Pub Date : 2001-11-11DOI: 10.1115/imece2001/ad-23727
P. Anusonti-Inthra, F. Gandhi
The present study examines the potential of using a semi-active controllable damper, whose damping coefficient can be modulated in real-time, for narrow-band disturbance rejection applications. A frequency-domain optimal control algorithm is developed for determining the controllable damper input (of twice the disturbance frequency) that minimizes the force transmitted to the support at the disturbance frequency. The effectiveness of both open-loop and closed-loop controllers in rejecting the transmitted disturbances are evaluated. The results of the study indicate that for physically achievable damping coefficient variations, the support force could be reduced by about an additional 30%, beyond the levels due to the passive isolation characteristics (no damping coefficient variation). When the disturbance phase changed during the simulation, the effectiveness of the open-loop controller reduced, while the closed-loop controller was still able to generally reduce vibrations to levels lower than those due to pure passive isolation. Even so, closed-loop control of the semi-active damper was not able to completely maintain the level of reduction in vibration when the disturbance phase changed, suggesting that an adaptive controller may be necessary.
{"title":"Narrow-Band Disturbance Rejection Using Semi-Active Control","authors":"P. Anusonti-Inthra, F. Gandhi","doi":"10.1115/imece2001/ad-23727","DOIUrl":"https://doi.org/10.1115/imece2001/ad-23727","url":null,"abstract":"\u0000 The present study examines the potential of using a semi-active controllable damper, whose damping coefficient can be modulated in real-time, for narrow-band disturbance rejection applications. A frequency-domain optimal control algorithm is developed for determining the controllable damper input (of twice the disturbance frequency) that minimizes the force transmitted to the support at the disturbance frequency. The effectiveness of both open-loop and closed-loop controllers in rejecting the transmitted disturbances are evaluated. The results of the study indicate that for physically achievable damping coefficient variations, the support force could be reduced by about an additional 30%, beyond the levels due to the passive isolation characteristics (no damping coefficient variation). When the disturbance phase changed during the simulation, the effectiveness of the open-loop controller reduced, while the closed-loop controller was still able to generally reduce vibrations to levels lower than those due to pure passive isolation. Even so, closed-loop control of the semi-active damper was not able to completely maintain the level of reduction in vibration when the disturbance phase changed, suggesting that an adaptive controller may be necessary.","PeriodicalId":264460,"journal":{"name":"Adaptive Structures and Material Systems","volume":"36 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116229374","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}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/ad-23729
M. Qidwai, V. Degiorgi, Rick K. Everett
Porous shape memory alloys (SMAs) are a relatively new group of materials that are of interest because of their potential use in the design of vibration-control, damping and shock mitigation systems. Essential to the use of these materials is an understanding of their mid to high strain-rate response. The emphasis of this research is to develop a computational methodology that will bridge the microstructural and macrostructural features of porous SMAs. In a first attempt, information obtained from x-ray computed micro tomography (XCMT) images is employed in producing realistic finite element meshes with the help of probabilistic pore generating algorithms. Average constitutive behavior of porous SMA in the intermediate strain rate of 103/s is studied by simulating the compressional split-Hopkinson bar test. Preliminary results are obtained for selected pore volume fractions and distinct trends in material behavior are observed.
