The mechanical health of any composite specimen can be monitored by recording the acoustic emissions (AE) from the surface and hence can be used to predict mechanical fracturing of the material. The AE technique, which is a nondestructive and noninvasive technique, is a common method to monitor the mechanical health of a structure/material. The AE data emanated from a specimen under mechanical stress appears to follow power law distribution that can be used to estimate the power exponent (b value). It has been observed that empirical data do not completely follow power law, which in turn makes the estimation to be significantly erroneous. Some attempts have been made by the researchers in the past to filter out the non‐power law parts of the dataset; however, issues such as choice of upper and lower bounds and fixed values of these bounds for different types of datasets remain a challenge for efficient and robust estimation of b value. In the presented work, an attempt has been made to rectify the inherent shortcomings of b value and improved b value (ib value) estimation methodology. The proposed method, which is computationally light to implement, has been verified on some synthetic and experimental datasets. The results show promising improvements in the estimation of b value parameter from the previous reported methods in the literature.
{"title":"Improvements in the estimation of b value: Limits of the power law","authors":"R. Sheoran, P. Datt, J. Shahi, P. K. Srivastava","doi":"10.1002/stc.3072","DOIUrl":"https://doi.org/10.1002/stc.3072","url":null,"abstract":"The mechanical health of any composite specimen can be monitored by recording the acoustic emissions (AE) from the surface and hence can be used to predict mechanical fracturing of the material. The AE technique, which is a nondestructive and noninvasive technique, is a common method to monitor the mechanical health of a structure/material. The AE data emanated from a specimen under mechanical stress appears to follow power law distribution that can be used to estimate the power exponent (b value). It has been observed that empirical data do not completely follow power law, which in turn makes the estimation to be significantly erroneous. Some attempts have been made by the researchers in the past to filter out the non‐power law parts of the dataset; however, issues such as choice of upper and lower bounds and fixed values of these bounds for different types of datasets remain a challenge for efficient and robust estimation of b value. In the presented work, an attempt has been made to rectify the inherent shortcomings of b value and improved b value (ib value) estimation methodology. The proposed method, which is computationally light to implement, has been verified on some synthetic and experimental datasets. The results show promising improvements in the estimation of b value parameter from the previous reported methods in the literature.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"abs/cs/0502074 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73565865","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}
Jianling Hou, Jin Wang, Wei‐bing Xu, Yanjiang Chen, Bo Wang, Junyan Liu, Botan Shen, Yan Li, Han Sun
Parameters' change of expansion joints has significant impact on the vehicle‐induced dynamic response of bridges. However, it is uneconomical to conduct health monitoring to evaluate the technical condition of expansion joint. To indirectly evaluate the service performance of expansion joint and clarify the impacts from variations of the expansion joint parameters on the vehicle–bridge coupling vibration response, an analysis method of vehicle–expansion joint–bridge coupling vibration (VBCV‐J) was established and verified. Then, taking a long‐span concrete filled steel tubular arch bridge as the prototype, the vehicle–bridge coupling vibration response were studied using the VBCV‐J model while considering the cases of design parameters and variation parameters of the expansion joint. The results show that, for the design parameters, the dynamic amplification factor (DAF) of the expansion joint and the beam‐end measuring points of the main girder are significant. The DAFs of the short suspenders near the expansion joint is also greater than that of suspenders in the 1/4 span and 1/2 span. For the variable parameters, the variation in the height difference between the middle transverse girder and the side transverse girder will lead to a significant increase in the vehicle‐induced impact on the end of the main girder, the short suspender, and in the reaction force of the supports. The decrease of the support stiffness will also make the DAFs of the above components exceed the design value. The variation of the vehicle‐induced dynamic response of main beam‐end and suspenders can indirectly reflect the service performance of expansion joint.
