基于OpenSEES数值模拟的工字形截面支撑低周疲劳性能研究  

Low-cycle fatigue performance of I-shaped steel bracing members based on openSEES numerical simulation

作　　者：曾立静 张文元[1,2] 丁玉坤[1,2] ZENG Lijing;ZHANG Wenyuan;DING Yukun(Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education,Harbin Institute of Technology,Harbin 150090,China;Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology,Harbin Institute of Technology,Harbin 150090,China)

机构地区：[1]哈尔滨工业大学结构工程灾变与控制教育部重点实验室,黑龙江哈尔滨150090 [2]哈尔滨工业大学土木工程智能防灾减灾工业和信息化部重点实验室,黑龙江哈尔滨150090

出　　处：《建筑结构学报》2019年第12期119-127,共9页Journal of Building Structures

基　　金：国家自然科学基金面上项目(51178145);国家自然科学基金青年基金项目(51108125)

摘　　要：为研究工字形截面支撑低周疲劳性能,进行了18根Q235和21根ST12材质焊接工字形钢支撑在等幅轴向循环位移作用下的OpenSEES有限元分析,在验证模拟结果和试验结果吻合较好的同时,提出利用支撑几何参数(长细比、宽厚比、高厚比、屈服点)修正的表征应变作为预测支撑低周疲劳寿命的控制参量,给出了对应修正公式和寿命预测公式。表征应变与支撑低周疲劳寿命满足对数线性关系,据此预测的支撑低周疲劳寿命离散性较小且基本位于试验值1. 5倍分散带内。对于变幅加载条件下的支撑寿命预测,利用Miner线性损伤理论对39组支撑试验数据进行以裂纹萌生寿命为终止点的损伤值统计,给出了容许损伤建议值作为预测寿命对应损伤值。而后,引入5组单斜工字钢支撑框架低周疲劳试验结果进行验证,其预测寿命均接近试验裂纹萌生寿命,可以较为保守地评估该类支撑的低周疲劳寿命,且支撑截面损伤分布与试验破坏模式保持一致。以上均证明该数值模拟方法和低周疲劳寿命预测方法的准确性和高效性,可为框架支撑结构低周疲劳性能的研究提供借鉴。In order to study the low-cycle fatigue behavior of I-shaped steel bracing members,numerical simulations of18 Q235 and 21 ST12 welded steel braces under constant amplitude cyclic axial displacement were carried out by using OpenSEES. Based on these results,which were consistent with the test ones,representative strain modified by geometric parameters( including slenderness ratio,width-to-thickness ratio,height-to-thickness ratio and yield stress)of braces was proposed as a new control parameter to predict low-cycle fatigue life of bracing members. And its corresponding formula for modification and prediction was given. It is shown that the predicted low-cycle fatigue lives are basically located within a safe scatter band of 1. 5 according to the logarithmic linear relationship between this strain and the low-cycle fatigue life. For the life prediction of brace under variable amplitude loading,the Miner linear damage theory was used to conduct damage statistics of 39 bracing members,with the crack initiation life as the termination point,and the recommended allowable damage value was given as the corresponding damage value of the predicted life. Then a simulation of five single diagonal braced frame tests was conducted. The predicted lives of all these specimens are close to crack initiation life of tests,which prove that it can give the brace a more conservative evaluation of the low-cycle fatigue behavior,and the section damage distribution is consistent with the experimental failure mode. All the results demonstrate the accuracy and efficiency of the method of numerical simulation and lowcycle fatigue life prediction,which can provide a reference for the research on the low-cycle fatigue performance of high-rise braced frames.

关 键 词：工字形截面支撑 容许损伤 OpenSEES模拟 低周疲劳性能 低周疲劳寿命 

分 类 号：TU391[建筑科学—结构工程] TU311.41