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1
Jia, Zhong Hu, Wei Han, Xiao Hong Zheng, and Yang Tao. "Analysis of the Arresting Dynamic Loads of Aircraft’s Landing Gear." Applied Mechanics and Materials 105-107 (September 2011): 470–73. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.470.
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The arresting landing of carrier aircraft is especial dynamic problem. During this process,the gear would bear the very big dynamic load,which does the biggest harm to gear .In this paper,it analyzed the landing gear shock strut in carrier aircraft arresting landing,and aiming at the runout of shock strut and the flexibility of the landing gear by using the Lagrange equation.Then it concluded the chaging of landing gear shock strut with symmetrical and straight arresting,3m of off-center distance arresting and 2°of rolling angle arresting after simulating.The conclusion showed that the landing gear shock strut would be stable after a short time concussion;rolling and unsymmetrical affected the shock strutmore severe than off-center and symmetrical arresting,and the qualities of concussion also being more acute.
2
Suresh, PS, Niranjan K. Sura, and K. Shankar. "Investigation of nonlinear landing gear behavior and dynamic responses on high performance aircraft." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 15 (July 1, 2019): 5674–88. http://dx.doi.org/10.1177/0954410019854628.
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The dynamic responses simulation of aircraft as rigid body considering heave, pitch, and roll motions, coupled onto a tricycle landing gear arrangement is presented. Equation of motion for each landing gear consists of un-sprung mass vertical and longitudinal motions considering strut nonlinear stiffness and damping combined with strut bending flexibility. Initially, the nonlinear dynamic response model is subjected to an input of riding over staggered bump and the responses are compared with linear landing gear model. It is observed that aircraft dynamics and important landing gear events such as vertical, spin-up and spring-back are truly represented with nonlinear stiffness and damping model considering strut bending flexibility. Later, landing response analysis is performed, with the input from nonlinear flight mechanics model for several vertical descent rate cases. The aircraft and landing gear dynamic responses such as displacement, velocity, acceleration, and reaction forces are obtained. The vertical and longitudinal drag forces from the nonlinear dynamic response model is compared with “Book-case method” outlined in landing gear design technical specifications. From the reaction force ratio calculation, it is shown that for lower vertical descent rate case the predicted loads are lesser using nonlinear dynamic response model. The same model for higher vertical descent rate cases predicts higher ratios on vertical reaction for main landing gear and longitudinal reaction for nose landing gear, respectively. The scope for increase in fatigue life for low vertical descent rate landing covering major design spectrum and the concern for static strength and structural integrity consideration for higher vertical descent rate cases are discussed in the context of event monitoring on aircraft in services.
3
Yadav, D., and R. P. Ramamoorthy. "Nonlinear Landing Gear Behavior at Touchdown." Journal of Dynamic Systems, Measurement, and Control 113, no. 4 (December 1, 1991): 677–83. http://dx.doi.org/10.1115/1.2896474.
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Landing gear dynamics for an aircraft has been analyzed with a heave-pitch model having telescopic main gear and articulated nose gear using oleopneumatic shock absorber. System equations have been presented incorporating the effects of linkage dynamics, frictional forces, and nonlinearities in the tyre, air spring, and oleo damping forces. Sensitivity of the system response to variations in some shock strut parameters has been investigated for the landing touchdown impact phase to bring about improvement in the performance.
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Chen, Fei, Yong Lv, and Zhi Wei Xing. "The Strength Analysis of Aircraft Landing Gear Strut Based on ANSYS." Advanced Materials Research 490-495 (March 2012): 2686–90. http://dx.doi.org/10.4028/www.scientific.net/amr.490-495.2686.
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Because the landing gear structure is complicated, it is difficult to draw accurate stress and strain distribution through the theoretical calculation. In this paper, based on the modeling and stress analysis of the buffer mechanism of aircraft landing gear, by converting the stress of a dynamic system into a static stress, the force of the landing gear struts are calculated. This paper analyzes the strength of the aircraft main landing gear by using computer simulation technology and finite element analysis, it provides an effective basis for maintenance and the damage prediction
5
Giridharan, V., and S. Sivakumar. "Shimmy analysis of light weight aircraft nose wheel landing gear." Vibroengineering PROCEDIA 47 (December 12, 2022): 8–15. http://dx.doi.org/10.21595/vp.2022.22988.
