薄壁管数控弯曲过程中失稳起皱的主要影响因素

Influences of Forming Parameters on Wrinkling in NC Thin-walled Tube Bending

针对薄壁管数控弯曲精确成形过程在多因素交互作用下可能发生失稳起皱这一复杂物理问题,基于起皱能量准则和有限元方法相结合,提出了预测该过程起皱发生的能量(数值)方法,研究了影响薄壁管数控弯曲成形过程起皱发生的主要因素及影响机制。结果表明,弯曲半径、相对管径、芯棒伸长量和摩擦因素是影响薄壁管数控弯曲精确成形过程起皱发生的主要因素,而材料的应力强度系数和加工速度等对起皱发生影响较小。研究结果为薄壁管数控弯曲精确成形过程参数的确定和优化创造了条件。

The NC thin-walled tube bending process is multiple-factor-coupling action, and wrinkling often occurs in the process. A numerical method is put forward to predict the wrinkling onset based on the energy method and FEM. At the same time, the influences of forming parameters, such as bending radius, relative tube radius, material properties, forming speed and so on, on the wrinkling initiation are also researched. The results indicate that the bending radius, the relative tube diameter, the extension of mandrel, the hardening factor of material and friction are the main factors determining the wrinkling onset in the process, while the strength coefficient of material and the forming speed only have a little effect. These results provide the guidance for the optimization of the forming parameters in tube bending.