压缩载荷对冷胀孔残余应力的影响

The Effects of Compressive Load on the Residual Stress Distributions Around Cold Expanded Holes

用考虑组合强化、增量理论的有限元法计算了２１２４－Ｔ８５１ 板件开缝衬套冷胀孔的残余应力场及其在压缩载荷作用下的变化情况。结果表明冷胀之后的压载循环将引起冷胀残余应力的衰减。一个足够大的压缩载荷能够使冷胀工艺给疲劳寿命带来的增益完全丧失。文中说明压缩载荷对冷胀的作用可以和超载后半周压载对裂纹的作用相比拟，建议在确定合理胀孔量时应当把它对所承受的载荷谱中压缩载荷的敏感性考虑在内，应当加强有关的疲劳对比试验研究及残余应力场测量研究。

The influence of remote compressive load on the residual stresses around cold expanded hole was investigated for 2124 T851 aluminium alloy plate by the elastic plastic finite element method considering kinematic work hardening. A single compressive load cycle which follows the cold expansion process does cause attenuation of the residual streses near the hole. The beneficial effect of a cold expansion on the fatigue behaviour may be totally lost under a heavy compressive load. It is awared that the effect of a compressive load cycle on a cold worked hole is analogous to that of a compressive overload on a crack which has just been loaded by a tensile overload. It is thereby suggested that the sensitivity of residual stresses near cold expanded hole to the compressive load should be taken into account while determining a reasonable cold expansion level. The corresponding experimental studies should be enhanced.