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This paper presents mathematical modeling and analysis of shimmy oscillations for a light weight airplane single wheel nose landing gear. Shimmy is a self-excited oscillation which occurs usually on the nose wheel landing gear assembly during ground maneuvers which is governed by the dynamic characteristics of the landing gear and tires. Shimmy oscillation may lead to reduce the fatigue life of the landing gear and fuselage structure. So, the study of dynamic response and stability boundaries of landing gear plays crucial role while designing of airplanes. In earlier studies of vehicle shimmy only 3 degrees of freedom (DOF) considered such as torsional mode, lateral bending mode and tire lateral deformation. In this work along with above mentioned DOF, two more additional DOF introduced such as axial vibration of strut and tire in order to include the effect of vertical dynamics on shimmy model. Gyroscopic coupling effect also included in the model to study its influence on shimmy. Analysis carried out to determine critical velocity region for occurrence of shimmy and to investigate the effectiveness of ground unevenness on the landing gear system for two different runway conditions such as flat runway and random roughness runway. The results are more helpful to study significant interaction between the different parameters of landing gear and to represent stability boundaries.
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Chen, Hu, Xingbo Fang, and Hong Nie. "Analysis of Carrier-Based Aircraft Catapult Launching Based on Variable Topology Dynamics." Applied Sciences 11, no. 19 (September 28, 2021): 9037. http://dx.doi.org/10.3390/app11199037.
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The catapult process of a carrier-based aircraft includes multiple links such as catapult tensioning, separation of the holding rod, dragging and running, separation of the catapult and drag shuttle, and free running. The connection relationships between the front landing gear of the carrier-based aircraft and other related components in each link are different, therefore, it is necessary to adjust the topological relationships of the dynamic model in real time, when solving the catapult dynamics of a carrier-based aircraft. In this paper, a dynamic model of the multibody system of the catapult take-off is established, and a variable topology solution is carried out for the dynamic model by adjusting dynamic augmentation equations; in addition, a dynamic analysis of a carrier-based aircraft catapult and take-off process is carried out. A catapult dynamics model and variable topology solution method were established, which solved the changes at the moment of the restraining rod separation, catapult rod separation, and catapult tackle during the aircraft catapult take-off. After the restraining rod was separated from the front landing gear, the catapult force was transmitted to the rear strut, which instantly increased the load of the rear strut by 238.5 kN. In addition, after the carrier-based aircraft reached the end of the catapult’s stroke, the catapult rod was separated from the catapult tow shuttle then unloaded, and the load of the rear strut was reduced from 486.2 kN to −20.3 kN. Under the protruding effect of the nose gear, the pitch angle of the carrier-based aircraft increased rapidly from −0.93° and reached 0.54° when the carrier-based aircraft rushed out of the deck.
7
Zhu, Xin Yu, and Jun Wen Lu. "Stress and Buckling Analysis of a Certain Type of All-Composite Landing Gear." Advanced Materials Research 663 (February 2013): 692–97. http://dx.doi.org/10.4028/www.scientific.net/amr.663.692.
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FEA method was conducted to investigate static stress and buckling analysis of a certain all-composite landing gear strut. The critical buckling load and bucking mode shapes of the landing gear is obtained using ANSYS finite element analysis code. The first six buckling mode shapes and static stress distribution are given. According to the analysis results, the dynamic characteristics of the landing gear are discussed. The analysis method and results in this paper can be used for further study on making maintenance plan and safety verification for the landing gear.
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Chondrou, I. T., G. Mavrantonakis, N. Tsagarakis, E. Vergis, D. Pangalos, and T. G. Chondros. "Design evaluation of the fractured main landing gear of a BAE Jetstream SX-SKY aircraft." International Journal of Structural Integrity 6, no. 4 (August 10, 2015): 468–92. http://dx.doi.org/10.1108/ijsi-08-2014-0039.
