Pub Date : 2013-01-07DOI: 10.5923/J.AEROSPACE.20120105.03
Thomas Sainthuile, S. Grondel, C. Delebarre, Stéphane Godts, C. Paget
Energy Harvesting is a pro mising solution for powering Structural Health Monitoring (SHM ) systems since various mechanical energy sources are generated by aircraft. Today, the main technique to harvest energy consists of using a specific conversion device to provide power to the SHM system. In this paper however, a novel technique to obtain a self-powered SHM system for aeronautical structures is proposed. This SHM system aims to have a double functionality: it will carry out classical SHM tasks using piezoelectric transducers bonded onto the aircraft structure and will also be fully autonomous since the same transducers will convert the mechanical v ibrations of the structure into electrical power. Using a bonded piezoelectric t ransducer to harvest energy will also bring wideband frequency energy harvesting capability. Th is autonomous system using a unique transducer being particularly innovative, the objective of this paper is to provide a complete Bond Graph model of the energy harvesting process in order to allow the optimisation of its performances. This approach is well-suited to monitor the power and energy transfer carried out during the process since it takes into account the interaction between mu ltiphysics systems, here the electrical and mechanical domains in terms of power and energy variables. Consequently, each part of the energy harvesting, i.e. the mechanical v ibration of the host structure, the vibration within the SHM energy harvester volume, the piezoelectric electro mechanical conversion and the terminal electric load have been modelled analytically using this Bond Graph approach. Then, each submodel has been verified with a baseline Fin ite Element model. Good agreements have been found and it has been possible to carry out an estimat ion of the power harvested by the SHM energy harvester for a given mechanical excitation using this innovative complete analytical Bond Graph model.
{"title":"Energy Harvesting Process Modelling of an Aeronautical Structural Health Monitoring System Using a Bond-Graph Approach","authors":"Thomas Sainthuile, S. Grondel, C. Delebarre, Stéphane Godts, C. Paget","doi":"10.5923/J.AEROSPACE.20120105.03","DOIUrl":"https://doi.org/10.5923/J.AEROSPACE.20120105.03","url":null,"abstract":"Energy Harvesting is a pro mising solution for powering Structural Health Monitoring (SHM ) systems since various mechanical energy sources are generated by aircraft. Today, the main technique to harvest energy consists of using a specific conversion device to provide power to the SHM system. In this paper however, a novel technique to obtain a self-powered SHM system for aeronautical structures is proposed. This SHM system aims to have a double functionality: it will carry out classical SHM tasks using piezoelectric transducers bonded onto the aircraft structure and will also be fully autonomous since the same transducers will convert the mechanical v ibrations of the structure into electrical power. Using a bonded piezoelectric t ransducer to harvest energy will also bring wideband frequency energy harvesting capability. Th is autonomous system using a unique transducer being particularly innovative, the objective of this paper is to provide a complete Bond Graph model of the energy harvesting process in order to allow the optimisation of its performances. This approach is well-suited to monitor the power and energy transfer carried out during the process since it takes into account the interaction between mu ltiphysics systems, here the electrical and mechanical domains in terms of power and energy variables. Consequently, each part of the energy harvesting, i.e. the mechanical v ibration of the host structure, the vibration within the SHM energy harvester volume, the piezoelectric electro mechanical conversion and the terminal electric load have been modelled analytically using this Bond Graph approach. Then, each submodel has been verified with a baseline Fin ite Element model. Good agreements have been found and it has been possible to carry out an estimat ion of the power harvested by the SHM energy harvester for a given mechanical excitation using this innovative complete analytical Bond Graph model.","PeriodicalId":336301,"journal":{"name":"Journal of the Aerospace Sciences","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114603134","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 : 2013-01-07DOI: 10.5923/J.AEROSPACE.20120105.02
M. B. Mashade
Our scope in this paper is to treat the problem of detecting what is called moderately fluctuating targets when the operating environment is contaminated with a number of outlying targets along with the target under test (mult iple -target situations). The illu mination of this impo rtant class of radar targets by a coherent pulse train, return a train of correlate d pulses with a correlation coefficient in the range 0<ρ<1 (intermediate between SW II & SWI). To achieve this goal, we choo se the OS based type of adaptive detectors owing to its immunity to interfering targets. However, the homogeneous performance of OS technique is always lower than that of the CA scheme. Therefore, it is preferab le to choose the more efficient version, which co mbines the benefits of these two schemes, of the adaptive detectors. This modified version is known as censored mean-level (CM L) in the literature. It imp lements trimmed averaging of a weighted ordered range samp les. Here, the detection performance of the CM L processor is analyzed on the assumption that the radar receiver collects data fro m M successive pulses and the radar system operates in target multip licity environ ments. The primary as well as the secondary interfering targets fluctuates in accordance with χ 2 fluctuation model. SWI and SWII cases represent the situations where the signal is comp letely correlated and completely decorrelated, respectively, fro m pulse to pulse. Exact exp ressions are derived for the detection and false alarm rate perfor mances in nonideal situations. For weak SNR, it is shown that the processor performance imp roves as the correlation coefficient ρ increases and this occurs either in the absence or in the presence of outlying targets. This behavior is rapid ly changed as the SNR beco mes stronger where the p rocessor performance degrades as ρ increases, and the SWII and SWI models emb race all the correlated target cases.
