Zhuodong Yang, L. Huo, Jingkai Wang, Jing Zhou, Xiaoyu Bai
Concrete has been widely used in underwater structures. However, accidental voids near the concrete protective layer may weaken the bearing capacity of the structures and can even lead to severe disasters. Therefore, it is necessary to develop an efficient and convenient method for quantitatively identifying voids in concrete and guaranteeing structural safety. A percussion–acoustic method is commonly used to identify voids in concrete exposed to air, owing to its high efficiency and low‐cost. Nevertheless, its feasibility for underwater concrete remains questionable, owing to the complexity of the underwater environment. To address this limitation, this study conducted experimental and theoretical studies by using a percussion–acoustic‐based method to identify voids in underwater concrete while considering the fluid–structure coupling effect. The results demonstrate that the frequency characteristics of percussive sound pressure underwater are significantly different from those in air and are determined by the void scopes and depths. Accordingly, this study provides a potentially applicable method for evaluating the voids in underwater concrete.
{"title":"Feasibility study of percussion–acoustic‐based void identification for underwater concrete","authors":"Zhuodong Yang, L. Huo, Jingkai Wang, Jing Zhou, Xiaoyu Bai","doi":"10.1002/stc.3101","DOIUrl":"https://doi.org/10.1002/stc.3101","url":null,"abstract":"Concrete has been widely used in underwater structures. However, accidental voids near the concrete protective layer may weaken the bearing capacity of the structures and can even lead to severe disasters. Therefore, it is necessary to develop an efficient and convenient method for quantitatively identifying voids in concrete and guaranteeing structural safety. A percussion–acoustic method is commonly used to identify voids in concrete exposed to air, owing to its high efficiency and low‐cost. Nevertheless, its feasibility for underwater concrete remains questionable, owing to the complexity of the underwater environment. To address this limitation, this study conducted experimental and theoretical studies by using a percussion–acoustic‐based method to identify voids in underwater concrete while considering the fluid–structure coupling effect. The results demonstrate that the frequency characteristics of percussive sound pressure underwater are significantly different from those in air and are determined by the void scopes and depths. Accordingly, this study provides a potentially applicable method for evaluating the voids in underwater concrete.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84684679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Deformation is an intuitive reflection of the safety status of a dam. The construction of a dam deformation prediction model can predict the deformation and interpret the effects of environmental loads. The current research mainly focuses on the predictive ability of the model and rarely involves the interpretation of the load impact on deformation. Meanwhile, the selection of the model factors, such as water pressure factors and temperature factors, mostly relies on prior knowledge. In addition, the complex structure of multiple arch dams makes it difficult to capture the relationship between deformation and environmental loads. Consequently, the performance of conventional models based only on time domain information may be insufficient. In this paper, a deformation prediction model is established by integrating time frequency domain information. First, the deformation and load monitoring data are decomposed and regrouped according to the frequency characteristic of signals via kurtosis index‐based VMD. Second, the sequence relationship between the dam deformation and loads under different frequency characteristics is automatically captured based on the temporal convolution network (TCN). Finally, a quantitative method of the load impact is proposed based on the network parameters. The case results show that the proposed modeling paradigm has significantly improved the prediction accuracy. The quantification result of the load impact on the horizontal displacement change of the dam conforms to the actual state of the project during the analysis period. The work effectively supplements the research on the prediction of ML‐based models and interpretation of the load impact on deformation.
