曲面件柔性轧制成形过程数值模拟及工艺参数优化设计

发布时间：2018-08-24 10:50

【摘要】：柔性轧制成形是一种曲面件连续成形新工艺,是将多点调形方法与轧制技术有机结合,依靠上、下柔性辊间特殊的辊缝分布和柔性工作辊自身旋转来实现板材的三维塑性变形和连续进给,从而实现三维曲面件无模、连续、高效成形,具有加工成本低、成形方式灵活、成形范围广等优点,容易满足诸多行业对曲面板类件个性化的需求,特别是在航空航天、舰船、民用工业等领域有着广泛的应用前景。本文对柔性轧制成形工艺进行理论分析,通过数值模拟与实验验证相结合的方法探究柔性轧制成形规律及工艺参数的影响规律,利用正交试验对主要工艺参数进行多因素试验设计,达到优化柔性轧制成形工艺的研究目的。本文的具体研究内容如下:(1)从塑性力学、几何学及板料变形角度分析柔性轧制成形工艺原理,分析两种典型曲面件—凸曲面件及鞍形件的成形特点。结合塑性成形理论,对成形过程进行力学分析,并分析板料纵向弯曲变形情况。基于上、下工作辊只能小挠度弯曲的实际情况,建立辊缝控制函数。(2)建立柔性轧制成形的有限元模型,从横、纵、厚三向对两种典型件进行轮廓分析,得到零件曲面光顺性良好,验证了柔性轧制成形辊缝设计的有效性及有限元模型的正确性。通过数值模拟分析,以成形件横、纵向曲率为研究指标,得到调形半径、最大减薄率以及板厚对鞍形件横、纵向曲率的影响规律。(3)在数值模拟的基础上,进一步对调形半径、最大减薄率及板厚三个主要工艺参数进行正交试验优化设计,采用极差和方差分析方法对试验数据进行分析,得到各工艺参数影响成形结果的主次关系,对比各工艺参数对考察指标影响的显著程度及贡献率,验证影响横、纵向变形因素之间的交互作用,优化得出最优的工艺参数组合。正交试验量化了各工艺参数对成形结果的贡献率,使影响程度更直观。参数对成形件形状影响的研究可以为工作辊形状调节、板形控制等提供理论基础。(4)柔性轧制成形的相关实验研究,对模拟结果进行实验验证。柔性轧制成形凸曲面件及鞍形件两种典型件,分析实验件形状与成形误差分布规律,实验件曲面光顺性良好。通过对比实验,分别研究在不同工艺参数下,零件曲率及成形误差规律,与数值模拟结果一致。通过实验对比验证了最优工艺参数组合下的零件成形误差小,质量良好,说明建立的正交试验优化是可行的。
[Abstract]:Flexible rolling forming is a new continuous forming process for curved parts, which combines multi-point adjustment method with rolling technology. Special roll gap distribution and flexible work roll rotation are used to realize the three-dimensional plastic deformation and continuous feed of the plate, so that the three-dimensional curved parts can be formed without die, continuously and efficiently, with low processing cost and flexible forming mode. Because of its wide range of forming advantages, it is easy to meet the individualized needs of curved panel parts in many industries, especially in the fields of aerospace, ship, civil industry and so on. In this paper, the flexible rolling forming process is theoretically analyzed, and the influence of the process parameters on the flexible rolling forming process is investigated by the method of numerical simulation and experimental verification. In order to optimize the flexible rolling forming process, the orthogonal test was used to design the main process parameters. The main contents of this paper are as follows: (1) from the angles of plastic mechanics, geometry and sheet metal deformation, the principle of flexible rolling forming process is analyzed, and the forming characteristics of two typical curved surface parts, convex curved parts and saddle parts, are analyzed. Combined with plastic forming theory, mechanical analysis of forming process and longitudinal bending deformation of sheet metal are carried out. Based on the fact that the upper and lower work rolls can only be bent with small deflection, the roll gap control function is established. (2) the finite element model of flexible rolling forming is established, and the contour of two typical parts is analyzed in three directions: transverse, longitudinal and thickness. The results show that the surface fairing is good, which verifies the validity of the roll gap design and the correctness of the finite element model. Through numerical simulation and analysis, the effects of shape adjustment radius, maximum thinning rate and plate thickness on the transverse and longitudinal curvature of saddle parts are obtained by taking the transverse and longitudinal curvature of forming parts as the research index. (3) on the basis of numerical simulation, the radius of shape adjustment is further adjusted. Three main process parameters, maximum thinning rate and plate thickness, are optimized by orthogonal test. The test data are analyzed by means of range and variance analysis, and the primary and secondary relationships between the process parameters and the forming results are obtained. By comparing the significance and contribution rate of each process parameter to the investigation index, the interaction between the influencing factors of transverse and longitudinal deformation was verified, and the optimal combination of process parameters was obtained. The orthogonal test quantifies the contribution rate of each process parameter to the forming result, which makes the influence degree more direct. The study of the influence of parameters on the shape of forming parts can provide a theoretical basis for shape adjustment and shape control of work rolls. (4) the experimental study on flexible rolling forming is carried out and the simulation results are verified by experiments. This paper analyzes the distribution of the shape of the experimental part and the forming error, and shows that the fairing of the curved surface of the experimental part is good. Through comparative experiments, the curvature and forming error of parts under different technological parameters are studied respectively, and the results are in agreement with the numerical simulation results. It is proved by experiments that the forming error is small and the quality is good under the optimal process parameter combination, which shows that the optimization of orthogonal test is feasible.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG335

【参考文献】