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四角钢组合约束型防屈曲支撑具有轻量化及装配化等特点,其组成特点是采用高强度螺栓把4个外围约束角钢连接成整体,形成对内核构件的整体约束作用。该类防屈曲支撑受轴压荷载作用时,4个外围约束角钢之间以及内核与外围约束构件之间存在复杂的相互作用,外围约束构件受力状态复杂。文中进行了5根四角钢组合约束型防屈曲支撑在轴压循环荷载作用下的试验研究,考察其受力性能与破坏机理、轴压承载力与骨架曲线以及约束比参数对它们的影响。对试验试件建立精细化有限元模型(螺栓单元与接触单元),模拟分析其加载过程的应力与变形发展历程。通过对比各试件的试验实测结果、理论计算结果与精细有限元模拟分析结果,表明有限元分析结果可偏于安全地预测试件的实际受力状态;如果计入内核端部附加偏心距的影响,理论设计公式可用于这类防屈曲构件的承载力设计,具有较高的可靠性。
The four-bar combination constrained buckling support has the characteristics of light weight and assembly, and is characterized in that four peripheral restraining angles are connected by a high-strength bolt to form an integral constraint on the inner core member. When the buckling brace of this kind is under axial load, there are complex interactions among the four peripheral restraining angles and between the inner core and the peripheral restraining members, and the stress conditions of the peripheral restraining members are complicated. In this paper, the experimental research on the restrained buckling brace of 5-square-steel constrained buckling under axial compression was carried out. The effects of mechanical behavior and failure mechanism, axial compressive load-carrying capacity, skeleton curve and restraint ratio parameters on the buckling behavior were studied. A refined finite element model (bolt unit and contact unit) was established on the test specimen to simulate the development process of stress and deformation during the loading process. By comparing the test results, the theoretical calculation results and the detailed finite element simulation results of the test specimens, it is shown that the finite element analysis results can safely predict the actual stress state of the specimen. If the eccentricity of the end of the core is added Influence, the theoretical design formula can be used for bearing capacity design of such buckling-proof members, with high reliability.