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Purpose – The purpose of this paper is to study the main landing gear (MLG) mechanism configuration. Design/methodology/approach – Mechanism kinematics and dynamics, stress analysis and sizing of the MLG structural members, and fatigue issues related with the mechanism operation. Spreadsheet solutions were incorporated to this survey to analyze the most conceivable loading situations, and important factors of the mechanism design for an initial evaluation of safety implications. Findings – MLG design approach along with conservative fatigue design factors lies in the area of accepted limits in commercial aircraft industry. Research limitations/implications – MLG loading associated with landing as well as those associated with ground maneuvers (steering, braking and taxiing) contribute significantly to fatigue damage, along with the stresses induced by manufacturing processes and assembly. The application of FEA methods for the design of the landing gear does not always guarantee a successful approach to the problem solution, if precise analytical solutions are not available in advance. Practical implications – From the investigation of this incident of fractured struts of the MLG it is confirmed that the reduction in Pintle Housing diameter on the upper part has contributed to the avoidance of damaging the fuel tank above the MLG that would lead to a catastrophic event. On the other hand, the airframe of the SKY-Jet was proved efficient for a belly landing with minor damages to the passengers and heavier damages for the aircraft. Social implications – On-line vibration monitoring sensors hooked up to the landing gear strut and Pintle House would greatly enhance safety, without relying in optical surveys in hard to access and inspect areas of the landing gears mechanisms housings. Originality/value – Analytic methods were adopted and spreadsheet solutions were developed for the MLG main loading situations, along with design issues concerning mechanism kinematics and dynamics, stress analysis and sizing of the MLG structural members, as well as fatigue issues related with the mechanism operation. Spreadsheet solutions were incorporated to this survey to analyze the most conceivable loading situations, and important factors of the mechanism design for an initial evaluation of safety implications.
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Pecora, Rosario. "A Rational Numerical Method for Simulation of Drop-Impact Dynamics of Oleo-Pneumatic Landing Gear." Applied Sciences 11, no. 9 (April 30, 2021): 4136. http://dx.doi.org/10.3390/app11094136.
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Oleo-pneumatic landing gear is a complex mechanical system conceived to efficiently absorb and dissipate an aircraft’s kinetic energy at touchdown, thus reducing the impact load and acceleration transmitted to the airframe. Due to its significant influence on ground loads, this system is generally designed in parallel with the main structural components of the aircraft, such as the fuselage and wings. Robust numerical models for simulating landing gear impact dynamics are essential from the preliminary design stage in order to properly assess aircraft configuration and structural arrangements. Finite element (FE) analysis is a viable solution for supporting the design. However, regarding the oleo-pneumatic struts, FE-based simulation may become unpractical, since detailed models are required to obtain reliable results. Moreover, FE models could not be very versatile for accommodating the many design updates that usually occur at the beginning of the landing gear project or during the layout optimization process. In this work, a numerical method for simulating oleo-pneumatic landing gear drop dynamics is presented. To effectively support both the preliminary and advanced design of landing gear units, the proposed simulation approach rationally balances the level of sophistication of the adopted model with the need for accurate results. Although based on a formulation assuming only four state variables for the description of landing gear dynamics, the approach successfully accounts for all the relevant forces that arise during the drop and their influence on landing gear motion. A set of intercommunicating routines was implemented in MATLAB® environment to integrate the dynamic impact equations, starting from user-defined initial conditions and general parameters related to the geometric and structural configuration of the landing gear. The tool was then used to simulate a drop test of a reference landing gear, and the obtained results were successfully validated against available experimental data.
10
Zhang, Songyang, Qiaozhi Yin, Xiaohui Wei, Jiayi Song, and Hong Nie. "Study of Brake Disc Friction Characteristics Effect on Low Frequency Brake Induced Vibration of Aircraft Landing Gear." Aerospace 9, no. 12 (December 9, 2022): 809. http://dx.doi.org/10.3390/aerospace9120809.
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During aircraft braking, the change of ground adhesion forces can cause forward and backward vibration of the landing gear, and the performance of the brake disc may exacerbate this vibration. In order to solve this problem, a rigid–flexible coupling dynamic model of a two-wheel strut landing gear considering the friction characters of brake discs with different materials and a hydraulic brake system model is established in this paper. The brake disc friction characteristics effect on the low-frequency brake-induced vibration of the landing gear given different brake disc materials and ambient temperatures is studied. It is shown that the C/SiC brake disc has a “negative slope” phenomenon between the friction coefficient of the brake disc and the wheel speed, and this variable friction characteristic has a great effect on the low-frequency braking-induced vibration of the landing gear. In addition, the variable friction characteristics of the C/SiC brake disc are easily affected by ambient temperature, while the friction coefficient of the C/C brake disc changes stably.
11
Shams, Taimur Ali, Syed Irtiza Ali Shah, Muhammad Ayaz Ahmad, Kashif Mehmood, Waseem Ahmad, and Syed Tauqeer ul Islam Rizvi. "Selection Methodology of an Electric Actuator for Nose Landing Gear of a Light Weight Aircraft." Applied Sciences 10, no. 23 (December 6, 2020): 8730. http://dx.doi.org/10.3390/app10238730.
