A Strain-equivalent Non-local Constitutive Model for Lamellar Dual-Phase Materials

Pearlitic steel is composed of numerous pearlitic colonies with randomly distributed orientations,and each colony is composed of many alternatively arranged parallel lamellas of ferrite and cementite.The pearlitic steel with fine interlamellar spacing possesses excellent mechanical properties,such as high strength,good resistance against wear,and high fatigue life,etc. Based on the inconsistency of the deformation between the two phases,a strain_equivalent and non_local constitutive model is proposed. Using this model,the effect of the interlamellar spacing of peailitic steel,a fundamental parmeter of the microstructure of pearlitic material, on its macroscopic mechanical behavior can be described without changing the local material parameters for each phase of the material.The asymmetrical cyclic plasticity of both the hot_rolled and the off_line full_length quenched pearlitic steel PD3 is analyzed.The comparison between the computational and the experimental results shows satisfactory agreement.     

Appropriate Technology and Corresponding Design Strategies for the Steel Construction Congregated Apartments

In this paper,notions on appropriate technology for the Steel Construction Congregated Apartments are proposed in order to deal with the technical impediment that arises from applying steel structural techniques to the congregated apartments.The appropriate technology for the steel construction congregated apartments is defined as systematic technologies that are in harmony with the status quo of Chinese productive force level,social culture and building technology,and as the strategies of choosing or balancing technology according to sustainable development principle.The principal design and constructing strategies of appropriate technology are as follows:(1) organization of residential space combined with steel construction techniques,(2) suitable structural system,(3) a new idea of fire resistance,and(4) kit building technique etc.A technological concept analysis about an ideal model of a steel construction system congregated apartment combined with the appropriate technology is also presented.     

Study and Practice of Safety Grade Assessment for Large Convention and Exhibition Centre

This paper takes "how to estimate the complex security of Large Convention and Exhibition Centre effectively" as the research goal.Based on analyzing the difficulties,target system,technical constitution,probing into the architecture,safety science,and using for reference the mathematics,operational research,statistics and modern system theory and method,trying to explore establishing an evaluation methodological system,which is provided with integrated characters on subject.Based on these ways,it exerts "quality to quantity" fuzzy analytical hierarchy process(FAHP) and aims at discussing the safety grade assessment of the Chongqing International Conference Exhibition Center focusing on designing theories.The aim is to enhance the integration of design practice and safe consciousness,strengthen the building safety management,and perfect city public security system.In practice,it is also an efficient tool for favoring values of architectural environmental safety.     

蠕变模型对约束钢梁抗火性能分析的影响

钢材在高温和荷载作用下产生明显蠕变变形,影响火灾中结构的变形和受力性能。现有的蠕变模型较多,但没有一个广泛适用的蠕变模型。不同的蠕变模型对钢结构抗火分析结果有很大影响。为了量化蠕变模型对约束钢梁抗火性能分析的影响,对5种常用的蠕变模型进行了对比分析。采用编写的约束钢梁计算程序,分别计算5种蠕变模型下约束钢梁的抗火性能并与试验数据进行对比。结果表明,采用Norton蠕变模型的计算结果与试验数据吻合最好。最后对影响约束钢梁抗火性能参数进行了研究,研究发现,Harmathy蠕变模型对约束梁抗火性能分析结果影响最大;不同蠕变模型对不同荷载比、约束刚度下的约束钢梁抗火性能影响程度均不同。     

闸门的优化设计

用平面体系的方法进行结构分析，对排灌机械中平面钢闸门的面板－梁格体系的优化设计进行了探讨，用边界搜索法将有约束优化问题转换为无约束优化问题，给出了优化设计程序框图进行实例理论验证，结果表明，彩本文介绍的优化方法设计，闸门的叶体积可减小２０％左右。     

现役钢闸门结构最低可靠度标准的确定

针对现役钢闸门结构最低可靠度标准的确定问题，在综合分析国内外相关文献的基础上，提出了基于经验校准法的现役钢闸门结构最低可靠度标准设置的方法，并确定出了现役钢闸门结构最低可靠度限值：大型闸门为0.8βT；中型闸门为0．9βT；小型闸门为0．85βT，从而为现役闸门结构剩余使用寿命的预测莫定了基础。