Pub Date : 2021-07-01DOI: 10.12989/SSS.2021.28.1.069
Thanh-Truong Nguyen, Jeong‐Tae Kim, Quoc-Bao Ta, Duc-Duy Ho, Thi Tuong Vy Phan, T. Huynh
The piezoelectric-based smart interface technique has shown promising prospects for electro-mechanical impedance (EMI)-based damage detection with various successful applications. During the process of EMI monitoring and damage identification, the operational functionality of the smart interface device is a major concern. In this study, common functional degradations that occurred in the smart interface are diagnosed using a deep learning-based method. Firstly, the effect of functional degradations on the EMI responses is analytically discussed. Secondly, a critical structural joint is selected as the test structure from which EM measurement using the smart interface is conducted. Thirdly, a numerical model corresponding to the experimental model is established and updated to reproduce the measured EMI responses. By using the updated numerical model, the EMI responses of the smart interface under the common functional degradations, such as the shear lag effect, the adhesive debonding, the sensor breakage, and the interface detaching, are simulated; then, the functional degradation-induced EMI changes are characterized. Finally, a convolutional neural network (CNN)-based functional assessment method is newly proposed for the smart interface. The CNN can automatically extract and directly learn optimal features from the raw EMI signals without preprocessing. The CNN is trained and tested using the datasets obtained from the updated numerical model. The obtained results show that the proposed method was successful to classify four types of common defects in the smart interface, even under the effect of noises.
{"title":"Deep learning-based functional assessment of piezoelectric-based smart interface under various degradations","authors":"Thanh-Truong Nguyen, Jeong‐Tae Kim, Quoc-Bao Ta, Duc-Duy Ho, Thi Tuong Vy Phan, T. Huynh","doi":"10.12989/SSS.2021.28.1.069","DOIUrl":"https://doi.org/10.12989/SSS.2021.28.1.069","url":null,"abstract":"The piezoelectric-based smart interface technique has shown promising prospects for electro-mechanical impedance (EMI)-based damage detection with various successful applications. During the process of EMI monitoring and damage identification, the operational functionality of the smart interface device is a major concern. In this study, common functional degradations that occurred in the smart interface are diagnosed using a deep learning-based method. Firstly, the effect of functional degradations on the EMI responses is analytically discussed. Secondly, a critical structural joint is selected as the test structure from which EM measurement using the smart interface is conducted. Thirdly, a numerical model corresponding to the experimental model is established and updated to reproduce the measured EMI responses. By using the updated numerical model, the EMI responses of the smart interface under the common functional degradations, such as the shear lag effect, the adhesive debonding, the sensor breakage, and the interface detaching, are simulated; then, the functional degradation-induced EMI changes are characterized. Finally, a convolutional neural network (CNN)-based functional assessment method is newly proposed for the smart interface. The CNN can automatically extract and directly learn optimal features from the raw EMI signals without preprocessing. The CNN is trained and tested using the datasets obtained from the updated numerical model. The obtained results show that the proposed method was successful to classify four types of common defects in the smart interface, even under the effect of noises.","PeriodicalId":51155,"journal":{"name":"Smart Structures and Systems","volume":"28 1","pages":"69"},"PeriodicalIF":3.5,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42908915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-01DOI: 10.12989/SSS.2021.28.1.043
H. Salehi, M. Shamshirsaz, M. M. Aghdam
In this study, the modulation of multiple frequency content of a single ultrasonic wave in nonlinear structures is investigated analytically, numerically and experimentally. An experimental technique is proposed based on nonlinear lamb wave propagation in aluminum bars using piezoelectric wafer active sensors (PWAS) to study intrinsic nonlinearity of structures. First, a one-dimensional analytical procedure is developed to study the modulation of one dimensional wave with multiple-frequency content in isotropic medium with quadratic nonlinearity. This procedure is implemented to study modulation of frequency contents of a well-known tone burst signal in nonlinear medium. Then, predictions obtained by the proposed analytical procedure are compared with the results of finite element model, which show strong correlations. The experimental and analytical results reveal that in excitation with a train of tone burst, due to frequency modulation, some new harmonics including a strong sub harmonic generation with frequency of f0/Np appear in the response. The amplitude of this harmonic is even higher than common second harmonic generation (2f0). This can be seen in the experimental results when the excitation frequencies are correctly selected. Finally, it is explained that, why the new sub harmonic generation is less affected by the nonlinearity induced by the excitation system.
