【作者】 熊耀清；

【导师】 姚谦峰；

【作者基本信息】 北京交通大学 ， 结构工程， 2008， 博士

【摘要】 密肋复合墙结构是一种生态、节能、减震型建筑结构新体系。到目前为止,已经在理论及应用上取得了重要的阶段性成果。然而在密肋复合墙体的损伤研究方面尚不完善,特别是地震作用下墙体材料、框格及墙体结构的损伤演化规律,墙体损伤评价以及墙体在蒸养生产时温、湿度条件下损伤控制等方面还有待进一步深入研究,以便为研究该结构的耗能减震机理及耐久性能提供有效途径。本文以密肋复合墙体为研究对象,从墙体填充材料、框格、结构层面对上述内容进行了较为详细的研究,完成的主要工作及成果如下:1.进行了轻质多孔混凝土材料的基本力学性能试验研究。通过蒸压加气混凝土和泡沫混凝土材料力学性能试验,得到了材料的立方体抗压强度、棱柱体抗压强度、弹性模量及应力—应变全曲线等,为墙体结构的有限元计算提供了试验依据。2.提出了轻质多孔混凝土多轴强度准则及弹脆塑性损伤本构模型。根据轻质多孔混凝土的破坏特征,提出了四参数强度准则模型;根据轻质多孔混凝土材料的弹脆塑性,以四参数强度准则模型为基础,建立了轻质多孔混凝土弹脆塑性损伤本构模型,并与试验数据对比验证了模型的合理性。3.建立了密肋复合墙体框格单元宏观损伤模型。在框格单元损伤破坏和能量耗散机理分析的基础上,考虑材料损伤提出了损伤纤维杆元刚架单元和拉压斜杆损伤单元,建立了框格单元宏观损伤模型。并在前期弹塑性有限元分析程序MRCS的基础上二次开发了宏观损伤分析程序MRCS-D,模拟了框格单元的损伤破坏过程,得到了各单元的损伤值,即局部损伤指标LDI。4.进行了密肋复合墙体整体损伤分析及构件耗能贡献率研究。基于能量理论与方法,由局部损伤指标LDI构造了一种可以用于评估结构的整体损伤指标GDI,合理解释了密肋复合墙体从材料细观损伤到结构宏观损伤的演化规律,并运用整体损伤指标将密肋复合墙体的损伤破坏过程划分为5个性能水平。同时,计算了各构件在破坏过程中的耗能贡献率并揭示了其相互转化规律。5.进行了温、湿度场下密肋复合墙体损伤研究。以框格单元为研究对象,进行了温、湿度传导机理及温、湿度损伤的研究,提出了温、湿度损伤弹性本构模型,运用有限元方法进行了数值模拟,量化了温、湿度因素在墙体损伤中的作用,分析了墙体损伤的原因,提出了控制裂缝的有效措施。更多还原

【Abstract】 Multi-ribbed composite wall structure is a new structural system, characterized by ecology, saving energy and good aseismic performance. Much progress has been achieved in previous study through a lot of systematic tests and theoretical researches on multi-ribbed composite walls. But further research on damage problems of multi-ribbed composite walls should be made, such as damage evolution of material, infilled frames and structure subject to loads in service, damage degree evaluation of walls, identify performance level of walls, control on performance damage of walls in the condition of temperature and humidity and so on. The preceding research provides effective means for determing the energy dissipation mechanism and endurance properties of this structure. Taking multi-ribbed composite wall for consideration, detailed research is made on the above contents. Main research works and productions are as follows:1. The basic mechanical performance tests of porous lightweight concrete were made for porous lightweight concrete concluding autoclaved aerated concrete and foamed concrete. Cube compression strength, prismoid compression strength, Young’s modulus and stress-strain curves were obtained. Those provide reliable foundation for finite element calculation.2. The elastic-brittle-plastic damage constitutive model and multi-axis strength criterion model were presented. According to damage properties of porous lightweight concrete, four parameters strength criterion model was proposed. Elastic-brittle-plastic damage constitutive model of porous lightweight concrete was presented. The basic theory of the damage constitutive model consists of elastic-brittle-plastic of porous lightweight concrete, continuous dielectric mechanics, basic principle of irreversible thermodynamics, and four parameters strength criterion model. Finally numerical simulation using test data was made.3. The macro-damage model of fundamental element of masonry infilled frame was presented. Based on the inner mechanism of damage and energy dissipation, the rigid frame elements of damage fiber bars were presented through considering damage of material and adopting fiber bars. Elementary stiffness matrix with damage was deduced. The damage variable was defined. Damage evolution equation was presented. Then the macro-damage model of fundamental element of masonry infilled frame was presented, combined with damage elements of tension and compression diagonal braces. Macro-damage finite element analysis program MRCS-D was developed. Mechanical analysis and numerical simulation were made using MRCS-D, and damage values of each element, named local damage index (LDI) were obtained.4. General damage analysis of multi-ribbed composite walls was made, and the performance levels of damage were determined. A new damage index, named general damage index (GDI) was proposed through energy method. It is also showed that the damage evolution rule between micro-damage of material and macro-damage of structure for multi-ribbed composite walls is right. Five performance levels for damage process of multi-ribbed composite walls were determined using GDI. Meanwhile, the contribution ratios and mutual change relations of masonry, ribbed-beam and ribbed-column were calculated, for the whole process from integrated to destroyed process when multi-ribbed composite walls subjected to loads.5. The research on damage of multi-ribbed composite walls subjected to temperature and humidity field were made. The research on temperature and humidity conduction mechanism and damage mechanism were made. The elastic constitutive model of temperature and humidity damage was presented. The element finite model accorded with practical situation was presented. It is found that sharp drop of temperature and humidity was the reason of sharp raise of surface stress. Appling temperature loads on concrete surfaces and preformed cracks were economic and effective methods for controlling surface temperature cracks in the production of multi-ribbed composite walls. And it is consistent with practical situations.更多还原