Galdos Lander, Trinidad Javier, Otegi Nagore, Garcia Carlos
Mondragon University, 20500 Arrasate-Mondragon, Spain.
Materials (Basel). 2022 Aug 17;15(16):5655. doi: 10.3390/ma15165655.
The final quality of sheet and tube metal-formed components strongly depends on the tribology and friction conditions between the tools and the material to be formed. Furthermore, it has been recently demonstrated that friction is the numerical input parameter that has the biggest effect in the numerical models used for feasibility studies and process design. For these reasons, industrial dedicated software packages have introduced friction laws which are dependent on sliding velocity, contact pressure and sometimes strain suffered by the sheet, and currently, temperature dependency is being implemented as it has also a major effect on friction. In this work, three lubricants having different viscosity have been characterized using the tube-sliding test. The final aim of the study is to fit friction laws that are contact pressure and sliding velocity dependent for their use in tube hydroforming modeling. The tests performed at various contact pressures and velocities have demonstrated that viscosity has a major effect on friction. Experimental hydroforming tests using the three different lubricants have corroborated the importance of the lubricant in the final forming of a triangular shape. The measurement of the axial forces and the final principal strains of the formed tubes have shown the importance of using advanced friction laws to properly model the hydroforming process using the finite element modeling.
薄板和管材金属成型部件的最终质量在很大程度上取决于工具与待成型材料之间的摩擦学和摩擦条件。此外，最近已经证明，摩擦是在用于可行性研究和工艺设计的数值模型中影响最大的数值输入参数。基于这些原因，工业专用软件包引入了依赖于滑动速度、接触压力以及有时还依赖于板材所受应变的摩擦定律，目前，由于温度对摩擦也有重大影响，温度相关性也正在被纳入考虑。在这项工作中，使用管材滑动试验对三种具有不同粘度的润滑剂进行了表征。该研究的最终目的是拟合依赖于接触压力和滑动速度的摩擦定律，以便将其用于管材液压成型建模。在不同接触压力和速度下进行的试验表明，粘度对摩擦有重大影响。使用这三种不同润滑剂进行的实验性液压成型试验证实了润滑剂在最终形成三角形形状中的重要性。对成型管材的轴向力和最终主应变的测量表明，使用先进的摩擦定律通过有限元建模对液压成型过程进行正确建模非常重要。
