摘要
摩擦对管材液压成形有极大的影响,管材摩擦因数的确定是一项极其重要的工作。在分析比较现有测试方法的基础上,基于径压胀形原理及其变形规律提出确定管材液压成形胀形区摩擦因数的新模型。该模型以恒定内压力下圆形管材径压胀形成方形断面后,以断面对角线长度差作为确定摩擦因数的测量指标。对比对角线长度差的有限元数值模拟结果及实测结果,以此确定管材液压成形时胀形区的摩擦因数。对低碳钢及不锈钢管的有限元数值模拟分析表明:对角线长度差与摩擦因数及内压力均成指数关系,该长度差对摩擦力很敏感且可方便测量,也可作为针对管材液压成形胀形区润滑剂特性的评定指标。所提出的新模型具有简单、实用等优点。
Friction plays an important role in tube hydroforming （THF）process, and then accurate determination of the coefficient of friction （COF） becomes a paramount task to promote the application of the process. After a detail discussion of the method in existence, a new measuring model of determining COF in expansion zone of THF is proposed on the basis of the principle of tube hydroforming with radial crushing The measuring model features a round tube hydro-formed into a square part under both a constant internal hydraulic pressure and a radial compression, with the difference of the two diagonal lengths in the square section of deformed part as a friction force or COF indicator. The COF can be determined through matching experimental and FEM simulation results by comparison of the variation of the indicator. The finite element method simulation results of low carbon steel and stainless steel tubes show that the indicator is conveniently measurable and extremely sensitive to the friction force or the COF, therefore can be used as a index to evaluate lubricant performance under realistic friction conditions occurring in the expansion zones of THF process. The results also indicate the measuring model is simple and feasible.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2007年第11期200-205,共6页
Journal of Mechanical Engineering
基金
广西科学基金(0135023)。
关键词
管材液压成形
径压
摩擦因数
有限元法
Tube hydroforming Radial crushing Friction coefficient Finite element method
