DN25薄壁不锈钢管卡压机制研究

Research on press connection mechanism of DN25 light gauge stainless steel tube

薄壁不锈钢管卡压式连接在工程建设中应用广泛,但对卡压机制研究较少.以DN25薄壁不锈钢管为对象,采用实体壳单元模拟钢管和等径接头、刚体模拟卡钳,并考虑卡压过程中材料非线性、边界非线性和几何非线性,对钢管卡压过程进行了数值模拟和试验验证,最后研究摩擦系数、钳口卡刃宽度和钢管材料对钢管卡压性能的影响.结果表明,计算结果和试验结果具有良好的一致性,U形槽外侧变形量高于内侧;钳口阻力受钳口-接头摩擦系数影响较大,减小该摩擦系数较有利于减小最大阻力矩和增加管件塑性变形;钳口阻力变化受卡刃宽度影响很小,但U形槽内侧对卡刃宽度变化比较敏感,增加钳口卡刃宽度有利于减小U形槽内、外侧塑性变形区域的最终尺寸差异;钢管屈服强度越高,钳口所受的阻力和管材平均回弹量越大,进行卡压工具设计时需考虑材料的差异.

Light gauge stainless steel tube press-fitting method is widely used in engineering construction.Research on the press mechanism,however,has been rarely reported.In this paper,DN25 light gauge stainless steel tube is takan as an example,continuum shell element is used to simulate tube and its joint,rigid body is used to simulate pressing tool,and the result is then compared with experiments.Geometric nonlinearity,boundary nonlinearity and material nonlinearity during pressing process are considered in the simulation.Finally,effects of friction coefficient,jaw size and tube material on the press performance are studied.The results show that,the numerical results correspond well with the experimental results,and the outside deformation of U groove is larger than the inside.Friction coefficient between jaw and joint had considerable influence on the jaw resistance,reducing the coefficient can reduce the jaw resistance and increase the plastic deformation.The jaw size has little influence on the jaw resistance but the jaw resistance is sensitive to the interior size of the U groove.Increasing the jaw size can reduce the size difference between the inside plastic area and outerside plastic area of the U groove.The higher the yield strength of the tube is,the larger the jaw resistance and average springback are,which should be considered in pressing tool design.