考虑到如紧凑拉伸和三点弯曲等标准试样的大尺寸要求以及高试验成本等突出问题,该文发展了含外侧径向裂纹C形环小试样(C-ring with an outer radial crack,CRO)的疲劳裂纹扩展行为试验方法。利用有限元分析建立了CRO小试样的高精度应力...考虑到如紧凑拉伸和三点弯曲等标准试样的大尺寸要求以及高试验成本等突出问题,该文发展了含外侧径向裂纹C形环小试样(C-ring with an outer radial crack,CRO)的疲劳裂纹扩展行为试验方法。利用有限元分析建立了CRO小试样的高精度应力强度因子算式以及基于柔度法理论的裂纹长度预测公式。采用5083-H112铝合金分别完成了CRO试样和标准CT试样的疲劳裂纹扩展速率试验,获得了相应的Paris方程中的幂指数。通过对比发现,CRO和CT试样的疲劳裂纹扩展规律基本一致,验证了新方法的有效性。基于上述方法对C250钢两种厚度CRO试样的疲劳裂纹扩展行为进行了应用研究。展开更多
Measuring the internal stress of Al alloy forgings accurately is critical for controlling the deformation during the subsequent machine process.In this work,the crack compliance method was used to calculate the intern...Measuring the internal stress of Al alloy forgings accurately is critical for controlling the deformation during the subsequent machine process.In this work,the crack compliance method was used to calculate the internal residual stress of Al-Cu high strength alloys,and the effect of various model parameters of crack compliance method on the calculated precision was studied by combining the numerical simulation and experimental method.The results show that the precision first increased and then decreased with increasing the crack range.The decreased precision when using a high crack range was due to the strain fluctuation during the machining process,and the optimized crack range was 71%of the thickness of forgings.Low orders of Legendre polynomial can result in residual stress curve more smooth,while high orders led to the occurrence of distortion.The Tikhonov regularization method effectively suppressed the distortion of residual stress caused by the fluctuation of strain data,which significantly improved the precision.In addition,The crack compliance method with optimized parameters was used to measure the residual stress of Al-Cu alloy with different quenching methods.The calculated results demonstrated that the distribution of residual stress was obtained accurately.展开更多
文摘考虑到如紧凑拉伸和三点弯曲等标准试样的大尺寸要求以及高试验成本等突出问题,该文发展了含外侧径向裂纹C形环小试样(C-ring with an outer radial crack,CRO)的疲劳裂纹扩展行为试验方法。利用有限元分析建立了CRO小试样的高精度应力强度因子算式以及基于柔度法理论的裂纹长度预测公式。采用5083-H112铝合金分别完成了CRO试样和标准CT试样的疲劳裂纹扩展速率试验,获得了相应的Paris方程中的幂指数。通过对比发现,CRO和CT试样的疲劳裂纹扩展规律基本一致,验证了新方法的有效性。基于上述方法对C250钢两种厚度CRO试样的疲劳裂纹扩展行为进行了应用研究。
基金Project(51875583)supported by the National Natural Science Foundation of ChinaProject(zzyjkt2018-03)supported by the State Key Laboratory of High Performance Complex Manufacturing,China。
文摘Measuring the internal stress of Al alloy forgings accurately is critical for controlling the deformation during the subsequent machine process.In this work,the crack compliance method was used to calculate the internal residual stress of Al-Cu high strength alloys,and the effect of various model parameters of crack compliance method on the calculated precision was studied by combining the numerical simulation and experimental method.The results show that the precision first increased and then decreased with increasing the crack range.The decreased precision when using a high crack range was due to the strain fluctuation during the machining process,and the optimized crack range was 71%of the thickness of forgings.Low orders of Legendre polynomial can result in residual stress curve more smooth,while high orders led to the occurrence of distortion.The Tikhonov regularization method effectively suppressed the distortion of residual stress caused by the fluctuation of strain data,which significantly improved the precision.In addition,The crack compliance method with optimized parameters was used to measure the residual stress of Al-Cu alloy with different quenching methods.The calculated results demonstrated that the distribution of residual stress was obtained accurately.