{"title":"Temporal convolution network‐based time frequency domain integrated model of multiple arch dam deformation and quantification of the load impact","authors":"Xingpin Wu, Dongmei Zheng, Yongtao Liu, Zhuoyan Chen, Xing‐Qiao Chen","doi":"10.1002/stc.3090","DOIUrl":"https://doi.org/10.1002/stc.3090","url":null,"abstract":"Deformation is an intuitive reflection of the safety status of a dam. The construction of a dam deformation prediction model can predict the deformation and interpret the effects of environmental loads. The current research mainly focuses on the predictive ability of the model and rarely involves the interpretation of the load impact on deformation. Meanwhile, the selection of the model factors, such as water pressure factors and temperature factors, mostly relies on prior knowledge. In addition, the complex structure of multiple arch dams makes it difficult to capture the relationship between deformation and environmental loads. Consequently, the performance of conventional models based only on time domain information may be insufficient. In this paper, a deformation prediction model is established by integrating time frequency domain information. First, the deformation and load monitoring data are decomposed and regrouped according to the frequency characteristic of signals via kurtosis index‐based VMD. Second, the sequence relationship between the dam deformation and loads under different frequency characteristics is automatically captured based on the temporal convolution network (TCN). Finally, a quantitative method of the load impact is proposed based on the network parameters. The case results show that the proposed modeling paradigm has significantly improved the prediction accuracy. The quantification result of the load impact on the horizontal displacement change of the dam conforms to the actual state of the project during the analysis period. The work effectively supplements the research on the prediction of ML‐based models and interpretation of the load impact on deformation.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88604899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
While structural displacements are essential information for structural health monitoring, they are not being widely used in practice due to the inconvenience. Recently, vision‐based displacement measurement methods have been introduced, which are more convenient and cost effective. However, vision‐based methods have generally not been used primarily for the continuous monitoring of structures, due to spatial constraints on obtaining an appropriate location to secure the field of view. A vision device shows not only the changes of objects in the scene but also the relative changes of view according to changes in the position to which it is mounted. Accordingly, this study proposes a methodology for measuring the structural displacement of a location where a camera is mounted, based on a camera motion‐induced relative view change. The method is organized into three steps. First, camera calibration is conducted with background targets to derive the camera parameters and coordinates of the target feature points. Second, by tracking the relative changes in the feature points according to the camera motion, the changed 2D‐image coordinates of the points are derived. Third, the displacement is calculated through the relationship between the changed 2D‐image coordinates and fixed 3D‐world coordinates of the target feature points using the camera parameters. The changes in view according to the camera motion are analyzed with simulation tests, and the applicability of the proposed method is verified through experimental tests. The results show that the proposed method can be used to rationally measure structural displacements.
{"title":"Vision‐based displacement measurement using a camera mounted on a structure with stationary background targets outside the structure","authors":"Yunwoo Lee, Geonhee Lee, D. Moon, H. Yoon","doi":"10.1002/stc.3095","DOIUrl":"https://doi.org/10.1002/stc.3095","url":null,"abstract":"While structural displacements are essential information for structural health monitoring, they are not being widely used in practice due to the inconvenience. Recently, vision‐based displacement measurement methods have been introduced, which are more convenient and cost effective. However, vision‐based methods have generally not been used primarily for the continuous monitoring of structures, due to spatial constraints on obtaining an appropriate location to secure the field of view. A vision device shows not only the changes of objects in the scene but also the relative changes of view according to changes in the position to which it is mounted. Accordingly, this study proposes a methodology for measuring the structural displacement of a location where a camera is mounted, based on a camera motion‐induced relative view change. The method is organized into three steps. First, camera calibration is conducted with background targets to derive the camera parameters and coordinates of the target feature points. Second, by tracking the relative changes in the feature points according to the camera motion, the changed 2D‐image coordinates of the points are derived. Third, the displacement is calculated through the relationship between the changed 2D‐image coordinates and fixed 3D‐world coordinates of the target feature points using the camera parameters. The changes in view according to the camera motion are analyzed with simulation tests, and the applicability of the proposed method is verified through experimental tests. The results show that the proposed method can be used to rationally measure structural displacements.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73627070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiaqi Chang, Hong-wei Huang, Dongming Zhang, Huiming Wu, Jing-ya Yan
In order to better understand the deformational behaviors of lining segments during shield tunneling, a case study of the real‐time monitoring on the deformation of a constructing shield tunnel in Shanghai by using the wireless sensor network (WSN) is presented. Eight tilt WSN nodes are installed on two rings with monitoring frequency of 10 min right after the erection of the rings. The nodes monitor the tilt change of segments in the tunnel cross section until the completion of the tunnel. The deformational behavior reflected by the rotation of segments reveals two kinds of deformation mode of tunnel ring during construction: the rotation and the ovalization. The rotation direction of tunnel ring is opposite to that of shield cutter. The direction of major axis of ovalization is horizontal most of the time and become vertical when the grouting of shield tail acts on the segments. When the lining segments are buried in the shield machine, the rotation of the ring plays an important role. The value of rotation is closely related to the cutter torque, and the relative rotation between the two monitored rings is 7.9 mm, which is large and needs considering as a load on tunnel structure during construction. While the lining segments are pulled out of the shield tail, the ovalization model are gradually dominant in these two modes. The horizontal diameters of rings show an increase–decrease–increase trend.
