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目的:板材固体颗粒介质成形工艺作为一种新型的软模成形技术,是采用固体颗粒代替刚性凸模或凹模(或弹性体、液体)对板料进行成形加工的工艺。固体颗粒介质板材拉深成形工艺为拉深和胀形两种变形模式的复合成形,其变形过程与传统拉深成形工艺有很大的区别。以抛物线型零件为研究对象,对其成形过程进行研究,建立固体颗粒介质板材软凸模拉深成形的几何条件和应变计算公式。创新点:1.首次提出了描述固体颗粒介质板材拉深成形变形机理的拉深权和胀形权的概念,并建立了相应的计算公式;2.建立了固体颗粒介质抛物线型零件软凸模拉深成形的几何条件和应变计算公式。方法:1.通过对抛物线型零件固体颗粒介质拉深成形的变形过程分析(图1~3),将变形过程和成形工件的变形区进行划分;2.将数学中权函数的思想引入到对抛物线型零件固体颗粒介质拉深成形的分析中,提出拉深权和胀形权的定义及相应表达式(公式(1)和(2));3.通过理论推导,构建不同成形阶段抛物线型零件拉深成形过程中的应变计算式(公式(28)~(30)和公式(62a)~(62c))和壁厚计算公式(公式(31)和(63));4.利用MATLAB编制抛物线型零件拉深成形应变计算程序(图14);5.以某航空零件为目标零件,通过试验试制不同成形条件下不同阶段的抛物线型工件(表2和3),将理论计算壁厚与实测厚度进行对比(图19),将试验轮廓与理论计算轮廓进行对比(图21),验证分析过程中所提假设及理论计算的可行性和正确性;将试验获得成形工件的几何尺寸(表3)代入MATLAB计算程序中,对该航空零件的变形过程进行分析(图15、18、19、21和22)。结论:1.固体颗粒介质拉深成形过程是胀形和拉深的复合成形,通过对其变形过程分析,首次提出了拉深权和胀形权的概念,并且给出了其计算公式。成形过程中,拉深权越大,工件成形后的壁厚差越小;胀形权则正好相反。2.利用拉深权和胀形权,建立了固体颗粒介质软凸模拉深成形变形区应变计算公式,且可以计算出应变分界圆位置半径,为分析固体颗粒介质软凸模拉深成形工艺变形过程提供了新的理论依据。3.设置合理的成形条件、拉深权的提高和应变分界圆半径的缩小可以降低拉深成形过程中底部的过度减薄,进而提高极限成形高度。
Objective: As a new soft mold forming technology, the solid particle media forming process of sheet metal is a process of forming and processing the sheet by using solid particles instead of rigid convex or concave mold (or elastomer and liquid). Solid particle media sheet drawing process is deep drawing and bulging two deformation modes of composite forming, the deformation process and the traditional deep drawing forming process is very different. Taking parabolic parts as the research object, the forming process was studied, and the geometrical conditions and strain calculation formulas of soft punch die drawing of solid particle media sheet were established. Innovative points: 1. For the first time, the concept of drawing right and bulging power for describing the deformation mechanism of solid particle media sheet is proposed and the corresponding formulas are established.2. Deformation geometry and strain calculation formula. Methods: 1.According to the analysis of the deformation process of the solid particle media of parabolic parts drawing (Figure 1 ~ 3), the deformation process and the deformation zone of the forming workpiece are divided; 2. The idea of the weight function in mathematics is introduced into In parabola-type solid particle media drawing, the definition and corresponding expressions of drawing right and bulging right (formulas (1) and (2)) are proposed. 3. By theoretical derivation, the parabola Strain calculation formula (28 ~ 30) and formula (62a ~ 62c)) and wall thickness calculation formula (formula (31) and (63)) during the part deep drawing process; (Figure 14); 5. Taking aero parts as the target parts, the parabolic workpieces at different stages under different forming conditions (Tables 2 and 3) were tested through experiments. The theoretical calculation of wall thickness and The measured thickness is compared (Figure 19) and the experimental profile is compared with the theoretical calculated profile (Figure 21) to verify the feasibility and correctness of the assumptions and theoretical calculations used in the analysis. The geometry of the formed workpiece 3) into the MATLAB calculation program, the deformation of the aviation parts into the process Line Analysis (Figures 15, 18, 19, 21 and 22). Conclusions: 1. The solid particle media drawing process is composite forming of bulging and drawing. The concept of drawing right and bulging power is proposed for the first time by analyzing its deformation process, and its formula is given. During the forming process, the larger the drawing power is, the smaller the wall thickness difference after the workpiece is formed; the right to bulge is the opposite. By using the drawing right and the bulging power, the strain calculation formula of the deformation zone in the soft pellet of the solid granular medium is established, and the radius of the circle of the strain boundary can be calculated. In order to analyze the soft punch deep drawing forming process of the solid granular medium, The deformation process provides a new theoretical basis. 3. Set a reasonable forming conditions, drawing right to improve and reduce the radius of the circle of the strain boundary can reduce the over-thinning at the bottom of the drawing process, thereby increasing the limit forming height.