护环液压胀形加载路径的数值模拟及实验研究

发布时间：2018-01-29 16:05

本文关键词： 护环液压胀形加载路径双线性　出处：《燕山大学》2014年硕士论文　论文类型：学位论文

【摘要】：大型发电设备的国产化是关系国家经济持续发展、关系国家战略安全的重要保障。护环是发电设备中重要的关键性零件之一。本文在NTA护环液压胀形新工艺的基础上，主要研究了55°模角下600MW大型护环液压胀形的加载路径。基于平面有限元模型，研究了液体压力单独作用下，护环液压胀形时内外层变形特点，并拟合了塑性变形阶段液体压力与护环的尺寸关系。基于轴对称模型，研究了液体压力和轴向力的变化对外层轮廓的影响规律。不同的模型内外层产生塑性变形所需的液体压力近似相等，在护环液压胀形过程中液体压力起主要作用；液体压力和轴向力匹配合适，，可以使护环既不凸也不凹。采用分段匹配的方法，把连续的胀形过程分成n个小过程，在满足护环成形几何质量的前提下，分别研究每一小段过程的轴向力F和液体压力P的匹配关系，确定了护环液压胀形的加载路径。进一步研究表明，加载路径中轴向力F和液体压力P的匹配关系可以近似简化为双线性线型，转折点的液体压力略小于护环外层发生塑性变形的临界液体压力。为了方便实际生产，把加载路径简化成双线性型，并确定其双线性拐点处的液体压力略小于护环外层发生塑性变形的临界液体压力。采用20#钢进行了1:8的护环液压胀形实验。基于上述研究方法，获得了20#钢双线性加载路径，并用确定的加载路径进行实验，验证了双线性加载路径的可行性。
[Abstract]:The localization of large-scale power generation equipment is related to the sustainable development of national economy. The protection ring is one of the most important parts in the power generation equipment. This paper is based on the new hydraulic bulging technology of NTA ring. The loading path of 600 MW large retaining ring hydraulic bulging under 55 掳die angle is studied. Based on the plane finite element model, the deformation characteristics of the inner and outer layers during the hydraulic bulging of the retaining ring under the liquid pressure alone are studied, and the relationship between the liquid pressure and the size of the retaining ring in the plastic deformation stage is fitted, based on the axisymmetric model. The influence of liquid pressure and axial force on the outer profile is studied. The liquid pressure required for plastic deformation in different inner and outer layers is approximately equal. Liquid pressure plays a major role in the hydraulic bulging process of retaining ring. The liquid pressure and axial force are matched properly to make the retaining ring neither convex nor concave. A piecewise matching method is used to divide the continuous bulging process into n small processes. The matching relationship between axial force F and liquid pressure P of each short process is studied respectively on the premise of satisfying the geometric quality of ring forming. The loading path of hydraulic bulging is determined. Further research shows that the matching relationship between axial force F and liquid pressure P in the loading path can be approximately simplified as a bilinear shape. The liquid pressure at the turning point is slightly smaller than the critical liquid pressure of plastic deformation in the outer layer of the protective ring. In order to facilitate practical production, the loading path is simplified as a bilinear type. It is determined that the liquid pressure at the bilinear inflection point is slightly smaller than the critical liquid pressure of plastic deformation in the outer layer of the retaining ring. The hydraulic bulging experiment of 1: 8 retaining ring was carried out with 20 # steel. Based on the above research method, the bilinear loading path of 20 # steel was obtained, and the experiment was carried out with the determined loading path. The feasibility of bilinear loading path is verified.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM31

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