{"title":"Transverse deformational behaviors of segmental lining during shield tunneling: A case study","authors":"Jiaqi Chang, Hong-wei Huang, Dongming Zhang, Huiming Wu, Jing-ya Yan","doi":"10.1002/stc.3097","DOIUrl":"https://doi.org/10.1002/stc.3097","url":null,"abstract":"In order to better understand the deformational behaviors of lining segments during shield tunneling, a case study of the real‐time monitoring on the deformation of a constructing shield tunnel in Shanghai by using the wireless sensor network (WSN) is presented. Eight tilt WSN nodes are installed on two rings with monitoring frequency of 10 min right after the erection of the rings. The nodes monitor the tilt change of segments in the tunnel cross section until the completion of the tunnel. The deformational behavior reflected by the rotation of segments reveals two kinds of deformation mode of tunnel ring during construction: the rotation and the ovalization. The rotation direction of tunnel ring is opposite to that of shield cutter. The direction of major axis of ovalization is horizontal most of the time and become vertical when the grouting of shield tail acts on the segments. When the lining segments are buried in the shield machine, the rotation of the ring plays an important role. The value of rotation is closely related to the cutter torque, and the relative rotation between the two monitored rings is 7.9 mm, which is large and needs considering as a load on tunnel structure during construction. While the lining segments are pulled out of the shield tail, the ovalization model are gradually dominant in these two modes. The horizontal diameters of rings show an increase–decrease–increase trend.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91376321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper develops linear high‐order electromagnetic shunt damping techniques, which offer enhanced effectiveness without sacrificing the structural simplicity and the ease of practical implementation. Inspired by the state‐of‐the‐art vibration control techniques involving the inerter, this paper proposes three high‐order resonant electromagnetic shunt dampers, which are analogous to three distinct nontraditional inerter‐based dynamic vibration absorbers. A systematic optimization for all proposed shunt circuits is carried out and their optimal parameters are tuned and analytically formulated according to the H∞ , H2 optimization criteria and the stability maximization criterion (SMC), respectively. Finally, the superior performance of proposed shunt circuits with respect to the conventional resistive‐inductive‐capacitive shunt is theoretically demonstrated via several metrics. Meanwhile, there is no need for electrically synthesizing any electrical components when realizing these high‐order shunts, facilitating their practical implementation.
