Comparison of flutter calculation methods based on ground vibration test result

2019 ◽  
Vol 91 (3) ◽  
pp. 466-476
Author(s):  
Wojciech Chajec
Keyword(s):  
Low Cost ◽  
Ground Vibration ◽  
Control Surface ◽  
Vibration Test ◽  
Problem Solution ◽  
Lattice Method ◽  
Mass Model ◽  
Content Type ◽  
Strip Theory ◽  
Flutter Analysis

PurposeA low-cost but credible method of low-subsonic flutter analysis based on ground vibration test (GVT) results is presented. The purpose of this paper is a comparison of two methods of immediate flutter problem solution: JG2 – low cost software based on the strip theory in aerodynamics (STA) and V-g method of the flutter problem solution and ZAERO I commercial software with doublet lattice method (DLM) aerodynamic model and G method of the flutter problem solution. In both cases, the same sets of measured normal modes are used. Design/methodology/approachBefore flutter computation, resonant modes are supplied by some non-measurable but existing modes and processed using the author’s own procedure. For flutter computation, the modes are normalized using the aircraft mass model. The measured mode orthogonalization is possible. The flutter calculation made by means of both methods are performed for the MP-02 Czajka UL aircraft and the Virus SW 121 aircraft of LSA category. FindingsIn most cases, both compared flutter computation results are similar, especially in the case of high aspect wing flutter. The Czajka T-tail flutter analysis using JG2 software is more conservative than the one made by ZAERO, especially in the case of rudder flutter. The differences can be reduced if the proposed rudder effectiveness coefficients are introduced. Practical implicationsThe low-cost methods are attractive for flutter analysis of UL and light aircraft. The paper presents the scope of the low-cost JG2 method and its limitations. Originality/valueIn comparison with other works, the measured generalized masses are not used. Additionally, the rudder effectiveness reduction was implemented into the STA. However, Niedbal (1997) introduced corrections of control surface hinge moments, but the present work contains results in comparison with the outcome obtained by means of the more credible software.

The effect of wing-tip propulsors on Icaré 2 aeroelasticity

2019 ◽  
Vol 91 (3) ◽  
pp. 509-524
Author(s):  
Wojciech Chajec ◽  
Wieslaw A. Krzymien ◽  
Andreas Strohmayer
Keyword(s):  
Electric Propulsion ◽  
Aircraft Design ◽  
Design Modification ◽  
Content Type ◽  
Test Execution ◽  
Strip Theory ◽  
Flutter Analysis ◽  
Solar Powered ◽  
The Impact ◽  
Wing Tip

Purpose The separation of energy conversion and propulsor is a promising aspect of hybrid-electric propulsion systems, allowing for increased installation efficiencies and setting the basis for distributed propulsion concepts. University of Stuttgart’s Institute of Aircraft Design has a long experience with electrically powered aircraft, starting with Icaré 2, a solar-powered glider flying, since 1996. Icaré 2 recently has been converted to a three-engine motor glider with two battery-powered wing-tip propellers, in addition to the solar-powered main electric motor. This adds propulsion redundancy and will allow analyzing yaw control concepts with differential thrust and the propeller-vortex interaction at the wing-tip. To ensure airworthiness for this design modification, new ground vibration tests (GVTs) and flutter calculations are required. The purpose of this paper is to lay out the atypical approach to test execution due to peculiarities of the Icaré 2 design such as an asymmetrical aileron control system, the long wing span with low frequencies of the first mode and elevated wing tips bending under gravity and thus affecting the accuracy of the wing torsion frequency measurements. Design/methodology/approach A flutter analysis based on GVT results is performed for the aircraft in basic configuration and with wing tip propulsors in pusher or tractor configuration. Apart from the measured resonant modes, the aircraft rigid body modes and the control surface mechanism modes are taken into consideration. The flutter calculations are made by a high-speed, low-cost software named JG2 based on the strip theory in aerodynamics and the V-g method of flutter problem solution. Findings With the chosen atypical approach to GVT the impact of the suspension on the test results was shown to be minimal. Flutter analysis has proven that the critical flutter speed of Icaré 2 is sufficiently high in all configurations. Practical implications The atypical approach to GVT and subsequent flutter analysis have shown that the effects of wing-tip propulsors on aeroelasticity of the high aspect ratio configuration do not negatively affect flutter characteristics. This analysis can serve as a basis for an application for a permit to fly. Originality/value The presented methodology is valuable for the flutter assessment of aircraft configurations with atypical aeroelastic characteristics.

