基于模型修正的海洋平台结构损伤识别试验研究
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摘要
损伤识别是海洋平台结构健康监测的核心问题,对于保障结构的安全服役具有重要的意义。文中将交叉模型交叉模态(CMCM)有限元模型修正方法应用到了导管架式海洋平台结构的损伤识别中。针对实测模态含噪声条件下该方法遇到的"病态"求解难题,引入了截断奇异值分解正则化方法,提出了基于正则化模型修正的损伤识别过程。为验证该过程的有效性,制做了某导管架平台的钢质缩尺简化模型,并在两个典型构件处设置了损伤;利用冲击激励对结构进行了振动测试;根据模态识别结果,采用正则化模型修正过程对各损伤工况进行了损伤识别。结果表明,利用有限的低阶含噪声模态,借助正则化求解技术,该模型修正方法可有效地识别导管架平台结构的损伤。
Damage identification is the key issue of structural health monitoring on offshore platforms, which is of great significance to ensure the safe service of structures. The Cross Model Cross Mode updating method is applied to identify the damages of the offshore platform structure. Regularization method of Truncated Singular Value Decomposition is introduced to solve the problem of "ill-conditioned" model updating equations, when the measured modes are noise polluted. Then, a damage identification process based on regularized model updating is produced. To ascertain the feasibility of the method, a simplified steel scale model of a jacket platform is manufactured, and damage is preset in two typical members. Vibration test of the model structure is carried out by impact excitation. Then, according to the results of model identification, the preset damage cases are identified by the regularized model updating process. Results show that using limited low-order and noise polluted modes,with the help of regularization solution technique, this model updating method can effectively identify the damage of the jacket platform structure.
Damage identification is the key issue of structural health monitoring on offshore platforms, which is of great significance to ensure the safe service of structures. The Cross Model Cross Mode updating method is applied to identify the damages of the offshore platform structure. Regularization method of Truncated Singular Value Decomposition is introduced to solve the problem of "ill-conditioned" model updating equations, when the measured modes are noise polluted. Then, a damage identification process based on regularized model updating is produced. To ascertain the feasibility of the method, a simplified steel scale model of a jacket platform is manufactured, and damage is preset in two typical members. Vibration test of the model structure is carried out by impact excitation. Then, according to the results of model identification, the preset damage cases are identified by the regularized model updating process. Results show that using limited low-order and noise polluted modes,with the help of regularization solution technique, this model updating method can effectively identify the damage of the jacket platform structure.
引文
[1] Wang S. Damage detection in offshore platform structures from limited modal data[J]. Applied Ocean Research, 2013, 41:48-56.
[2] Alvandi A, Cremona C. Assessment of vibration-based damage identification techniques[J]. Journal of Sound and Vibration, 2006, 292(1-2):179-202.
[3] Simoen E, Roeck G D, Lombaert G. Dealing with uncertainty in model updating for damage assessment:A review[J]. Mechanical Systems and Signal Processing, 2015, 56-57:123-149.
[4]尹涛,朱宏平,余岭.基于敏感性的结构损伤识别中的噪声分析[J].应用数学和力学,2007, 28(6):659-667.
[5]肖书敏,闫云聚,姜波澜.基于小波神经网络方法的桥梁结构损伤识别研究[J].应用数学和力学,2016,37(2):149-159.
[6]朱劲松,孙雅丹.基于小波包能量的桥梁损伤识别指标[J].振动、测试与诊断,2015, 35(4):715-721.
[7] Entezami A, Shariatmadar H. Damage detection in structural systems by improved sensitivity of modal strain energy and Tikhonov Regularization Method[J]. International Journal of Dynamics and Control, 2014, 2(4):509-520.
[8] Hu S-L J, LI H, Wang S. Cross-model Cross-mode Method for model updating[J]. Mechanical Systems and Signal Processing, 2007, 21:1690-1703.
[9] Li H, Wang J, Hu S-L J. Using Incomplete modal data for damage detection in offshore jacket structures[J]. Ocean Engineering, 2008,35:1793-1799.
[10]李英超.基于模态参数识别的海洋平台结构模型修正技术研究[D].青岛:中国海洋大学,2012.
