Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation最新文献
Yisheng Zheng, Zhen Wu, Xinong Zhang, Kon-Well Wang
In this paper, we present a piezoelectric metamaterial integrated with bistable circuits to realize adaptive non-reciprocal elastic wave transmission. Dynamics of the bistable circuit and the piezoelectric metamaterial are investigated numerically to analyze the wave transmission characteristics of the proposed system. Results reveal that when the excitation amplitude exceeds certain threshold, wave energy is able to propagate even with excitation frequency inside the local-resonance bandgap of the piezoelectric metamaterial. This bandgap transmission phenomenon is also known as supratransmission. It is shown that by introducing spatial asymmetry, the system could exhibit different supratransmission thresholds when it is actuated in opposite directions, and hence there exists an excitation range within which wave energy is only able to propagate in one direction. Furthermore, this excitation range to facilitate non-reciprocal energy transmission is adaptable by adjusting the stable equilibria of the bistable circuits, which can be conveniently tuned utilizing only DC voltage sources. Additionally, it is shown that by adjusting the stable equilibria, the wave propagation direction, analogous to the forward direction of an electrical diode, can be easily reversed. Lastly, in contrast to many nonlinearity enabled non-reciprocal systems, the proposed system is able to realize non-reciprocal elastic energy transmission with majority of the transmitted energy preserved at the original input frequency. Overall, these results illustrate a new means of utilizing nonlinear piezoelectric metamaterial to manipulate elastic wave transmission.
{"title":"A Piezoelectric Metamaterial With Bistable Circuit Shunts for Adaptive Non-Reciprocal Elastic Wave Transmission","authors":"Yisheng Zheng, Zhen Wu, Xinong Zhang, Kon-Well Wang","doi":"10.1115/SMASIS2018-7924","DOIUrl":"https://doi.org/10.1115/SMASIS2018-7924","url":null,"abstract":"In this paper, we present a piezoelectric metamaterial integrated with bistable circuits to realize adaptive non-reciprocal elastic wave transmission. Dynamics of the bistable circuit and the piezoelectric metamaterial are investigated numerically to analyze the wave transmission characteristics of the proposed system. Results reveal that when the excitation amplitude exceeds certain threshold, wave energy is able to propagate even with excitation frequency inside the local-resonance bandgap of the piezoelectric metamaterial. This bandgap transmission phenomenon is also known as supratransmission. It is shown that by introducing spatial asymmetry, the system could exhibit different supratransmission thresholds when it is actuated in opposite directions, and hence there exists an excitation range within which wave energy is only able to propagate in one direction. Furthermore, this excitation range to facilitate non-reciprocal energy transmission is adaptable by adjusting the stable equilibria of the bistable circuits, which can be conveniently tuned utilizing only DC voltage sources. Additionally, it is shown that by adjusting the stable equilibria, the wave propagation direction, analogous to the forward direction of an electrical diode, can be easily reversed. Lastly, in contrast to many nonlinearity enabled non-reciprocal systems, the proposed system is able to realize non-reciprocal elastic energy transmission with majority of the transmitted energy preserved at the original input frequency. Overall, these results illustrate a new means of utilizing nonlinear piezoelectric metamaterial to manipulate elastic wave transmission.","PeriodicalId":392289,"journal":{"name":"Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127463666","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}
João Henrique Ribeiro Dainezi, Gabriel Bellomi Schiavon, C. D. Marqui
In this work the aeroelastic behavior of locally resonating periodic structures is investigated. The plate-like wing behavior will be obtained from the Love-Kirchhoff plate model with a finite number of mechanical resonators periodically distributed along its surface and using assumed-modes expansion. The unsteady aerodynamic loads are obtained from the doublet lattice model. By combining the structural and aerodynamic models, the aeroelastic behavior of the wing over a range of airflow speeds is discussed. Frequency response functions due to simultaneous base and flow excitations are calculated from the absence of flow speed to the linear flutter speed of the system without resonators. The effects of bandgap presence on the flutter boundary of the wing are also discussed.