scholarly journals Minimization of Ground Vibration Test Configurations for F-16 Aircraft by Subtractive Modification

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Sertac Koksal ◽  
Erdinc Nuri Yildiz ◽  
Yigit Yazicioglu ◽  
Gokhan Osman Ozgen
Keyword(s):  
Structural Model ◽  
Ground Vibration ◽  
Aircraft Design ◽  
Vibration Test ◽  
Fe Model ◽  
Certification Process ◽  
Critical Configurations ◽  
Flutter Analysis ◽  
Primary Test ◽  
Coarse Model

The certification process of external loads designed for aircraft needs to satisfy various criteria where compatibility with existing systems is one of the essential requirements. Flight flutter testing is a critical part of a certification process that requires many preliminary studies. Computational flutter analysis must precede actual flutter test to determine an approximately safe flight envelope to ensure the safety of the personnel and aircraft. To be able to perform flutter analysis of an aircraft, an accurate structural model such as finite element (FE) model is required. An accurate FE model can be obtained from a coarse model using ground vibration test (GVT) which is also the primary test campaign for certification of a new external load, new aircraft design, or modification on existing aircraft. On the other hand, performing GVT for each configuration of an aircraft is both time consuming and costly. It would be more practical to determine the critical configurations for an aircraft using computational tools and perform actual GVT for those configurations. The objective of this study is to simulate GVT characteristics for downloading and fuel configurations of F-16 aircraft. A novel methodology is proposed where various loading configurations can be simulated by subtractive modification from loaded GVT data so that joint stiffnesses between stores and aircraft need not be identified. The proposed technique decreases the number of necessary physical GVT testing campaigns.

scholarly journals Experimental and numerical study of dynamic characteristic of a complex all-movable rudder system

2017 ◽  
Vol 37 (3) ◽  
pp. 654-664
Author(s):  
Yuguang Bai ◽  
Wei Qian ◽  
Xiangyan Chen ◽  
Taojun Lu
Keyword(s):  
Modal Analysis ◽  
Numerical Study ◽  
Ground Vibration ◽  
System Modelling ◽  
Flight Vehicle ◽  
Lattice Method ◽  
Coupling Vibration ◽  
Hypersonic Flight Vehicle ◽  
Hypersonic Flight ◽  
Flutter Analysis

Modal analysis and flutter computation of a complex tail cabin system including six all-movable rudders for hypersonic flight vehicle was studied in this paper. Recently, some complex all-movable rudder system has been applied to hypersonic flight vehicle. Many investigations were taken to analyse a single all-movable rudder, such as modal analysis, flutter analysis, aero-heating analysis, etc. But most of existing investigations emphasized on single rudder. In this paper, a complex tail cabin system including six all-movable rudders from the X-51A vehicle was investigated. Modal analysis was presented based on accurate finite element modelling and bending and twisting modes of the structure were computed. Ground vibration test was provided to confirm the accuracy of computation. Then flutter characteristic of this complex system was analysed based on doublet lattice method. With flight Mach number 3 and 4, flutter analysis relating to both symmetric mode and antisymmetric mode was presented. It can be found from the presented results of flutter analysis that there were obvious and non-negligible coupling vibration effects among rudders in such a complex rudder system. So flutter characteristic of hypersonic flight vehicle should be analysed based on the whole system modelling including all of rudders. This analysis process can play a significant role for the design and flight of hypersonic vehicle.

