摘要
目的为实现结构的损伤定位及损伤程度评估,研究一种适用于实际结构的智能损伤检测策略.方法利用结构振动时程响应进行结构的损伤检测,提出针对结构损伤前的加速度响应,运用遗传算法和Newmark常平均加速度法识别出结构损伤前的层间刚度值;运用同样的方法对损伤后的加速度响应处理识别出层间刚度值;结合假设检验,在验证损伤阈值有效的基础上,比较结构损伤前后的层间刚度值,完成损伤定位与损伤程度检测.结果数值模拟与实验室试验测试发现损伤定位位置与实际情况一致,该损伤检测策略直接运用时域内的加速度响应来构造适应度函数,不仅简化了损伤检测的过程,同时也避免了时频域转换时的误差,损伤程度预测相对误差最大为3.18%.结论笔者提出的损伤检测方法是可行、有效的,有较好的抗噪性、鲁棒性.
This paper proposes an intelligent damage detection strategy in terms of measured acceleration responses in practical structures,which is applicable to damage location and extent assessment.Firstly,genetic algorithm(GA)and the Newmark constant average acceleration method are employed to identify the undamaged stiffness with the acceleration responses in healthy state;Secondly,acceleration responses in damage or practical states are processed by the above same methods so as to identify the current stiffness;Thirdly,after the damage threshold is determined by the hypothesis testing,damage localization and extent detection are performed by comparing the stiffness difference between the undamaged and current stiffness.Localization results through the validation of a numerical simulation and a laboratory experiment agree well with their practical cases.This damage detection strategy not only reduces the complexity of the detection progress,but also avoids the occurrence of the time-frequency domain transform error owing to the acceleration responses in the time domain being constructed the fitness function directly.Additionally,the maximum relative error is 3.18% for damage extent prediction.This implies that the intelligent method is effective and applicable to damage detection;furthermore,it has good noise tolerance and robustness.
引文
[1]姜绍飞.基于神经网络的结构优化与损伤检测[M].北京:科学出版社,2002.(Jiang Shaofei.Structural optimization and damagedetection based on neural netw ork[M].北京:科学出版社,2002.)
[2]姜绍飞,吴兆旗.结构健康监测与智能信息处理技术及应用[M].北京:中国建筑工业出版社,2011.(Jiang Shaofei,Wu Zhaoqi.The technique and itsapplication of structural health monitoring and intelli-gent information[M].Beijing:China Architecture&Building Press,2011.)
[3]姜绍飞,姚娟.基于粗集的PNN结构损伤识别方法[J].沈阳建筑大学学报:自然科学版,2008,24(3):357-361.(Jiang Shaofei,Yao Juan.Structural damage identifi-cation method based rough set and probabilistic neu-ral netw ork[J].Journal of Shenyang Jianzhu Univer-sity:Nature Science,2008,24(3):357-361.)
[4]Perry M J,Koh C G.Output-only structural identifi-cation in time domain:numerical and experimentalstudies[J].Earthquake Engng Struct.Dyn.,2008,37:517-533.
[5]Andrzej Swiercz,Przemyslaw Kolakowski,JanHolnicki-Szulc.Damage identification in skeletalstructures using the virtual distortion method in fre-quency domain[J].Mechanical Systems and SignalProcessing,2008,22(8):1826-1839.
[6]Lang Z Q,Park G,Farrar C R,et al.Transmissibilityof non-linear output frequency response functionsw ith application in detection and location of damagein MDOF structural systems[J].International Journalof Non-Linear Mechanics,2011,46(6):841-853.
[7]Mark W D,Lee H,Patrick R,et al.A simple fre-quency-domain algorithm for early detection of dam-aged gear teeth[J].Mechanical Systems and SignalProcessing,2010,24(8):2807-2823.
[8]易伟建,刘霞.基于遗传算法的结构损伤诊断研究[J].工程力学,2001,18(2):64-71.(Yi Weijian,Liu Xia.Study on structural damage di-agnosis based on genetic algorithm[J].EngineeringMechanics,2001,18(2):64-71.)
[9]袁颖,林皋,闫东明.基于残余力向量法和改进遗传算法的结构损伤识别研究[J].计算力学学报,2007,24(2):224-230.(Yuan Ying,Lin Gao,Yan Dongming.Study onstructural damage identification based on residualforce method and improved genetic algorithm[J].Journal of China Computational Mechanics,2007,24(2):224-230.)
[10]Chou J H,Ghaboussi J.Genetic algorithm in structur-al damage detection[J].Computers and Structures,2001,79:1335-1353.
[11]Mares C,Surace C.An application of genetic algo-rithms to identify damage in elastic structures[J].Journal of Sound and Vibration,1996,195(2):195-215.
[12]刘坚,李睿,于德介,等.正向选择免疫算法在结构损伤诊断中的应用[J].工程力学,2008,25(7):40-44.(Liu Jian,Li Rui,Yu Dejie,et al.Application ofstructural damage diagnosis based on positive selec-tion algorithm inspired by immune system[J].Engi-neering Mechanics,2008,25(7):40-44.)
[13]Perera R,Fang Shengen,Huerta C.Structural crackdetection w ithout updated baseline model by singleand multiobjective optimization[J].Mechanical Sys-tems and Signal Processing,2009(23):752-768.
[14]Raich A M,ASCE A M,Liszkai T R.Improving theperformance of structural damage detection methodsusing advanced genetic algorithms[J].Journal ofStructural Engineering,2007,133(3):49-461.
[15]谢礼立,吕大刚.结构动力学理论及其在地震工程中的应用[M].北京:高等教育出版社,2005.(Xie Lili,LüDagang.Structural dynamics theoryand its application in earthquake engineering[M].Beijing:Higher Education Publishing House,2005.)
[16]王勖成,邵敏.有限单元法基本原理和数值方法[M].北京:清华大学出版社,1997.(Wang Maocheng,Xiao Min.Basis principles andnumerical method of finite element method[M].Beijing:Tsinghua University Press,1997.)