{"title":"Investigation on modulation of multi-frequency ultrasonic waves in structures with quadratic nonlinearity","authors":"H. Salehi, M. Shamshirsaz, M. M. Aghdam","doi":"10.12989/SSS.2021.28.1.043","DOIUrl":"https://doi.org/10.12989/SSS.2021.28.1.043","url":null,"abstract":"In this study, the modulation of multiple frequency content of a single ultrasonic wave in nonlinear structures is investigated analytically, numerically and experimentally. An experimental technique is proposed based on nonlinear lamb wave propagation in aluminum bars using piezoelectric wafer active sensors (PWAS) to study intrinsic nonlinearity of structures. First, a one-dimensional analytical procedure is developed to study the modulation of one dimensional wave with multiple-frequency content in isotropic medium with quadratic nonlinearity. This procedure is implemented to study modulation of frequency contents of a well-known tone burst signal in nonlinear medium. Then, predictions obtained by the proposed analytical procedure are compared with the results of finite element model, which show strong correlations. The experimental and analytical results reveal that in excitation with a train of tone burst, due to frequency modulation, some new harmonics including a strong sub harmonic generation with frequency of f0/Np appear in the response. The amplitude of this harmonic is even higher than common second harmonic generation (2f0). This can be seen in the experimental results when the excitation frequencies are correctly selected. Finally, it is explained that, why the new sub harmonic generation is less affected by the nonlinearity induced by the excitation system.","PeriodicalId":51155,"journal":{"name":"Smart Structures and Systems","volume":"28 1","pages":"43"},"PeriodicalIF":3.5,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66187585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In long-distance railways, some particular spans of high-speed railway simply supported beam bridges (HSRSBs) are commonly selected as the target structure. The target structure is the part of interest for the study and intended to be analyzed. Due to longitudinal constraints of the track system, the target structure is tightly coupled with other spans within certain range, and is affected by the coupled spans under longitudinal earthquake condition. A massive amount of time-consuming computation is required to determine the coupling span number using current finite element models. In an effort to overcome this challenge, an equivalent method for the longitudinal constraints of the track system is proposed, which greatly reduces the complexity of finite element model while retaining calculation precision. The coupling span number was determined by seismic analyses of a large number of cases using equivalent finite element models. Moreover, the influence of pier height and bottom pier stiffness on coupling span number was studied. Based on the relationship between the equivalent boundary sensitivity critical point and coupling span number, a method to quickly obtain coupling span number of the target structure in arbitrary HSRSB was constructed.