Value communication: low-cost marketing initiatives for “Guru Ki Bani 58282”

2013 ◽  
Vol 3 (3) ◽  
pp. 1-9
Author(s):  
Neeraj Pandey ◽  
Gaganpreet Singh
Keyword(s):  
Interactive Voice Response ◽  
Low Cost ◽  
Value Added ◽  
Subject Area ◽  
Marketing Management ◽  
Digital Marketing ◽  
Content Type ◽  
Mba Students ◽  
Marketing Team ◽  
Value Communication

Subject area Pricing, digital marketing, marketing management and strategic marketing. Study level/applicability The case can be used for pricing or digital marketing courses as well as marketing management courses to MBA students and/or for management development programmes. Case overview Goldfinch Mobile Solutions, a Hong-Kong based value added services (VAS) and gaming platform provider, had an exclusive tie up with Bharti Airtel in India for providing value added voice applications on an interactive voice response system (IVRS) platform. The Goldfinch flagship service is “Guru Ki Bani” which may be subscribed to by dialing the short code 58282. This “58282” service has a repository of all Sikh religion daily prayers, religious songs, teachings, stories from Guru's life and similar information that is derived from the Sikh Holy book Guru Granth Sahib Ji. As per mutual agreement between Goldfinch Mobile Solutions and Bharti Airtel, the telecom operator had the responsibility to promote Goldfinch's Guru Ki Bani service amongst its subscriber base through its below the line (BTL) promotional channels such as short messaging service (SMS), outbound calls, cell information, notification SMS after call and above the line (ATL) activities such as posters, leaflets, print, promoters, regional TV, outdoors, etc. The revenue sharing arrangement between Airtel and Golfinch was in the ratio of 75 percent and 25 percent. However, with recent changes in the policies of Telephone Regulatory Authority of India (TRAI), promotional marketing used by telecom operators has been constrained. Declining customer share, decreasing profits (after Bharti Airtel halted promotions) and increasing organization cost per customer have made MD and CEO Mr Newton Bubber think of various options including low-cost marketing initiatives besides digital marketing to promote Guru Ki Bani services. Value communication to its huge potential customer base, i.e. 184.19 million Bharti Airtel subscribers was another challenge facing Mr Newton and his marketing team at Goldfinch. Expected learning outcomes The case enables students to learn the concepts and application of value creation, effective value communication, price waterfall analysis, importance of costing parameters in pricing decisions, low-cost marketing strategies and digital marketing. Supplementary materials Teaching notes are available for educators only. Please contact your library to gain login details or email [email protected] to request teaching notes.

A review of passive self-sensing tag

Sensor Review ◽  
2017 ◽  
Vol 37 (3) ◽  
pp. 338-345 ◽  
Author(s):  
Yawei Xu ◽  
Lihong Dong ◽  
Haidou Wang ◽  
Jiannong Jing ◽  
Yongxiang Lu
Keyword(s):  
Radio Frequency Identification ◽  
Large Scale ◽  
Low Cost ◽  
Integrated Sensor ◽  
Content Type ◽  
Passive Sensing ◽  
Static Information ◽  
Potential Applications ◽  
Frequency Identification ◽  
Identification Tags

Purpose Radio frequency identification tags for passive sensing have attracted wide attention in the area of Internet of Things (IoT). Among them, some tags can sense the property change of objects without an integrated sensor, which is a new trend of passive sensing based on tag. The purpose of this paper is to review recent research on passive self-sensing tags (PSSTs). Design/methodology/approach The PSSTs reported in the past decade are classified in terms of sensing mode, composition and the ways of power supply. This paper presents operation principles of PSSTs and analyzes the characteristics of them. Moreover, the paper focuses on summarizing the latest sensing parameters of PSSTs and their matching equipment. Finally, some potential applications and challenges faced by this emerging technique are discussed. Findings PSST is suitable for long-term and large-scale monitoring compared to conventional sensors because it gets rid of the limitation of battery and has relatively low cost. Also, the static information of objects stored in different PSSTs can be identified by a single reader without touch. Originality/value This paper provides a detailed and timely review of the rapidly growing research in PSST.