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Landing gear system of an aircraft enables it to take off and land with safety and comfort. Because of the horizontal and vertical velocity of aircraft, upon landing, the complete aircraft undergoes different forcing functions in the form of the impact force that is absorbed by landing gears, shock absorbers, and actuators. In this research, a selection methodology has been proposed for an electrical actuator to be installed in the retraction mechanism of nose landing gear of an aircraft having 1600 kg gross takeoff weight. Nose landing gear and its associated components, like strut and shock absorbers, were modeled in CAD software. Analytical expressions were then developed in order to calculate the actuator stroke, translational velocity, force, and power for complete cycle of retraction, and some were subsequently compared with the computational results that were obtained using MSC ADAMS®. Air in the oleo-pneumatic shock absorber of nose landing gear was modeled as a nonlinear spring with equivalent spring constant, whereas hydraulic oil was modeled as a nonlinear damper with equivalent damping constant. The nose landing gear system was modeled as a mass-spring-damper system for which a solution for sinusoidal forcing functions is proposed. Finally, an electrical actuator has been selected, which can retract and extend nose landing gear, meeting all of the constraints of aircraft, like fuselage space, aircraft ground clearance, locking loads, power consumption, retraction and extension time, and dynamic response of aircraft. It was found that the selection of an electrical actuator is based upon the quantification of forces transmitted to electrical actuator during one point load at gross takeoff weight. The ability of retraction and extension time, as dictated by Federal Aviation Regulation, has also been given due consideration in the proposed methodology as significant criteria. The proposed system is now in the process of ground testing, followed by flight testing in the near future.
12
Kang, Byung-Hyuk, Bang-Hyun Jo, Bo-Gyu Kim, Jai-Hyuk Hwang, and Seung-Bok Choi. "Linear and Nonlinear Models for Drop Simulation of an Aircraft Landing Gear System with MR Dampers." Actuators 12, no. 7 (July 13, 2023): 287. http://dx.doi.org/10.3390/act12070287.
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In this study, our focus is on the drop test simulation of an MR (Magnetorheological) damper-based main landing gear (MRMLG), aiming to explore multi-degree-of-freedom (DOF) dynamic models during aircraft landing. Three different 6-DOF dynamic models are proposed in this work, and their drop performances are compared with results achieved by commercial software. The proposed models include a nonlinear aircraft model (NLAM); a linearized approximated aircraft model (LAAM) linearizing from the nonlinear equations of motion in NLAM; and a fully approximated aircraft model (FAAM) which linearizes the MRMLG’s strut force model. In order to evaluate the drop performance of the aircraft landing gear system with MR dampers, a 7-DOF aircraft model incorporating the nonlinear MRMLG was formulated using RecurDyn. The principal comparative parameters are the coefficient of determination (R2) for the system response of each model with the RecurDyn model and root mean square error (RMSE), which is the ensemble of CG displacement data for each model. In addition, the ensemble of time series data is created for diverse drop scenarios, providing valuable insights into the performance of the proposed drop test models of an aircraft landing gear system featuring MR dampers.
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Asthana, Chandra B., and Rama B. Bhat. "A Novel Design of Landing Gear Oleo Strut Damper Using MR Fluid for Aircraft and UAV’s." Applied Mechanics and Materials 225 (November 2012): 275–80. http://dx.doi.org/10.4028/www.scientific.net/amm.225.275.
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Most landing gears used in aircraft employ very efficient oleo-pneumatic dampers to absorb and dissipate the impact kinetic energy of the aircraft body frame. A single-acting shock absorber is most commonly used in the oleo strut that has a metering pin extending through the orifice, which can vary the orifice area upon compression and extension of the strut. This variation is adjusted by shaping the metering pin so that the strut load is fairly constant under dynamic loading. In this paper, it is proposed to further change the damping coefficient as a function of time in order to achieve a semi-active control of the aircraft vibrations during landing by using Magnetorheological (MR) fluid in the Oleo. With the metering pin designed for a nominal flight condition, further variation in the fluid viscosity would help achieve the optimal performance in off-nominal flight conditions. A simulation approach is employed to show the effect of different profiles for viscosity variation in the MR fluid. The utility of such a damper can be very well exploited to include different criteria such as the landing distance after touchdown. This type of system can be used also in Unmanned Aerial Vehicle (UAV) application where the focus of design may be to accomplish the task without the consideration of passenger comfort.
