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{"title":"IMECE2021 Front Matter","authors":"","doi":"10.1115/imece2021-fm7a","DOIUrl":"https://doi.org/10.1115/imece2021-fm7a","url":null,"abstract":"\u0000 The front matter for this proceedings is available by clicking on the PDF icon.","PeriodicalId":23585,"journal":{"name":"Volume 7A: Dynamics, Vibration, and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78759741","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}
Hannah M. Sweatland, Brendon C. Allen, Max L. Greene, W. Dixon
Closed-loop functional electrical stimulation (FES) control methods are developed to facilitate motor-assisted cycling as a rehabilitative strategy for individuals with neurological disorders. One challenge for this type of control design is accounting for an input delay called the electromechanical delay (EMD) that exists between stimulation and the resultant muscle force. The EMD can cause an otherwise stable system to become unstable. A real-time deep neural network (DNN)-based motor control architecture is used to estimate the nonlinear and uncertain dynamics of each leg of the cycle-rider system. The DNN estimate of the system’s dynamics updates in real-time and is used as a feedforward term in the motor controller allowing the cycle crank to meet position and cadence tracking objectives. The nonsmooth Lyapunov-based stability analysis proves semiglobal asymptotic tracking.
{"title":"Deep Neural Network Real-Time Control of a Motorized Functional Electrical Stimulation Cycle With an Uncertain Time-Varying Electromechanical Delay","authors":"Hannah M. Sweatland, Brendon C. Allen, Max L. Greene, W. Dixon","doi":"10.1115/imece2021-73687","DOIUrl":"https://doi.org/10.1115/imece2021-73687","url":null,"abstract":"\u0000 Closed-loop functional electrical stimulation (FES) control methods are developed to facilitate motor-assisted cycling as a rehabilitative strategy for individuals with neurological disorders. One challenge for this type of control design is accounting for an input delay called the electromechanical delay (EMD) that exists between stimulation and the resultant muscle force. The EMD can cause an otherwise stable system to become unstable. A real-time deep neural network (DNN)-based motor control architecture is used to estimate the nonlinear and uncertain dynamics of each leg of the cycle-rider system. The DNN estimate of the system’s dynamics updates in real-time and is used as a feedforward term in the motor controller allowing the cycle crank to meet position and cadence tracking objectives. The nonsmooth Lyapunov-based stability analysis proves semiglobal asymptotic tracking.","PeriodicalId":23585,"journal":{"name":"Volume 7A: Dynamics, Vibration, and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75220651","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}
Dynamics of a two degree of freedom suspension mechanism design is incorporated with a nonlinear robust controller to enable trajectory tracking under human walking pattern scenarios. To facilitate model-based control design, the system dynamic model is first extracted by applying Lagrange’s technique in non-conservative form. An inverse kinematic analysis is performed to transform a specific walking pattern trajectory in the workspace to the joint space to extract the target joint variables for control testing. An open-loop numerical simulation is also performed to demonstrate the sensitivity of the lifting force against the link inertia under dynamic conditions. Finally, the system dynamic model is incorporated with a feedback controller based on a nonlinear, sliding mode control strategy. The tracking performance of the proposed nonlinear controller is validated in closed-loop numerical simulations to demonstrate possible performance improvements under feedback control.
{"title":"Nonlinear Robust Control Design for a Gravity Compensation Mechanism Under Human Walking Pattern Scenarios","authors":"Z. Ilhan, M. Chew","doi":"10.1115/imece2021-71712","DOIUrl":"https://doi.org/10.1115/imece2021-71712","url":null,"abstract":"\u0000 Dynamics of a two degree of freedom suspension mechanism design is incorporated with a nonlinear robust controller to enable trajectory tracking under human walking pattern scenarios. To facilitate model-based control design, the system dynamic model is first extracted by applying Lagrange’s technique in non-conservative form. An inverse kinematic analysis is performed to transform a specific walking pattern trajectory in the workspace to the joint space to extract the target joint variables for control testing. An open-loop numerical simulation is also performed to demonstrate the sensitivity of the lifting force against the link inertia under dynamic conditions. Finally, the system dynamic model is incorporated with a feedback controller based on a nonlinear, sliding mode control strategy. The tracking performance of the proposed nonlinear controller is validated in closed-loop numerical simulations to demonstrate possible performance improvements under feedback control.","PeriodicalId":23585,"journal":{"name":"Volume 7A: Dynamics, Vibration, and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87437174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents the continued development of HARQ (Human Assistive and Robust Quadruped) which has been designed and built by ART (Assistive Robot Team) in University of Hartford since 2019. To enable the robot to deal with various obstacles with different sizes, HARQ’s mechanical design and building process was focused on the achievement of kinematic adjustability as its main technical design requirement. In this study, the mechanical design changes, which are implemented to increase the robot’s balancing capability and to prevent the slippery between end-effectors and ground, are described first. Based on the changes, the kinematic analysis is also upgraded and various walking trajectories are designed to enable HARQ to locomote with different gaits. To simplify the previous inverse kinematics process which was built based on the numerical method, the analytical equations are newly derived for HARQ. Lastly, the upgraded robot is tested and evaluated in human-centered environments which include both indoor and outdoor task spaces.