{"title":"Target-Multiplicity Analysis of CML Processor for Partially-Correlated χ2 Targets","authors":"M. B. Mashade","doi":"10.5923/J.AEROSPACE.20120105.02","DOIUrl":"https://doi.org/10.5923/J.AEROSPACE.20120105.02","url":null,"abstract":"Our scope in this paper is to treat the problem of detecting what is called moderately fluctuating targets when the operating environment is contaminated with a number of outlying targets along with the target under test (mult iple -target situations). The illu mination of this impo rtant class of radar targets by a coherent pulse train, return a train of correlate d pulses with a correlation coefficient in the range 0<ρ<1 (intermediate between SW II & SWI). To achieve this goal, we choo se the OS based type of adaptive detectors owing to its immunity to interfering targets. However, the homogeneous performance of OS technique is always lower than that of the CA scheme. Therefore, it is preferab le to choose the more efficient version, which co mbines the benefits of these two schemes, of the adaptive detectors. This modified version is known as censored mean-level (CM L) in the literature. It imp lements trimmed averaging of a weighted ordered range samp les. Here, the detection performance of the CM L processor is analyzed on the assumption that the radar receiver collects data fro m M successive pulses and the radar system operates in target multip licity environ ments. The primary as well as the secondary interfering targets fluctuates in accordance with χ 2 fluctuation model. SWI and SWII cases represent the situations where the signal is comp letely correlated and completely decorrelated, respectively, fro m pulse to pulse. Exact exp ressions are derived for the detection and false alarm rate perfor mances in nonideal situations. For weak SNR, it is shown that the processor performance imp roves as the correlation coefficient ρ increases and this occurs either in the absence or in the presence of outlying targets. This behavior is rapid ly changed as the SNR beco mes stronger where the p rocessor performance degrades as ρ increases, and the SWII and SWI models emb race all the correlated target cases.","PeriodicalId":336301,"journal":{"name":"Journal of the Aerospace Sciences","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123349074","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 : 2013-01-07DOI: 10.5923/J.AEROSPACE.20120105.01
I. K. Panditta, M. Wani
A new methodology for obtaining deflections of structures is presented in this paper. It is based on Principle of Quasi Work, which connects two topologically similar systems thereby leading to a unique concept of standard elements for every category of structural problems. Using a priory known equation of deformation/deflection of elastic axis of these elements, solution for equation of deformed/ deflected elastic line of other structural members of similar category having different loading and boundary conditions is presented here. Th is methodology is easy to use as deflection of a given structure is obtained mostly by simple mu ltiplications and it also eliminates the use of internal force/bending mo ment expressions unlike conventional methods. Even though this methodology can be applied to any structure, its use is illustrated for one dimensional structural elements (viz. axial bars, torsion rods and beams) for the sake of conciseness and clarity. The concept of topologically similar system is exp lored for each category of elements as it lies at the heart of the principle of quasi work.
{"title":"Deflection of Structures Using Principle of Quasi Work","authors":"I. K. Panditta, M. Wani","doi":"10.5923/J.AEROSPACE.20120105.01","DOIUrl":"https://doi.org/10.5923/J.AEROSPACE.20120105.01","url":null,"abstract":"A new methodology for obtaining deflections of structures is presented in this paper. It is based on Principle of Quasi Work, which connects two topologically similar systems thereby leading to a unique concept of standard elements for every category of structural problems. Using a priory known equation of deformation/deflection of elastic axis of these elements, solution for equation of deformed/ deflected elastic line of other structural members of similar category having different loading and boundary conditions is presented here. Th is methodology is easy to use as deflection of a given structure is obtained mostly by simple mu ltiplications and it also eliminates the use of internal force/bending mo ment expressions unlike conventional methods. Even though this methodology can be applied to any structure, its use is illustrated for one dimensional structural elements (viz. axial bars, torsion rods and beams) for the sake of conciseness and clarity. The concept of topologically similar system is exp lored for each category of elements as it lies at the heart of the principle of quasi work.","PeriodicalId":336301,"journal":{"name":"Journal of the Aerospace Sciences","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122401827","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 : 2013-01-07DOI: 10.5923/J.AEROSPACE.20120105.04
A. Oveisi, M. Gudarzi
The purpose of this paper is comparing the performance of two robust control designing approaches in smart structures. First, an accurate model of a homogeneous plate with special boundary conditions is derived by using of modal analysis. Then, some primitive p late's modes are considered as nominal system and the remaining modes are left as a mu ltip licat ive unstructured modelling uncertainty. Next, t wo robust controller are designed using µ-Synthesis & LMI-Based Design approaches based on the augmented plant composed of the nominal model and its accompanied uncertainty. Finally, the robustness of two uncertain closed-loop models and the d ifference between t wo controller performances has been investigated. Obtained results show the higher performance of LMI-Based Design approach in rejection of random disturbances.