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Huang, Mingyang, Hong Nie, and Ming Zhang. "Analysis of ground handling characteristic of aircraft with electric taxi system." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 233, no. 6 (April 11, 2018): 1546–61. http://dx.doi.org/10.1177/0954407018764163.
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Electric landing gear drive equipped with traction motors can provide taxi capability without the use of main engines or tractor. The ground handling characteristic of aircraft with electric taxi system is analyzed. The new mathematic model of aircraft ground maneuver is established, considering the 6-degree-freedom aircraft body and the flexible main strut and the powered wheel. Quasi-steady method is applied to calculate tire side forces and moments, to determine side slip. The simulation for the ground steering response of aircraft with electric taxi system is done by employing ADAMS and Simulink co-simulation platform. The dynamic responses of aircraft ground steering and landing gear spin-up and spring back are simulated. Different taxi conditions including powered nose wheel mode and powered main wheel mode are compared. Four conclusions are obtained: electric taxi system helps the aircraft turn on the spot and the turning radius is smaller than the aircraft using engines; differential powered main wheel mode has the minimum turning radius while turning-circle with uniform velocity, and it has smaller difference between two vertical loads of main landing gear than powered nose wheel mode; in the case of the same steering angle, the extreme velocity of differential powered main wheel mode before side slip is larger than powered nose wheel mode; and pre-rotation of powered main wheel decreases the spin-up drag load and spring back drag load.
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Liu, Jun, Lin Xuan Zhang, and Bing Cui. "Real-Time Semi-Physical Simulation of Industry Design System Based on Virtual Reality Technology." Applied Mechanics and Materials 607 (July 2014): 413–16. http://dx.doi.org/10.4028/www.scientific.net/amm.607.413.
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Research how to realize real-time hardware in the loop (HIL) of industry design system by utilizing a variety of virtual reality (VR) hardware and software. In this paper, it introduces VR and virtual prototyping technology, and then proposes joint control and simulation based on ADAMS / Aircraft, Simulink, Flightgear three software. Moreover, the virtual scene, data gloves and real-time semi-physical simulation are analyzed and researched; finally as an example, build a real-time semi-physical simulation platform of the landing gear system for multi-wheel and multi-strut aircraft. The system can do kinematic and dynamic analysis, real-time control by visual prototyping and digital models through real-time data acquisition and co-simulation.
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Li, Feifan, and Yanying Zhao. "Amplitude reduction optimization of time delay semi-active control for aircraft landing gear shimmy." Journal of Physics: Conference Series 2230, no. 1 (March 1, 2022): 012009. http://dx.doi.org/10.1088/1742-6596/2230/1/012009.
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Abstract Considering the time delay issue in the process of aircraft landing gear shimmy, the time delay semi-active control is used to achieve the purpose of amplitude reduction optimization. Firstly, in order to eliminate the influence of dimensionality and make the results better describe the objective universal law, after dimensionless treatment of the shimmy equations, the influence of dimensionless lateral bending damping coefficient and lateral bending stiffness coefficient of strut on the shimmy amplitude is analyzed. Then, in order to further reduce the amplitude, the time delay semi-active control term is introduced into the shimmy equations, and a mathematical method for solving the characteristic equation of the time-delay dynamic equation is proposed. Designing optimization criterion limits the amplitude of the first resonance to a small enough range. The time delay semi-active control can achieve good vibration reduction effect in the whole frequency domain and eliminate the second resonance. Finally, it is verified and compared in the frequency domain and time domain, the correctness of the calculation and the superiority of time delay semi-active control are proved.
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Mallapur, Shashidhar, and Roland Platz. "Quantification of Uncertainty in the Mathematical Modelling of a Multivariable Suspension Strut Using Bayesian Interval Hypothesis-Based Approach." Applied Mechanics and Materials 885 (November 2018): 3–17. http://dx.doi.org/10.4028/www.scientific.net/amm.885.3.
