Development of analysis system to assess ultimate seismic behavior of steel piers accompanying fracture due to strain localization

开发分析系统来评估因应变局部化而导致断裂的钢桥墩的极限抗震性能

• 批准号: 11650483
• 负责人: GOTO Yoshiaki
• 金额: $ 2.11万
• 依托单位: Nagoya Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650483/
• 关键词: plasticity; constitutive equation; ductile fracture; seismic design; large deformation; 鋼製橋脚; 耐震; き裂; 繰り返し載荷; 有限要素解析

The major damages observed for thin-walled steel piers in the Great Kobe Earthquake are the fracture as well as the local bucklins of plate elements. Since the Kobe Earthquake, intensive cyclic loading tests on steel piers have been carried out to examine the ductility deterioration due the local buckling of plate elements. Furthermore, it is shown that the ultimate local buckling behavior of steel piers under cyclic loading can be accurately analyzed by the geometrically and materially nonlinear FEM analysis based on shell elements if some adequate cyclic plasticity model is used for the constitutive relation of steel. In contrast, the fracture observed in the Kobe Earthquake did not similarly occur in the cyclic loading tests and, hence, it is still a controversial issue how and why this fracture happened. The only fact obtained by the detailed observation on the fractured section of the damaged steel piers is that the brittle fracture initiated from a small ductile fracture. This im … More plies that the occurrence of the small ductile fracture is a necessary requirement for the occurrence of the brittle fracture. Therefore, the investigation into the ductile fracture of steel piers will make it possible to explain the cause of the fracture observed in the Kobe Earthquake.Herein, we present a numerical analysis method to predict the fracture of steel piers under cyclic loading and examine the applicability of this method by cyclic loading test on steel piers. In the analysis, the Gurson constitutive model is modified in order takes into account the cyclic behavior of steel and is implemented in the 3-dimentional solid element. The Gurson model is the most widely used plasticity model that can consider the nucleation and growth of micro voids closely related to the ductile fracture. In order to investigate the validity of the modified Gurson model, the initiation of ductile fracture is observed by conducting a cyclic loading test on thin-walled steel piers with circular cross section. From the comparison between the numerical analysis and the test results, it is shown that the locations of the ductile fracture in the steel piers can be qualitatively predicted by the modified Gurson model. However, regarding the deformation at the initiation of ductile cracks, some difference is observed between the analysis and the experiment. There still remains a difficult problem how to identify the initiation of the ductile cracks in experiment. This problem must be further examined in the future. Less

科比大地震中薄壁钢桥墩的主要破坏形式是板单元的断裂和局部屈曲。自科比地震以来，人们对钢桥墩进行了密集的循环荷载试验，以研究由于板单元的局部屈曲而导致的延性劣化。此外，研究表明，采用适当的循环塑性本构模型，基于壳单元的几何非线性和材料非线性有限元分析可以准确地分析钢桥墩在循环荷载作用下的极限局部屈曲行为。相反，在科比地震中观察到的断裂在循环载荷试验中没有类似地发生，因此，这种断裂是如何以及为什么发生的仍然是一个有争议的问题。通过对受损钢桥墩断裂断面的详细观察，得出的唯一事实是脆性断裂是由一个小的韧性断裂开始的。此im ...更多信息 指出小韧性断裂的发生是脆性断裂发生的必要条件。因此，对钢桥墩延性断裂的研究将有助于解释科比地震中钢桥墩断裂的原因。本文提出了一种预测钢桥墩在循环荷载作用下断裂的数值分析方法，并通过钢桥墩的循环荷载试验验证了该方法的适用性。在分析中，Gurson本构模型进行了修改，以考虑循环行为的钢，并在三维实体单元中实现。Gurson模型是目前应用最广泛的塑性模型，它可以考虑与韧性断裂密切相关的微孔洞的形核和长大。为了验证修正Gurson模型的有效性，通过对圆形截面薄壁钢桥墩进行循环加载试验，观察了延性断裂的起裂过程。数值分析结果与试验结果的对比表明，修正的Gurson模型可以定性地预测钢桥墩延性断裂的位置。然而，关于韧性裂纹萌生时的变形，分析和实验之间观察到一些差异。在实验中如何识别韧性裂纹的萌生一直是一个难题。今后必须进一步审查这个问题。少

项目成果

Obata,Mizutani,Goto: "Numerical approach to the ductile fracture of steel members"Proc.ICASS'99. Vol.2. 1021-1027 (1999)

Obata，Mizutani，Goto：“钢构件延性断裂的数值方法”Proc.ICASS99。

小畑,水谷,後藤: "鋼構造の延性破壊の有限要素法解析への導入に関する基礎的検討"土木学会論文集. I-48. 185-196 (1999)

Obata、Mizutani、Goto：“将钢结构延性断裂引入有限元分析的基础研究”日本土木工程师学会会刊 I-48（1999）。

M.Obata, A.Mizunita, Y.Goto: "Numerical approach to the ductile fracture of steel members"Proc. ICASS'99. 2. 1021-1027 (1999)

M.Obata，A.Mizunita，Y.Goto：“钢构件延性断裂的数值方法”Proc。

Obata,Mizutani,Goto: "Numerical approach to the ductile fracture of steel members"Proc.ICASS'99. 2. 1021-1027 (1999)

Obata，Mizutani，Goto：“钢构件延性断裂的数值方法”Proc.ICASS99。

M.Obata, A.Mizutani, Y.Goto: "The verification of plastic constitutive relation and its application to FEM analysis of plastic fracture of steel members"Proc. JSCE, I-48. 626. 185-196 (1999)

M.Obata，A.Mizutani，Y.Goto：“塑性本构关系的验证及其在钢构件塑性断裂有限元分析中的应用”Proc。