{"title":"Image-Based Modeling of Dynamic Porous SMA Behavior","authors":"M. Qidwai, V. Degiorgi, Rick K. Everett","doi":"10.1115/imece2001/ad-23729","DOIUrl":"https://doi.org/10.1115/imece2001/ad-23729","url":null,"abstract":"\u0000 Porous shape memory alloys (SMAs) are a relatively new group of materials that are of interest because of their potential use in the design of vibration-control, damping and shock mitigation systems. Essential to the use of these materials is an understanding of their mid to high strain-rate response. The emphasis of this research is to develop a computational methodology that will bridge the microstructural and macrostructural features of porous SMAs. In a first attempt, information obtained from x-ray computed micro tomography (XCMT) images is employed in producing realistic finite element meshes with the help of probabilistic pore generating algorithms. Average constitutive behavior of porous SMA in the intermediate strain rate of 103/s is studied by simulating the compressional split-Hopkinson bar test. Preliminary results are obtained for selected pore volume fractions and distinct trends in material behavior are observed.","PeriodicalId":264460,"journal":{"name":"Adaptive Structures and Material Systems","volume":"298 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123190276","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}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/ad-23707
G. Park, E. Ruggiero, Marion Sausse, D. Inman
This paper presents experimental investigations of vibration testing of an inflated, thin-film torus using smart materials. Lightweight, inflatable structures are very attractive in satelite applications. However, the lightweight, flexible, and highly-damped nature of inflated structures poses difficulties in ground vibration testing. In this study, we show that PVDF patches and recently developed Macro-Fiber Composite actuators may be used as sensors and actuators in identifying modal parameters. Both smart materials can be integrated unobtrusively into the skin of a torus or space device forming an attractive testing arrangement. The addition of actuators and the PVDF sensors to the torus does not significantly interfere with the suspension modes of a free-free boundary condition, and both the actuators and PVDF sensors can be considered an integral part of the inflated structure. The results indicate the potential of using smart materials to measure and control the dynamic response of inflated structures.
{"title":"Vibration Testing and Analysis of Inflatable Structures Using Smart Materials","authors":"G. Park, E. Ruggiero, Marion Sausse, D. Inman","doi":"10.1115/imece2001/ad-23707","DOIUrl":"https://doi.org/10.1115/imece2001/ad-23707","url":null,"abstract":"\u0000 This paper presents experimental investigations of vibration testing of an inflated, thin-film torus using smart materials. Lightweight, inflatable structures are very attractive in satelite applications. However, the lightweight, flexible, and highly-damped nature of inflated structures poses difficulties in ground vibration testing.\u0000 In this study, we show that PVDF patches and recently developed Macro-Fiber Composite actuators may be used as sensors and actuators in identifying modal parameters. Both smart materials can be integrated unobtrusively into the skin of a torus or space device forming an attractive testing arrangement. The addition of actuators and the PVDF sensors to the torus does not significantly interfere with the suspension modes of a free-free boundary condition, and both the actuators and PVDF sensors can be considered an integral part of the inflated structure. The results indicate the potential of using smart materials to measure and control the dynamic response of inflated structures.","PeriodicalId":264460,"journal":{"name":"Adaptive Structures and Material Systems","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126279785","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}
Compliant mechanisms are elastic continua used to transmit or transform force and motion mechanically. The topology optimization methods developed for compliant mechanisms also give the shape for a chosen parameterization of the design domain with a fixed mesh. However, in these methods, the shapes of the flexible segments in the resulting optimal solutions are restricted either by the type or the resolution of the design parameterization. This limitation is overcome here by focusing on optimizing the skeletal shape of the compliant segments in a given topology. It is accomplished by identifying such segments in the topology and representing them using Bezier curves. The vertices of the Bezier control polygon are used to parameterize the shape-design space. Uniform parameter steps of the Bezier curves naturally enable adaptive finite element discretization of the segments as their shapes change. Practical constraints such as avoiding intersections with other segments and self-intersections, and restrictions on the available space and material, are incorporated into the formulation. A multi-criteria function from our prior work is used as the objective. Analytical sensitivity analysis for the objective and constraints is presented and is used in the numerical optimization. Examples are included to illustrate the shape optimization method.
