【作者】 童育强；

【导师】 赵人达；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2004， 硕士

【摘要】 近半个世纪以来，各国学者在混凝土力学和混凝土非线性分析理论方面进行了大量深入的研究，取得了丰硕的成果。另一方面，随着工程界对混凝土结构的安全性、适用性和耐久性的日益关注，有必要把非线性有限元分析技术运用到实际的混凝土结构。但是如果在实际工程中采用复杂的混凝土本构模型和单元模型，势必加大计算开销，阻碍了这项技术在工程中的广泛应用。 本文是基于混凝土结构非线性有限元分析实用化的考虑，寻找一套能简单精确高效进行混凝土结构非线性有限元分析的方法，充分考虑与混凝土结构施工过程相关的、影响结构非线性行为的种种因素，抓住主要矛盾，忽略一些次要因素，以实现将混凝土非线性有限元分析技术应用到大型实际结构的非线性有限元分析。为此，本文主要进行了以下几个方面的工作。 1．本文首先推导了一种采用混凝土一维本构模型，可以应用于空间有限元分析的退化梁单元。这种的退化梁单元不仅能够精确高效地处理各种截面形式的梁，而且在非线性有限元分析时能够很好地模拟混凝土结构开裂、压溃和钢筋的塑性流动等结构非线性行为。 2．在退化梁单元的基础上，本文对影响结构非线性行为的关键因素进行了分析：预应力问题、空间温度场分析、结构按施工阶段分析和混凝土结构徐变效应等问题。 3．本文开发了一套能够进行混凝土结构非线性有限元分析的有限元计算程序，对大量的算例进行验证分析，说明了退化梁单元能够进行混凝土结构非线性有限元分析和本文提出的对预应力问题、空间温度场分析、结构按施工阶段分析和混凝土结构徐变问题的有限元处理方法的正确性与高效性。 4．本文简单介绍了混凝土结构非线性有限元计算软件“扬华桥梁”。 5．利用非线性有限元计算软件，对两座实际桥梁进行了非线性有限元分析，说明本文开发的非线性有限元计算软件能够应用到实际大型桥梁结构的有限元分析中去。更多还原

【Abstract】 During the past half of century, through fruitful researches of scholars around the world, great achievements on the basic theory of concrete mechanics and concrete nonlinear analysis have been obtained. On the other hand, with increasing attentions paid to the safety, serviceability and durability of concrete structures, it is necessary to apply the nonlinear FEM to the analysis of large practical concrete structures. Conversely, if the sophisticated concrete constitutive model and the complicated finite element model are adopted in the analysis of real size concrete structures, great computation effort is scaled up, and this computational drawback prevents further application of this technology to large scale structure engineering.Considering the practical application of nonlinear FEM analysis technology to the concrete structures, this thesis devotes to develop an efficient and accurate nonlinear FEM methodology which can take into account all the factors related to the structure construction process, and which is capable of simulating the nonlinear response of large concrete structural system. Employing some effective FEM models involved with simple constitutive laws, taking account of the important factors in the structure analysis, and neglecting the secondary aspects, the concrete structure nonlinear FEM analysis technology can be widely applied to real size concrete structure system. Therefore, the following research works have been carried out in this master degree thesis.1. A 3D Degenerated Beam Element, adopting the uniaxial concrete constitutive laws, is developed in this thesis. This Degenerated Beam Element can not only accurately and effectively treat with the beams with all kinds of section configurations, but also expediently describe the nonlinear structural behaviors such as the crack and the crush of concrete and steel’s plastic flow after the yielding stress.2. Based on the degenerated beam element, the important factors affecting the structural nonlinear behaviors are studied such as prestressing, 3D temperature field analysis, construction process analysis and the creep effect of concrete structures etc.3. A nonlinear FEM program is developed for analyzing real size concrete structures by nonlinear FEM technology. A great number of numerical examples are tested to demonstrate the accuracy and effectiveness of the FEM algorithmsdescribing the prestressing effect, the 3D temperature effect, and construction process analysis and the creep effect.4. A nonlinear FEM analysis software entitled "YANGHUA Bridge" is developed for the nonlinear FEM analysis of concrete structures.5. Employing the "YANGHUA Bridge" software, two concrete bridges are analyzed. The results demonstrate that this nonlinear FEM software can be widely applied to the FEM analysis of real concrete structures.更多还原