用改进扩展有限元法研究重力坝强震断裂过程
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摘要
采用改进的扩展有限元法(Extended Finite Element Method,XFEM),即引入虚结点的XFEM,在静力功能基础上实现了动力断裂分析功能,并用于强震中结构多条裂缝的同时扩展分析。采用混凝土Ⅰ型和Ⅰ-Ⅱ混合型动力断裂试验进行了精度验证,然后将该方法应用于Koyna坝的地震开裂分析。结果表明,这一方法在求解混凝土Ⅰ型和Ⅰ-Ⅱ混合型动力断裂问题方面具有良好精度,其避免了网格不断重剖分的问题,也无需采用开裂单元的子域积分来描述非连续位移场,即可实现单元内连续断裂过程的模拟。
An improved Extended Finite Element Method namely phantom node XFEM,is introduced to analyze the dynamic fracture process of multiple cracks in gravity dams subjected to strong earthquake.Experiments of dynamic fracture of mode Ⅰ and mixed-mode Ⅰ-Ⅱ for concrete are used for accuracy verification.On this basis the seismic fracture of the Koyna Gravity Dam is analyzed using the proposed procedure.The results demonstrate that the improved dynamic XFEM has sufficient accuracy for analysis of concrete.It is also found that the simulation of progressive fracture process using this method can be carried out without using remeshing scheme,and it is not necessary to use subdomain integration to describe discontinuities.
An improved Extended Finite Element Method namely phantom node XFEM,is introduced to analyze the dynamic fracture process of multiple cracks in gravity dams subjected to strong earthquake.Experiments of dynamic fracture of mode Ⅰ and mixed-mode Ⅰ-Ⅱ for concrete are used for accuracy verification.On this basis the seismic fracture of the Koyna Gravity Dam is analyzed using the proposed procedure.The results demonstrate that the improved dynamic XFEM has sufficient accuracy for analysis of concrete.It is also found that the simulation of progressive fracture process using this method can be carried out without using remeshing scheme,and it is not necessary to use subdomain integration to describe discontinuities.
引文
[1]Belytschko T,Black T.Elastic crack growth in finite elements with minimal remeshing[J].International Journalfor Numerical Methods in Engineering,1999,45(5):601-620.
[2]Moes N,Dolbow J,Belytschko T.A finite element method for crack growth without remeshing[J].InternationalJournal for Numerical Methods in Engineering,1999,46(1):131-150.
[3]Hansbo A,Hansbo P.A finite element method for the simulation of strong and weak discontinuities in solid me chanics[J].Computer Methods in Applied Mechanics and Engineering,2004,193:3523-3540.
[4]Mergheim J,Kuhl E,Steinmann P A.A finite element method for the computational modelling of cohesive cracks[J].International Journal for Numerical Methods in Engineering,2005,63:276-289.
[5]Song J,Areias P M A,Belytschko T.A method for dynamic crack and shear band propagation with phantomnodes[J].International Journal for Numerical Methods in Engineering,2006,67:868-893.
[6]潘坚文,张楚汉,金峰.基于扩展有限元法的含纵向裂缝重力坝破坏分析[J].水力发电学报,2011,30(3):138-144.
[7]方修君,金峰,王进廷.基于扩展有限元法的Koyna重力坝地震开裂过程模拟[J].清华大学学报(自然科学版),2008,48(12):2065-2069.
[8]王进廷,杜修力.有阻尼体系动力分析的一种显式差分法[J].工程力学,2002,19(3):109-112.
[9]Du J,Yon J H,Hawkins N M,et al.Fracture process zone for concrete for dynamic loading[J].ACI MaterialJournal,1992,89(3):252-258.
[10]Guo J K,Kobayashi A S,Hawkins N M.Dynamic mixed mode fracture of concrete[J].International Journal ofSolids and Structures,1995,32(17-18):2591-2607.
[11]Wang Guanglun,Pekau O A,Zhang Chuhan,et al.Seismic fracture analysis of concrete gravity dams based onnonlinear fracture mechanics[J].Engineering Fracture Mechanics,2000,65(1):67-87.
[12]沈怀至,潘坚文,金峰,等.混凝土坝坝体配筋抗震措施研究[J].水利学报,2007,38(1):39-46.
[2]Moes N,Dolbow J,Belytschko T.A finite element method for crack growth without remeshing[J].InternationalJournal for Numerical Methods in Engineering,1999,46(1):131-150.
[3]Hansbo A,Hansbo P.A finite element method for the simulation of strong and weak discontinuities in solid me chanics[J].Computer Methods in Applied Mechanics and Engineering,2004,193:3523-3540.
[4]Mergheim J,Kuhl E,Steinmann P A.A finite element method for the computational modelling of cohesive cracks[J].International Journal for Numerical Methods in Engineering,2005,63:276-289.
[5]Song J,Areias P M A,Belytschko T.A method for dynamic crack and shear band propagation with phantomnodes[J].International Journal for Numerical Methods in Engineering,2006,67:868-893.
[6]潘坚文,张楚汉,金峰.基于扩展有限元法的含纵向裂缝重力坝破坏分析[J].水力发电学报,2011,30(3):138-144.
[7]方修君,金峰,王进廷.基于扩展有限元法的Koyna重力坝地震开裂过程模拟[J].清华大学学报(自然科学版),2008,48(12):2065-2069.
[8]王进廷,杜修力.有阻尼体系动力分析的一种显式差分法[J].工程力学,2002,19(3):109-112.
[9]Du J,Yon J H,Hawkins N M,et al.Fracture process zone for concrete for dynamic loading[J].ACI MaterialJournal,1992,89(3):252-258.
[10]Guo J K,Kobayashi A S,Hawkins N M.Dynamic mixed mode fracture of concrete[J].International Journal ofSolids and Structures,1995,32(17-18):2591-2607.
[11]Wang Guanglun,Pekau O A,Zhang Chuhan,et al.Seismic fracture analysis of concrete gravity dams based onnonlinear fracture mechanics[J].Engineering Fracture Mechanics,2000,65(1):67-87.
[12]沈怀至,潘坚文,金峰,等.混凝土坝坝体配筋抗震措施研究[J].水利学报,2007,38(1):39-46.
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