{"title":"Effects of Bandgap Formation on the Aeroelastic Behavior of a Plate-Like Wing","authors":"João Henrique Ribeiro Dainezi, Gabriel Bellomi Schiavon, C. D. Marqui","doi":"10.1115/SMASIS2018-8095","DOIUrl":"https://doi.org/10.1115/SMASIS2018-8095","url":null,"abstract":"In this work the aeroelastic behavior of locally resonating periodic structures is investigated. The plate-like wing behavior will be obtained from the Love-Kirchhoff plate model with a finite number of mechanical resonators periodically distributed along its surface and using assumed-modes expansion. The unsteady aerodynamic loads are obtained from the doublet lattice model. By combining the structural and aerodynamic models, the aeroelastic behavior of the wing over a range of airflow speeds is discussed. Frequency response functions due to simultaneous base and flow excitations are calculated from the absence of flow speed to the linear flutter speed of the system without resonators. The effects of bandgap presence on the flutter boundary of the wing are also discussed.","PeriodicalId":392289,"journal":{"name":"Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124033466","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}
Aircraft wing design optimization typically requires the consideration of many competing factors accounting for both aerodynamics and structures. To address this, research on morphing aircraft has shown its potential by providing large benefits on aircraft performance. In particular, by adapting wing lift distribution, morphing winglets are capable to improve aircraft aerodynamic efficiency in off-design conditions and reduce wing loads at critical flight points. For those reasons, it is expected that these devices will be applied to the aircraft of the very next generation. In the study herein presented, a preliminary failure analysis and structural design of a morphing winglet are presented. The research is collocated within the Clean Sky 2 Regional Aircraft IADP, a large European programme targeting the development of novel technologies for the next generation regional aircraft. The safety-driven design of the proposed kinematic system includes a thorough examination of the potential hazards associated with the system faults, by taking into account the overall operating environment and functions. The mechanical system is characterized by movable surfaces sustained by a winglet skeleton and completely integrated with a devoted actuation system. Such a load control device requires sufficient operational reliability to operate on the applicable flight load envelope in order to match the needs of the structural design. One of the most critical failure modes is assessed to get key requirements for the system architecture consistency. Possible impacts of the defined morphing outline on the FHA analysis are investigated. The structural design process is then addressed in compliance with the demanding requirements posed by the implementation on regional airplanes. The layout static robustness is verified by means of linear stress analyses at the most critical conditions, including possible failure scenarios. Results focus on the assessment of the device static and dynamic structural response and the preliminary definition of the morphing system kinematics, including the integrated actuator system.
{"title":"Preliminary Failure Analysis and Structural Design of a Morphing Winglet for Green Regional Aircraft","authors":"I. Dimino, S. Ameduri, A. Concilio","doi":"10.1115/SMASIS2018-8236","DOIUrl":"https://doi.org/10.1115/SMASIS2018-8236","url":null,"abstract":"Aircraft wing design optimization typically requires the consideration of many competing factors accounting for both aerodynamics and structures. To address this, research on morphing aircraft has shown its potential by providing large benefits on aircraft performance. In particular, by adapting wing lift distribution, morphing winglets are capable to improve aircraft aerodynamic efficiency in off-design conditions and reduce wing loads at critical flight points. For those reasons, it is expected that these devices will be applied to the aircraft of the very next generation. In the study herein presented, a preliminary failure analysis and structural design of a morphing winglet are presented. The research is collocated within the Clean Sky 2 Regional Aircraft IADP, a large European programme targeting the development of novel technologies for the next generation regional aircraft. The safety-driven design of the proposed kinematic system includes a thorough examination of the potential hazards associated with the system faults, by taking into account the overall operating environment and functions. The mechanical system is characterized by movable surfaces sustained by a winglet skeleton and completely integrated with a devoted actuation system. Such a load control device requires sufficient operational reliability to operate on the applicable flight load envelope in order to match the needs of the structural design. One of the most critical failure modes is assessed to get key requirements for the system architecture consistency. Possible impacts of the defined morphing outline on the FHA analysis are investigated. The structural design process is then addressed in compliance with the demanding requirements posed by the implementation on regional airplanes. The layout static robustness is verified by means of linear stress analyses at the most critical conditions, including possible failure scenarios. Results focus on the assessment of the device static and dynamic structural response and the preliminary definition of the morphing system kinematics, including the integrated actuator system.","PeriodicalId":392289,"journal":{"name":"Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131625850","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}
A new passive damper coupling the energy dissipative mechanisms of dry friction and piezoelectric shunting circuit is proposed. The idea is to embed the shunted piezoelectric materials to the dry friction dampers at appropriate positions, so that the elastic deformation of the dry friction dampers can be utilized to generate additional damping. Moreover, this provides a more practical way to install the piezoelectric dampers into realistic mechanical systems such as aero-engines. A five Degree-of-freedom (DOFs) lumped system model is introduced to demonstrate the feasibility of such an idea. The damping performance is revealed using the forced response results obtained by the Multi Harmonic Balance Method (MHBM). We show that the coupled damper significantly outperforms the standalone piezoelectric or dry friction dampers. The coupled damper is better than, at least equivalent to, the case where both piezoelectric and dry friction dampers are applied but in uncoupled manner. Eventually, the mechanism of the proposed damper is further explained from the perspective of vibrational mode and energy conversion.