{"title":"Freeform Skeletal Shape Optimization of Compliant Mechanisms","authors":"Dong Xu, G. K. Ananthasuresh","doi":"10.1115/1.1563634","DOIUrl":"https://doi.org/10.1115/1.1563634","url":null,"abstract":"\u0000 Compliant mechanisms are elastic continua used to transmit or transform force and motion mechanically. The topology optimization methods developed for compliant mechanisms also give the shape for a chosen parameterization of the design domain with a fixed mesh. However, in these methods, the shapes of the flexible segments in the resulting optimal solutions are restricted either by the type or the resolution of the design parameterization. This limitation is overcome here by focusing on optimizing the skeletal shape of the compliant segments in a given topology. It is accomplished by identifying such segments in the topology and representing them using Bezier curves. The vertices of the Bezier control polygon are used to parameterize the shape-design space. Uniform parameter steps of the Bezier curves naturally enable adaptive finite element discretization of the segments as their shapes change. Practical constraints such as avoiding intersections with other segments and self-intersections, and restrictions on the available space and material, are incorporated into the formulation. A multi-criteria function from our prior work is used as the objective. Analytical sensitivity analysis for the objective and constraints is presented and is used in the numerical optimization. Examples are included to illustrate the shape optimization method.","PeriodicalId":264460,"journal":{"name":"Adaptive Structures and Material Systems","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125999191","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}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/ad-23741
G. Song, N. Ma
This paper presents the design and experimental results of control of an SMA actuator using PWPF modulation to reduce the energy consumption by the SMA actuator. An SMA wire test stand is used in this research. Based on results of open-loop testing of the SMA wire actuator and parameter analysis of the PWPF modulator, a PWPF modulator is designed to modulate a Proportional plus Derivative (PD) controller. Experiments demonstrate that control of the SMA actuator using PWPF modulation effectively save actuation energy whiling maintaining same control accuracy as compared to continuous PD control.
本文介绍了利用 PWPF 调制控制 SMA 执行器以降低 SMA 执行器能耗的设计和实验结果。本研究使用了 SMA 线测试台。根据对 SMA 线执行器的开环测试结果和 PWPF 调制器的参数分析，设计了一个 PWPF 调制器来调制比例加微分 (PD) 控制器。实验证明，与连续 PD 控制相比，使用 PWPF 调制对 SMA 执行器进行控制可有效节省执行能量，同时保持相同的控制精度。
{"title":"Control of Shape Memory Alloy Actuators Using Pulse Width Pulse Frequency (PWPF) Modulation","authors":"G. Song, N. Ma","doi":"10.1115/imece2001/ad-23741","DOIUrl":"https://doi.org/10.1115/imece2001/ad-23741","url":null,"abstract":"\u0000 This paper presents the design and experimental results of control of an SMA actuator using PWPF modulation to reduce the energy consumption by the SMA actuator. An SMA wire test stand is used in this research. Based on results of open-loop testing of the SMA wire actuator and parameter analysis of the PWPF modulator, a PWPF modulator is designed to modulate a Proportional plus Derivative (PD) controller. Experiments demonstrate that control of the SMA actuator using PWPF modulation effectively save actuation energy whiling maintaining same control accuracy as compared to continuous PD control.","PeriodicalId":264460,"journal":{"name":"Adaptive Structures and Material Systems","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131552436","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}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/ad-23732
Kiran Mallavarapu, D. Leo
Ionic polymer actuators exhibit large bending response under the application of an electric field but their slow time constant limits the actuation bandwidth. Recent results have demonstrated the ability of feedback control to increase the actuation bandwidth of ionic polymer bender actuators. A critical parameter in the control system is the frequency of the first elastic resonance of the actuator. Longer polymers exhibit a lower frequency resonance which limits the closed-loop performance. In this paper, an empirical model of ionic polymer actuator developed by Kanno (1994) is used for closed-loop control. The empirical model is modified to incorporate the resonant dynamics of the actuator and optimized. The empirical model is based on experimental measurements obtained through a series of open-loop responses for an ionic polymer actuator in a cantilever configuration. The empirical model is optimized and used to design a feedback compensator by state space modeling techniques. Since the ionic polymer actuator has slow settling time in the open-loop, the design objectives are to minimize the settling time and constrain the control voltage to be less than a prescribed value. The controller is designed using Linear Quadratic Regulator (LQR) techniques which reduced the number of design parameters to one variable. Simulations are performed which shows settling times of 0.03 seconds for closed-loop feedback control are possible as compared to the open-loop settling time of 15–20 seconds. The maximum control voltage varied from 1.2 Volts to 3.5 Volts depending on the LQR design parameter. The controller is implemented and results obtained are consistent with the simulations. Closed-loop settling time is observed to be 6–10 seconds and the ratio of the peak response to the steady-state response is reduced by an order of magnitude. Discrepancies between the experiment and the simulations are attributed to the inconsistencies in the resonant frequency of the actuator. Experiments demonstrate that changes in the surface hydration of the polymer result in 6.5%–12.5% variations in the actuator resonance. Variations in the actuator resonance require a more conservative compensator design, thus limiting the performance of the feedback control system.