{"title":"Investigation on high‐order resonant electromagnetic shunt dampers for vibration control: Methodology and optimum tuning","authors":"Shaoyi Zhou, Bin Bao","doi":"10.1002/stc.3094","DOIUrl":"https://doi.org/10.1002/stc.3094","url":null,"abstract":"This paper develops linear high‐order electromagnetic shunt damping techniques, which offer enhanced effectiveness without sacrificing the structural simplicity and the ease of practical implementation. Inspired by the state‐of‐the‐art vibration control techniques involving the inerter, this paper proposes three high‐order resonant electromagnetic shunt dampers, which are analogous to three distinct nontraditional inerter‐based dynamic vibration absorbers. A systematic optimization for all proposed shunt circuits is carried out and their optimal parameters are tuned and analytically formulated according to the H∞ , H2 optimization criteria and the stability maximization criterion (SMC), respectively. Finally, the superior performance of proposed shunt circuits with respect to the conventional resistive‐inductive‐capacitive shunt is theoretically demonstrated via several metrics. Meanwhile, there is no need for electrically synthesizing any electrical components when realizing these high‐order shunts, facilitating their practical implementation.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74190941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jian-Hua Shu, Wei Ding, Jiawei Zhang, F. Lin, Yuan-yu Duan
Existing convolutional neural network (CNN)‐based methods have limitations in long‐term multi‐damage recognition for civil infrastructures. Owing to catastrophic forgetting, the recognition accuracy of such networks decreases when structural damage types keep increasing progressively, not to mention other issues such as an increased number of model parameters and data storage. Thus, this study proposes a continual‐learning‐based damage recognition model (CLDRM) for the recognition of multi‐damage and relevant structural components in civil infrastructures. By integrating the Learning without Forgetting (LwF) method into the residual network with 34 layers, the CLDRM can be continuously trained for multiple recognition tasks without using the data from old tasks. The performance of the CLDRM is experimentally validated through four recognition tasks, namely, damage level, spalling check, component‐type determination, and damage‐type determination, and it is compared to the performance of a conventional CNN with feature extraction, fine‐tuning, duplication and fine‐tuning, and joint training, respectively. In addition, the effects of changes in three parameters, namely, distillation temperature, feature correlation between tasks, and learning order, are further investigated to explore the optimal model parameters and applicable scenarios in multi‐damage recognition. CLDRM gradually aggregates the features of continuous tasks through knowledge distillation, which provides higher recognition accuracy for both old and new tasks while maintaining the advantages of computational cost and data storage. The research outcome is expected to meet the long‐term requirements of handling progressively increasing multi‐type damage recognition tasks for civil infrastructures.
{"title":"Continual‐learning‐based framework for structural damage recognition","authors":"Jian-Hua Shu, Wei Ding, Jiawei Zhang, F. Lin, Yuan-yu Duan","doi":"10.1002/stc.3093","DOIUrl":"https://doi.org/10.1002/stc.3093","url":null,"abstract":"Existing convolutional neural network (CNN)‐based methods have limitations in long‐term multi‐damage recognition for civil infrastructures. Owing to catastrophic forgetting, the recognition accuracy of such networks decreases when structural damage types keep increasing progressively, not to mention other issues such as an increased number of model parameters and data storage. Thus, this study proposes a continual‐learning‐based damage recognition model (CLDRM) for the recognition of multi‐damage and relevant structural components in civil infrastructures. By integrating the Learning without Forgetting (LwF) method into the residual network with 34 layers, the CLDRM can be continuously trained for multiple recognition tasks without using the data from old tasks. The performance of the CLDRM is experimentally validated through four recognition tasks, namely, damage level, spalling check, component‐type determination, and damage‐type determination, and it is compared to the performance of a conventional CNN with feature extraction, fine‐tuning, duplication and fine‐tuning, and joint training, respectively. In addition, the effects of changes in three parameters, namely, distillation temperature, feature correlation between tasks, and learning order, are further investigated to explore the optimal model parameters and applicable scenarios in multi‐damage recognition. CLDRM gradually aggregates the features of continuous tasks through knowledge distillation, which provides higher recognition accuracy for both old and new tasks while maintaining the advantages of computational cost and data storage. The research outcome is expected to meet the long‐term requirements of handling progressively increasing multi‐type damage recognition tasks for civil infrastructures.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"1940 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91216642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Inerters have been widely used in the vibration suppression of automobile and civil structures, due to its large capability in kinetic energy. When applying inerters at the free end of a structure, additional lumped mass has to be involved for obtaining the driving force, which may not be beneficial to the integrity of the device. In this paper, an integrated equivalent tuned mass damper with inerter (ETMDI), having the mass with respect to both translational motion and rotation in a single device, is proposed. First, the equation of motion for the proposed ETMDI system is derived from the Lagrange's equation. The extended fixed‐point theory is next used to obtain the closed‐form expression for the optimal parameters. Taking a single degree‐of‐freedom system and a wind turbine tower, numerical simulations are further performed considering base excitations. Compared to the classical TMD and the inerter‐based vibration absorber (IDVA‐C4), the efficiency and robustness of the proposed ETMDI have been confirmed, showing its potential in energy absorbing and vibration mitigation applications.
