Dynamic Damage of Aircraft Wing Leading Edge Impacted by Birds

2013 ◽  
Vol 385-386 ◽  
pp. 292-295 ◽  
Author(s):  
Liu Jun
Keyword(s):  
High Speed ◽  
Leading Edge ◽  
Test Results ◽  
Aircraft Wing ◽  
Camera System ◽  
Edge Structure ◽  
Whole Process ◽  
Laser Velocity ◽  
Certification Requirements ◽  
Structure Configuration

In order to verify the preliminary design of Aircraft Wing Leading Edge structures to bird impacting loads. The tests of bird impacting on Wing Leading Edge structure configurations were carried out using the relevant experimental facility. The impacting velocity was measured by laser velocity finder. The structure configuration was impacted by bird on three points and the whole process of dynamic deformation and damage on bird and Wing Leading Edge structure were recorded using high speed camera system. The test results showed that the leading edge slat was weak in anti-bird impacting and can not satisfy the airworthiness certification requirements. At the meantime the test results provid abundant experimental validation datas for the numerical simulation model applied in birds impacting.

Precision Jetting of Glob Top Materials – a methodology for process optimization

2012 ◽  
Vol 2012 (1) ◽  
pp. 000351-000358 ◽  
Author(s):  
K.-F. Becker ◽  
M. Koch ◽  
J. Bauer ◽  
T. Braun ◽  
R. Aschenbrenner ◽  
...  
Keyword(s):  
High Speed ◽  
Process Development ◽  
Droplet Diameter ◽  
High Volume ◽  
High Viscosity ◽  
Process Data ◽  
Camera System ◽  
Ceramic Substrates ◽  
Whole Process ◽  
Material Deposition

During the last years, jetting processes for higher viscosity materials have gained widespread interest in microelectronics manufacturing. Main reasons for this interest are high throughput/productivity of jetting, contactless material deposition, high volume precision and freely designable deposition patterns. In previous studies we have demonstrated the jetability of different resin-based materials, being exemplary for unfilled adhesive, for low viscous Underfill resin and for higher viscosity Glob Top materials. The focus of our previous work was on the dosing of Underfill material, where this study is dealing with more complex materials – Glob Top resins. These materials are non-Newtonian fluids - the flow curves of the filled materials can be described by models of Cross or Herschel/Bulkey. Furthermore, highly filled and paste-like mixtures show a significant time dependency of formation of structural equilibrium after deformation, so process development needs to take this into account, so detailed material analysis is described within this study. To illustrate the potential of jetting as a flexible and powerful tool for Chip on Board encapsulation, both, simple test-structures (dots, lines, dams) but also more complex demonstrators have been assembled using wire bonded ICs on ceramic substrates and encapsulants showing viscosities ranging from 10 Pas to > 100 Pas. Not only basic process data on droplet diameter, resulting material depot size and positioning accuracy have been evaluated, but also statistical means have been employed to determine process homogeneity and stability depending on the respective parameter set. Additionally, the whole process was followed by a high-speed camera system, providing detailed information on actual jetting behaviour during droplet release, flight and impact. Summarized this paper gives a detailed insight into jet process development for high viscosity Glob Top materials and describes process design rules and limitations and thus allows the optimized use of advanced jetting technology for Chip on Board assemblies.

Bird Impact Analysis of Wing Leading Edge Structure Based on SPH Method

2011 ◽  
Vol 462-463 ◽  
pp. 524-529 ◽  
Author(s):  
Xiao Peng Wan ◽  
Wen Zhi Wang ◽  
Mei Ying Zhao
Keyword(s):  
High Speed ◽  
Impact Analysis ◽  
Leading Edge ◽  
Design Parameters ◽  
Sph Method ◽  
Finite Element Program ◽  
Edge Structure ◽  
Bird Impact ◽  
Sph Model ◽  
Element Program

In this paper, a new bird model which combined the visco-elastic material properties and Smooth Particle Hydrodynamics (SPH) method has been proposed to simulate the bird features in high-speed conditions. A rigid plate impact test was adopted to compare the reaction of SPH and Lagrangian bird model. Compared with the results of Lagrangian bird model, new SPH model was more in line with the experimental data, and has better computational efficiency. The SPH bird model was further used to bird impacting with the wing leading edge by using finite element program LS-DYNA. Two kinds of leading edge structural enhancement programs have been proposed and carried out simulation of bird impact. Basis of calculation, the design parameters of experimental structure was determined and was produced to wait for final testing.

scholarly journals Numerical and Experimental Investigation of Deployment Behaviour of Folded Fin Mechanism based on the Dynamic Loading Conditions

2020 ◽  
Author(s):  
MURAT AVCI ◽  
ÖZER TAGA ◽  
ÖMER KELEŞ
Keyword(s):  
High Speed ◽  
Numerical Models ◽  
Test Results ◽  
Test Device ◽  
Camera System ◽  
Mechanism Model ◽  
Body Dynamics ◽  
Deployment Time ◽  
Dynamic Loading Conditions ◽  
Multi Body