{"title":"Feasibility Research on Coupled Friction/Piezoelectric Dampers","authors":"Lin Li, Yaguang Wu, Yu Fan","doi":"10.1115/SMASIS2018-7933","DOIUrl":"https://doi.org/10.1115/SMASIS2018-7933","url":null,"abstract":"A new passive damper coupling the energy dissipative mechanisms of dry friction and piezoelectric shunting circuit is proposed. The idea is to embed the shunted piezoelectric materials to the dry friction dampers at appropriate positions, so that the elastic deformation of the dry friction dampers can be utilized to generate additional damping. Moreover, this provides a more practical way to install the piezoelectric dampers into realistic mechanical systems such as aero-engines. A five Degree-of-freedom (DOFs) lumped system model is introduced to demonstrate the feasibility of such an idea. The damping performance is revealed using the forced response results obtained by the Multi Harmonic Balance Method (MHBM). We show that the coupled damper significantly outperforms the standalone piezoelectric or dry friction dampers. The coupled damper is better than, at least equivalent to, the case where both piezoelectric and dry friction dampers are applied but in uncoupled manner. Eventually, the mechanism of the proposed damper is further explained from the perspective of vibrational mode and energy conversion.","PeriodicalId":392289,"journal":{"name":"Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130803035","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}
A. Benouhiba, K. Rabenorosoa, P. Rougeot, M. Ouisse, N. Andreff
In the growing field of origami engineering, self-folding is of a high regard. The latter is regularly used by nature as an efficient approach for autonomous growing and reorganizing. In this work, we present a self-folding approach based on Electro-Active Polymer (EAP), especially Conductive Polymers (CP). This approach proposes lightweight, compact and energy efficient self-folding structures, as well as large angle and reversible folding. We study the behavior of a three-segment milli-structure containing two passive segments made of paper, separated by an active segment made of CP. The folding motion of the structure was modeled and experimentally validated. Furthermore, as a proof of concept, a self-folding origami cube is presented.
{"title":"Electro-Active Polymer Based Self-Folding Approach Devoted to Origami-Inspired Structures","authors":"A. Benouhiba, K. Rabenorosoa, P. Rougeot, M. Ouisse, N. Andreff","doi":"10.1115/SMASIS2018-8153","DOIUrl":"https://doi.org/10.1115/SMASIS2018-8153","url":null,"abstract":"In the growing field of origami engineering, self-folding is of a high regard. The latter is regularly used by nature as an efficient approach for autonomous growing and reorganizing. In this work, we present a self-folding approach based on Electro-Active Polymer (EAP), especially Conductive Polymers (CP). This approach proposes lightweight, compact and energy efficient self-folding structures, as well as large angle and reversible folding. We study the behavior of a three-segment milli-structure containing two passive segments made of paper, separated by an active segment made of CP. The folding motion of the structure was modeled and experimentally validated. Furthermore, as a proof of concept, a self-folding origami cube is presented.","PeriodicalId":392289,"journal":{"name":"Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132216109","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, we investigate the coupled band gaps created by the locking phenomenon between the electrical and flexural waves in piezoelectric composite plates. To do that, the distributed piezoelectric materials should be interconnected via a ‘global’ electric network rather than the respective ‘local’ impedance. Once the uncoupled electrical wave has the same wavelength and opposite group velocity as the uncoupled flexural wave, the desired coupled band gap emerges. The Wave Finite Element Method (WFEM) is used to investigate the evolution of the coupled band gap with respect to propagation direction and electric parameters. Further, the bandwidth and directionality of the coupled band gap are compared with the LR and Bragg gaps. An indicator termed ratio of single wave (RSW) is proposed to determine the effective band gap for a given deformation (electric, flexural, etc.). We show that the coupled band gap, despite directional, can be much wider than the LR gap with the same overall inductance. This might lead to an alternative to create sub-wavelength band gaps.