{"title":"An integrated equivalent tuned‐mass‐inerter vibration absorber and its optimal design","authors":"K. Dai, Jiawei Tang, Songhan Zhang","doi":"10.1002/stc.3089","DOIUrl":"https://doi.org/10.1002/stc.3089","url":null,"abstract":"Inerters have been widely used in the vibration suppression of automobile and civil structures, due to its large capability in kinetic energy. When applying inerters at the free end of a structure, additional lumped mass has to be involved for obtaining the driving force, which may not be beneficial to the integrity of the device. In this paper, an integrated equivalent tuned mass damper with inerter (ETMDI), having the mass with respect to both translational motion and rotation in a single device, is proposed. First, the equation of motion for the proposed ETMDI system is derived from the Lagrange's equation. The extended fixed‐point theory is next used to obtain the closed‐form expression for the optimal parameters. Taking a single degree‐of‐freedom system and a wind turbine tower, numerical simulations are further performed considering base excitations. Compared to the classical TMD and the inerter‐based vibration absorber (IDVA‐C4), the efficiency and robustness of the proposed ETMDI have been confirmed, showing its potential in energy absorbing and vibration mitigation applications.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75289366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jagajyoti Panda, Sanjukta Chakraborty, S. Ray‐Chaudhuri
In this article, a new full‐ and reduced‐order proportional–integral (PI) controller is developed such that the target‐tracking or command‐following problems become generic for a wide range of frequency inputs. The proposed controller has been developed for better control of seismic responses of structures. The integral part of the proposed controller in this case is formulated by proper factorization of relevant components in closed loop to avoid the presence of uncontrollable poles in the feedback system. Further, the controller–observer framework is designed through suboptimal H∞ control algorithm. The robustness and stability of the algorithm are evaluated in terms of tracking a wide range of frequency inputs, while mitigating the influence of sensor noise and modelling uncertainties at the same time. The efficiency of the proposed PI controller is established with respect to the suboptimal H∞ ‐based proportional controller in terms of reduction in error signal of a nominal and perturbed single degree‐of‐freedom spring–mass–damper system. Further, the applicability of the proposed controller in a realistic scenario is studied using a base‐isolated building under strong seismic excitation. The performance of the control algorithm is evaluated in terms of isolator displacement, inter‐storey drift and top‐floor drift of the nominal model. The results from this work highlight that the proposed controller has significant potential for practical implementation in civil engineering structures.