Abstract In this study, the friction and damping values ​​that arise during the deployment of the folded fin mechanism were obtained based on the experimental data. Although there are recommended values ​​for friction in the literature, damping is a phenomenon that varies from system to system and must be obtained through test data. In this study, firstly, the mechanism was operated on the test device with a specific drive pressure and the actual drive pressure generated in the system was measured. The dynamic behaviour of the mechanism was recorded by a High-Speed camera system as well. Adams MBD (multi-body dynamics) was used to define the mechanism model and drive pressure data from the test was defined as input to the model. With the help of Adams DOE (Design of Experiments), certain intervals were defined for friction and damping, multiple analyses were carried out at the friction and damping intervals defined and total deployment time of the mechanism and the dynamic behaviours it exhibited during deployment were obtained. From these numerical results obtained, friction and damping values ​​were obtained based on the model with the highest correlation and test results. The same mechanism was tested for different drive pressures with the specified friction and damping values ​​and the results were compared to the numerical models. It was decided that the friction and damping values ​​determined as a result of the comparison could be used in future numerical analyses.

Experimental Characterization of a Novel Piezoelectric Fan

2019 ◽  
Author(s):  
Jingru Benner ◽  
Eric Shilyuk ◽  
Jarrod Coletta ◽  
Mehdi Mortazavi ◽  
Anthony D. Santamaria ◽  
...  
Keyword(s):  
Numerical Model ◽  
Flow Rate ◽  
High Speed ◽  
Leading Edge ◽  
Low Noise ◽  
Camera System ◽  
Low Energy Consumption ◽  
2D Numerical Model ◽  
Piezoelectric Fans

Abstract Piezoelectric fans have attracted attentions in the past decades because of their low energy consumption, low noise level, light weight and reliability. A novel form of piezoelectric flapping fan is characterized experimentally and numerically. An experimental setup was built to measure the pressure and flow rate of piezoelectric fans with low static pressure at various frequencies. The fan performance curve was established. A high speed camera system was used to analyze the oscillation motion of the fan wings. The displacement of the leading edge and trailing edge of the piezoelectric fan wings are used as inputs to describe the deflection of the fan in the numerical model. The flow field obtained from the model is analyzed. The vortex shedding is observed and discussed. The pressure and flow rate obtained from the 2D numerical model are compared with the experimental results. The results provide a fundamental understanding of a piezoelectric fan with opposing oscillating wings.

scholarly journals EFFECT OF SEED FILLING AND RELEASING ANGLES ON THE PERFORMANCE OF COMPOUND VACUUM SEED METERING DEVICE

2021 ◽  
pp. 153-162
Author(s):  
Zeqi Liu ◽  
Zhang Meng ◽  
Jie Han ◽  
Yajun Zhuang ◽  
Xiang Yin ◽  
...  
Keyword(s):  
Negative Pressure ◽  
High Speed ◽  
Test Results ◽  
Camera System ◽  
Seed Filling ◽  
Evaluation Indexes ◽  
Air Chamber ◽  
The Subject ◽  
Seed Metering Device

In this paper, taking compound air-suction seed metering device as the subject, the effect rule of seed filling angle and seed releasing angle on the performance of seed filling and seed metering is studied. An indoor test was conducted with a JPS-12 metering test bench and a high-speed camera system. The starting and ending angles of the air chamber were changed by adjusting the regulating plate, that is, the angles of seed filling and seed releasing, and the filling and seed metering performance was taken as evaluation indexes. The test results show that: the seed filling angle has significant effect on the seed filling effect, and the miss fill index decreases with the increase of the quality of fill index. When the seed filling angle exceeds 50°, they will stabilize gradually ending at the multiple fill index of 0%. The negative pressure and operating speed are interactive and have a significant effect on filling performance. The seed releasing angle has significant effect on the metering performance. With the increase of the angle, the quality of feed index increases firstly and then decreases. The multiple index and miss index are opposite to the quality of feed index which is the max at the seed releasing angle of 39.5°. The negative pressure and forward speed are interactive and have a significant effect on metering performance. The quality of feed index under the same condition is lower than that of fill index.