[11]常晓通,闫云聚,刘鎏. Landweber迭代正则化方法在动态载荷识别中的应用[J].应用数学和力学,2013,34(9):948-955.
[12] Hansen P C. The discrete picard condition for ill-posed problems[J]. BIT,1990,30:658-672.
[13] Tikhonov A N. Solution of incorrectly formulated problems and the regularization method[J]. Soviet Math Dokl, 1963,4:1035-1038.
[14] Friswell M I, Mottershead J E, Ahmadian H. Finite-element model updating using experimental test data:Parametrization and regularization[J]. Philosophical Transactions of the Royal Society of London, 2001, 359:169-186
[15]李萍,王树青,李华军.特征系统实现算法中的噪声问题研究[J].中国海洋大学学报,2011,41(7/8):176-182.
[16] Wang S, Zhang J, Liu J, et al. Comparative study of modal strain energy based damage localization methods for three-dimensional structure[C]//Proceedings of the 20th International Offshore and Polar Engineering Conference, Beijing, 2010:398-403.
[17] Wang S, Liu F, Zhang M. Modal strain energy based structural damage localization for offshore platform using simulated and measured data[J]. Journal of Ocean University of China(Oceanic and Coastal Sea Research), 2014, 13(3):397-406.
[2] Alvandi A, Cremona C. Assessment of vibration-based damage identification techniques[J]. Journal of Sound and Vibration, 2006, 292(1-2):179-202.
[3] Simoen E, Roeck G D, Lombaert G. Dealing with uncertainty in model updating for damage assessment:A review[J]. Mechanical Systems and Signal Processing, 2015, 56-57:123-149.
[4]尹涛,朱宏平,余岭.基于敏感性的结构损伤识别中的噪声分析[J].应用数学和力学,2007, 28(6):659-667.
[5]肖书敏,闫云聚,姜波澜.基于小波神经网络方法的桥梁结构损伤识别研究[J].应用数学和力学,2016,37(2):149-159.
[6]朱劲松,孙雅丹.基于小波包能量的桥梁损伤识别指标[J].振动、测试与诊断,2015, 35(4):715-721.
[7] Entezami A, Shariatmadar H. Damage detection in structural systems by improved sensitivity of modal strain energy and Tikhonov Regularization Method[J]. International Journal of Dynamics and Control, 2014, 2(4):509-520.
[8] Hu S-L J, LI H, Wang S. Cross-model Cross-mode Method for model updating[J]. Mechanical Systems and Signal Processing, 2007, 21:1690-1703.
[9] Li H, Wang J, Hu S-L J. Using Incomplete modal data for damage detection in offshore jacket structures[J]. Ocean Engineering, 2008,35:1793-1799.
[10]李英超.基于模态参数识别的海洋平台结构模型修正技术研究[D].青岛:中国海洋大学,2012.
[11]常晓通,闫云聚,刘鎏. Landweber迭代正则化方法在动态载荷识别中的应用[J].应用数学和力学,2013,34(9):948-955.
[12] Hansen P C. The discrete picard condition for ill-posed problems[J]. BIT,1990,30:658-672.
[13] Tikhonov A N. Solution of incorrectly formulated problems and the regularization method[J]. Soviet Math Dokl, 1963,4:1035-1038.
[14] Friswell M I, Mottershead J E, Ahmadian H. Finite-element model updating using experimental test data:Parametrization and regularization[J]. Philosophical Transactions of the Royal Society of London, 2001, 359:169-186
[15]李萍,王树青,李华军.特征系统实现算法中的噪声问题研究[J].中国海洋大学学报,2011,41(7/8):176-182.
[16] Wang S, Zhang J, Liu J, et al. Comparative study of modal strain energy based damage localization methods for three-dimensional structure[C]//Proceedings of the 20th International Offshore and Polar Engineering Conference, Beijing, 2010:398-403.
[17] Wang S, Liu F, Zhang M. Modal strain energy based structural damage localization for offshore platform using simulated and measured data[J]. Journal of Ocean University of China(Oceanic and Coastal Sea Research), 2014, 13(3):397-406.