{"title":"Critical coupling span number in high-speed railway simply supported beam bridge","authors":"Yun-tai Zhang, Jiang Lizhong, Zhou Wangbao, Yulin Feng, Xiang Liu, Lai Zhipeng","doi":"10.12989/SSS.2021.28.1.013","DOIUrl":"https://doi.org/10.12989/SSS.2021.28.1.013","url":null,"abstract":"In long-distance railways, some particular spans of high-speed railway simply supported beam bridges (HSRSBs) are commonly selected as the target structure. The target structure is the part of interest for the study and intended to be analyzed. Due to longitudinal constraints of the track system, the target structure is tightly coupled with other spans within certain range, and is affected by the coupled spans under longitudinal earthquake condition. A massive amount of time-consuming computation is required to determine the coupling span number using current finite element models. In an effort to overcome this challenge, an equivalent method for the longitudinal constraints of the track system is proposed, which greatly reduces the complexity of finite element model while retaining calculation precision. The coupling span number was determined by seismic analyses of a large number of cases using equivalent finite element models. Moreover, the influence of pier height and bottom pier stiffness on coupling span number was studied. Based on the relationship between the equivalent boundary sensitivity critical point and coupling span number, a method to quickly obtain coupling span number of the target structure in arbitrary HSRSB was constructed.","PeriodicalId":51155,"journal":{"name":"Smart Structures and Systems","volume":"28 1","pages":"13"},"PeriodicalIF":3.5,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44248163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-01DOI: 10.12989/SSS.2021.28.1.121
B. Firouzi, A. Abbasi, P. Şendur
In this paper we study the static deflection, natural frequency, primary resonance of an electrostatically actuated cracked gas sensor. Besides, a novel hybrid metaheuristic algorithm is proposed to detect the location and depth of possible crack on the microcantilever systems. The gas sensor configuration consists of a microcantilever with a rigid plate attached to its end. The nonlinear effects of the electrostatic force and fringing field are taken into account in the mathematical model. The crack is represented by a rotational spring. In the first part, the effect of crack on the static and dynamic pull-in instability are studied. The equations of motion are solved by the application of the perturbation methods. Next, an inverse problem is formulated to predict the location and depth of the crack in the gas sensor. For that purpose, the weighted squared difference of the analytical and predicted frequency response is considered as the objective function. The location and depth of the crack in the microsystem are determined using the hybrid Harris Hawk and Nelder Mead optimization algorithms. The accuracy and efficiency of the proposed algorithm are compared with the HHO, DA, GOA, and WOA algorithms. Taguchi design of experiments method is used in order to tune the parameters of optimization algorithms systematically. It is shown that the proposed algorithm can predict the exact location and depth of the open-edge crack on an electrostatically actuated microbeam with proof mass.
{"title":"Identification and evaluation of cracks in electrostatically actuated resonant gas sensors using Harris Hawk / Nelder Mead and perturbation methods","authors":"B. Firouzi, A. Abbasi, P. Şendur","doi":"10.12989/SSS.2021.28.1.121","DOIUrl":"https://doi.org/10.12989/SSS.2021.28.1.121","url":null,"abstract":"In this paper we study the static deflection, natural frequency, primary resonance of an electrostatically actuated cracked gas sensor. Besides, a novel hybrid metaheuristic algorithm is proposed to detect the location and depth of possible crack on the microcantilever systems. The gas sensor configuration consists of a microcantilever with a rigid plate attached to its end. The nonlinear effects of the electrostatic force and fringing field are taken into account in the mathematical model. The crack is represented by a rotational spring. In the first part, the effect of crack on the static and dynamic pull-in instability are studied. The equations of motion are solved by the application of the perturbation methods. Next, an inverse problem is formulated to predict the location and depth of the crack in the gas sensor. For that purpose, the weighted squared difference of the analytical and predicted frequency response is considered as the objective function. The location and depth of the crack in the microsystem are determined using the hybrid Harris Hawk and Nelder Mead optimization algorithms. The accuracy and efficiency of the proposed algorithm are compared with the HHO, DA, GOA, and WOA algorithms. Taguchi design of experiments method is used in order to tune the parameters of optimization algorithms systematically. It is shown that the proposed algorithm can predict the exact location and depth of the open-edge crack on an electrostatically actuated microbeam with proof mass.","PeriodicalId":51155,"journal":{"name":"Smart Structures and Systems","volume":"28 1","pages":"121"},"PeriodicalIF":3.5,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49284662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-01DOI: 10.12989/SSS.2021.27.6.1011
Shiang‐Jung Wang, Yi-Lin Sung