{"title":"Coupled Band Gaps in the Piezoelectric Composite Plate With Interconnected Electric Impedance","authors":"Lin Li, Zhou Jiang, Yu Fan, Jun Li","doi":"10.1115/SMASIS2018-7948","DOIUrl":"https://doi.org/10.1115/SMASIS2018-7948","url":null,"abstract":"In this paper, we investigate the coupled band gaps created by the locking phenomenon between the electrical and flexural waves in piezoelectric composite plates. To do that, the distributed piezoelectric materials should be interconnected via a ‘global’ electric network rather than the respective ‘local’ impedance. Once the uncoupled electrical wave has the same wavelength and opposite group velocity as the uncoupled flexural wave, the desired coupled band gap emerges. The Wave Finite Element Method (WFEM) is used to investigate the evolution of the coupled band gap with respect to propagation direction and electric parameters. Further, the bandwidth and directionality of the coupled band gap are compared with the LR and Bragg gaps. An indicator termed ratio of single wave (RSW) is proposed to determine the effective band gap for a given deformation (electric, flexural, etc.). We show that the coupled band gap, despite directional, can be much wider than the LR gap with the same overall inductance. This might lead to an alternative to create sub-wavelength band gaps.","PeriodicalId":392289,"journal":{"name":"Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation","volume":"40 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133036825","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}
S. Vasista, J. Riemenschneider, Torsten Mendrock, H. Monner
Early research on a new concept for a morphing system based on unit structures or cells containing pressurized fluid is presented in this article. The motivation stems from the desire to achieve 3D smooth variations with multiple degrees of freedom and variations in surface area. Such a cell is composed of a hybrid between elastomeric material and stiffening material, creating an orthotropic system. When connected in a network of cells, the morphing system is highly integrated in terms of the components of the skin, substructure and actuation means. Numerical predictions of small simple prismatic cells show a force and axial strain capability of above 200 N and 14% respectively for typical elastomeric and stiffening materials at 8 bar pressure. PolyJet™ additively-manufactured models of wings show how such actuators can be integrated into aircraft structures, including when 3D geometry is highly challenging. These additively-manufactured models were operated at low pressures in the order of 0.5 bar, and a number of open questions on the design, manufacture and operation of such structures are discussed along with intended future work towards higher grade materials and working pressures.
{"title":"Pressure-Driven Morphing Devices for 3D Shape Changes With Multiple Degrees-of-Freedom","authors":"S. Vasista, J. Riemenschneider, Torsten Mendrock, H. Monner","doi":"10.1115/SMASIS2018-7949","DOIUrl":"https://doi.org/10.1115/SMASIS2018-7949","url":null,"abstract":"Early research on a new concept for a morphing system based on unit structures or cells containing pressurized fluid is presented in this article. The motivation stems from the desire to achieve 3D smooth variations with multiple degrees of freedom and variations in surface area. Such a cell is composed of a hybrid between elastomeric material and stiffening material, creating an orthotropic system. When connected in a network of cells, the morphing system is highly integrated in terms of the components of the skin, substructure and actuation means. Numerical predictions of small simple prismatic cells show a force and axial strain capability of above 200 N and 14% respectively for typical elastomeric and stiffening materials at 8 bar pressure. PolyJet™ additively-manufactured models of wings show how such actuators can be integrated into aircraft structures, including when 3D geometry is highly challenging. These additively-manufactured models were operated at low pressures in the order of 0.5 bar, and a number of open questions on the design, manufacture and operation of such structures are discussed along with intended future work towards higher grade materials and working pressures.","PeriodicalId":392289,"journal":{"name":"Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130103190","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}