{"title":"Robust Active Vibration Control of Smart Structures; a Comparison between Two Approaches: µ-Synthesis & LMI-Based Design","authors":"A. Oveisi, M. Gudarzi","doi":"10.5923/J.AEROSPACE.20120105.04","DOIUrl":"https://doi.org/10.5923/J.AEROSPACE.20120105.04","url":null,"abstract":"The purpose of this paper is comparing the performance of two robust control designing approaches in smart structures. First, an accurate model of a homogeneous plate with special boundary conditions is derived by using of modal analysis. Then, some primitive p late's modes are considered as nominal system and the remaining modes are left as a mu ltip licat ive unstructured modelling uncertainty. Next, t wo robust controller are designed using µ-Synthesis & LMI-Based Design approaches based on the augmented plant composed of the nominal model and its accompanied uncertainty. Finally, the robustness of two uncertain closed-loop models and the d ifference between t wo controller performances has been investigated. Obtained results show the higher performance of LMI-Based Design approach in rejection of random disturbances.","PeriodicalId":336301,"journal":{"name":"Journal of the Aerospace Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131061386","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 : 2012-12-01DOI: 10.5923/J.AJSP.20120205.03
M. B. Mashade
A constant false alarm rate in the presence of variable levels of noise is usually a requirement placed on any modern radar. The CA - and OS-CFAR detectors are the most widely used ones in the CFAR world. The cell-averaging (CA) is the optimu m CFA R detector in terms of detection probability in ho mogeneous background when the reference cells have identical, independent and exponentially distributed signals. The ordered-statistic (OS) is an alternative to the CA processor, which trades a small loss in detection performance, relative to the CA scheme, in ideal conditions for much less performance degradation in non-ideal background environments. To benefice the merits of these well-known schemes, two modified versions (MX- & MN-CFAR) have been recently suggested. This paper is devoted to the detection performance evaluation of these modified versions as well as a novel one (ML-CFA R). Exact formu las for their false alarm and detection performances are derived, in the absence as well as in the presence of spurious targets. The results of these performances obtained for Rayleigh clutter and Rayleigh target indicate that the MN-CFAR scheme performs nearly as good as OS detector in the presence of outlying targets and all the developed versions perform much better than that processor when the background environment is homogeneous. When compared to CA-CFAR, the modified schemes perform better in an ideal condition, and behave much better in the presence of interfering targets.
{"title":"Performance Analysis of CFAR Detection of Fluctuating Radar Targets in Nonideal Operating Environments","authors":"M. B. Mashade","doi":"10.5923/J.AJSP.20120205.03","DOIUrl":"https://doi.org/10.5923/J.AJSP.20120205.03","url":null,"abstract":"A constant false alarm rate in the presence of variable levels of noise is usually a requirement placed on any modern radar. The CA - and OS-CFAR detectors are the most widely used ones in the CFAR world. The cell-averaging (CA) is the optimu m CFA R detector in terms of detection probability in ho mogeneous background when the reference cells have identical, independent and exponentially distributed signals. The ordered-statistic (OS) is an alternative to the CA processor, which trades a small loss in detection performance, relative to the CA scheme, in ideal conditions for much less performance degradation in non-ideal background environments. To benefice the merits of these well-known schemes, two modified versions (MX- & MN-CFAR) have been recently suggested. This paper is devoted to the detection performance evaluation of these modified versions as well as a novel one (ML-CFA R). Exact formu las for their false alarm and detection performances are derived, in the absence as well as in the presence of spurious targets. The results of these performances obtained for Rayleigh clutter and Rayleigh target indicate that the MN-CFAR scheme performs nearly as good as OS detector in the presence of outlying targets and all the developed versions perform much better than that processor when the background environment is homogeneous. When compared to CA-CFAR, the modified schemes perform better in an ideal condition, and behave much better in the presence of interfering targets.","PeriodicalId":336301,"journal":{"name":"Journal of the Aerospace Sciences","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130630457","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 aerodynamic and geometric characteristics of two-dimensional sails in a hypersonic flow are investigated in this paper. These surfaces would have very large lift and drag per unit weight. Therefore, they appear attractive wherever large values of the parameters CLA/W or CDA/W are needed. Simple closed expressions are derived for the sail shape and the corresponding lift, drag, and moment coefficients. Charts of these quantities are presented for the entire useful design range. The results can also be applied to two-dimensional parachutes.