With the same horizontal acceleration control performance, the horizontal displacement control performances of sloped rolling-type seismic isolators passively provided with stepwise variable parameters, as well as constant ones, are numerically investigated in this study. The first design possesses a smaller sloping angle with larger damping force at smaller horizontal isolation displacement and a larger sloping angle with smaller damping force at larger horizontal isolation displacement. In other words, this design has stepwise increased sloping angles and stepwise decreased damping force with increasing horizontal isolation displacement. The second design has an opposite design philosophy to the first one, i.e., it has stepwise decreased sloping angles and stepwise increased damping force with increasing horizontal isolation displacement. A series of numerical results present that for sloped rolling-type seismic isolators designed with a constant sloping angle and damping force, in general, the larger the damping force (in other words, the smaller the sloping angle), the smaller and the larger the horizontal maximum and residual displacement responses presented, respectively. The first and second designs with stepwise variable parameters each have its advantage for suppressing horizontal isolation displacement under far-field and pulse-like near-fault ground motions because of their larger energy dissipation capabilities designed at different stages. When the horizontal isolation displacement responses at the end of ground motions are still within the first slope rolling range with a larger sloping angle of the second design, as expected, adopting the second design can exhibit a better re-centering performance than adopting the first design. To have acceptable displacement control performances and without scarifying acceleration control performances under diverse seismic demands, compared with adopting the designs with constant parameters and the first design, adopting the second design could be an alternative solution and better choice.
{"title":"Control performance of sloped rolling-type isolators designed with stepwise variable parameters","authors":"Shiang‐Jung Wang, Yi-Lin Sung","doi":"10.12989/SSS.2021.27.6.1011","DOIUrl":"https://doi.org/10.12989/SSS.2021.27.6.1011","url":null,"abstract":"With the same horizontal acceleration control performance, the horizontal displacement control performances of sloped rolling-type seismic isolators passively provided with stepwise variable parameters, as well as constant ones, are numerically investigated in this study. The first design possesses a smaller sloping angle with larger damping force at smaller horizontal isolation displacement and a larger sloping angle with smaller damping force at larger horizontal isolation displacement. In other words, this design has stepwise increased sloping angles and stepwise decreased damping force with increasing horizontal isolation displacement. The second design has an opposite design philosophy to the first one, i.e., it has stepwise decreased sloping angles and stepwise increased damping force with increasing horizontal isolation displacement. A series of numerical results present that for sloped rolling-type seismic isolators designed with a constant sloping angle and damping force, in general, the larger the damping force (in other words, the smaller the sloping angle), the smaller and the larger the horizontal maximum and residual displacement responses presented, respectively. The first and second designs with stepwise variable parameters each have its advantage for suppressing horizontal isolation displacement under far-field and pulse-like near-fault ground motions because of their larger energy dissipation capabilities designed at different stages. When the horizontal isolation displacement responses at the end of ground motions are still within the first slope rolling range with a larger sloping angle of the second design, as expected, adopting the second design can exhibit a better re-centering performance than adopting the first design. To have acceptable displacement control performances and without scarifying acceleration control performances under diverse seismic demands, compared with adopting the designs with constant parameters and the first design, adopting the second design could be an alternative solution and better choice.","PeriodicalId":51155,"journal":{"name":"Smart Structures and Systems","volume":"27 1","pages":"1011"},"PeriodicalIF":3.5,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44167038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-01DOI: 10.12989/SSS.2021.27.6.1041
Yan Cao, Y. Zandi, M. Gholizadeh, Leijie Fu, Jiang Du, Xueming Qian, Wang Zhijie, Á. Roco-Videla, A. Selmi, A. Issakhov
The principles of productive active and semi-active civil and infrastructure engineering structural control date back 40 years and significant progress has been recorded in those four decades. Smart structures typically have some control systems that enable them to deal with perturbations. The active vibration management techniques have been applied numerically and experimentally in order to reduce the vibrational levels of lightweight economic composite structures. Smart composite beams and plates have been produced and tested with surface-based piezoelectric sensors and actuators. It has been found that an effective model of smart composite plates can predict the dynamic characteristics. Utilizing Genetic Algorithm (GA) was designed and implemented. Two regression model as root mean square (RMSE) and determination coefficient (R2) were used. The first and second bending modes are operated effectively by a beam, and simultaneous vibration levels are significantly reduced for the conductive plates by the simultaneous operation of the bending and twisting modes. Vibration management is realized by using efficient control. GA could show better performance for managing linear feedback laws under given assumptions.
