薄壁管纯弯曲塑性成形分析及回弹计算

回弹是薄壁管数控弯曲常见的质量缺陷。文章基于薄壁管弯曲变形微体受力分析,建立了薄壁管圆周方向上力的平衡微分方程和切向应力在薄壁管横截面上的分布函数。由此可确定中性层的位置,求出外加弯矩,并用虚功原理解得回弹角度。论文针对不同几何参数的薄壁管进行了数控弯曲实验,分析了弯曲角度和相对弯曲半径对回弹角度的影响规律,并验证了理论计算结果与实验结果基本相符。利用该文介绍的计算方法可在实际弯曲之前计算出回弹补偿量,以提高管件弯曲成形精度。

Plastic-formation analysis and springback calculating of thin-wall tube pure-bending

Springback is one of usual quality defects in NC bending process of thin-wall tube.Based on the force analysis for a small volume element of bending tube,the differential equation of force balance on circumference direction and the stress function along the span angle of cross section are built.The position of neutral layer and bending moment are derived,and the springback angle based on principle of virtual work can be deduced.The NC bending experiments of thin wall tube with different geometry parameters are finished,and the theory prediction model is proved accordant with the experiment results.Finally the rule of springback angle affected by the bending angle and relative bending radius is analyzed.Springback compensation can be calculated before bending to improve the formation precision of tube bending.