Social media: a blessing or a curse? Voice of owners in the beauty and wellness industry

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kulvinder Kaur ◽  
Pawan Kumar
Keyword(s):  
Social Media ◽  
Low Cost ◽  
Growth Potential ◽  
Social Media Marketing ◽  
Small Scale ◽  
Content Type ◽  
Social Media Platforms ◽  
Pros And Cons ◽  
Marketing Tool ◽  
Use Of Internet

PurposeThe rise in the use of Internet technologies and social media has shifted the marketing practices from offline to online. This study aims to determine the pros and cons of social media marketing in the beauty and wellness industry.Design/methodology/approachIn-depth interviews were conducted with the owners and marketing executives of beauty and wellness centers to understand the use of popular social media platforms in this industry and their pros and cons.FindingsThe researchers identified eight merits and seven demerits of social media in the beauty and wellness industry. Every respondent is happy and satisfied with social media use, particularly Instagram and Facebook. Irrespective of the demerits, they have shown the intention to increase its usage in the future. The merits override demerits; thus, social media is a blessing for this industry from the owners' perspective.Research limitations/implicationsThe research is exploratory and is confined to just one industry. Research implication is that the visual nature of social media makes it a powerful tool for the promotion of the beauty and wellness industry.Practical implicationsThe study's findings will be beneficial for small-scale businesses as it will push them to take advantage of this low-cost marketing tool.Social implicationsSocial media marketing is helpful for communication and marketing purposes for society.Originality/valueThe beauty and wellness industry remained unfocused by researchers because it is highly unorganized, fragmented and not regulated, yet has huge growth potential. This research will provide a closer look at this industry as well as social media marketing.

Virtual medical learning: a comprehensive study on the role of new technologies

Kybernetes ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mi Tang ◽  
Hongmei Zhou ◽  
Qingyan Yan ◽  
Ruoyu Li ◽  
Hui Lu
Keyword(s):  
Literature Review ◽  
New Technologies ◽  
Low Cost ◽  
Access Point ◽  
Learning Technologies ◽  
Learning Technology ◽  
Content Type ◽  
Services Delivery ◽  
Medical Learning ◽  
Intellectual Knowledge

PurposeHealthcare employs informatics to offer its services through information technology where the social network can aid virtual medical learning. Since the usage of the internet and other electronic tools for medical services delivery is at the initial stage, it is essential to examine the factors that condition patients and medical elements in a virtual environment can develop relationship models on the health services. So, the authors have systematically reviewed virtual medical learning and offered some suggestions for the upcoming works. The authors have also discovered gaps in the state-of-the-art papers and provided solutions for them.Design/methodology/approachNumerous novel advancements have changed the old exercise of therapeutic and analytic learning. Virtual spaces have quickly turned into a section of the learning technology vision. Given the importance of its achievements and endless low-cost expansion of the educational system, virtual education has been considered as one of the issues raised by the information communities. Medicine and health are some of the most important fields in virtual technologies. Hence, in this paper, we have used a systematic literature review to deeply examine virtual medical learning. After establishing exclusion and inclusion criteria, an independent systematic search in Google Scholar, ACM, Scopus, Eric, Science Direct, Springer link, Emerald, Global ProQuest and IEEE for relevant studies have been performed, and 21 papers have been analyzed. Detailed data have been mined out of the papers.FindingsThe authors have found that virtual medical learning improves and expands the knowledge core and meaningfully affects the exercise. Virtual learning (VL) has been used in many therapeutic zones, like therapeutic learning, surgery, diagnosing, combining and regularizing processes. It has presented a fundamental access point and a referral mechanism for all of a course's component communities. It can also simplify communicative education, allowing learners to get abilities before applying them in a real-world situation. Also, the communicative characteristics of different VL programs can somehow be like direct teaching.Research limitations/implicationsSome excellent work may be removed owing to applying the filters to select the primary papers. Surveying all the documents on the topic of virtual medical learning is impossible, too. Nevertheless, the authors have tried to present a perfect survey of virtual medical learning. The results will be helpful for scholars to propose better virtual medical learning techniques.Practical implicationsE-learning has become an indispensable additional learning tool in medical education. The introduction of new learning technologies, the exponential growth of Internet usage and the advent of the World Wide Web can change the face of higher education. The results will be helpful for scholars for the upcoming works. The application of a literature review of partial least squares theory was useful for offering comprehensive literary coverage and completing the knowledge development analysis. The authors have backed scholars and experts for better understanding the development of virtual medical learning systems via presenting comparative data and scrutinizing the present advances.Originality/valueThe paper enhances intellectual knowledge by improving the conception of virtual medical learning. It informs the development, use of virtual medical learning and the upcoming works. The lack of comprehensive papers in this field has increased the importance of this paper. The present paper can handle the pace of publications.