{"title":"Development and performance evaluation of a robust suboptimal H∞‐based proportional–integral controller–observer system with target tracking for better control of seismic responses","authors":"Jagajyoti Panda, Sanjukta Chakraborty, S. Ray‐Chaudhuri","doi":"10.1002/stc.3084","DOIUrl":"https://doi.org/10.1002/stc.3084","url":null,"abstract":"In this article, a new full‐ and reduced‐order proportional–integral (PI) controller is developed such that the target‐tracking or command‐following problems become generic for a wide range of frequency inputs. The proposed controller has been developed for better control of seismic responses of structures. The integral part of the proposed controller in this case is formulated by proper factorization of relevant components in closed loop to avoid the presence of uncontrollable poles in the feedback system. Further, the controller–observer framework is designed through suboptimal H∞ control algorithm. The robustness and stability of the algorithm are evaluated in terms of tracking a wide range of frequency inputs, while mitigating the influence of sensor noise and modelling uncertainties at the same time. The efficiency of the proposed PI controller is established with respect to the suboptimal H∞ ‐based proportional controller in terms of reduction in error signal of a nominal and perturbed single degree‐of‐freedom spring–mass–damper system. Further, the applicability of the proposed controller in a realistic scenario is studied using a base‐isolated building under strong seismic excitation. The performance of the control algorithm is evaluated in terms of isolator displacement, inter‐storey drift and top‐floor drift of the nominal model. The results from this work highlight that the proposed controller has significant potential for practical implementation in civil engineering structures.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88071640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, a negative stiffness device based on the magnetic principle is presented and experimentally tested. Then, a tuned mass damper with a negative stiffness device (denoted as TMD_NSD) subjected to harmonic support excitation is optimized in terms of H∞ optimization criterion, H2 optimization criterion, and stability maximization criterion (SMC). Closed‐form expressions for the optimal tuning parameters are derived in terms of both H∞ criterion and SMC, while the optimal tuning parameters are numerically determined in terms of H2 criterion. The control performance of the TMD_NSD is compared with the classical TMD in terms of maximum dynamic amplification factor (DAFmax). It is found that the performance of the TMD_NSD based on these three optimization methods is superior to that of the classical TMD. Besides, the performance based on H∞ and H2 optimization is almost similar, while the performance based on SMC is less than the first two methods. Compared with the classical TMD, the TMD_NSD could significantly reduce the primary system's peak value and broaden the efficient frequency range of vibration mitigation. However, surprisingly, the DAFmax decreases with the increase in the mass ratio of the classical TMD, while the DAFmax for the TMD_NSD increases with the increase in mass ratio. Finally, the effectiveness of optimization methods in seismic response control is examined via time history analyses (THA) under 20 real earthquake excitations. The THA findings suggest that the TMD_NSD is superior to the TMD for seismic response mitigation for the three optimization methods. However, it is noted that the displacement response of TMD_NSD based on H∞ and H2 optimization is comparable but slightly better than that of the SMC method. Nevertheless, in terms of absolute acceleration control, it is shown that TMD_NSD performance based on the SMC method is better than that of the H∞ and H2 methods. Overall, the three optimization methods are validated to be effective for seismic mitigation of the un‐damped single‐degree‐of‐freedom (SDOF) primary structure subjected to real seismic excitations.
{"title":"Optimum design of a tuned‐mass damper with negative stiffness device subjected to ground excitation","authors":"Yuxuan Zhang, Kun Ye, Patrice Nyangi","doi":"10.1002/stc.3086","DOIUrl":"https://doi.org/10.1002/stc.3086","url":null,"abstract":"In this study, a negative stiffness device based on the magnetic principle is presented and experimentally tested. Then, a tuned mass damper with a negative stiffness device (denoted as TMD_NSD) subjected to harmonic support excitation is optimized in terms of H∞ optimization criterion, H2 optimization criterion, and stability maximization criterion (SMC). Closed‐form expressions for the optimal tuning parameters are derived in terms of both H∞ criterion and SMC, while the optimal tuning parameters are numerically determined in terms of H2 criterion. The control performance of the TMD_NSD is compared with the classical TMD in terms of maximum dynamic amplification factor (DAFmax). It is found that the performance of the TMD_NSD based on these three optimization methods is superior to that of the classical TMD. Besides, the performance based on H∞ and H2 optimization is almost similar, while the performance based on SMC is less