{"title":"Optimization algorithms for composite beam as smart active control of structures using genetic algorithms","authors":"Yan Cao, Y. Zandi, M. Gholizadeh, Leijie Fu, Jiang Du, Xueming Qian, Wang Zhijie, Á. Roco-Videla, A. Selmi, A. Issakhov","doi":"10.12989/SSS.2021.27.6.1041","DOIUrl":"https://doi.org/10.12989/SSS.2021.27.6.1041","url":null,"abstract":"The principles of productive active and semi-active civil and infrastructure engineering structural control date back 40 years and significant progress has been recorded in those four decades. Smart structures typically have some control systems that enable them to deal with perturbations. The active vibration management techniques have been applied numerically and experimentally in order to reduce the vibrational levels of lightweight economic composite structures. Smart composite beams and plates have been produced and tested with surface-based piezoelectric sensors and actuators. It has been found that an effective model of smart composite plates can predict the dynamic characteristics. Utilizing Genetic Algorithm (GA) was designed and implemented. Two regression model as root mean square (RMSE) and determination coefficient (R2) were used. The first and second bending modes are operated effectively by a beam, and simultaneous vibration levels are significantly reduced for the conductive plates by the simultaneous operation of the bending and twisting modes. Vibration management is realized by using efficient control. GA could show better performance for managing linear feedback laws under given assumptions.","PeriodicalId":51155,"journal":{"name":"Smart Structures and Systems","volume":"27 1","pages":"1041"},"PeriodicalIF":3.5,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44471716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-01DOI: 10.12989/SSS.2021.27.6.943
Ju-Won Kim, Jooyoung Park, D. Kang, S. Park
This paper used a magnetic flux leakage (MFL) method compatible with steel structures to analyze quantitative change in a leakage signal due to defects on the surface of a railroad. A numerical simulation using a two-dimensional finite element method (2D-FEM) was used to analyze MFL signals from defects on the railroad. An experiment was then carried out to investigate the capability of the MFL-based non-destructive evaluation (NDE). We also focused on the velocity effect of the MFL signals by analyzing the magnetic hysteresis phenomenon. The quantitative change in leakage signals was determined by selecting depth of the defect and inspection velocity as parameters in a simulation and in an experiment. The MFL signals obtained showed variations that were simultaneously affected by inspection velocity and defect depth. MFL-based damage detection in a railroad is conclusively confirmed to be sufficiently feasible within the range of operational speeds of an inspection train.