{"title":"Mechanical Upgrade and Gait Development of Re-Sizable Quadruped, HARQ","authors":"Salman Hussain, Akin Tatoglu, Kiwon Sohn","doi":"10.1115/imece2021-69421","DOIUrl":"https://doi.org/10.1115/imece2021-69421","url":null,"abstract":"\u0000 This paper presents the continued development of HARQ (Human Assistive and Robust Quadruped) which has been designed and built by ART (Assistive Robot Team) in University of Hartford since 2019. To enable the robot to deal with various obstacles with different sizes, HARQ’s mechanical design and building process was focused on the achievement of kinematic adjustability as its main technical design requirement. In this study, the mechanical design changes, which are implemented to increase the robot’s balancing capability and to prevent the slippery between end-effectors and ground, are described first. Based on the changes, the kinematic analysis is also upgraded and various walking trajectories are designed to enable HARQ to locomote with different gaits. To simplify the previous inverse kinematics process which was built based on the numerical method, the analytical equations are newly derived for HARQ. Lastly, the upgraded robot is tested and evaluated in human-centered environments which include both indoor and outdoor task spaces.","PeriodicalId":23585,"journal":{"name":"Volume 7A: Dynamics, Vibration, and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83186587","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 effects of the mass moment of inertia of the load on the anti-swing control of an overhead crane are studied with realistic computer simulations. First, the dynamic equations of motion are derived for a 2-dimensional overhead crane, based on Lagrange’s equations, in which the rotational load swing dynamics is included. Then, based on a coupled sliding surface [4], an anti-swing control scheme is designed without considering the rotational swing dynamics. In this case, the rotational load swing dynamics can be considered as unmodelled dynamics. The conventional anti-swing control scheme with an anti-swing trajectory generator will be simulated on the control of the overhead crane having the unmodelled dynamics. In this simulation, a delay of one-sampling period will be included in the feedback loop as in practical control applications in industry. For high simulation accuracy, the dynamic model of the crane including the rotational load swing dynamics will be solved by using the fourth-order Runge-Kutta formula with an adaptive step size.
{"title":"A Study on the Effects of Unmodelled Rotational Load Swing Dynamics on the Anti-Swing Control of an Overhead Crane","authors":"Ho-Hoon Lee","doi":"10.1115/imece2021-68336","DOIUrl":"https://doi.org/10.1115/imece2021-68336","url":null,"abstract":"\u0000 In this paper, the effects of the mass moment of inertia of the load on the anti-swing control of an overhead crane are studied with realistic computer simulations. First, the dynamic equations of motion are derived for a 2-dimensional overhead crane, based on Lagrange’s equations, in which the rotational load swing dynamics is included. Then, based on a coupled sliding surface [4], an anti-swing control scheme is designed without considering the rotational swing dynamics. In this case, the rotational load swing dynamics can be considered as unmodelled dynamics. The conventional anti-swing control scheme with an anti-swing trajectory generator will be simulated on the control of the overhead crane having the unmodelled dynamics. In this simulation, a delay of one-sampling period will be included in the feedback loop as in practical control applications in industry. For high simulation accuracy, the dynamic model of the crane including the rotational load swing dynamics will be solved by using the fourth-order Runge-Kutta formula with an adaptive step size.","PeriodicalId":23585,"journal":{"name":"Volume 7A: Dynamics, Vibration, and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83965508","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 project puts forth a framework for spatial collision models for bodies. The framework leverages a new method in dynamics to calculate the relevant post-collision trajectory in 3D space. The new method exploits Cartan’s notion of moving frames and places frames of reference on all moving (and colliding) bodies. Next, it exploits Lie group theory SO(3) and its associated algebra, so(3), to relate such frames to each other. Finally, it exploits a compact notation to streamline the mathematics. This project presents a numerical validation of the results using MSC Adams and compares the rotation and translation values of the bodies with those found using the new method. ThreeD web pages display the results using WebGL.
