scholarly journals Fuzzy uncertainty analysis and reliability assessment of aeroelastic aircraft wings

2020 ◽  
Vol 124 (1275) ◽  
pp. 786-811
Author(s):  
M. Rezaei ◽  
S.A. Fazelzadeh ◽  
A. Mazidi ◽  
M.I. Friswell ◽  
H.H. Khodaparast
Keyword(s):  
Structural Parameters ◽  
Low Cost ◽  
Fuzzy Variable ◽  
Fuzzy Uncertainty ◽  
Aircraft Wings ◽  
Wing Flutter ◽  
Flutter Speed ◽  
Wing Model ◽  
Safe Region ◽  
Air Speed

ABSTRACTIn the present study, fuzzy uncertainty and reliability analysis of aeroelastic aircraft wings are investigated. The uncertain air speed and structural parameters are represented by fuzzy triangular membership functions. These uncertainties are propagated through the wing model using a fuzzy interval approach, and the uncertain flutter speed is obtained as a fuzzy variable. Further, the reliability of the wing flutter is based on the interference area in the pyramid shape defined by the fuzzy flutter speed and air speed. The ratio between the safe region volume and the total volume of the pyramid gives the reliability value. Two different examples are considered—a typical wing section, and a clean wing—and the results are given for various wind speed conditions. The results show that the approach considered is a low-cost but suitable method to estimate the reliability of the wing flutter speed in the presence of uncertainties.

scholarly journals Analisis Flutter Pada Uji Model Separuh Sayap Pesawat N219 di Terowongan Angin Kecepatan Rendah

WARTA ARDHIA ◽  
2017 ◽  
Vol 42 (4) ◽  
pp. 165
Author(s):  
Sayuti Syamsuar ◽  
Muhamad Kusni ◽  
Adityo Suksmono ◽  
Muhamad Ivan Aji Saputro
Keyword(s):  
Wind Tunnel ◽  
Computational Analysis ◽  
Aerodynamic Force ◽  
Unstable Condition ◽  
Low Speed ◽  
Wing Flutter ◽  
Flutter Speed ◽  
Wing Model ◽  
Speed Range ◽  
Low Speed Wind Tunnel

Fenomena flutter akan terjadi apabila ada gaya dan momen aerodinamika yang berinteraksi berlebihan di permukaan sayap di dalam terowongan angin atau pesawat sesungguhnya. Sayap akan bergetar dan berosilasi bertambah besar menuju ke keadaan tidak stabil. Osilasi osilasi membuat osilasi yang lebih besar terjadi sehingga frekuensi dan damping pada daerah kecepatan tertentu dengan mudah terlihat apabila terjadi flutter pada model separuh sayap. Penelitian ini, digunakan model separuh sayap dari pesawat N219 yang di uji pada terowongan angin kecepatan rendah BBTA3, kawasan Puspiptek, Serpong. Kecepatan flutter terjadi pada 40,5 m/s pada hasil analisis komputasional dan hasil pengujian di terowongan angin sebesar 40,83 m/s. [The Analysis of Half Wing Flutter Test N219 Aircraft Model in The Low Speed Wind Tunnel] The flutter phenomenon will occur when the aerodynamic force and moment excessively interacted on the wing surface, whether it takes place in the wind tunnel or on the real aircraft. The wing will vibrate and oscillate towards an unstable condition. Each oscillation will subsequently build a greater one until the damping and frequency on a certain speed range can be seen easily when flutter occur on the half wing model. On this research, the half wing model of N219 aircraft was tested in the low speed wind tunnel of BBTA3, Puspitek Serpong. The flutter speed occurred at 40,5 m/s based on computational analysis while the wind tunnel result is at the speed of 40,83 m/s.

Control of Structural Flutter Using Piezoelectric Patches

2008 ◽  
Author(s):  
M. Hariri ◽  
S. John ◽  
P. Trivailo
Keyword(s):  
Strain Energy ◽  
Piezoelectric Materials ◽  
Active Material ◽  
Structural Vibrations ◽  
Wing Flutter ◽  
Flutter Speed ◽  
Aerodynamic Loading ◽  
Air Stream ◽  
Air Speed

Aero-elasticity is a major concern in aerospace field. It resultes from the interaction between the air-stream and the structure. Wing flutter is a well known problem of the aero-elasticity. It which occurs when the two lowest system eigenvalues (plunge and pitch motion) coalesce at a certain air speed known as the flutter speed. The increasing use of active material induced-strain actuation such as piezoelectric materials in suppression of structural vibrations has seen its extension to wing flutter control. Higher flutter speed and hence, a wider operating envelope was achieved by delaying the coalescence of these two eigenvalues. This delaying is obtained by adding more strain energy to the system as a result of the activation of the piezoelectric actuators. This paper models a simple beam under nominal aerodynamic loading conditions for the determination of analytically-derived onset of flutter speeds. Also shown in this paper is the effect of orientation of actuated piezoelectric patches on the shift of the flutter speed.