than the first two methods. Compared with the classical TMD, the TMD_NSD could significantly reduce the primary system's peak value and broaden the efficient frequency range of vibration mitigation. However, surprisingly, the DAFmax decreases with the increase in the mass ratio of the classical TMD, while the DAFmax for the TMD_NSD increases with the increase in mass ratio. Finally, the effectiveness of optimization methods in seismic response control is examined via time history analyses (THA) under 20 real earthquake excitations. The THA findings suggest that the TMD_NSD is superior to the TMD for seismic response mitigation for the three optimization methods. However, it is noted that the displacement response of TMD_NSD based on H∞ and H2 optimization is comparable but slightly better than that of the SMC method. Nevertheless, in terms of absolute acceleration control, it is shown that TMD_NSD performance based on the SMC method is better than that of the H∞ and H2 methods. Overall, the three optimization methods are validated to be effective for seismic mitigation of the un‐damped single‐degree‐of‐freedom (SDOF) primary structure subjected to real seismic excitations.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"29-30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82720454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to identify the hysteretic behavior in the form of nonlinear restoring force (NRF) and the unknown dynamic excitation when the acceleration measurement at the degree of freedom (DOF) of the excitation is unknown, and considering the fact that it is difficult to establish a general parametric mathematical model in advance to describe the real hysteretic behavior of an engineering structure, in this paper, a nonparametric identification approach for both NRF and dynamic loading is presented using an updated general extended Kalman filter with unknown input (UGEKF‐UI) algorithm with limited acceleration measurements excluding that at the DOF of the dynamic excitation. The NRF is expressed with a Legendre polynomial model, and no assumption on the parametric model of structure nonlinearity is required for the identification. Numerical studies on lumped mass multi‐DOFs numerical models equipped with different numbers of magnetorheological (MR) dampers modeled with different parametric mathematical models are carried out to verify the effectiveness of the proposed approach. Furthermore, experimental study is conducted on a four‐story shear frame structure with an MR damper under unknown external dynamic excitation. The unknown dynamic responses including the acceleration at the location where the excitation is applied, damping force provided by the MR damper, and the dynamic excitation are identified and compared with the test measurements. Both numerical and experimental results demonstrate the proposed approach is capable of identifying the NRF and the unknown dynamic excitation in a nonparametric way even the acceleration response at the DOF where the excitation is applied is unknown.
{"title":"Hysteresis and dynamic loading nonparametric identification for multi‐degree‐of‐freedom structures using an updated general extended Kalman filter and a Legendre polynomial model","authors":"Ye Zhao, Bin Xu, Baichuan Deng, H. Ge","doi":"10.1002/stc.3088","DOIUrl":"https://doi.org/10.1002/stc.3088","url":null,"abstract":"In order to identify the hysteretic behavior in the form of nonlinear restoring force (NRF) and the unknown dynamic excitation when the acceleration measurement at the degree of freedom (DOF) of the excitation is unknown, and considering the fact that it is difficult to establish a general parametric mathematical model in advance to describe the real hysteretic behavior of an engineering structure, in this paper, a nonparametric identification approach for both NRF and dynamic loading is presented using an updated general extended Kalman filter with unknown input (UGEKF‐UI) algorithm with limited acceleration measurements excluding that at the DOF of the dynamic excitation. The NRF is expressed with a Legendre polynomial model, and no assumption on the parametric model of structure nonlinearity is required for the identification. Numerical studies on lumped mass multi‐DOFs numerical models equipped with different numbers of magnetorheological (MR) dampers modeled with different parametric mathematical models are carried out to verify the effectiveness of the proposed approach. Furthermore, experimental study is conducted on a four‐story shear frame structure with an MR damper under unknown external dynamic excitation. The unknown dynamic responses including the acceleration at the location where the excitation is applied, damping force provided by the MR damper, and the dynamic excitation are identified and compared with the test measurements. Both numerical and experimental results demonstrate the proposed approach is capable of identifying the NRF and the unknown dynamic excitation in a nonparametric way even the acceleration response at the DOF where the excitation is applied is unknown.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89418708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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