{"title":"An analysis method of vehicle–bridge coupling vibration considering effects of expansion joint parameters and its application","authors":"Jianling Hou, Jin Wang, Wei‐bing Xu, Yanjiang Chen, Bo Wang, Junyan Liu, Botan Shen, Yan Li, Han Sun","doi":"10.1002/stc.3065","DOIUrl":"https://doi.org/10.1002/stc.3065","url":null,"abstract":"Parameters' change of expansion joints has significant impact on the vehicle‐induced dynamic response of bridges. However, it is uneconomical to conduct health monitoring to evaluate the technical condition of expansion joint. To indirectly evaluate the service performance of expansion joint and clarify the impacts from variations of the expansion joint parameters on the vehicle–bridge coupling vibration response, an analysis method of vehicle–expansion joint–bridge coupling vibration (VBCV‐J) was established and verified. Then, taking a long‐span concrete filled steel tubular arch bridge as the prototype, the vehicle–bridge coupling vibration response were studied using the VBCV‐J model while considering the cases of design parameters and variation parameters of the expansion joint. The results show that, for the design parameters, the dynamic amplification factor (DAF) of the expansion joint and the beam‐end measuring points of the main girder are significant. The DAFs of the short suspenders near the expansion joint is also greater than that of suspenders in the 1/4 span and 1/2 span. For the variable parameters, the variation in the height difference between the middle transverse girder and the side transverse girder will lead to a significant increase in the vehicle‐induced impact on the end of the main girder, the short suspender, and in the reaction force of the supports. The decrease of the support stiffness will also make the DAFs of the above components exceed the design value. The variation of the vehicle‐induced dynamic response of main beam‐end and suspenders can indirectly reflect the service performance of expansion joint.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78085787","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}
Zhen Wang, Dong‐Hui Yang, T. Yi, G. Zhang, Jiaqi Han
Modal frequencies are widely used for vibration‐based structural health monitoring (SHM) and for capturing the dynamics of a monitored structure to reveal possible failures. However, changing environmental and operational conditions (i.e., temperature, humidity, wind load, and traffic load) may submerge the modal variability induced by structural damage, thereby falsely identifying damage of interest. This paper presents a comprehensive summary review of SHM for the prediction of modal frequency and the elimination of environment‐induced masking effects based on the data normalization method. The influence mechanisms of external variations on modal frequencies extensively reported in the literature are first described. Next, the research progress in predicting and eliminating the operational modal variability is reviewed emphatically; this progress can be primarily divided into an input–output method that focuses on the establishment of the relationship model between structural frequency and environmental conditions and an output‐only method that separates the embedded environmental variable‐induced changes depending on whether the environmental measurements are measured. Finally, the conclusions and future studies are summarized and discussed. As an overview, the major contribution of this paper is to provide objective technical references for engineers and owners and to further evaluate structural safety conditions more effectively and in a timely manner.
{"title":"Eliminating environmental and operational effects on structural modal frequency: A comprehensive review","authors":"Zhen Wang, Dong‐Hui Yang, T. Yi, G. Zhang, Jiaqi Han","doi":"10.1002/stc.3073","DOIUrl":"https://doi.org/10.1002/stc.3073","url":null,"abstract":"Modal frequencies are widely used for vibration‐based structural health monitoring (SHM) and for capturing the dynamics of a monitored structure to reveal possible failures. However, changing environmental and operational conditions (i.e., temperature, humidity, wind load, and traffic load) may submerge the modal variability induced by structural damage, thereby falsely identifying damage of interest. This paper presents a comprehensive summary review of SHM for the prediction of modal frequency and the elimination of environment‐induced masking effects based on the data normalization method. The influence mechanisms of external variations on modal frequencies extensively reported in the literature are first described. Next, the research progress in predicting and eliminating the operational modal variability is reviewed emphatically; this progress can be primarily divided into an input–output method that focuses on the establishment of the relationship model between structural frequency and environmental conditions and an output‐only method that separates the embedded environmental variable‐induced changes depending on whether the environmental measurements are measured. Finally, the conclusions and future studies are summarized and discussed. As an overview, the major contribution of this paper is to provide objective technical references for engineers and owners and to further evaluate structural safety conditions more effectively and in a timely manner.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"51 Pt 2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83897690","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}
Qi‐Ang Wang, Yang Dai, Zhan-guo Ma, Y. Ni, Jia‐Qi Tang, Xiao‐Qi Xu, Zi-yan Wu
Despite continuous evolution and development of structural health monitoring (SHM) technology, interpreting a huge amount of sensed data from a sophisticated SHM system to extract useful information about structural health condition remains a challenge. Aiming to resolve this problem, a novel application of probabilistic data‐driven damage detection method was proposed in the context of Sparse Bayesian Learning (SBL) scheme. The framework involves constructing a new structural damage index and establishing SBL regression model as reference base only using the data acquired in health state. The construction of the structural damage index is based on damage‐sensitive frequency band, which is determined by NExT using vibration monitoring data. The structure will be classified to be damaged as the structural damage index based on new data deviates from the index predicted by SBL regression reference model, and further, the Bayes factor is adopted to quantify the damage degree. In addition, the relationship between the Bayes factors and the resonance frequency change rate is investigated in detail. The proposed methodology features the following merits: (i) It is probabilistic data‐driven method exempting from physical model of the structure, excitation/loading information, and (ii) it belongs to the unsupervised model in need for structural damage detection, which can be formulated using only monitoring data from health state in the absence of monitoring data from damaged state. Damage detection and discrimination capabilities of the proposed methodology are verified using field monitoring data acquired from a cable‐stayed bridge. Finally, a discussion of the SBL‐based approach is made and further challenges pertaining to damage detection processes in the context of SHM are identified.