Modern nanobiotechnologies for efficient detection and remediation of mercury

Sensor Review ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mulayam Singh Gaur ◽  
Rajni Yadav ◽  
Mamta Kushwah ◽  
Anna Nikolaevna Berlina
Keyword(s):  
Heavy Metals ◽  
Water Samples ◽  
Low Cost ◽  
High Sensitivity ◽  
Environmental Water ◽  
Mercury Ions ◽  
Content Type ◽  
Efficient Detection ◽  
Sensitivity And Selectivity ◽  
Selection Of

Purpose This information will be useful in the selection of materials and technology for the detection and removal of mercury ions at a low cost and with high sensitivity and selectivity. The purpose of this study is to provide the useful information for selection of materials and technology to detect and remove the mercury ions from water with high sensitivity and selectivity. The purpose of this study is to provide the useful information for selection of materials and technology to detect and remove the mercury ions from water with high sensitivity and selectivity. Design/methodology/approach Different nano- and bio-materials allowed for the development of a variety of biosensors – colorimetric, chemiluminescent, electrochemical, whole-cell and aptasensors – are described. The materials used for their development also make it possible to use them in removing heavy metals, which are toxic contaminants, from environmental water samples. Findings This review focuses on different technologies, tools and materials for mercury (heavy metals) detection and remediation to environmental samples. Originality/value This review gives up-to-date and systemic information on modern nanotechnology methods for heavy metal detection. Different recognition molecules and nanomaterials have been discussed for remediation to water samples. The present review may provide valuable information to researchers regarding novel mercury ions detection sensors and encourage them for further research/development.

Preparation and application of water-based nano-silver conductive ink in paper-based 3D printing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chenfei Zhao ◽  
Jun Wang ◽  
Lini Lu
Keyword(s):  
Flexible Electronics ◽  
Low Cost ◽  
Methyl Cellulose ◽  
Conductive Ink ◽  
Content Type ◽  
Nano Silver ◽  
Printed Circuit ◽  
Silver Ink ◽  
Sintering Time ◽  
Water Based

Purpose In flexible electronics applications, organic inks are mostly used for inkjet printing. Three-dimensional (3 D) printing technology has the advantages of low cost, high speed and good precision in modern electronic printing. The purpose of this study is to solve the high cost of traditional printing and the pollution emissions of organic ink. It is necessary to develop a water-based conductive ink that is easily degradable and can be 3 D printed. A nano-silver ink printed circuit pattern with high precision, high conductivity and good mechanical properties is a promising strategy. Design/methodology/approach The researched nano-silver conductive ink is mainly composed of silver nanoparticles and resin. The effect of adding methyl cellulose on the ink was also explored. A simple 3 D circuit pattern was printed on photographic paper. The line width, line length, line thickness and conductivity of the printed circuit were tested. The influence of sintering temperature and sintering time on pattern resistivity was studied. The relationship between circuit pattern bending performance and electrical conductivity is analyzed. Findings The experimental results show that the ink has the characteristics of low silver content and good environmental protection effect. The printing feasibility of 3 D printing circuit patterns on paper substrates was confirmed. The best printing temperature is 160°C–180°C, and the best sintering time is 30 min. The circuit pattern can be folded 120°, and the cycle is folded more than 60 times. The minimum resistivity of the circuit pattern is 6.07 µΩ·cm. Methyl cellulose can control the viscosity of the ink. The mechanical properties of the pattern have been improved. The printing method of 3 D printing can significantly reduce the sintering time and temperature of the conductive ink. These findings may provide innovation for the flexible electronics industry and pave the way for alternatives to cost-effective solutions. Originality/value In this study, direct ink writing technology was used to print circuit patterns on paper substrates. This process is simple and convenient and can control the thickness of the ink layer. The ink material is nonpolluting to the environment. Nano-silver ink has suitable viscosity and pH value. It can meet the requirements of pneumatic 3 D printers. The method has the characteristics of simple process, fast forming, low cost and high environmental friendliness.

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