{"title":"The Characteristics of Two-Dimensional Sails in Hypersonic Flow","authors":"W. Daskin","doi":"10.2514/8.7483","DOIUrl":"https://doi.org/10.2514/8.7483","url":null,"abstract":"The aerodynamic and geometric characteristics of two-dimensional sails in a hypersonic flow are investigated in this paper. These surfaces would have very large lift and drag per unit weight. Therefore, they appear attractive wherever large values of the parameters CLA/W or CDA/W are needed. Simple closed expressions are derived for the sail shape and the corresponding lift, drag, and moment coefficients. Charts of these quantities are presented for the entire useful design range. The results can also be applied to two-dimensional parachutes.","PeriodicalId":336301,"journal":{"name":"Journal of the Aerospace Sciences","volume":"389 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126741820","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}
{"title":"Minimum-Energy Intercepts Originating From a Circular Orbit","authors":"W. Tempelman","doi":"10.2514/8.9261","DOIUrl":"https://doi.org/10.2514/8.9261","url":null,"abstract":"","PeriodicalId":336301,"journal":{"name":"Journal of the Aerospace Sciences","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122786654","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}
2 Lees, L., Recent Developments in Hypersonic Flew, Jet Propulsion, November, 1957. 3 Schaaf, S. A., Hurlbut, F. C , and Talbot, L., Induced Pressure on Flat Plates in Hypersonic Low Density Flow, to be published. Also, Aroesty, J., Induced Pressures on Flat Plates at M = 4 in Low Density Flow, Univ. of Calif., Project Rep. HE-150-157, 1958. 4 Sherman, F. S., Transport Phenomena in Low Density Gases, Proc. 2nd Biennial Gas Dynamics Symposium, Northwestern Univ. Press, 1958.
2 Lees, L.，高超音速飞行的最新发展，喷气推进，1957年11月。3 Schaaf, S. A.， Hurlbut, F. C .，和Talbot, L.，高超声速低密度流动中平板上的诱导压力，即将发表。同时，Aroesty, J.，低密度流中M = 4时平板上的诱导压力，加州大学，项目代表HE-150-157, 1958。4谢尔曼，F. S.，低密度气体中的输运现象，第二届两年一次的气体动力学研讨会，西北大学出版社，1958。
{"title":"On the Stable Shape of an Ablating Graphite Body","authors":"D. Christensen","doi":"10.2514/8.7922","DOIUrl":"https://doi.org/10.2514/8.7922","url":null,"abstract":"2 Lees, L., Recent Developments in Hypersonic Flew, Jet Propulsion, November, 1957. 3 Schaaf, S. A., Hurlbut, F. C , and Talbot, L., Induced Pressure on Flat Plates in Hypersonic Low Density Flow, to be published. Also, Aroesty, J., Induced Pressures on Flat Plates at M = 4 in Low Density Flow, Univ. of Calif., Project Rep. HE-150-157, 1958. 4 Sherman, F. S., Transport Phenomena in Low Density Gases, Proc. 2nd Biennial Gas Dynamics Symposium, Northwestern Univ. Press, 1958.","PeriodicalId":336301,"journal":{"name":"Journal of the Aerospace Sciences","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114138200","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}
{"title":"Special Solutions to the Equations of Motion for Maneuvering Entry","authors":"W. S. Jackson","doi":"10.2514/8.9377","DOIUrl":"https://doi.org/10.2514/8.9377","url":null,"abstract":"","PeriodicalId":336301,"journal":{"name":"Journal of the Aerospace Sciences","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124520439","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}
{"title":"Real-Gas Effects on Oblique-Shock Detachment Angles","authors":"C. W. Hartsell","doi":"10.2514/8.9331","DOIUrl":"https://doi.org/10.2514/8.9331","url":null,"abstract":"","PeriodicalId":336301,"journal":{"name":"Journal of the Aerospace Sciences","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132026814","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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