Modelling Piezoelectric Actuation During Structural Flutter

2009 ◽  
Author(s):  
M. Hariri ◽  
S. John ◽  
P. Trivailo
Keyword(s):  
Structural Control ◽  
Strain Energy ◽  
Piezoelectric Materials ◽  
Active Material ◽  
Structural Vibrations ◽  
Wing Flutter ◽  
Flutter Speed ◽  
Air Stream ◽  
Air Speed

Aeroelasticity is a major concern in structural control. It results from the interaction between the air-stream and the structure. Wing flutter is a well known problem of the aero-elasticity. It occurs when the two lowest system eigenvalues (plunge and pitch motion) coalesce at a certain air speed known as the flutter speed. The increasing use of active material induced-strain actuation such as piezoelectric materials in the suppression of structural vibrations has seen its extension to wing flutter control. Higher flutter speed and hence, a wider operating envelope was achieved by delaying the coalescence of these two eigenvalues. This delay is obtained by adding more strain energy to the system as a result of the activation of the piezoelectric actuators. This paper models a simple beam under nominal aerodynamic loading conditions for the determination of analytically-derived onset of flutter speeds. Also shown in this paper, is the effect of orientation of actuated piezoelectric patches, on the shift of the flutter speed.

scholarly journals Numerical Investigation of Aeroelastic Mode Distribution for Aircraft Wing Model in Subsonic Air Flow

2010 ◽  
Vol 2010 ◽  
pp. 1-23 ◽  
Author(s):  
Marianna A. Shubov ◽  
Stephen Wineberg ◽  
Robert Holt
Keyword(s):  
Boundary Value Problem ◽  
Numerical Investigation ◽  
Air Flow ◽  
Affirmative Answer ◽  
Positive Answer ◽  
Aircraft Wing ◽  
Aircraft Wings ◽  
Flutter Speed ◽  
Wing Model ◽  
Analytical Formulas

In this paper, the numerical results on two problems originated in aircraft wing modeling have been presented.The first problemis concerned with the approximation to the set of the aeroelastic modes, which are the eigenvalues of a certain boundary-value problem. The affirmative answer is given to the following question: can the leading asymptotical terms in the analytical formulas be used as reasonably accurate description of the aeroelastic modes? The positive answer means that these leading terms can be used by engineers for practical calculations.The second problemis concerned with the flutter phenomena in aircraft wings in a subsonic, incompressible, inviscid air flow. It has been shown numerically that there exists a pair of the aeroelastic modes whose behavior depends on a speed of an air flow. Namely, when the speed increases, the distance between the modes tends to zero, and at some speed that can be treated as the flutter speed these two modes merge into one double mode.

Design of Separating Screen for Tenebrio molitor L

2014 ◽  
Vol 543-547 ◽  
pp. 258-262
Author(s):  
Li Ping Wang ◽  
Yi Guo ◽  
Gang Fu ◽  
Jiang Hui Dong
Keyword(s):  
Performance Test ◽  
High Efficiency ◽  
Structural Parameters ◽  
Low Cost ◽  
Tenebrio Molitor ◽  
Vector Method ◽  
Working Principle ◽  
Design Requirements ◽  
And Performance ◽  
Easy Operation

In order to meet requirement of separation screen for tenebrio molitor L, one separation screen was designed, this product has a good separation, simple structure, low cost, high efficiency, easy operation. Based on the analysis of design requirement of separating screen for tenebrio molitor L, overall structure, working principle and the main structural parameters were determined. The kinematic mathematical model of shaking mechanism was established by using the vector method. The kinematics analysis of shaking mechanism was conducted by using Matlab, the displacement, velocity and acceleration curves of sieve box were obtained. The performance test showed that the prototype machine can screen different instar tenebrio molitor L and frass, this machine has good screening effect. In addition, machine design and performance are able to meet the design requirements.

Fabrication of a Carbon Nanotube Gas Sensor Microelectrodes and its Application for Ammonia Detection

2013 ◽  
Vol 431 ◽  
pp. 306-311
Author(s):  
Xiang Tao Ran ◽  
Zhi Wang ◽  
Li Yang
Keyword(s):  
Gas Sensors ◽  
High Performance ◽  
Gas Sensing ◽  
Structural Parameters ◽  
Low Cost ◽  
Manufacturing Method ◽  
Multi Walled Carbon Nanotubes ◽  
Ammonia Detection ◽  
Low Cost Manufacturing ◽  
Walled Carbon Nanotubes

With the increasing needs for high-performance gas sensors in industrial production, environmental monitoring and so on, the research on gas sensors is becoming more and more important. In this paper, the electric field intensity distribution simulation process of the interdigital microelectrodes (IMEs) is discussed in details to get the proper electrode structural parameters. The IMEs on the ITO surface with a minimum gap of about 4μm are achieved by lithography, which provides a reliable, low-cost manufacturing method. Sensitive components are made of the multi-walled carbon nanotubes modified materials. The gas-sensing property of the sensor is detected for ammonia. The experiment result shows that the performance of the nanomodified sensor is obviously improved.