{"title":"A Framework for Spatial 3D Collision Models: Theory and Validation","authors":"Terje Sværen, B. Nygård, T. Impelluso","doi":"10.1115/imece2021-72981","DOIUrl":"https://doi.org/10.1115/imece2021-72981","url":null,"abstract":"\u0000 This project puts forth a framework for spatial collision models for bodies. The framework leverages a new method in dynamics to calculate the relevant post-collision trajectory in 3D space. The new method exploits Cartan’s notion of moving frames and places frames of reference on all moving (and colliding) bodies. Next, it exploits Lie group theory SO(3) and its associated algebra, so(3), to relate such frames to each other. Finally, it exploits a compact notation to streamline the mathematics. This project presents a numerical validation of the results using MSC Adams and compares the rotation and translation values of the bodies with those found using the new method. ThreeD web pages display the results using WebGL.","PeriodicalId":23585,"journal":{"name":"Volume 7A: Dynamics, Vibration, and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74515330","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}
Metasurfaces, treated as equivalent two-dimensional (2D) metamaterials, have the advantages of compactness and simplicity. In spite of the recent related booming researches, the non-perforated or surface-bonded ultrathin elastic metasurfaces have seldom been reported, since there exists a big challenge in designing such a single unit to satisfy the requirements of 2π phase span and simultaneous high transmission. In this paper, an elastic meta-structural functional unit is carefully designed, enabling an effective wave manipulation application for Structural Health Monitoring (SHM) and Non-destructive Evaluation (NDE) communities. Through conducting a series of parametric studies, the full 2π phase span and high transmittance can be achieved by a singl-elayer meta-structural unit. When proceeding to calculate the phase profile for realizing the full 2π phase span, the height of the unit cell stub is tuned by exploring a finite element model (FEM) using harmonic analysis. The nephograms of the phase shift varying with the stub height and excitation frequency exhibit the successful achievement of a full 2π span covering a wide frequency range. Further, to enable a high transmittance at the same time, two sets of parametric studies are complementally carried out through adjusting two additional structural parameters. Subsequently, various single-layer elastic meta-structures are designed with the proposed unit cell for the peculiar transmission manipulation of antisymmetric Lamb waves demonstrated by numerical simulations. The paper finishes with summary, concluding remarks, and suggestions for future work.
{"title":"Peculiar Transmission Manipulation of Antisymmetric Lamb Waves via a Surface-Bonded Single-Layer Elastic Meta-Structure","authors":"Yiran Tian, Yanfeng Shen","doi":"10.1115/imece2021-70726","DOIUrl":"https://doi.org/10.1115/imece2021-70726","url":null,"abstract":"\u0000 Metasurfaces, treated as equivalent two-dimensional (2D) metamaterials, have the advantages of compactness and simplicity. In spite of the recent related booming researches, the non-perforated or surface-bonded ultrathin elastic metasurfaces have seldom been reported, since there exists a big challenge in designing such a single unit to satisfy the requirements of 2π phase span and simultaneous high transmission. In this paper, an elastic meta-structural functional unit is carefully designed, enabling an effective wave manipulation application for Structural Health Monitoring (SHM) and Non-destructive Evaluation (NDE) communities. Through conducting a series of parametric studies, the full 2π phase span and high transmittance can be achieved by a singl-elayer meta-structural unit. When proceeding to calculate the phase profile for realizing the full 2π phase span, the height of the unit cell stub is tuned by exploring a finite element model (FEM) using harmonic analysis. The nephograms of the phase shift varying with the stub height and excitation frequency exhibit the successful achievement of a full 2π span covering a wide frequency range. Further, to enable a high transmittance at the same time, two sets of parametric studies are complementally carried out through adjusting two additional structural parameters. Subsequently, various single-layer elastic meta-structures are designed with the proposed unit cell for the peculiar transmission manipulation of antisymmetric Lamb waves demonstrated by numerical simulations. The paper finishes with summary, concluding remarks, and suggestions for future work.","PeriodicalId":23585,"journal":{"name":"Volume 7A: Dynamics, Vibration, and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78506489","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}
Blake Hament, Paul Y. Oh, Danielle Carr, C. Moore, S. Dev, Ian Ferguson, Pedro Pena, J. Ehrlich
The integration of robotics with agriculture in a controlled or closed environment is attractive because it enables remote production of food and oxygen without siphoning valuable hours of astronaut labor. Similar techniques can also be applied to terrestrial habitats to improve food security in areas that may not be well-suited to outdoor and/or labor-intensive traditional agricultural practices. In this paper, a robotic system for plant tending is presented with reflections on results of early demonstrations. The system includes remote teleoperation capabilities, a 6-DOF robotic arm, vision system for 3D reconstruction of plants, pneumatic multi-tool changer, and custom end-effectors including an enclosure latch tool and a plant shear tool. This work is a collaborative effort between NASA Kennedy Space Center, Lockheed Martin Space, and university partners to test the technologies of autonomous plant growth systems in deep space.
