Deformation Characteristics of Beams and Beam-Columns Subjected to Nonstationary Loading History at Strain Hardening Region.

本研究采用循环塑性模型分析结构钢弹塑性滞回特性。该模型是在Petersson和Popov提出的多面塑性模型的基础上改进而成的。该模型适用于低碳钢和高强度钢。利用得到的材料特性函数，对控制应变下反复拉压加载的圆杆试件进行弹塑性有限元分析。通过与相应试验结果的比较，证实了从工程角度看，用该模型计算的应力-应变关系具有足够的精度。为了利用所提出的应力-应变模型计算梁和梁柱的M-<PHI>关系，采用了Chen和Atsuta提出的切线刚度法，并进行了一些修正。JIS（日本工业标准）-5型试件由h形梁试件成形。材料性能函数由拉伸试验和拉伸压缩试验相结合确定。采用钻孔法分析了残余应力的分布，并假设残余应力为简单型分布。将计算得到的M-<PHI>关系与作者进行的实验结果进行了比较，从工程角度证实了用该模型计算的滞后M-<PHI>关系的精度是足够好的。

In this study, a cyclic plasticity model for elasto-plastic hysteretic behaviors of structural steel is employed. The model is constructed by the refinements of a multi surface plasticity model introduced by Petersson and Popov. This model is applied to mild steel and high strength steel. Using material property functions obtained, elasto-plastic finite element analyses are carried out for round-bar specimens subjected to repetitive tension- compression loading under controlled strain. By comparing the results with those of corresponding experiments, it is confirmed that the accuracy of the stress-strain relations calculated by means of the proposed model is good gnough from the engineering standpoint. In order to calculate M-<PHI> relations of beams and beam-columns by means of the proposed stress-strain odel, the tangent stiffness method introduced by Chen and Atsuta is employed with some amendments. JIS(Japanese Industrial Standards)-5 typespecimens were shaped from a H-shaped beam specimen. Material property functions were determined by a combination of tension tests and tension-compression tests. Distribution of residual stress was analyzed by the drilling method and a simple type distribution was assumed. The calculated M-<PHI> relations are compared with those obtained by experiments which the author has carried out and it is confirmed that the accuracy of the hysteretic M-<PHI> relations calculated by means of the proposed model is good enough from the engineering standpoint.