{"title":"Towards probabilistic data‐driven damage detection in SHM using sparse Bayesian learning scheme","authors":"Qi‐Ang Wang, Yang Dai, Zhan-guo Ma, Y. Ni, Jia‐Qi Tang, Xiao‐Qi Xu, Zi-yan Wu","doi":"10.1002/stc.3070","DOIUrl":"https://doi.org/10.1002/stc.3070","url":null,"abstract":"Despite continuous evolution and development of structural health monitoring (SHM) technology, interpreting a huge amount of sensed data from a sophisticated SHM system to extract useful information about structural health condition remains a challenge. Aiming to resolve this problem, a novel application of probabilistic data‐driven damage detection method was proposed in the context of Sparse Bayesian Learning (SBL) scheme. The framework involves constructing a new structural damage index and establishing SBL regression model as reference base only using the data acquired in health state. The construction of the structural damage index is based on damage‐sensitive frequency band, which is determined by NExT using vibration monitoring data. The structure will be classified to be damaged as the structural damage index based on new data deviates from the index predicted by SBL regression reference model, and further, the Bayes factor is adopted to quantify the damage degree. In addition, the relationship between the Bayes factors and the resonance frequency change rate is investigated in detail. The proposed methodology features the following merits: (i) It is probabilistic data‐driven method exempting from physical model of the structure, excitation/loading information, and (ii) it belongs to the unsupervised model in need for structural damage detection, which can be formulated using only monitoring data from health state in the absence of monitoring data from damaged state. Damage detection and discrimination capabilities of the proposed methodology are verified using field monitoring data acquired from a cable‐stayed bridge. Finally, a discussion of the SBL‐based approach is made and further challenges pertaining to damage detection processes in the context of SHM are identified.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90111179","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}
Jianxi Qiu, Saqlain Abbas, Yanping Zhu, Zulkarnain Abbas
Bolt connection is mostly used to transfer the load between the mechanical components and plays a significant role in fixing and connecting the parts, especially in complex engineering structures. About 20% of mechanical system failure cases are related to bolt looseness; hence, timely bolt condition detection and maintenance can extend the working life of the mechanical system. To this purpose, current research proposes an integrated approach that significantly simplifies the test system in the conventional method and facilitates the online monitoring of bolted state, especially for small size and compact measured components. Using the proposed integrated acoustic‐vibration frequency‐modulation (FM) method, the signal characteristics are analyzed in the frequency domain to find out the frequency components associated with bolt looseness. Further, the proposed method is also experimentally verified by applying it to examine the specimen containing fatigue cracks, and the damage characteristics are obtained without a reference signal. In this framework, the proposed method is found to be more convenient and flexible than the traditional FM technology in the application of contact nonlinear condition monitoring.