Graphene nanoplatelets (GNPs) have the same chemical structures as carbon nanotubes but their internal structure consists of multiple layers of graphene with thicknesses of only a few nanometers. Due to their increased thickness, GNPs are less prone to agglomeration and entanglement when they are used as nanofillers in composite materials. Although it has been shown that self-sensing cementitious composites can be fabricated using GNPs, further studies are needed to reveal effect of various factors on the performance of such composites. Here, a fabrication method that mainly employs polycarboxylate-based superplasticizers together with high-speed shear mixing to disperse GNPs in cement composites is used to prepare GNP-reinforced mortar composites. The molecular structure of polycarboxylate-based superplasticizer can considerably affect the performance of GNP-cement composites. Therefore, two commercially available polycarboxylate-based superplasticizers that possess varying backbone and side-chain lengths are systematically incorporated to prepare GNP-reinforced multifunctional composites. In addition, the effects of mixing durations on the electrical properties of the developed composites are assessed. Another essential challenge in the development of multifunctional cement composites is to improve the interfacial interaction between GNPs and the hydration products of cement such as calcium-silicate-hydrates (CSH). Here, incorporation of supplementary materials such as silica fume into the matrix is studied to improve the bond between a cementitious matrix and nano reinforcement. The bulk resistivity of the mortar specimens is measured using the four-probe measurement method. The piezoresistive behavior and sensing ability of the GNP-reinforced mortar composites are investigated through compressive tests at quasi-static.
{"title":"Evaluation of Various Factors on Electrical Properties of GNP-Reinforced Mortar Composites","authors":"O. Ozbulut, Zhangfan Jiang, G. Xing","doi":"10.1115/SMASIS2018-8062","DOIUrl":"https://doi.org/10.1115/SMASIS2018-8062","url":null,"abstract":"Graphene nanoplatelets (GNPs) have the same chemical structures as carbon nanotubes but their internal structure consists of multiple layers of graphene with thicknesses of only a few nanometers. Due to their increased thickness, GNPs are less prone to agglomeration and entanglement when they are used as nanofillers in composite materials. Although it has been shown that self-sensing cementitious composites can be fabricated using GNPs, further studies are needed to reveal effect of various factors on the performance of such composites. Here, a fabrication method that mainly employs polycarboxylate-based superplasticizers together with high-speed shear mixing to disperse GNPs in cement composites is used to prepare GNP-reinforced mortar composites. The molecular structure of polycarboxylate-based superplasticizer can considerably affect the performance of GNP-cement composites. Therefore, two commercially available polycarboxylate-based superplasticizers that possess varying backbone and side-chain lengths are systematically incorporated to prepare GNP-reinforced multifunctional composites. In addition, the effects of mixing durations on the electrical properties of the developed composites are assessed. Another essential challenge in the development of multifunctional cement composites is to improve the interfacial interaction between GNPs and the hydration products of cement such as calcium-silicate-hydrates (CSH). Here, incorporation of supplementary materials such as silica fume into the matrix is studied to improve the bond between a cementitious matrix and nano reinforcement. The bulk resistivity of the mortar specimens is measured using the four-probe measurement method. The piezoresistive behavior and sensing ability of the GNP-reinforced mortar composites are investigated through compressive tests at quasi-static.","PeriodicalId":392289,"journal":{"name":"Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114357761","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 a multi-segment beam, in what is called an inertial four-point loaded configuration, is proposed and its dynamic response is analyzed. In this configuration, two symmetrical overhanging free segments extend beyond the pinned supports, and two tip masses are attached to these free segments yielding symmetrical inertial loading at the tips. By varying the configuration parameters of this multi-segment beam, such as support locations and tip loading, the dynamic response of the system can be significantly altered. The harmonically excited transverse vibration of a piezocomposite beam with four-point loaded boundary conditions is analyzed as a function of the support location and tip mass. Experimental data for several support locations is presented for validation of the analytical model and the predicted relationship between the system natural frequency, support locations, and tip masses. Comparisons are also made between the multi-point loaded cases and a reference cantilevered beam. The analytical and experimental results demonstrate that the natural frequency of a multi-point loaded beam can be continuously adjusted in a relatively wide range using the configuration changes investigated.
