本文用数字散斑相关方法测量了五种不同幂硬化指数韧性金属材料(铝和铜),双边裂纹尖端细观区域内应变场.对所得结果用韧性损伤模型进行了分析.在此法中以金属自然表面结构为散斑场,不同加载状态的散斑场进行比较,得到相对变形与应变.图...本文用数字散斑相关方法测量了五种不同幂硬化指数韧性金属材料(铝和铜),双边裂纹尖端细观区域内应变场.对所得结果用韧性损伤模型进行了分析.在此法中以金属自然表面结构为散斑场,不同加载状态的散斑场进行比较,得到相对变形与应变.图象之间相关性 C 是变形参数或是位移及其导数的泛函.使其相关性 C 取最大值的试凑变形即为其真实变形场.这一方法在细观测量中应用得到满意的结果.展开更多
Using the nano-moiré method, we measure the near tip nanoscopic deformation on the [111] plane of single crystal silicon with a loaded quasi-cleavage crack running in the [110] direction. The measured strain dist...Using the nano-moiré method, we measure the near tip nanoscopic deformation on the [111] plane of single crystal silicon with a loaded quasi-cleavage crack running in the [110] direction. The measured strain distribution ahead of the crack tip agrees with the linear elastic fracture mechanics prediction up to 10 nm from the crack tip. Dislocations of Peierls type are detected and they extend from the crack tip over a length of hundreds of Burgers vectors.展开更多
Crack growth in particle reinforced composites is significantly influenced by the character of the reinforcement particles.To accurately deal with such problems,the extended finite element method （XFEM） was employed...Crack growth in particle reinforced composites is significantly influenced by the character of the reinforcement particles.To accurately deal with such problems,the extended finite element method （XFEM） was employed and improved.The simulations are accomplished by using a new domain expression of an interaction integral for evaluating stress intensity factors （SIFs）,and by adopting the maximum hoop stress criterion for crack-growth direction prediction.Crack deflection/attraction mechanisms and their associated energy release rate variations are investigated.It is shown that the applied numerical method allows a considerable flexibility and can be used in more general situations.The crack-tip shielding and amplifying behaviors are clearly observed.展开更多
文摘本文用数字散斑相关方法测量了五种不同幂硬化指数韧性金属材料(铝和铜),双边裂纹尖端细观区域内应变场.对所得结果用韧性损伤模型进行了分析.在此法中以金属自然表面结构为散斑场,不同加载状态的散斑场进行比较,得到相对变形与应变.图象之间相关性 C 是变形参数或是位移及其导数的泛函.使其相关性 C 取最大值的试凑变形即为其真实变形场.这一方法在细观测量中应用得到满意的结果.
文摘Using the nano-moiré method, we measure the near tip nanoscopic deformation on the [111] plane of single crystal silicon with a loaded quasi-cleavage crack running in the [110] direction. The measured strain distribution ahead of the crack tip agrees with the linear elastic fracture mechanics prediction up to 10 nm from the crack tip. Dislocations of Peierls type are detected and they extend from the crack tip over a length of hundreds of Burgers vectors.
基金supported by the Program for New Century Excellent Talents in University (No. NCET-08-0152)the Program of Excellent Team in Harbin Institute of Technology
文摘Crack growth in particle reinforced composites is significantly influenced by the character of the reinforcement particles.To accurately deal with such problems,the extended finite element method （XFEM） was employed and improved.The simulations are accomplished by using a new domain expression of an interaction integral for evaluating stress intensity factors （SIFs）,and by adopting the maximum hoop stress criterion for crack-growth direction prediction.Crack deflection/attraction mechanisms and their associated energy release rate variations are investigated.It is shown that the applied numerical method allows a considerable flexibility and can be used in more general situations.The crack-tip shielding and amplifying behaviors are clearly observed.