Optimization Dressing Method of Amplitude Transformer Based on Finite Element

2013 ◽  
Vol 278-280 ◽  
pp. 315-318
Author(s):  
Ming Li Zhao ◽  
Bo Zhao ◽  
Yu Qing Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Resonant Frequency ◽  
Structural Parameters ◽  
Low Cost ◽  
Dressing Method ◽  
Finite Element Software ◽  
System Vibration ◽  
Vibration Performance ◽  
Element Method

The node position of amplitude transformer was determined by the finite element method, and the flange was designed at the nod position for conveniently installation. By the finite element software, the amplitude transformer with flange was optimized and dressed, and its structural parameters were determined. During the actual manufacturing process, it was used impedance analyzer to test its vibration performance, the testing results show that this system vibration performance is good, its resonant frequency is 34.771kHz, anti-resonant frequency is 35.008kHz. The above-mentioned results are very much coincided with the system natural frequency of 34.893kHz which is drew by finite element method. Compared to the traditional dressing this method has many advantages such as convenience, green, environmental protection, low cost and others.

scholarly journals Desain dan Eksperimen Uji Getaran di Tanah dari Model Separuh Sayap Pesawat N219

WARTA ARDHIA ◽  
2017 ◽  
Vol 42 (3) ◽  
pp. 123
Author(s):  
Sayuti Syamsuar ◽  
Leonardo Gunawan ◽  
Martina Widiramdhani ◽  
Nina Kartika
Keyword(s):  
Wind Tunnel ◽  
Critical Phenomenon ◽  
Damping Ratio ◽  
Wind Tunnel Test ◽  
Ground Vibration ◽  
Parameter Analysis ◽  
Vibration Test ◽  
Software Analysis ◽  
Flutter Speed ◽  
Wing Model

Fenomena flutter merupakan salah satu fenomena yang kritis dan dapat membahayakan pesawat. Ketika, pesawat terbang semakin cepat dan mencapai kecepatan flutter, maka akan terjadi ketidakstabilan struktur. Oleh sebab itu, untuk menjamin keselamatan Pilot saat uji terbang, perlu dilakukan analisis awal pada kecepatan flutter. Uji terowongan angin selalu dilakukan untuk memvalidasi hasil dari analisis numerikal. Penelitian ini meliputi analisis program NASTRAN pada model separuh sayap pesawat N219 saat uji getaran di tanah. Prediksi kecepatan flutter secara analisis hampir sama dengan hasil uji terowongan angin. Parameter modus struktur yang ditemukan, seperti frekuensi natural, modus getar dan rasio redaman, dapat digunakan untuk analisis parameter flutter sebagai metoda analisis baru. [The Design and Experiment of Ground Vibration Test of N219 Aircraft Half Wing Model] Flutter phenomena is a critical phenomenon that can be dangerous for aircraft. When an aircraft fly faster until reach flutter speed, the structure will become unstable. Therefore, it is important to conduct preliminary analysis of flutter speed to ensure the safety of Pilot. Wind tunnel test is necessary to be conducted to validate numerical analysis results. This research consist of NASTRAN software analysis of half wing model of N219 aircraft for ground vibration test. The prediction of flutter speed which is obtained from software analysis is similar with the wind tunnel test result. It is found that the modus parameter of structure like natural frequency, modus of vibration and damping ratio can be used on the parameter analysis as a new analysis method.

scholarly journals Assessing Low-Cost Terrestrial Laser Scanners for Deriving Forest Structure Parameters

2021 ◽  
Author(s):  
Atticus E. L. Stovall ◽  
Jeff W Atkins
Keyword(s):  
Structural Parameters ◽  
Low Cost ◽  
Laser Scanner ◽  
Point Clouds ◽  
Model Reconstruction ◽  
Tree Model ◽  
Factors Affecting ◽  
Laser Scanners ◽  
Tree Models ◽  
Profile Reconstruction

The increasingly affordable price point of terrestrial laser scanners has led to a democratization of instrument availability, but the most common low-cost instruments have yet to be compared in terms of the consistency to measure forest structural attributes. Here, we compared two low-cost terrestrial laser scanners (TLS): the Leica BLK360 and the Faro Focus 120 3D. We evaluate the instruments in terms of point cloud quality, forest inventory estimates, tree-model reconstruction, and foliage profile reconstruction. Our direct comparison of the point clouds showed reduced noise in filtered Leica data. Tree diameter and height were consistent across instruments (4.4% and 1.4% error, respectively). Volumetric tree models were less consistent across instruments, with ~29% bias, depending on model reconstruction quality. In the process of comparing foliage profiles, we conducted a sensitivity analysis of factors affecting foliage profile estimates, showing a minimal effect from instrument maximum range (for forests less than ~50 m in height) and surprisingly little impact from degraded scan resolution. Filtered unstructured TLS point clouds must be artificially re-gridded to provide accurate foliage profiles. The factors evaluated in this comparison point towards necessary considerations for future low-cost laser scanner development and application in detecting forest structural parameters.

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