摘要
近年来国内钢桥、钢-混组合梁桥等钢结构桥梁的应用十分广泛。为保障桥梁的安全耐久,深入开展钢桥疲劳状态评估研究至关重要。这其中,将数字图像采集和传输等现代化技术应用于疲劳监测和评估是研究的热点之一。为了解数字图像在钢桥构造细节疲劳研究中的形态和数据特征,采用常用桥梁钢Q345qD试件进行疲劳与三维数字应变图像同步测量试验。针对图像最大应变,研究自动处理和快速提取方法。分析图像最大应变随疲劳次数变化的形态特征,将试验数据拟合形成实测曲线函数并予以优化。结合疲劳S-N曲线方程研究应变随疲劳过程变化的计算通式。试验结果表明:通过批处理程序对实测最大应变值图像进行剪裁、识别和数字转换,可满足快速提取需求;实测应变曲线随着疲劳次数增加呈现指数函数的上升趋势,且趋势线伴随疲劳加载的往复具有一定的宽度;提取疲劳加载峰值点数据,则可在大约70%寿命或者更早时段出现应变明显上升变化。研究表明:数字图像应变曲线是疲劳S-N曲线上单个测点损伤过程的细化;所提出的应变曲线与S-N曲线相融合的ε-N′通式,体现出疲劳构造细节固有的损伤特征。
In recent years,steel bridges,steel-concrete composite girder bridges and other steel bridges have been widely used in China.In order to ensure the safety and durability of bridges,it is very important to carry out in-depth research on fatigue state assessment of steel bridges.Among them,the application of modern technology such as digital image acquisition and transmission in fatigue monitoring and assessment is one of the research hotspots.In order to understand the morphological and data characteristics of digital image in the fatigue research of steel bridge structure details,the fatigue and three-dimensional digital strain image measurement tests were carried out synchronously by using common bridge steel Q345qD specimens.Automatic processing and fast extraction methods were explored for the maximum strain on the image.The morphological characteristics of the maximum strain of the image with the number change of fatigue cycles were analyzed.In addition the test data were fitted to form a measured curve function and were optimized.Combined with the fatigue S-N curve equation,the general formula for calculating the strain changes with the fatigue process was determined.The results showed that the measured maximum strain value image could be cropped,identified and converted digitally by a batch program,which could meet the requirements of fast extraction.The measured strain curve showed an upward trend of exponential function with the increase of number of fatigue cycles,and the trend curve had a certain width with the cyclic loading of fatigue.By extracting the peak point data,the strain showed a significant upward change at approximately 70%of fatigue life,or earlier.It was shown that the curve of digital image strain was the refinement of the damage process at a single measuring point on the fatigue S-N curve.The proposedε-N′general formula integrated strain curve with S-N curve exhibited the inherent damage characteristics of the structural details.
作者
王昌将
马芹纲
张玉玲
李金波
杨云涛
张楠
谢爱华
高占军
张贤卿
WANG Changjiang;MA Qingang;ZHANG Yuling;LI Jinbo;YANG Yuntao;ZHANG Nan;XIE Aihua;GAO Zhanjun;ZHANG Xianqing(Zhejiang Shuzhi Jiaoyuan Technology Co.,Ltd.,Hangzhou 310030,China;China Academy of Railway Sciences Co.,Ltd.,Beijing 100081,China;Zhejiang Shuren University,Hangzhou 310015,China;Beijing Jiaotong University,Beijing 100044,China;China Railway Fifth Survey and Design Institute Group Co.,Ltd.,Beijing 102600,China)
出处
《工业建筑》
北大核心
2023年第10期157-163,134,共8页
Industrial Construction
基金
浙江省交通运输厅科技计划项目(2020001)。
关键词
疲劳试验
ARAMIS应变测量
疲劳损伤过程
应变曲线
fatigue test
ARAMIS optical strain measuring technique
fatigue damage process
strain curve
作者简介
第一作者:王昌将,男,1971年出生,高级工程师。电子信箱:wangcj@zjic.com。
