打结器绕扣机构可靠性设计与打结试验研究

发布时间：2018-08-11 14:04

【摘要】：本文针对D型打结器在打结嘴铰扭绳扣过程中出现的捆绳缠死在打结嘴凸台上导致的成结失败和钩钳扭转变形问题,以非均匀三次B样条曲线造型方法和基于累积损伤理论的可靠性设计方法对打结器绕扣机构进行改进设计,运用基于刚柔接触动力学的打结器虚拟打结方法,对改进前后的绕扣机构进行成结对比试验,验证了绕扣机构改进设计的有效性,并利用打结器性能检测与可靠性试验台对改进后的绕扣机构进行打结正交试验。本文的主要研究工作如下:(1)打结嘴的曲面造型设计:提出利用非均匀三次B样条曲线造型方法表征打结嘴纵向截面轮廓曲线,对比分析构造的打结嘴纵向截面轮廓曲线与三维扫描的打结嘴模型对应截面曲线,二者的弧度变化率相差0.05,表明此方法可行。建立了打结嘴表面的非均匀三次B样条曲面函数,利用C++的OPENGL可视化模块构造打结嘴曲面。通过对打结嘴绕扣过程的受力分析,得出捆绳不发生缠死在打结嘴凸台上的曲面曲率要求,利用非均匀三次B样条曲线造型方法对打结嘴侧向曲面进行改进设计。(2)基于累积损伤理论的钩钳可靠性设计:以实测的绕扣机构在成结过程中所受捆绳拉力为钩钳载荷,利用ANSYS有限元软件建立钩钳的静力学分析模型,通过加载与求解计算得出钩钳危险点位置。再利用ANSYS的疲劳分析模块对危险点进行疲劳分析,结果显示:经过10万次循环加载,钩钳的疲劳耗损系数达到1.87476,发生疲劳失效。采用强度-应力干涉理论,以钩钳危险截面积最小为优化目标函数,约束钩钳刚度和强度条件,建立钩钳模糊可靠性优化设计模型,得出6×6圆角矩形截面的20CrMnTi为最优解,且ANSYS的疲劳分析结果显示,经过10万次循环加载,钩钳的疲劳耗损系数达到0.79256,钩钳没有发生疲劳失效。(3)双齿盘驱动打结器绕扣机构动力学仿真:利用ADAMS动力学仿真软件建立改进前后的绕扣机构与捆绳刚柔接触的动力学模型,对比分析了改进前后的绕扣机构动作过程,表明改进后的绕扣机构成结更加可靠。利用打结器性能检测与可靠性试验台对改进后的绕扣机构进行打结试验,16000次打结试验结果表明:改进后的打结嘴曲面可约束捆绳缠绕在打结嘴凸台下方表面,未发生捆绳缠死在打结嘴凸台上导致的成结失败现象。(4)绕扣机构正交疲劳试验:以捆绳拉力、打结器主轴转速和捆绳直径为因素,对改进后的绕扣机构进行打结正交试验,同时利用测量钩钳截面与打结嘴安装截面间距变化,以此分析钩钳是否发生变形,试验结果表明:在经过16000次的打结正交试验后,绕扣机构成结率达到100%,钩钳截面与打结嘴安装面的间距保持初始值0.52mm,并未发生变形,与ANSYS的疲劳分析结果一致。
[Abstract]:In this paper, the problems of knot forming failure and torsion deformation of hook pliers caused by bundles wrapped on the knotted protruding platform in the process of knot joint hinges and twisting rope buckling of D type knots are discussed in this paper. The nonuniform cubic B-spline curve modeling method and the reliability design method based on cumulative damage theory are used to improve the design of knot winding mechanism, and the virtual knotting method based on rigid and flexible contact dynamics is used. The effect of the improved design on the improved mechanism is verified by the comparison test of the improved winding mechanism, and the orthogonal test of the improved winding mechanism is carried out by using the performance test and reliability test bench of the knotting device. The main work of this paper is as follows: (1) Surface modeling design of knots: a non-uniform cubic B-spline curve modeling method is proposed to characterize the profile curve of longitudinal section of knots. The curve of longitudinal section profile constructed by comparison with that of the model of 3D scanning is compared with the curve of section, and the difference of radians between them is 0.05, which shows that this method is feasible. The nonuniform cubic B-spline surface function of the knotted surface is established, and the knotted surface is constructed by using C's OPENGL visualization module. Through the analysis of the force on the winding process of the knots, it is concluded that the curvature requirements of the curved surface of the bundles do not occur when they are wrapped on the knotted protruding table. The non-uniform cubic B-spline curve modeling method is used to improve the design of the lateral surface of knot nozzles. (2) the reliability design of hook and clamp based on cumulative damage theory. The statics analysis model of hook forceps was established by using ANSYS finite element software, and the dangerous point position of hook pliers was obtained by loading and solving calculation. The fatigue analysis of the dangerous point is carried out by using the fatigue analysis module of ANSYS. The results show that after 100000 cycles, the fatigue wear coefficient of the hook clamp reaches 1.87476, and the fatigue failure occurs. Using the theory of strength and stress interference, taking the minimum dangerous cross section of hook clamp as the optimization objective function, and restricting the stiffness and strength condition of hook clamp, the fuzzy reliability optimization design model of hook clamp is established, and the optimal solution of 6 脳 6 corner rectangular section 20CrMnTi is obtained. The fatigue analysis results of ANSYS show that, after 100000 cyclic loading, The fatigue wear coefficient of hook pliers reaches 0.79256, and there is no fatigue failure of hook pliers. (3) dynamic simulation of winding mechanism of double-toothed disc driven knotting device: the dynamic model of rigid and flexible contact between winding mechanism and bundle rope before and after improvement is established by using ADAMS dynamic simulation software. The operation process of the improved winding mechanism is compared and analyzed, which shows that the improved winding mechanism is more reliable. Using the knotter performance test and reliability test bench, the results of 16000 knotting tests on the improved winding mechanism show that the improved knotted curved surface can constrain the binding rope winding on the surface of the knotted protruding table. (4) orthogonal fatigue test of the winding mechanism: taking the tension of the rope, the rotation speed of the main shaft and the diameter of the tie rope as the factors, the improved winding mechanism was tested by orthogonal knotting test. At the same time, by measuring the distance between the cross section of hook pliers and the installation section of knot nozzles, the deformation of hook pliers is analyzed. The results show that: after 16000 times of knotting orthogonal test, The connection rate of the winding mechanism is 100 and the distance between the hook and clamp section and the mounting surface of the knot nozzle keeps the initial value of 0.52 mm, and no deformation occurs, which is consistent with the fatigue analysis results of ANSYS.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S225

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