An experimental investigation of cloud cavitation about a sphere

2010 ◽  
Vol 656 ◽  
pp. 147-176 ◽  
Author(s):  
P. A. BRANDNER ◽  
G. J. WALKER ◽  
P. N. NIEKAMP ◽  
B. ANDERSON
Keyword(s):  
Boundary Layer ◽  
High Speed ◽  
Single Phase ◽  
Leading Edge ◽  
Series Data ◽  
Variable Pressure ◽  
Cloud Cavitation ◽  
Pixel Intensity ◽  
Edge Structure ◽  
Cavity Shedding

Cloud cavitation occurrence about a sphere is investigated in a variable-pressure water tunnel using low- and high-speed photography. The model sphere, 0.15 m in diameter, was sting-mounted within a 0.6 m square test section and tested at a constant Reynolds number of 1.5 × 106 with cavitation numbers varying between 0.36 and 1.0. High-speed photographic recordings were made at 6 kHz for several cavitation numbers providing insight into cavity shedding and nucleation physics. Shedding phenomena and frequency content were investigated by means of pixel intensity time series data using wavelet analysis. Instantaneous cavity leading edge location was investigated using image processing and edge detection.The boundary layer at cavity separation is shown to be laminar for all cavitation numbers, with Kelvin–Helmholtz instability and transition to turbulence in the separated shear layer the main mechanism for cavity breakup and cloud formation at high cavitation numbers. At intermediate cavitation numbers, cavity lengths allow the development of re-entrant jet phenomena, providing a mechanism for shedding of large-scale Kármán-type vortices similar to those for low-mode shedding in single-phase subcritical flow. This shedding mode, which exists at supercritical Reynolds numbers for single-phase flow, is eliminated at low cavitation numbers with the onset of supercavitation.Complex interactions between the separating laminar boundary layer and the cavity were observed. In all cases the cavity leading edge was structured in laminar cells separated by well-known ‘divots’. The initial laminar length and divot density were modulated by the unsteady cavity shedding process. At cavitation numbers where shedding was most energetic, with large portions of leading edge extinction, re-nucleation was seen to be circumferentially periodic and to consist of stretched streak-like bubbles that subsequently became fleck-like. This process appeared to be associated with laminar–turbulent transition of the attached boundary layer. Nucleation occurred periodically in time at these preferred sites and formed the characteristic cavity leading edge structure after sufficient accumulation of vapour had occurred. These observations suggest that three-dimensional instability of the decelerating boundary layer flow may have significantly influenced the developing structure of the cavity leading edge.

scholarly journals Design of a Variable-Stiffness Compliant Skin for a Morphing Leading Edge

2021 ◽  
Vol 11 (7) ◽  
pp. 3165
Author(s):  
Zhigang Wang ◽  
Yu Yang
Keyword(s):  
Composite Laminate ◽  
Large Scale ◽  
Design Method ◽  
Leading Edge ◽  
Variable Stiffness ◽  
Manufacturing Constraints ◽  
Aircraft Wing ◽  
Noise Abatement ◽  
Civil Aircraft ◽  
Final Profile

A seamless and smooth morphing leading edge has remarkable potential for noise abatement and drag reduction of civil aircraft. Variable-stiffness compliant skin based on tailored composite laminate is a concept with great potential for morphing leading edge, but the currently proposed methods have difficulty in taking the manufacturing constraints or layup sequence into account during the optimization process. This paper proposes an innovative two-step design method for a variable-stiffness compliant skin of a morphing leading edge, which includes layup optimization and layup adjustment. The combination of these two steps can not only improve the deformation accuracy of the final profile of the compliant skin but also easily and effectively determine the layup sequence of the composite layup. With the design framework, an optimization model is created for a variable-stiffness compliant skin, and an adjustment method for its layups is presented. Finally, the deformed profiles between the directly optimized layups and the adjusted ones are compared to verify its morphing ability and accuracy. The final results demonstrate that the obtained deforming ability and accuracy are suitable for a large-scale aircraft wing.

scholarly journals The Optimization of Alternating Current Electrospun PA 6 Solutions Using a Visual Analysis System

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2098
Author(s):  
Tomas Kalous ◽  
Pavel Holec ◽  
Jakub Erben ◽  
Martin Bilek ◽  
Ondrej Batka ◽  
...  
Keyword(s):  
High Voltage ◽  
High Speed ◽  
Visual Analysis ◽  
Polyamide 6 ◽  
Alternating Current ◽  
Sine Wave ◽  
Electrospinning Process ◽  
Camera System ◽  
Polymeric Solutions ◽  
Analysis System

The electrospinning process that produces fine nanofibrous materials have a major disadvantage in the area of productivity. However, alternating current (AC) electrospinning might help to solve the problem via the modification of high voltage signal. The aforementioned productivity aspect can be observed via a camera system that focuses on the jet creation area and that measures the average lifespan. The paper describes the optimization of polyamide 6 (PA 6) solutions and demonstrates the change in the behavior of the process following the addition of a minor dose of oxoacid. This addition served to convert the previously unspinnable (using AC) solution to a high-quality electrospinning solution. The visual analysis of the AC electrospinning of polymeric solutions using a high-speed camera and a programmable power source was chosen as the method for the evaluation of the quality of the process. The solutions were exposed to high voltage applying two types of AC signal, i.e., the sine wave and the step change. All the recordings presented in the paper contained two sets of data: firstly, camera recordings that showed the visual expression of electrospinning and, secondly, signal recordings that provided information on the data position in the signal function.

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