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Mathematical models of a suspension strut such as an aircraft landing gear are utilized by engineers in order to predict its dynamic response under different boundary conditions. The prediction of the dynamic response, for example the external loads, the stress and the strength as well as the maximum compression in the spring-damper component aids engineers in early decision making to ensure its structural reliability under various operational conditions. However, the prediction of the dynamic response is influenced by model uncertainty. As far as the model uncertainty is concerned, the prediction of the dynamic behavior via different mathematical models depends upon various factors such as the model's complexity in terms of the degrees of freedom, material and geometrical assumptions, their boundary conditions and the governing functional relations between the model input and output parameters. The latter can be linear or nonlinear, axiomatic or empiric, time variant or time-invariant. Hence, the uncertainty that arises in the prediction of the dynamic response of the resulting different mathematical models needs to be quantified with suitable validation metrics, especially when the system is under structural risk and failure assessment. In this contribution, the authors utilize the Bayesian interval hypothesis-based method to quantify the uncertainty in the mathematical models of the suspension strut.
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Yousif, Ismail Abdelrahman, Mohammed Abdelmageed M. Zein, and Mohammed Elhadi Ahmed Elsayed. "Computational Analysis of a Truss Type Fuselage." Applied Mechanics and Materials 225 (November 2012): 183–88. http://dx.doi.org/10.4028/www.scientific.net/amm.225.183.
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The strength of a welded truss type fuselage of a light aircraft – named SAFAT 01 – is considered in this paper. The aircraft is a monoplane with high strut-braced wings configuration with flaps. The fuselage is of welded tubular steel fabric-covered construction. According to its production contract; the aircraft is fully produced and assembled in Sudan whereas the documentation is limited to technical side only with no information available about design procedures and calculations. This makes it difficult to further modify or upgrade the aircraft. The fuselage geometry has been modeled using a CAD program. The main dimensions have been obtained using 2-D drawings and the missing dimensions and data due to lack of documents were extracted experimentally from a built aircraft. Aerodynamic loads were determined using computational fluid dynamic program for the horizontal tail. Static structural analysis was conducted by finite element method (FEM) using fastened connection property between the tubes. The results were observed in three main parts; rear part which supports the vertical and horizontal stabilizers and the rear landing gear; the mid part which provides cantilever reaction for the wing and supports front landing gear, and the front part on which the engine is mounted. The Von Mises stresses, displacements and principal stresses were observed in the three parts and found acceptable except for a small region near the attachment between wing and fuselage. However, further experimental validation is needed. Presently, experimental and dynamic analyses are being conducted and the results will be published later.
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Nishanth P, Prabakaran N, Akshay R Walikar, Rakesh Ichangi, Ravishankar R N, and Vijay. "Material Replacement and Fatigue Analysis of Nose Landing Gear’s Shock Strut." ACS Journal for Science and Engineering 3, no. 1 (March 10, 2023): 32–41. http://dx.doi.org/10.34293/acsjse.v3i1.59.
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Landing, take off are one of the most maneuvering occurring in aircraft. The landing gear is considered as a non-linear structure due to its complicate behavior during landing period large amount of impact forces transferred into nose gear and main landing gear. Nose landing gear bears approx. 5% of aircraft's weight and is used for operations like landing, takeoff, as well as steering purpose. The cyclic loads acting on the landing gear which cause fatigue failure of landing gear or its parts. The current work includes the design of the nose landing gear which is retractable type of landing gear. During the ground operation of the aircraft, various types of loads will be encountered. Each of these loads will cause axial compression and tension on the wheels and strut of the landing gear. In this work the landing gear part we have chosen is shock strut which is one of the parts in landing gear on which most of the fatigue failures are observed is modeled using CATIA V5 Software. The analysis is carried out in ANSYS 20 R1.
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Gan, Shengyong, Xingbo Fang, and Xiaohui Wei. "Parametric Analysis on Landing Gear Strut Friction of Light Aircraft for Touchdown Performance." Applied Sciences 11, no. 12 (June 11, 2021): 5445. http://dx.doi.org/10.3390/app11125445.
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The aim of this paper is to obtain the strut friction–touchdown performance relation for designing the parameters involving the strut friction of the landing gear in a light aircraft. The numerical model of the landing gear is validated by drop test of single half-axle landing gear, which is used to obtain the energy absorption properties of strut friction in the landing process. Parametric studies are conducted using the response surface method. Based on the design of the experiment results and response surface functions, the sensitivity analysis of the design variables is implemented. Furthermore, a multi-objective optimization is carried out for good touchdown performance. The results show that the proportion of energy absorption of friction load accounts for more than 35% of the total landing impact energy. The response surface model characterizes well for the landing response, with a minimum fitting accuracy of 99.52%. The most sensitive variables for the four landing responses are the lower bearing width and the wheel moment of inertia. Moreover, the max overloading of sprung mass in LC-1 decreases by 4.84% after design optimization, which illustrates that the method of analysis and optimization on the strut friction of landing gear is efficient for improving the aircraft touchdown performance.