{"title":"Integrated acoustic‐vibration frequency‐modulation technology to detect the contact nonlinear features of mechanical structure","authors":"Jianxi Qiu, Saqlain Abbas, Yanping Zhu, Zulkarnain Abbas","doi":"10.1002/stc.3057","DOIUrl":"https://doi.org/10.1002/stc.3057","url":null,"abstract":"Bolt connection is mostly used to transfer the load between the mechanical components and plays a significant role in fixing and connecting the parts, especially in complex engineering structures. About 20% of mechanical system failure cases are related to bolt looseness; hence, timely bolt condition detection and maintenance can extend the working life of the mechanical system. To this purpose, current research proposes an integrated approach that significantly simplifies the test system in the conventional method and facilitates the online monitoring of bolted state, especially for small size and compact measured components. Using the proposed integrated acoustic‐vibration frequency‐modulation (FM) method, the signal characteristics are analyzed in the frequency domain to find out the frequency components associated with bolt looseness. Further, the proposed method is also experimentally verified by applying it to examine the specimen containing fatigue cracks, and the damage characteristics are obtained without a reference signal. In this framework, the proposed method is found to be more convenient and flexible than the traditional FM technology in the application of contact nonlinear condition monitoring.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"84 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85610195","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 article presents a resonant sensing and control approach for the structural health monitoring (SHM) and rehabilitation of cantilever mechanical designs where independent, detachable shape memory alloy (SMA) wire with gravity bias functions as a resonating module that resonates the beam. Resonant stiffness sensing is implemented as the diagnostic tool for the structural health assessment, and the motor coupled linear actuation and positioning equipment is used for recuperation in this work. In this implementation, SMA acts as a vibration inducer to generate controlled vibration, and the corresponding resonant frequency shift for the identification of defects in the structure is sensed by an external sensor. The presence of cracks or misalignment on the structure affects the stiffness of the assembly that in turn is realized as a resonant frequency shift. Stiffness, the parameter that is prominently affected due to the deterioration of the health of the structure is controlled by the motor coupled lead screw that positions the cantilever engineering structure with desired stiffness by displacing the flexible beam. The experimental results demonstrate the effectiveness of the proposed approach for SHM and rehabilitation.
{"title":"Defect mitigation and structural control of cantilevered structures using shape memory wire based resonant stiffness sensing","authors":"T. G., D. K.","doi":"10.1002/stc.3060","DOIUrl":"https://doi.org/10.1002/stc.3060","url":null,"abstract":"This article presents a resonant sensing and control approach for the structural health monitoring (SHM) and rehabilitation of cantilever mechanical designs where independent, detachable shape memory alloy (SMA) wire with gravity bias functions as a resonating module that resonates the beam. Resonant stiffness sensing is implemented as the diagnostic tool for the structural health assessment, and the motor coupled linear actuation and positioning equipment is used for recuperation in this work. In this implementation, SMA acts as a vibration inducer to generate controlled vibration, and the corresponding resonant frequency shift for the identification of defects in the structure is sensed by an external sensor. The presence of cracks or misalignment on the structure affects the stiffness of the assembly that in turn is realized as a resonant frequency shift. Stiffness, the parameter that is prominently affected due to the deterioration of the health of the structure is controlled by the motor coupled lead screw that positions the cantilever engineering structure with desired stiffness by displacing the flexible beam. The experimental results demonstrate the effectiveness of the proposed approach for SHM and rehabilitation.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"288 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85375247","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}
Structural health monitoring and natural control (SHMC) for post‐earthquake realignment and repairs (PERR) are one of the most challenging issues facing earthquake engineers worldwide. Currently, neither SHMC nor PERR are parts of contemporary curricula and codes of practice. SHMC aims to help achieve a viable degree of structural sustainability (SS) under predictable environmental conditions. In the present context, SHMC refers to the effort that aims at achieving structural operability before, during, and after severe earthquakes. SHMC is generally associated with the use of piezoelectric sensors and similar devices to measure changes in stresses and strains and detect flaws within the elements of engineering structures. Regardless of the effectiveness of the SHMC systems, no structure can lend itself well to PERR unless it has been designed specifically for the purpose; otherwise, it would be disposable with no gains from the SHMC effort. A seismically sustainable structure can prevent actual collapse, overcome residual effects, and lend itself well to PERR. The purpose of the current article is to introduce a practical basis for efficient use of SHMC concepts in multi‐objective earthquake resisting structures (ERSs). Replaceable energy dissipating moment connections (REDMC), rigid rocking cores (RRCs), high strength tendons, and support level grade beams have been introduced as instruments of natural structural control. The use of monitoring devices has been extended to the evaluation of the effects of formations or elimination of plastic hinges and the variations of the global drift of the system.
