A detailed elastic-plastic finite element analysis of the effect on crack tip plasticity is studied. The crack tip parameters of aluminum alloy long-short crack effect on compressive loading in a tension-compression loading are analyzed. In this paper two centre-cracked panel finite element models are established. The analysis shows that the compressive loading has a significant contribution towards the crack tip plasticity and the crack tip stress at the same stress intensity factor. In a tension-compression loading the maximum spread of the crack tip reverse plastic zone increases with the increase of the compressive stress and the crack tip compress stress increases with the increase of the compressive stress. The applied compressive stress is the main factor controlling the near crack tip parameters.%应用弹塑性有限元方法,研究压应力对铝合金长短疲劳裂纹尖端应力场、塑性区的影响.分别建立两个具有长短中心穿透裂纹高强铝合金板的有限元模型,进行拉压加载模拟分析.结果表明,压应力对铝合金长短疲劳裂纹尖端应力有显著影响,相同的应力强度因子条件下,在一拉-压加载周期,当拉应力减小到零时裂纹尖端应力不为零,裂纹尖端应力对裂尖的挤压作用产生反向塑性区,裂尖反向塑性区随压应力的增加而增加,压应力的大小是决定铝合金裂纹尖端应力和裂纹尖端塑性区大小的主要因素,压应力对短裂纹的影响比长裂纹大.
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