{"title":"Feedback Control of Resonant Modes in Bending Response of Ionic Polymer Actuators","authors":"Kiran Mallavarapu, D. Leo","doi":"10.1115/imece2001/ad-23732","DOIUrl":"https://doi.org/10.1115/imece2001/ad-23732","url":null,"abstract":"\u0000 Ionic polymer actuators exhibit large bending response under the application of an electric field but their slow time constant limits the actuation bandwidth. Recent results have demonstrated the ability of feedback control to increase the actuation bandwidth of ionic polymer bender actuators. A critical parameter in the control system is the frequency of the first elastic resonance of the actuator. Longer polymers exhibit a lower frequency resonance which limits the closed-loop performance. In this paper, an empirical model of ionic polymer actuator developed by Kanno (1994) is used for closed-loop control. The empirical model is modified to incorporate the resonant dynamics of the actuator and optimized. The empirical model is based on experimental measurements obtained through a series of open-loop responses for an ionic polymer actuator in a cantilever configuration. The empirical model is optimized and used to design a feedback compensator by state space modeling techniques. Since the ionic polymer actuator has slow settling time in the open-loop, the design objectives are to minimize the settling time and constrain the control voltage to be less than a prescribed value. The controller is designed using Linear Quadratic Regulator (LQR) techniques which reduced the number of design parameters to one variable. Simulations are performed which shows settling times of 0.03 seconds for closed-loop feedback control are possible as compared to the open-loop settling time of 15–20 seconds. The maximum control voltage varied from 1.2 Volts to 3.5 Volts depending on the LQR design parameter. The controller is implemented and results obtained are consistent with the simulations. Closed-loop settling time is observed to be 6–10 seconds and the ratio of the peak response to the steady-state response is reduced by an order of magnitude. Discrepancies between the experiment and the simulations are attributed to the inconsistencies in the resonant frequency of the actuator. Experiments demonstrate that changes in the surface hydration of the polymer result in 6.5%–12.5% variations in the actuator resonance. Variations in the actuator resonance require a more conservative compensator design, thus limiting the performance of the feedback control system.","PeriodicalId":264460,"journal":{"name":"Adaptive Structures and Material Systems","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132863975","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}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/ad-23716
A. Lumsdaine
Active Constrained Layer Damping (ACLD), involving a hybrid of active and passive damping elements, has been shown to be a promising method for maximizing vibration damping effectiveness. Active damping can be effective at reducing vibration of a given single mode. Passive damping has dissipative qualities for all modes. There has been much discussion comparing and contrasting the uses of these different methods in the literature. It has been found that using a hybrid ACLD layer can be more effective than just using an active control (AC) approach or a Passive Constrained Layer Damper (PCLD) approach, in some cases. ACLD structures are characterized in the literature either by the development of analytic equations, or by finite element modeling. In cases where the ACLD structure is modeled using finite elements, the formulation is done by the author in developing a code. This limits the availability of the result beyond a specific application. For the modeling of ACLD structures to be more generally applicable, and available, modeling could be done using a commercial finite element code. A greater variety of different structures could be modeled, and structural optimization could easily be integrated. The study of ACLD structures would be available to an audience without the resources to construct their own elements. To the author’s knowledge, no studies of ACLD structures exist using a generally available finite element code. The ABAQUS commercial finite element code, with certain customizations, is used in this study. Results compare favorably with other sources in the literature.