{"title":"Sustainable seismic design and health monitoring","authors":"M. Grigorian, A. S. Moghadam, Siavash Sedighi","doi":"10.1002/stc.3058","DOIUrl":"https://doi.org/10.1002/stc.3058","url":null,"abstract":"Structural health monitoring and natural control (SHMC) for post‐earthquake realignment and repairs (PERR) are one of the most challenging issues facing earthquake engineers worldwide. Currently, neither SHMC nor PERR are parts of contemporary curricula and codes of practice. SHMC aims to help achieve a viable degree of structural sustainability (SS) under predictable environmental conditions. In the present context, SHMC refers to the effort that aims at achieving structural operability before, during, and after severe earthquakes. SHMC is generally associated with the use of piezoelectric sensors and similar devices to measure changes in stresses and strains and detect flaws within the elements of engineering structures. Regardless of the effectiveness of the SHMC systems, no structure can lend itself well to PERR unless it has been designed specifically for the purpose; otherwise, it would be disposable with no gains from the SHMC effort. A seismically sustainable structure can prevent actual collapse, overcome residual effects, and lend itself well to PERR. The purpose of the current article is to introduce a practical basis for efficient use of SHMC concepts in multi‐objective earthquake resisting structures (ERSs). Replaceable energy dissipating moment connections (REDMC), rigid rocking cores (RRCs), high strength tendons, and support level grade beams have been introduced as instruments of natural structural control. The use of monitoring devices has been extended to the evaluation of the effects of formations or elimination of plastic hinges and the variations of the global drift of the system.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"2014 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86524260","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 paper, the optimal design of a non‐traditional tuned mass damper (NTTMD) with negative stiffness for a damped primary system is studied in detail. The dynamical differential equation is established and the analytical solution of the system is obtained. Closed‐form expression for the optimum tuning parameter is analytically derived using the fixed‐points approach based on the assumption that the damped primary structure is lightly or moderately damped. Then, the optimum damping ratio and the optimum negative stiffness ratio of NTTMD are found numerically by solving a set of nonlinear equations established by Chebyshev's equioscillation theorem. Extended numerical simulations are carried out to examine the efficiency of the optimally designed NTTMD as well as the sensitivity of the optimal parameters. Finally, the utmost control performance of the proposed NTTMD is compared with those of two existing typical TMDs, which were presented by Pennestri and Liu, respectively. The comparison results show that the proposed non‐traditional TMD with negative stiffness can significantly improve the vibration control performance in terms of mitigating the normalized frequency responses of damped primary structures and confining the stroke length of NTTMDs.
{"title":"A variant design of tuned mass damper with negative stiffness for vibration control of a damped primary system","authors":"Okba Abid Charef, S. Khalfallah","doi":"10.1002/stc.3068","DOIUrl":"https://doi.org/10.1002/stc.3068","url":null,"abstract":"In this paper, the optimal design of a non‐traditional tuned mass damper (NTTMD) with negative stiffness for a damped primary system is studied in detail. The dynamical differential equation is established and the analytical solution of the system is obtained. Closed‐form expression for the optimum tuning parameter is analytically derived using the fixed‐points approach based on the assumption that the damped primary structure is lightly or moderately damped. Then, the optimum damping ratio and the optimum negative stiffness ratio of NTTMD are found numerically by solving a set of nonlinear equations established by Chebyshev's equioscillation theorem. Extended numerical simulations are carried out to examine the efficiency of the optimally designed NTTMD as well as the sensitivity of the optimal parameters. Finally, the utmost control performance of the proposed NTTMD is compared with those of two existing typical TMDs, which were presented by Pennestri and Liu, respectively. The comparison results show that the proposed non‐traditional TMD with negative stiffness can significantly improve the vibration control performance in terms of mitigating the normalized frequency responses of damped primary structures and confining the stroke length of NTTMDs.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82675794","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}
Thanh-Truong Nguyen, Nhat-Duc Hoang, Trung-Hau Nguyen, T. Huynh
The concept of the piezoelectric‐based smart strand has been recently developed for low‐cost prestress force monitoring of post‐tensioned structures. However, the previous study uses the single‐degree‐of‐freedom system that is inadequate to describe multiple resonances in a realistic electromechanical impedance (EMI) signature. Furthermore, the EMI‐based prestress force prediction has mostly relied on statistical regression models that are difficult to apply to existing prestressed structures, where the collection of EMI data in failure cases is almost impossible. In this study, we newly propose a high‐fidelity analytical EMI model for the smart strand technique and develop a simple model‐update‐based method for prestress force prediction. The experimental result shows that the proposed analytical model is capable to generate the realistic EMI response of multiple modes at a similar frequency band with identical patterns. Also, the prestress force in the smart strand can be reliably predicted by minimizing the gap between the analytical EMI response and the experimental data through a genetic algorithm‐based model‐updating process.
