Hertze,Michell和Timoshenko等力学大师得到圆盘和圆环的弹性力学解;巴西、日本、英国和美国的先驱学者先后提出基于圆盘和圆环这两种构形的试样测试岩石、混凝土等脆性材料的拉伸强度的方法.作者在这些大师和先驱者工作的基础上,提出...Hertze,Michell和Timoshenko等力学大师得到圆盘和圆环的弹性力学解;巴西、日本、英国和美国的先驱学者先后提出基于圆盘和圆环这两种构形的试样测试岩石、混凝土等脆性材料的拉伸强度的方法.作者在这些大师和先驱者工作的基础上,提出平台巴西圆盘(flattened Brazillian disc,FBD),中心圆孔平台巴西圆盘(holed cracked flattened Brazilian disc,HCFBD)和压缩单裂纹圆孔板(single crack drilled compression,SCDC)等试样和相应的测试方法,对国际岩石力学学会(International Society for Rock Mechanics,ISRM)建议的测试拉伸强度和断裂韧度的方法做出了改进,尤其重要的是扩展到动态力学性能的测试,包括动态起裂,动态裂纹扩展和止裂.这些研究工作得益于作者讲授《弹性力学》和《断裂力学》两门基础课以及指导研究生,说明教学与科研是相辅相成的.展开更多
The dynamic stress intensity factor (DSIF) and the scattering of SH wave by circle canyon and crack are studied with Green's function. In order to solve the problem, a suitable Green's function is constructed...The dynamic stress intensity factor (DSIF) and the scattering of SH wave by circle canyon and crack are studied with Green's function. In order to solve the problem, a suitable Green's function is constructed first, which is the solution of displacement fields for elastic half space with circle canyon under output plane harmonic line loading at horizontal surface. Then the integral equation for determining the unknown forces in the problem can be changed into the algebraic one and solved numerically so that crack DSIF can be determined. Last when the medium parameters are altered, the influence on the crack DSIF is discussed partially with the displacement between circle canyon and crack.展开更多
文章采用有限元方法,对带裂纹中心圆孔圆盘(hollow centre cracked disc,HCCD)试样的复合型断裂进行了数值模拟研究。采用相互作用积分法计算了试样裂尖的Ⅰ型和Ⅱ型应力强度因子(KⅠ和KⅡ)。根据大量算例结果并结合量纲分析,得到了复...文章采用有限元方法,对带裂纹中心圆孔圆盘(hollow centre cracked disc,HCCD)试样的复合型断裂进行了数值模拟研究。采用相互作用积分法计算了试样裂尖的Ⅰ型和Ⅱ型应力强度因子(KⅠ和KⅡ)。根据大量算例结果并结合量纲分析,得到了复合型加载条件下HCCD试样裂尖KⅠ和KⅡ的拟合公式。该组公式含有试样圆盘内径r、裂纹长度a、裂纹倾角θ3个参量,从纯Ⅰ型断裂至纯Ⅱ型断裂,以及Ⅰ-Ⅱ复合型断裂均具有较高的精度。对于KⅠ拟合公式,当θ在0°~15°,r/R在0.05~0.50,a/(R-r)在0.1~0.6范围内时,其计算误差小于8%;当θ在15°~30°,r/R在0.05~0.50,a/(R-r)在0.1~0.4范围内时,其计算误差小于9%。对于KⅡ拟合公式,当θ在0°~30°,r/R在0.10~0.50,a/(R-r)在0.1~0.6范围内时,其计算误差小于10%。展开更多
The problem of scattering of SH-wave by a circular cavity and an arbitrary beeline crack in right-angle plane was investigated using the methods of Green's function,complex variables and muti-polar coordinates.Fir...The problem of scattering of SH-wave by a circular cavity and an arbitrary beeline crack in right-angle plane was investigated using the methods of Green's function,complex variables and muti-polar coordinates.Firstly,we constructed a suitable Green's function,which is an essential solution to the displacement field for the elastic right-angle plane possessing a circular cavity while bearing out-of-plane harmonic line source load at arbitrary point.Secondly,based on the method of crack-division,integration for solution was established,then expressions of displacement and stress were obtained while crack and circular cavities were both in existence.Finally,the dynamic stress concentration factor around the circular cavity and the dynamic stress intensity factor at crack tip were discussed to the cases of different parameters in numerical examples.Calculation results show that the crack produces adverse engineering influence on both of the dynamic stress concentration factor and the dynamic stress intensity factor.展开更多