{"title":"Simulation and experimental study on MFL-based damage detection capability considering velocity condition for railroad NDE","authors":"Ju-Won Kim, Jooyoung Park, D. Kang, S. Park","doi":"10.12989/SSS.2021.27.6.943","DOIUrl":"https://doi.org/10.12989/SSS.2021.27.6.943","url":null,"abstract":"This paper used a magnetic flux leakage (MFL) method compatible with steel structures to analyze quantitative change in a leakage signal due to defects on the surface of a railroad. A numerical simulation using a two-dimensional finite element method (2D-FEM) was used to analyze MFL signals from defects on the railroad. An experiment was then carried out to investigate the capability of the MFL-based non-destructive evaluation (NDE). We also focused on the velocity effect of the MFL signals by analyzing the magnetic hysteresis phenomenon. The quantitative change in leakage signals was determined by selecting depth of the defect and inspection velocity as parameters in a simulation and in an experiment. The MFL signals obtained showed variations that were simultaneously affected by inspection velocity and defect depth. MFL-based damage detection in a railroad is conclusively confirmed to be sufficiently feasible within the range of operational speeds of an inspection train.","PeriodicalId":51155,"journal":{"name":"Smart Structures and Systems","volume":"27 1","pages":"943"},"PeriodicalIF":3.5,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45103664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-01DOI: 10.12989/SSS.2021.27.6.1001
R. Jahadi, H. Beheshti, M. Heidari-Rarani, A. H. Navarchian
In this study, the effect of agitation speed as a key process parameter on the morphology and particle size of epoxy-Poly (methyl methacrylate) (PMMA) microcapsules was investigated. Thus, a new interpretation is presented to relate between the microcapsule size to rotational speed so as to predict the particle size at different agitation speeds from the initial capsule size. The PMMA shell capsules containing EC 157 epoxy and hardener as healing materials were fabricated through the internal phase separation method. The process was performed at 600 and 1000 rpm mechanical mixing rates. Scanning electron microscopy (SEM) revealed the formation of spherical microcapsules with smooth surfaces. According to static light scattering (SLS) results, the average diameter size of the epoxy/PMMA capsules at two mixing rates were 7.49 and 5.11
{"title":"Effect of agitation speed on microencapsulation of healing agent in PMMA shell and study on the mechanical properties of epoxy/PMMA microcapsules","authors":"R. Jahadi, H. Beheshti, M. Heidari-Rarani, A. H. Navarchian","doi":"10.12989/SSS.2021.27.6.1001","DOIUrl":"https://doi.org/10.12989/SSS.2021.27.6.1001","url":null,"abstract":"In this study, the effect of agitation speed as a key process parameter on the morphology and particle size of epoxy-Poly (methyl methacrylate) (PMMA) microcapsules was investigated. Thus, a new interpretation is presented to relate between the microcapsule size to rotational speed so as to predict the particle size at different agitation speeds from the initial capsule size. The PMMA shell capsules containing EC 157 epoxy and hardener as healing materials were fabricated through the internal phase separation method. The process was performed at 600 and 1000 rpm mechanical mixing rates. Scanning electron microscopy (SEM) revealed the formation of spherical microcapsules with smooth surfaces. According to static light scattering (SLS) results, the average diameter size of the epoxy/PMMA capsules at two mixing rates were 7.49 and 5.11","PeriodicalId":51155,"journal":{"name":"Smart Structures and Systems","volume":"27 1","pages":"1001"},"PeriodicalIF":3.5,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46030357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-01DOI: 10.12989/SSS.2021.27.6.917
Tim Chen, Ying Huang, C. C. Hung, Suzanne Frias, J. A. Muhammad, Cyj Chen
This paper has proposed an intelligent Evolutionary Bat Algorithm (afterward, EBA) Fuzzy NN (Neural Network) controller used to ensure the asymptotic simulation stability of a mathematics nonlinear system for a smart structure. The smart evolutionary fuzzy NN model adopts an NN numerical model and the linear differential inclusion (LDI) concept. Denotation of the nonlinear dynamics is constructed by transforming the nonlinear model into a multi-rule-based sector nonlinear form of mathematics linear numerical models, and implementing a new sufficient mathematics condition whereby the asymptotic simulation stability of the intelligent structure is guaranteed by the Lyapunov mathematics function, linear matrix inequality (LMI). The high frequency is also injected as an auxiliary to stabilize these nonlinear systems. According to the relaxed method injected with dithered auxiliary, the nonlinear system can be guaranteed stable by appropriately regulating the parameters. Finally, there is a numerical resultant example with simulation results which is designated in order to precisely demonstrate the advantages of the smart intelligent controller and the proposed control scheme compared to previous schemes.
