristic of the beating-up mechanism on looms, the Step function is adopted to convert the beating-up resistance to an equivalent torque acting on the rocking shaft, and a new method of calculating and simulating the resistance is hereby raised. In accordance with the two-state joint clearance, the paper establishes a double-side model of the four-bar beating-up system in clearance status via ADAMS/View software, and under the consideration of both beating-up resistance and flexible deformation conditions, the contact simulation of beating-up motion with different clearances (0.01∼0.12 mm) is achieved. The main findings are as follows: the actual working condition could be reflected more accurately if the beating-up resistance and component flexibility are included into the simulation computing; from the perspective of the impact on sley moving and beating-up loads, 0.08 mm clearance is obviously less then another three clearances (0.01 mm, 0.04 mm and 0.12 mm); the multi-point contact and collision with peak load greater than 4000 N is existed in connecting rod bearing in the 0∼350 Hz low frequency area, which is likely to exacerbate the wear and fatigue rupture of the bearing; the dynamic shock load of rocking shaft on the loom frame is far greater than that of the crankshaft, indicating that the rocking shaft is the main carrier for delivering the beating-up power; compared to the clearance of 0.08 mm and 0.12 mm, the dynamic impact load generated by the clearance of 0.01 mm and 0.04 mm on the loom frame is obvious greater. In addition, under the clearance condition, transverse vibration could be occurred for the flexible crankshaft due to the deviation of its centroid trajectory, which is detrimental to vibration and noise reduction for the loom system. On the basis of the work, a number of viewpoints with theoretical and practical significance could be provided to the design of beating-up system on the loom with clearance.
To respond to high-speed characteristics and complicated airflow of the air-extraction rotor, the paper takes advantage of ANSYS parametric design language to develop the parametric finite element modeling program by taking the geometric feature of the slip plane as the design variable, so as to propose a mathematical model applicable to dynamics optimization of the rotor. The optimal design parameters of the slip plane are obtained through dynamics optimization ( α ≈ 13.92°, L ≈ 11.17 mm), and the centrifugal stress and static deformation of the rotor body are further reduced while increasing its fundamental frequency by about 7.15%, so that it can adapt to higher safety critical speed. The RNG k- ε turbulence physics model is applied to the numerical simulation of the airflow field in the optimal spinning channel, and a computational domain of single-phase steady fluid with nonstructural mesh is constructed by using ICEM CFD and FLUENT software. On this basis, the simulation result with excellent convergence of the flow field is obtained through the SIMPLE algorithm and pressure-velocity coupled solution. In addition, by virtue of the two-dimensional and three-dimensional flow field characteristic analysis for key fields (like the rotor wall, fiber pipeline, false twister, collecting groove, inlet and outlet), the airflow field state in the spinning channel (like the static pressure, dynamic pressure, velocity vector field, turbulence intensity and streamline trajectory) is confirmed, which will be conducive to gain a deep insight into the open-end spinning mechanism of the air-extraction rotor.
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