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Kuznetsov, D. S., Y. N. Tikhtey, V. V. Kremenchutsky, and A. G. Vilesov. "Investigation of the feasibility of using wing struts and non-retractable landing gear struts on a light multi-purpose aircraft." E3S Web of Conferences 383 (2023): 05004. http://dx.doi.org/10.1051/e3sconf/202338305004.
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In this paper, we consider a method for determining the feasibility of using a wing strut and non-retractable landing gear on a light multi-purpose aircraft. In a certain range of cruising speeds and flight ranges, it is advisable to use non-retractable landing gear and wing strut. With an increase in cruising speed and flight range, these engineering solutions must be abandoned to improve aerodynamic characteristics. The dependencies obtained in this work make it possible to make decisions on the use of a wing strut and non-retractable landing gear at the early design stages. To obtain aerodynamic characteristics in the Siemens NX program, a three-dimensional model of a light multi-purpose aircraft was created and an aerodynamic experiment was performed in the FloEFD program. Then the calculation of flight performance was carried out. As a result of the study, the dependence of the speed up to which it is advisable to use the undercarriage strut and fixed landing gear on the flight range for a light multi-purpose aircraft weighing 2000 kg was obtained. When designing an aircraft, it is necessary to make decisions about the use of one or another engineering solution, which, on the one hand, has a positive effect on aerodynamics and negatively on the weight of the aircraft, and vice versa. In this article, using the example of a wing strut and fixed landing gear in the first version of the aircraft, and a cantilever wing and retractable landing gear in the second version, a model for solving such a problem is shown.
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Ahmad, Muhammad Ayaz, Syed Irtiza Ali Shah, Sabih Ahmad Khan, Haris Ali Khan, and Taimur Ali Shams. "A Novel Framework for Qualification of a Composite-Based Main Landing Gear Strut of a Lightweight Aircraft." Polymers 15, no. 6 (March 11, 2023): 1402. http://dx.doi.org/10.3390/polym15061402.
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The determination of suitable testing and qualification procedures for fiber-reinforced polymer matrix composite structures is an active area of research due to the increased demand, especially in the field of aerospace. This research illustrates the development of a generic qualification framework for a composite-based main landing gear strut of a lightweight aircraft. For this purpose, a landing gear strut composed of T700 carbon fiber/epoxy material was designed and analyzed for a given lightweight aircraft having mass of 1600 kg. Computational analysis was performed on ABAQUS CAE® to evaluate the maximum stresses and critical failure modes encountered during one-point landing condition as defined in the UAV Systems Airworthiness Requirements (USAR) and Air Worthiness Standards FAA FAR Part 23. A three-step qualification framework including material, process and product-based qualification was then proposed against these maximum stresses and failure modes. The proposed framework revolves around the destructive testing of specimens initially as per ASTM standards D 7264 and D 2344, followed by defining the autoclave process parameters and customized testing of thick specimens to evaluate material strength against the maximum stresses in specific failure modes of the main landing gear strut. Once the desired strength of the specimens was achieved based on material and process qualifications, qualification criteria for the main landing gear strut were proposed which would not only serve as an alternative to drop test the landing gear struts as defined in air worthiness standards during mass production, but would also give confidence to manufacturers to undertake the manufacturing of main landing gear struts using qualified material and process parameters.
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Guo, Zhifei, Peiqing Liu, Jin Zhang, and Hao Guo. "Numerical simulation of aeroacoustic noise from landing gear and rectangular cavity." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 234, no. 7 (January 17, 2020): 1259–71. http://dx.doi.org/10.1177/0954410019900722.
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This paper is aimed at researching the interaction between aeroacoustic noise radiated from a rectangular cavity (gear bay) and from landing gear. It is a complicated flow-induced noise problem, involving the nonlinear, unsteady evolution of the turbulent structure inside the airflow bypassing the landing gear and the cavity. The generation and radiation mechanism of aeroacoustic noise are also concerned. In fact, it is a problem about the nonlinear interaction between the vortices shedding from the boundary layer of bluff bodies and the cavity-limited shear layer. To simplify this issue, a two-wheel landing gear named LAGOON is chosen as the landing gear model. The unsteady flow field and aerodynamic noise from it is simulated by applying the commercial software ANSYS Fluent. Good agreement is achieved between the numerical simulation and wind tunnel measurements in terms of the aerodynamic and aeroacoustic results. According to the size of LAGOON, a simple rectangular cavity is designed as the landing gear bay. Both the cavity combined with LAGOON and the cavity alone are simulated and compared. The results show that under the blocking effect of a strut, most small pieces of vortices at the trailing edge of the cavity bottom would dissipate rather than move forward along with the backflow, leading to the correlation of cavity resonance being more contrasting and increasing its amplitude. The blockage effect induced by rear wall could also enhance the turbulence kinetic energy at the wake of the strut, thus increasing the low-frequency noise radiated from the strut and cavity.