{"title":"Robotic System for Plant Tending in Remote Habitat","authors":"Blake Hament, Paul Y. Oh, Danielle Carr, C. Moore, S. Dev, Ian Ferguson, Pedro Pena, J. Ehrlich","doi":"10.1115/imece2021-69733","DOIUrl":"https://doi.org/10.1115/imece2021-69733","url":null,"abstract":"\u0000 The integration of robotics with agriculture in a controlled or closed environment is attractive because it enables remote production of food and oxygen without siphoning valuable hours of astronaut labor. Similar techniques can also be applied to terrestrial habitats to improve food security in areas that may not be well-suited to outdoor and/or labor-intensive traditional agricultural practices. In this paper, a robotic system for plant tending is presented with reflections on results of early demonstrations. The system includes remote teleoperation capabilities, a 6-DOF robotic arm, vision system for 3D reconstruction of plants, pneumatic multi-tool changer, and custom end-effectors including an enclosure latch tool and a plant shear tool. This work is a collaborative effort between NASA Kennedy Space Center, Lockheed Martin Space, and university partners to test the technologies of autonomous plant growth systems in deep space.","PeriodicalId":23585,"journal":{"name":"Volume 7A: Dynamics, Vibration, and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76098385","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}
Elliptical machines are exercising or training machines that are used to imitate walking, jogging, running or climbing exercises. Different from treadmill machines, elliptical machine users never leave their feet away from the pedals, which reduces the pressures to the ankle, knee, and hip joints, and significantly lowers the impact injuries of users’ joints. The configurations of the elliptical motion commonly mimic the natural paths of the ankle, knee, and hip joints for walking, jogging or running, which further decreases the strains and stresses on users’ joints. In addition to low joint impact, another feature of elliptical machines is their integrated leg and arm movements that provide the dual lower and upper body exercises. Users of elliptical machines not only exercise their legs, but also push and pull the handlebars to strengthen their arms. Unlike treadmills, ellipticals are self-powered by user-generated motion and have no need for motor and belt conveyance. The closed trajectories of elliptical machines are generated through their linkages. The shapes and sizes of the closed trajectories depend on the linkage dimensions. The trajectory of an elliptical machine needs to meet the requirements for different exercises, and various short and tall people with a wide range of arm or leg sizes. If an elliptical machine has fixed linkage dimensions, its elliptical trajectory has only one shape and size, which does not provide flexibility. In order for an elliptical machine to have flexibility, its linkage has to be adjustable. Adjustable linkages are more difficult to design than linkages without adjustability. This research is motived by surmounting the challenges facing elliptical machines. Different types of elliptical machines (rear, front, and central drives) without and with adjustability are analyzed. Their elliptical output motions are simulated. The research results will provide useful guidelines for developing and promoting elliptical machines.