{"title":"A Multi-Point Loaded Piezocomposite Beam: Mechanics and Response to Harmonic Excitation","authors":"P. S. Heaney, O. Bilgen","doi":"10.1115/SMASIS2018-7940","DOIUrl":"https://doi.org/10.1115/SMASIS2018-7940","url":null,"abstract":"In this paper a multi-segment beam, in what is called an inertial four-point loaded configuration, is proposed and its dynamic response is analyzed. In this configuration, two symmetrical overhanging free segments extend beyond the pinned supports, and two tip masses are attached to these free segments yielding symmetrical inertial loading at the tips. By varying the configuration parameters of this multi-segment beam, such as support locations and tip loading, the dynamic response of the system can be significantly altered. The harmonically excited transverse vibration of a piezocomposite beam with four-point loaded boundary conditions is analyzed as a function of the support location and tip mass. Experimental data for several support locations is presented for validation of the analytical model and the predicted relationship between the system natural frequency, support locations, and tip masses. Comparisons are also made between the multi-point loaded cases and a reference cantilevered beam. The analytical and experimental results demonstrate that the natural frequency of a multi-point loaded beam can be continuously adjusted in a relatively wide range using the configuration changes investigated.","PeriodicalId":392289,"journal":{"name":"Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125302634","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}
There has been increasing focus in the area of in-situ structural health monitoring since the advent of embedded nano-composites. This experimental research investigates the structural health monitoring abilities of polymer bonded energetics embedded with a uniformly dispersed but randomly oriented carbon nanotube (CNT) sensing network within the polymer binder. A common formulation of the recent solid propellants consists of ammonium perchlorate (oxidizer) and aluminum powder (combustive fuel)-often shaped using a polymer binder, rather than the older techniques of power pressing. Since this study focuses on the structural health of the material and not its thermal properties, monoclinic sugar crystals were used as a substitute for ammonium perchlorate as it has very similar mechanical properties and is much safer in terms of material handling. Thus, a combination of sugar crystals and aluminum powder bound by a Polydimethylsiloxane (PDMS) binder is fabricated in varying concentrations to simulate actual solid rocket propellants. The main focus of this study lies in characterizing the mechanical and electrical properties of the CNT embedded energetic material through subjecting it under mechanical loads; followed by a detailed observation and study of the real time electro-mechanical response under tension and compression. The addition of carbon nanotubes to the polymer binder, thus translates to a real time sensing technique for detection of multi-scale damage in polymer bonded energetics. The results of this study aim to establish a proof of concept for CNT embedded structural health monitoring systems.
{"title":"Structural Health Monitoring of Solid Rocket Propellants Using Piezoresistive Properties of Dispersed Carbon Nano-Tube Sensing Networks","authors":"N. Shirodkar, S. Rocker, G. Seidel","doi":"10.1115/SMASIS2018-8250","DOIUrl":"https://doi.org/10.1115/SMASIS2018-8250","url":null,"abstract":"There has been increasing focus in the area of in-situ structural health monitoring since the advent of embedded nano-composites. This experimental research investigates the structural health monitoring abilities of polymer bonded energetics embedded with a uniformly dispersed but randomly oriented carbon nanotube (CNT) sensing network within the polymer binder. A common formulation of the recent solid propellants consists of ammonium perchlorate (oxidizer) and aluminum powder (combustive fuel)-often shaped using a polymer binder, rather than the older techniques of power pressing. Since this study focuses on the structural health of the material and not its thermal properties, monoclinic sugar crystals were used as a substitute for ammonium perchlorate as it has very similar mechanical properties and is much safer in terms of material handling. Thus, a combination of sugar crystals and aluminum powder bound by a Polydimethylsiloxane (PDMS) binder is fabricated in varying concentrations to simulate actual solid rocket propellants. The main focus of this study lies in characterizing the mechanical and electrical properties of the CNT embedded energetic material through subjecting it under mechanical loads; followed by a detailed observation and study of the real time electro-mechanical response under tension and compression. The addition of carbon nanotubes to the polymer binder, thus translates to a real time sensing technique for detection of multi-scale damage in polymer bonded energetics. The results of this study aim to establish a proof of concept for CNT embedded structural health monitoring systems.","PeriodicalId":392289,"journal":{"name":"Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation","volume":"108 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124301971","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}
Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：