{"title":"Smart structural stability and NN based intelligent control for nonlinear systems","authors":"Tim Chen, Ying Huang, C. C. Hung, Suzanne Frias, J. A. Muhammad, Cyj Chen","doi":"10.12989/SSS.2021.27.6.917","DOIUrl":"https://doi.org/10.12989/SSS.2021.27.6.917","url":null,"abstract":"This paper has proposed an intelligent Evolutionary Bat Algorithm (afterward, EBA) Fuzzy NN (Neural Network) controller used to ensure the asymptotic simulation stability of a mathematics nonlinear system for a smart structure. The smart evolutionary fuzzy NN model adopts an NN numerical model and the linear differential inclusion (LDI) concept. Denotation of the nonlinear dynamics is constructed by transforming the nonlinear model into a multi-rule-based sector nonlinear form of mathematics linear numerical models, and implementing a new sufficient mathematics condition whereby the asymptotic simulation stability of the intelligent structure is guaranteed by the Lyapunov mathematics function, linear matrix inequality (LMI). The high frequency is also injected as an auxiliary to stabilize these nonlinear systems. According to the relaxed method injected with dithered auxiliary, the nonlinear system can be guaranteed stable by appropriately regulating the parameters. Finally, there is a numerical resultant example with simulation results which is designated in order to precisely demonstrate the advantages of the smart intelligent controller and the proposed control scheme compared to previous schemes.","PeriodicalId":51155,"journal":{"name":"Smart Structures and Systems","volume":"27 1","pages":"917"},"PeriodicalIF":3.5,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43204932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-01DOI: 10.12989/SSS.2021.27.6.927
P. Nguyen, Jeong-Hoi Kim, J. Oh, Youngshik Park, Sejung Lee, Dongkyun Lee
This paper presents a first proposed real-sized Hidden boundary Void precast concrete Slab, a so-called HVS. In order to assess and investigate push-over behaviors of the novel structural system, five types of real size specimens manufactured in factory are tested by corresponding static loading protocol experiments. Bending tests along with shear tests in both cases of presence and absence of topping concrete slabs are performed. Besides, composite slabs, which are two half-unit products connected by steel plates and U-bolts in the long edges, are surveyed to assess uniform characteristics of slab systems. Simultaneously, estimating calculations are proposed for the structural bearing capacity of partially prestressed concrete flagged sections. Proposed equations are developed according to provisions of several current global and local design standards. Moreover, this study provides another predicting approach using finite element analysis of MIDAS FEA for analytical performances of specimens. Thanks to these experimental and analytical results, the general characteristic of HVS may be observed, and then studied for realization in the field of prestressed precast concrete industries for construction.
{"title":"Push-over bending and shear behavior assessments of hidden boundary void precast concrete slab with bi-tensional prestress","authors":"P. Nguyen, Jeong-Hoi Kim, J. Oh, Youngshik Park, Sejung Lee, Dongkyun Lee","doi":"10.12989/SSS.2021.27.6.927","DOIUrl":"https://doi.org/10.12989/SSS.2021.27.6.927","url":null,"abstract":"This paper presents a first proposed real-sized Hidden boundary Void precast concrete Slab, a so-called HVS. In order to assess and investigate push-over behaviors of the novel structural system, five types of real size specimens manufactured in factory are tested by corresponding static loading protocol experiments. Bending tests along with shear tests in both cases of presence and absence of topping concrete slabs are performed. Besides, composite slabs, which are two half-unit products connected by steel plates and U-bolts in the long edges, are surveyed to assess uniform characteristics of slab systems. Simultaneously, estimating calculations are proposed for the structural bearing capacity of partially prestressed concrete flagged sections. Proposed equations are developed according to provisions of several current global and local design standards. Moreover, this study provides another predicting approach using finite element analysis of MIDAS FEA for analytical performances of specimens. Thanks to these experimental and analytical results, the general characteristic of HVS may be observed, and then studied for realization in the field of prestressed precast concrete industries for construction.","PeriodicalId":51155,"journal":{"name":"Smart Structures and Systems","volume":"27 1","pages":"927"},"PeriodicalIF":3.5,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46630263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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