{"title":"Elliptical Machines Using Adjustable Linkages","authors":"Ali Safdar Naif, Hong Zhou","doi":"10.1115/imece2021-70047","DOIUrl":"https://doi.org/10.1115/imece2021-70047","url":null,"abstract":"\u0000 Elliptical machines are exercising or training machines that are used to imitate walking, jogging, running or climbing exercises. Different from treadmill machines, elliptical machine users never leave their feet away from the pedals, which reduces the pressures to the ankle, knee, and hip joints, and significantly lowers the impact injuries of users’ joints. The configurations of the elliptical motion commonly mimic the natural paths of the ankle, knee, and hip joints for walking, jogging or running, which further decreases the strains and stresses on users’ joints. In addition to low joint impact, another feature of elliptical machines is their integrated leg and arm movements that provide the dual lower and upper body exercises. Users of elliptical machines not only exercise their legs, but also push and pull the handlebars to strengthen their arms. Unlike treadmills, ellipticals are self-powered by user-generated motion and have no need for motor and belt conveyance. The closed trajectories of elliptical machines are generated through their linkages. The shapes and sizes of the closed trajectories depend on the linkage dimensions. The trajectory of an elliptical machine needs to meet the requirements for different exercises, and various short and tall people with a wide range of arm or leg sizes. If an elliptical machine has fixed linkage dimensions, its elliptical trajectory has only one shape and size, which does not provide flexibility. In order for an elliptical machine to have flexibility, its linkage has to be adjustable. Adjustable linkages are more difficult to design than linkages without adjustability. This research is motived by surmounting the challenges facing elliptical machines. Different types of elliptical machines (rear, front, and central drives) without and with adjustability are analyzed. Their elliptical output motions are simulated. The research results will provide useful guidelines for developing and promoting elliptical machines.","PeriodicalId":23585,"journal":{"name":"Volume 7A: Dynamics, Vibration, and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77453572","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}
The electro-mechanical impedance method is a useful tool for structural health assessment in a broad range of applications. In the past, the electro-mechanical impedance method was utilized for assessment of metallic aerospace structures. However, advancements in materials engineering have led to the emergence of composite materials as the preferred choice for many aerospace applications. Limited work exists on application of the electro-mechanical impedance method to composite materials. To evaluate the behavioral differences between metallic and composite materials, a study into the impedance response of one dimensional beam structures with surface-bonded thin piezoelectric wafer sensors was conducted. Euler-Bernoulli beam theory is incorporated in the development of an analytical solution, along with viscous and strain-rate damping models, to evaluate the interaction between the piezoelectric wafer and the resulting bending moment and axial force in the beam. Modeling results were compared to experimental observations. Experimentally obtained damping characteristics were utilized to update analytical and numerical electro-mechanical impedance models. The sensitivity of the electromechanical impedance method to detect damage at various distances from a piezoelectric sensor was evaluated in composite and metallic materials using beams of different lengths. Using the results from these studies and evaluation of the effects of attenuation and structural geometry suggestions for structural evaluation using the electro-mechanical impedance method are presented.
{"title":"On Structural Damping Characteristics in the Electro-Mechanical Impedance Method","authors":"Aaron Misla, Andrei N. Zagrai","doi":"10.1115/imece2021-72024","DOIUrl":"https://doi.org/10.1115/imece2021-72024","url":null,"abstract":"\u0000 The electro-mechanical impedance method is a useful tool for structural health assessment in a broad range of applications. In the past, the electro-mechanical impedance method was utilized for assessment of metallic aerospace structures. However, advancements in materials engineering have led to the emergence of composite materials as the preferred choice for many aerospace applications. Limited work exists on application of the electro-mechanical impedance method to composite materials. To evaluate the behavioral differences between metallic and composite materials, a study into the impedance response of one dimensional beam structures with surface-bonded thin piezoelectric wafer sensors was conducted. Euler-Bernoulli beam theory is incorporated in the development of an analytical solution, along with viscous and strain-rate damping models, to evaluate the interaction between the piezoelectric wafer and the resulting bending moment and axial force in the beam. Modeling results were compared to experimental observations. Experimentally obtained damping characteristics were utilized to update analytical and numerical electro-mechanical impedance models. The sensitivity of the electromechanical impedance method to detect damage at various distances from a piezoelectric sensor was evaluated in composite and metallic materials using beams of different lengths. Using the results from these studies and evaluation of the effects of attenuation and structural geometry suggestions for structural evaluation using the electro-mechanical impedance method are presented.","PeriodicalId":23585,"journal":{"name":"Volume 7A: Dynamics, Vibration, and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74234962","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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