A Study on Development of Constitutive Equation for Structural Steel under Cyclic Loading and Application the Constitutive Equation to the Finite Element Method

提出了一种描述钢的塑性应变与真实应力关系的本构方程，该方程可以用单调加载曲线来预测钢的循环行为。采用有限元法分析了钢结构的循环性能。单向拉压下钢板的滞回性能分析了等轴向位移幅值下方板的循环性能。结果表明，当宽厚比参数大于0.5时，受压构件的抗压强度降低。对箱形钢短柱的强度和延性进行了分析，结果表明，在地震荷载作用下，宽厚比参数是影响局部屈曲的主要因素。对宽厚比参数的限制对提高钢管的强度和延性是有效的。钢管抗震性能的分析研究对钢管进行了2种轴压和3种循环荷载作用下的有限元分析。根据分析结果，提出了参数钢管在循环荷载作用下的极限径厚比。日本兵库县南部地震中受损钢管桥墩的数值模拟采用弹塑性有限元法对受损桥墩的循环荷载作用进行了分析。1.桥梁钢阻尼器装置的研制提出了一种超低屈服应力钢管阻尼器，并通过非线性地震反应分析阐明了这种钢管阻尼器对桥梁地震反应控制的实用性。

The constitutive equation to express the relationship between plastic strain and true stress is proposed, which predicts cyclic behavior of steels, using a monotonic loading curve. By the finite element method in which this constitutive equation is introduced, the cyclic behaviors of steel structures are analyzed.Hystreretic Behavior of Steel Plates under Uniaxial Tension and Compression The cyclic behaviors of square plates are analyzed with constant axial displacement amplitude. It is shown that the compression strength reduces when width-to-thickness ratio parameter is greater then 0.5Strength and Ductulity of Steel Box Stub-Columns Subjected to Compression and Cyclic Bending Analysis results show that the width-to-thickness ratio parameter is main factor of local buckling under seismic loading. Restriction of whidth-to-thickness ratio parameter is effective to improve the strength and ductility.An Analytical Study on Earthquake-Resistance of Steel Pipe The finite element analyzes are carried out under 2 types of axial compression and 3 types of cyclic loading. The limiting radius-to-thickness ratio of parameter steel pipe under cyclic loading is suggested according to the results of analysis.Numerical Simulation on Dameged Steel Pipe Piers in Hyogoken-Nanbu Earthquake The cyclic behavior of damaged piers are analyzed by the elasto-plastic finite element method. Comparing with actual damage, the buckling mode and the yielded zone match the actual damageDevelopment of Steel Damper Device for Bridges A histeretic damper using ultra-low yield stress steel pipe is presented and it is clarified that this steel pipe damper is useful for the seismic-response-control for the bridge by non-linear seismic response analysis.