{"title":"Modeling of Active Constrained Layer Damping Structures Using a Commercial Finite Element Code","authors":"A. Lumsdaine","doi":"10.1115/imece2001/ad-23716","DOIUrl":"https://doi.org/10.1115/imece2001/ad-23716","url":null,"abstract":"\u0000 Active Constrained Layer Damping (ACLD), involving a hybrid of active and passive damping elements, has been shown to be a promising method for maximizing vibration damping effectiveness. Active damping can be effective at reducing vibration of a given single mode. Passive damping has dissipative qualities for all modes. There has been much discussion comparing and contrasting the uses of these different methods in the literature. It has been found that using a hybrid ACLD layer can be more effective than just using an active control (AC) approach or a Passive Constrained Layer Damper (PCLD) approach, in some cases.\u0000 ACLD structures are characterized in the literature either by the development of analytic equations, or by finite element modeling. In cases where the ACLD structure is modeled using finite elements, the formulation is done by the author in developing a code. This limits the availability of the result beyond a specific application. For the modeling of ACLD structures to be more generally applicable, and available, modeling could be done using a commercial finite element code. A greater variety of different structures could be modeled, and structural optimization could easily be integrated. The study of ACLD structures would be available to an audience without the resources to construct their own elements. To the author’s knowledge, no studies of ACLD structures exist using a generally available finite element code. The ABAQUS commercial finite element code, with certain customizations, is used in this study. Results compare favorably with other sources in the literature.","PeriodicalId":264460,"journal":{"name":"Adaptive Structures and Material Systems","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132431211","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}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/ad-23725
D. Mayer, S. Herold, H. Hanselka
Both for active noise control (ANC) and active vibration control (AVC) the well known F-X-LMS-algorithm can be used. This approach requires a proper model of the path from the actuator to the error sensor, preferably received with an on-line identification. In the field of ANC adaptive finite impulse response (FIR) filters work well for this task, but for lightly damped mechanical systems with long impulse responses FIR filters with up to several thousand coefficients would have to be used. One alternative are adaptive IIR filters, but these can get unstable while adapting or the adapting process can get stuck in local minima. In this work, adaptive Kautz models are introduced, which need some a priori knowledge about the poles of the system. On the other hand, they represent an infinite impulse response while maintaining the transversal structure of the adaptive filter. This is reached by generalization of the FIR filter, for which the delay operator is substituted by discrete allpass filters, the Kautz filters. The adaptive filter bank is implemented by means of the straightforward LMS algorithm in the Matlab/Simulink environment. As an example, system identification with Kautz models and their usage in AVC for a simple mechanical system will be studied.
对于主动噪声控制(ANC)和主动振动控制(AVC)，众所周知的f - x - lms算法都可以使用。这种方法需要从执行器到误差传感器的路径的适当模型，最好带有在线识别。在ANC领域，自适应有限脉冲响应(FIR)滤波器可以很好地完成这项任务，但对于具有长脉冲响应的轻阻尼机械系统，必须使用多达数千个系数的FIR滤波器。另一种选择是自适应IIR滤波器，但这些滤波器在自适应时可能变得不稳定，或者自适应过程可能陷入局部最小值。在这项工作中，引入了自适应Kautz模型，该模型需要一些关于系统极点的先验知识。另一方面，它们表示一个无限的脉冲响应，同时保持自适应滤波器的横向结构。这是通过FIR滤波器的泛化来实现的，其中延迟算子被离散的全通滤波器，即考茨滤波器所取代。在Matlab/Simulink环境下，采用直观的LMS算法实现了自适应滤波器组。作为一个例子，系统识别与Kautz模型及其在AVC对一个简单的机械系统的应用将进行研究。
{"title":"Application of Kautz Models for Adaptive Vibration Control","authors":"D. Mayer, S. Herold, H. Hanselka","doi":"10.1115/imece2001/ad-23725","DOIUrl":"https://doi.org/10.1115/imece2001/ad-23725","url":null,"abstract":"\u0000 Both for active noise control (ANC) and active vibration control (AVC) the well known F-X-LMS-algorithm can be used. This approach requires a proper model of the path from the actuator to the error sensor, preferably received with an on-line identification. In the field of ANC adaptive finite impulse response (FIR) filters work well for this task, but for lightly damped mechanical systems with long impulse responses FIR filters with up to several thousand coefficients would have to be used. One alternative are adaptive IIR filters, but these can get unstable while adapting or the adapting process can get stuck in local minima. In this work, adaptive Kautz models are introduced, which need some a priori knowledge about the poles of the system. On the other hand, they represent an infinite impulse response while maintaining the transversal structure of the adaptive filter. This is reached by generalization of the FIR filter, for which the delay operator is substituted by discrete allpass filters, the Kautz filters. The adaptive filter bank is implemented by means of the straightforward LMS algorithm in the Matlab/Simulink environment. As an example, system identification with Kautz models and their usage in AVC for a simple mechanical system will be studied.","PeriodicalId":264460,"journal":{"name":"Adaptive Structures and Material Systems","volume":"143 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132436850","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}