{"title":"Analytical impedance model for piezoelectric‐based smart Strand and its feasibility for prestress force prediction","authors":"Thanh-Truong Nguyen, Nhat-Duc Hoang, Trung-Hau Nguyen, T. Huynh","doi":"10.1002/stc.3061","DOIUrl":"https://doi.org/10.1002/stc.3061","url":null,"abstract":"The concept of the piezoelectric‐based smart strand has been recently developed for low‐cost prestress force monitoring of post‐tensioned structures. However, the previous study uses the single‐degree‐of‐freedom system that is inadequate to describe multiple resonances in a realistic electromechanical impedance (EMI) signature. Furthermore, the EMI‐based prestress force prediction has mostly relied on statistical regression models that are difficult to apply to existing prestressed structures, where the collection of EMI data in failure cases is almost impossible. In this study, we newly propose a high‐fidelity analytical EMI model for the smart strand technique and develop a simple model‐update‐based method for prestress force prediction. The experimental result shows that the proposed analytical model is capable to generate the realistic EMI response of multiple modes at a similar frequency band with identical patterns. Also, the prestress force in the smart strand can be reliably predicted by minimizing the gap between the analytical EMI response and the experimental data through a genetic algorithm‐based model‐updating process.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"138 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86504573","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}
Seyed Masoud Sajjadi Alehashem, Junfang Wang, Y. Ni, A. Keyhani
Near‐field earthquakes, characterized by long‐period velocity pulses with large peak ground velocities and accelerations, have led to severe damage to many civil structures designed in accordance with the current seismic codes. A novel hydro‐pneumatic semi‐active resettable device (HSRD) is proposed for vibration suppression of building structures subjected to near‐field earthquakes. The main portion of this device is a cylinder‐piston assemblage comprising four separate chambers filled with two different materials, that is, magneto‐rheological (MR) fluid and pressurized air. The two sides of a bypass pipe are connected to the two adjacent MR fluid chambers in the middle of the cylinder, forming a closed‐circulating loop. The bypass pipe has an on–off valve controlling the stiffness by adjusting its on–off threshold and a functional valve controlling the damping by changing the MR fluid's property. The initial stiffness of HSRD is set by adjusting the pressures or lengths of the two gas chambers. Simulation studies with a five‐story and a 10‐story building structures subjected to three near‐field earthquakes are conducted to evaluate the performance of HSRD. Three semi‐active control schemes are considered to create optimal hysteresis loops of HSRD for achieving prominent vibration mitigation. It is revealed that the device with all the control schemes is effective in vibration suppression of the structures suffering from near‐field earthquakes, and the resetting control strategy has the best performance among them. The results validate the capability of HSRD assisted by a semi‐active control strategy for vibration mitigation of buildings subjected to near‐field earthquakes.
{"title":"Vibration control of structures against near‐field earthquakes by using a novel hydro‐pneumatic semi‐active resettable device","authors":"Seyed Masoud Sajjadi Alehashem, Junfang Wang, Y. Ni, A. Keyhani","doi":"10.1002/stc.3054","DOIUrl":"https://doi.org/10.1002/stc.3054","url":null,"abstract":"Near‐field earthquakes, characterized by long‐period velocity pulses with large peak ground velocities and accelerations, have led to severe damage to many civil structures designed in accordance with the current seismic codes. A novel hydro‐pneumatic semi‐active resettable device (HSRD) is proposed for vibration suppression of building structures subjected to near‐field earthquakes. The main portion of this device is a cylinder‐piston assemblage comprising four separate chambers filled with two different materials, that is, magneto‐rheological (MR) fluid and pressurized air. The two sides of a bypass pipe are connected to the two adjacent MR fluid chambers in the middle of the cylinder, forming a closed‐circulating loop. The bypass pipe has an on–off valve controlling the stiffness by adjusting its on–off threshold and a functional valve controlling the damping by changing the MR fluid's property. The initial stiffness of HSRD is set by adjusting the pressures or lengths of the two gas chambers. Simulation studies with a five‐story and a 10‐story building structures subjected to three near‐field earthquakes are conducted to evaluate the performance of HSRD. Three semi‐active control schemes are considered to create optimal hysteresis loops of HSRD for achieving prominent vibration mitigation. It is revealed that the device with all the control schemes is effective in vibration suppression of the structures suffering from near‐field earthquakes, and the resetting control strategy has the best performance among them. The results validate the capability of HSRD assisted by a semi‐active control strategy for vibration mitigation of buildings subjected to near‐field earthquakes.","PeriodicalId":22049,"journal":{"name":"Structural Control and Health Monitoring","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88382355","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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