文摘Hertze,Michell和Timoshenko等力学大师得到圆盘和圆环的弹性力学解;巴西、日本、英国和美国的先驱学者先后提出基于圆盘和圆环这两种构形的试样测试岩石、混凝土等脆性材料的拉伸强度的方法.作者在这些大师和先驱者工作的基础上,提出平台巴西圆盘(flattened Brazillian disc,FBD),中心圆孔平台巴西圆盘(holed cracked flattened Brazilian disc,HCFBD)和压缩单裂纹圆孔板(single crack drilled compression,SCDC)等试样和相应的测试方法,对国际岩石力学学会(International Society for Rock Mechanics,ISRM)建议的测试拉伸强度和断裂韧度的方法做出了改进,尤其重要的是扩展到动态力学性能的测试,包括动态起裂,动态裂纹扩展和止裂.这些研究工作得益于作者讲授《弹性力学》和《断裂力学》两门基础课以及指导研究生,说明教学与科研是相辅相成的.
文摘The dynamic stress intensity factor (DSIF) and the scattering of SH wave by circle canyon and crack are studied with Green's function. In order to solve the problem, a suitable Green's function is constructed first, which is the solution of displacement fields for elastic half space with circle canyon under output plane harmonic line loading at horizontal surface. Then the integral equation for determining the unknown forces in the problem can be changed into the algebraic one and solved numerically so that crack DSIF can be determined. Last when the medium parameters are altered, the influence on the crack DSIF is discussed partially with the displacement between circle canyon and crack.
文摘文章采用有限元方法,对带裂纹中心圆孔圆盘(hollow centre cracked disc,HCCD)试样的复合型断裂进行了数值模拟研究。采用相互作用积分法计算了试样裂尖的Ⅰ型和Ⅱ型应力强度因子(KⅠ和KⅡ)。根据大量算例结果并结合量纲分析,得到了复合型加载条件下HCCD试样裂尖KⅠ和KⅡ的拟合公式。该组公式含有试样圆盘内径r、裂纹长度a、裂纹倾角θ3个参量,从纯Ⅰ型断裂至纯Ⅱ型断裂,以及Ⅰ-Ⅱ复合型断裂均具有较高的精度。对于KⅠ拟合公式,当θ在0°~15°,r/R在0.05~0.50,a/(R-r)在0.1~0.6范围内时,其计算误差小于8%;当θ在15°~30°,r/R在0.05~0.50,a/(R-r)在0.1~0.4范围内时,其计算误差小于9%。对于KⅡ拟合公式,当θ在0°~30°,r/R在0.10~0.50,a/(R-r)在0.1~0.6范围内时,其计算误差小于10%。
文摘The problem of scattering of SH-wave by a circular cavity and an arbitrary beeline crack in right-angle plane was investigated using the methods of Green's function,complex variables and muti-polar coordinates.Firstly,we constructed a suitable Green's function,which is an essential solution to the displacement field for the elastic right-angle plane possessing a circular cavity while bearing out-of-plane harmonic line source load at arbitrary point.Secondly,based on the method of crack-division,integration for solution was established,then expressions of displacement and stress were obtained while crack and circular cavities were both in existence.Finally,the dynamic stress concentration factor around the circular cavity and the dynamic stress intensity factor at crack tip were discussed to the cases of different parameters in numerical examples.Calculation results show that the crack produces adverse engineering influence on both of the dynamic stress concentration factor and the dynamic stress intensity factor.
