基于扩展有限元法的混凝土梁断裂性能数值分析
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摘要
用扩展有限元法对混凝土梁的断裂性能进行了数值研究。以试验所测具有尺寸效应的混凝土断裂能G_f作为基础数据,利用局部断裂能的双线性模型,通过最小二乘法拟合得到与尺寸无关的混凝土真实断裂能G_F。在此基础上,基于扩展有限元法,首先对比分析了采用断裂能G_f、G_F的模型,然后以真实断裂能G_F作为混凝土的参数,对不同缝高比和不同梁宽的混凝土三点弯曲梁的断裂性能进行数值分析。分析结果表明:当利用扩展有限元法对混凝土断裂问题进行计算时,采用真实断裂能G_F作为混凝土材料参数更准确有效;随着初始缝高比增大,混凝土梁断裂韧度先增大后逐渐减小;混凝土梁断裂韧度与梁宽无关。
It presents a numerical study on the fracture behavior of concrete beams by extended finite element method.Based on the measured fracture energy G_f with size effect and the bilinear model of local fracture energy,the real fracture energy G_F of concrete is obtained by least squares fitting.The models of two kinds of fracture energy G_f and G_F are compared and analyzed by extended finite element method,and then real fracture energy G_F is used as the parameter of concrete to analyze the fracture behavior of three-point bending beams with different crack heights and different beam widths.The analysis results indicate that it is more accurate and effective to use real fracture energy as the concrete material parameters.When the initial crack height ratio increase,the fracture toughness of concrete beams increase first and then decrease gradually.The fracture toughness of concrete beams are independent on beam width.
It presents a numerical study on the fracture behavior of concrete beams by extended finite element method.Based on the measured fracture energy G_f with size effect and the bilinear model of local fracture energy,the real fracture energy G_F of concrete is obtained by least squares fitting.The models of two kinds of fracture energy G_f and G_F are compared and analyzed by extended finite element method,and then real fracture energy G_F is used as the parameter of concrete to analyze the fracture behavior of three-point bending beams with different crack heights and different beam widths.The analysis results indicate that it is more accurate and effective to use real fracture energy as the concrete material parameters.When the initial crack height ratio increase,the fracture toughness of concrete beams increase first and then decrease gradually.The fracture toughness of concrete beams are independent on beam width.
引文
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[8]胡少伟,米正祥.基于扩展有限元法的混凝土裂缝扩展过程数值模拟[J].水利学报,2014,45(S1):51-56.
[9]RILEM-Draft-Recommendation(50-FCM).Determination of the fracture energy of mortar and concrete by means of three-point bend tests on notched beams[J].Materials and Structures,1985,18(106):285-290.
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[12]米正祥.混凝土断裂过程试验研究与扩展有限元模拟[D].南京:南京水利科学研究院,2013.
[13]水工混凝土断裂试验规程:DL/T 5332—2005[S].北京:中国电力出版社,2006.
[14]顾兆军.混凝土三点弯曲梁断裂参数的新算法及尺寸效应的研究[D].大连:大连理工大学,2005.
[2]MO魮S N,DOLBOW J,BELYTSCHKO T.A finite element method for crack growth without remeshing[J].International Journal for Numerical Methods in Engineering,1999,46(1):131-150.
[3]方修君,金峰,王进廷.基于扩展有限元法的黏聚裂纹模型[J].清华大学学报(自然科学版),2007,47(3):344-347.
[4]董玉文,任青文,余天堂.扩展有限元法在重力坝断裂分析中的应用研究[J].重庆建筑大学学报,2008,30(3):36-40.
[5]潘坚文,张楚汉,徐艳杰.用改进扩展有限元法研究重力坝强震断裂过程[J].水利学报,2012,43(2):168-174.
[6]茹忠亮,申崴,赵洪波.基于扩展有限元法的钢筋混凝土梁复合断裂过程模拟研究[J].工程力学,2013,30(5):215-220.
[7]朱杰,方从启.混凝土结构锈胀开裂的扩展有限元数值分析[J].力学季刊,2013,34(1):32-40.
[8]胡少伟,米正祥.基于扩展有限元法的混凝土裂缝扩展过程数值模拟[J].水利学报,2014,45(S1):51-56.
[9]RILEM-Draft-Recommendation(50-FCM).Determination of the fracture energy of mortar and concrete by means of three-point bend tests on notched beams[J].Materials and Structures,1985,18(106):285-290.
[10]DUAN K,HU X,WITTMANN F H.Boundary effect on concrete fracture and non-constant fracture energy distribution[J].Engineering Fracture Mechanics,2003,70(16):2257-2268.
[11]赵艳华,徐世烺,聂玉强.混凝土断裂能的边界效应[J].水利学报,2005,36(11):1320-1325.
[12]米正祥.混凝土断裂过程试验研究与扩展有限元模拟[D].南京:南京水利科学研究院,2013.
[13]水工混凝土断裂试验规程:DL/T 5332—2005[S].北京:中国电力出版社,2006.
[14]顾兆军.混凝土三点弯曲梁断裂参数的新算法及尺寸效应的研究[D].大连:大连理工大学,2005.