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本文用极限分析法得到确定护环液压胀形极限载荷的上限解,由于选取的允许速度场相当接近真实速度场,故在此基础上研究了胀形过程的速度分布,变形分布问题,得到了相应的公式。分析了护环胀形后毛坯强度指标的变化规律,提出护环毛坯尺寸的计算公式和胀形后强度指标的计算方法,这样可准确地计算变形力,合理地选定护环胀形的变形量,准确地计算护环毛坯轮廓尺寸。这些公式经模拟护环和大型生产护环验证准确可靠,为护环生产工艺参数的确定提供了理论根据和实用的公式。液压胀形法是一种新工艺,许多理论问题还不完善,如变形力的计算仍借用受均匀内压作用厚壁圆筒的平面变形解[1][2],因护环胀形的高缩较大,显然忽略护环高度的变形与实际不符,而算得的变形力偏高。护环变形前毛坯尺寸的确定依赖于经验,而胀形护环内部变形分布和速度分布等问题还无文献记载。为此本文提出求解这类问题的上限解。
In this paper, the upper limit solution to determine the ultimate load of retaining ring hydraulic bulging is obtained by the limit analysis method. Because the selected allowable velocity field is quite close to the true velocity field, the velocity distribution and deformation distribution of the bulging process are studied. The corresponding formula. The variation rules of blank strength after bulging of retaining ring were analyzed. The formulas for calculating the size of retaining ring blank and the calculating method of strength index after bulging were given, which could accurately calculate the deformation force and reasonably select the deformation of retaining ring bulge Accurately calculate the amount of guard blank outline size. These formulas are accurate and reliable verified by the simulation retaining ring and the large-scale production retaining ring, which provides the theoretical basis and practical formula for determining the process parameters of the retaining ring production. Hydraulic bulging method is a new technology, many theoretical problems are not perfect, such as the deformation force is still borrowed by the uniform internal pressure of the thick-walled cylinder deformation solution [1] [2], due to retaining ring bulging High shrinkage, apparently ignore the height of the retaining ring deformation and the actual discrepancies, while the calculated high deformation force. The determination of the size of the blank before the deformation of the grommet depends on the experience, and the problems of deformation distribution and velocity distribution within the bulging grommet are not documented. For this reason, this paper proposes a solution to the upper limit of such problems.