结构用泡沫钢材本构模型及泡沫钢构件受力性能研究

Foamed steel is a new porous metal material, which can alter the density, elastic modulus and yield strength by introducing voids. Reasonable design can greatly increase the capacity of global and local stability of structural member in same steel consuming, so as to increase its bearing capacity and save steel with reasonable design. Meanwhile, as large quantity energy is absorbed by plastic compressing of voids under severe earthquake, at the same time the structure has enough bearing capacity, so brittle failure of buildings may be avoided. The application of foamed steel will promote the development of steel structures vastly, but the research of properties of structural foamed steel and foamed steel structure is still rare up to now. Based on the study of foamed steel material, the project will carry out the study on mechanical properties of structural foamed steel, and on the bearing behavior of members as follows: (1) the mecanical propertity and the constitutive model of structural foamed steel; (2) the global stability and local buckling of foamed steel members under static load; (3) hysteretic behavior of foamed steel members under cyclic load; (4) design method of foamed steel members, design index and details. The research will greatly improve the research level and provide the criterion for compiling relative standard, promote the practice of foamed steel structures in China.

泡沫钢是一种新型多孔金属材料，通过改变孔隙率和孔结构来改变钢材密度、弹性模量和屈服强度。在相同用钢量的情况下，合理的设计可以有效地提高结构构件整体稳定和局部稳定性能，从而提高承载力，达到节约钢材的目的。同时，在强烈地震或冲击荷载作用下，孔隙的塑性压缩能够吸收大量的能量且结构具有足够的承载力，避免结构发生脆性破坏。泡沫钢的应用将会极大地促进钢结构的发展，但目前在泡沫钢结构构件性能方面还鲜有研究。项目在已有泡沫钢材料性能研究的基础上，选择可用于钢结构的泡沫钢材，进行材料的力学性能和构件的受力性能研究。主要内容包括：（1）结构用泡沫钢材的材料性能和本构模型；（2）泡沫钢构件在静力荷载下的整体稳定与局部稳定性能；（3）泡沫钢构件在循环荷载下的滞回性能；（4）泡沫钢构件设计方法、设计指标和构造措施。项目的研究成果将极大地提升我国泡沫钢结构的研究水平，为制订相关标准提供依据，从而促进工程应用。

项目用造孔剂法制备出了不同孔径、不同孔隙率的泡沫钢，分析工艺参数对泡沫钢孔结构和孔隙率的影响，建立了中低孔隙率泡沫钢的成品孔隙率非线性计算公式。进行泡沫钢材料力学性能试验，研究不同制备工艺参数对力学性能的影响，分析了制备过程中造孔剂碎屑对泡沫钢力学性能的影响，并建立了泡沫钢材料力学性能与孔隙率的关系式。在工厂车间中制备出大尺寸泡沫钢，进行了材料滞回性能研究，使用Ramberg-Osgood模型拟合了泡沫钢循环骨架曲线，标定了Chaboche本构模型以及Giuffre-Menegotto-Pinto本构模型的关键参数，发现这两个模型均可较好地描述泡沫钢的滞回特性。进行了泡沫钢轴压构件整体和局部稳定性能试验，研究了构件的承载力和破坏模式，发现泡沫钢材的应变强化效应对轴压构件承载力的提高作用很小。