孔挤压强化和工艺参数研究

Research of hole expansion residual stress and process parameters

孔挤压强化可以显著提高机械连接的疲劳强度。采用有限元方法建立了孔挤压强化轴对称模型,得到了孔壁残余应力分布状态,建立了孔壁残余应力和孔径、板件厚度、挤压强化过盈量等工艺参数之间的关系曲线。结果表明,周向残余应力和孔径、挤压强化过盈量之间为对数关系,和板件厚度之间为线性关系;径向残余应力和孔径、挤压强化过盈量之间为对数关系,和板厚(以2.5mm为分界线)之间为线性关系,为孔挤压强化效果的定量化认识奠定了基础。

The hole expansion process is a well-known technique used to improve the fatigue life in mechanical linkage.An axial symmetry model of expansion hole was established with finite element method to obtain residual stress distributing status at the hole wall so that the relation curve between the residual stress and the hole diameter,the plate thickness,cold expansion ratio was drawn.The results show the relationship between radial residual stress and hole diameters,hole expansion ratio were logarithmic;relationship between radial residual stress and plate thickness is linear,which laid a foundation for quantitatively understanding the residual stress status around hole after cold expansion.