It is known that, when the mechanical coupling between the substructures is weak, small imperfections in a periodic structure can induce vibration localization. This will cause drastic and harmful changes in structure dynamic property. In this study, it is shown that the proposed coupled piezoelectric circuits can greatly relieve or even eliminate such vibration localization problems. Part of the structural vibration energy will be transferred into electrical energy by the piezoelectric materials, and the newly created electro-mechanical wave/energy channel due to the strong capacitive coupling between the piezoelectric circuits applied to the substructures will sustain the energy propagation throughout the structure. The effectiveness of the coupled piezoelectric circuits on reducing vibration localization is demonstrated, and qualitative analyses and design criteria are given.
{"title":"Vibration Delocalization of Nearly Periodic Structures Using Coupled Piezoelectric Networks","authors":"Jiong Tang, K. W. Wang","doi":"10.1115/1.1521951","DOIUrl":"https://doi.org/10.1115/1.1521951","url":null,"abstract":"\u0000 It is known that, when the mechanical coupling between the substructures is weak, small imperfections in a periodic structure can induce vibration localization. This will cause drastic and harmful changes in structure dynamic property. In this study, it is shown that the proposed coupled piezoelectric circuits can greatly relieve or even eliminate such vibration localization problems. Part of the structural vibration energy will be transferred into electrical energy by the piezoelectric materials, and the newly created electro-mechanical wave/energy channel due to the strong capacitive coupling between the piezoelectric circuits applied to the substructures will sustain the energy propagation throughout the structure. The effectiveness of the coupled piezoelectric circuits on reducing vibration localization is demonstrated, and qualitative analyses and design criteria are given.","PeriodicalId":264460,"journal":{"name":"Adaptive Structures and Material Systems","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114573378","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}
Pub Date : 2001-11-11DOI: 10.1115/imece2001/ad-23706
Y. Aoki, A. Shoji, O. Byon
This paper presents modal-based structural damage detection. Specifically, we focus on localized flexibility properties that can be deduced from the experimentally determined global flexibility matrix. We present the underlying theory that can be viewed a generalized flexibility formulation in three different generalized coordinates, viz., localized or substructural displacement-basis, elemental deformation-basis and element strain-basis. Then, the present methods are applied to a CFRP pipes and shells having interior damage and the numerical and experimental results show that the elemental strain-basis method is quite useful for detecting the inside damage of the CFRP filament winding pipes.
{"title":"Damage Detection of CFRP Pipes and Ladder Structure by Using Localized Flexibility Method","authors":"Y. Aoki, A. Shoji, O. Byon","doi":"10.1115/imece2001/ad-23706","DOIUrl":"https://doi.org/10.1115/imece2001/ad-23706","url":null,"abstract":"\u0000 This paper presents modal-based structural damage detection. Specifically, we focus on localized flexibility properties that can be deduced from the experimentally determined global flexibility matrix. We present the underlying theory that can be viewed a generalized flexibility formulation in three different generalized coordinates, viz., localized or substructural displacement-basis, elemental deformation-basis and element strain-basis. Then, the present methods are applied to a CFRP pipes and shells having interior damage and the numerical and experimental results show that the elemental strain-basis method is quite useful for detecting the inside damage of the CFRP filament winding pipes.","PeriodicalId":264460,"journal":{"name":"Adaptive Structures and Material Systems","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130938022","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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