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Ahmad, Muhammad Ayaz, Hamza Rafiq, Syed Irtiza Ali Shah, Sabih Ahmad Khan, Syed Tauqeer ul Islam Rizvi, and Taimur Ali Shams. "Selection Methodology of Composite Material for Retractable Main Landing Gear Strut of a Lightweight Aircraft." Applied Sciences 12, no. 11 (June 3, 2022): 5689. http://dx.doi.org/10.3390/app12115689.
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The design and development of high-strength and low-weight composite landing gear struts is still a challenge in today’s world. In this study, a selection methodology for fiber-reinforced composite material for retractable main landing gear struts for specified lightweight aircraft up to 1600 kg mass is proposed. Four different fiber-reinforced composite materials, two each from the glass-fiber and carbon-fiber families, including E-glass fiber/epoxy, S-glass fiber/epoxy, T300 carbon fiber/epoxy, and AS carbon fiber/epoxy, were considered for analysis. For the design and analysis of a main landing gear strut, maximum landing loads for one point and two point landing conditions were calculated using FAA FAR 23 airworthiness requirements. Materials were categorized based on their strength-to-weight ratio and the Tsai-Wu failure criterion. Landing gear struts meeting the Tsai-Wu failure criterion, and having a maximum strength-to-weight ratio, were then modeled for performance under a collision detection test. This research concludes that T300 carbon fibre/epoxy is a recommended material for the manufacture of landing gear struts for specified lightweight aircraft.
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Li, Long Shuang, Hong Nie, and Xin Xu. "Simulation and Experiment on Landing Gear Component Noise." Applied Mechanics and Materials 170-173 (May 2012): 3454–59. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.3454.
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Simulation analysis and experiment research are performed on the aeroacoustic noise of a landing gear component in this paper. Detached Eddy Simulation (DES) is used to produce the flow field of the model. The Ffowcs-Williams/Hawkings (FW-H) equation is used to calculate the acoustic field. The sound field radiated from the model is measured in the acoustic wind tunnel. A comparison shows that the simulation results agree well with the experiment results under the acoustic far field condition. The results show that the noise radiated from the model is broadband noise. The directivity of the noise source is like a type of dipole. The location between shock absorber and strut, shock absorber and bogie can induce the interaction noise which is presented by two energy peaks in the spectra. The shock absorber and the bogie is the main contributor while the strut is the least contributor to the total noise.
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Parat, Camille, Zu-Yun Li, and Jing-Shan Zhao. "Design and stiffness analysis of an overconstrained landing gear retraction mechanism with four side-stays." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 12 (January 13, 2019): 4421–35. http://dx.doi.org/10.1177/0954410018824509.
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It is the first mission for a landing gear retraction system to extend the structure during the phases of take-off and landing of the flight. Besides, the structure should be available to improve the reliability, strength and stability of the system while reducing the influence of the landing gear on the total drag. However, a large number of airplane accidents are due to the malfunctions or failures of the landing gear retraction system. In this paper, a novel design of retraction system is proposed. Instead of having only one side-stay to execute the desired motion, this new design proposed an over-constrained mechanism with four side-stays, which augments the structural strength and stability of the landing gear system with six over constraints. With such configuration, a second actuating motor to retract the landing gear can be inserted regardless of the first actuator to augment the reliability on the execution of the mechanism. Analyses on the properties of the landing gear retraction system with four side-stays show that the landing gear strut has a vertical motion, which decreases the working and storage spaces used for the system. Finally, this paper examines the statics and the stiffness coefficients of the retraction system with respect to its structure parameters. This provides the optimum structure for the landing gear system in terms of strength and reliability.
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Mikułowski, Grzegorz, and Łukasz Jankowski. "Adaptive Landing Gear: Optimum Control Strategy and Potential for Improvement." Shock and Vibration 16, no. 2 (2009): 175–94. http://dx.doi.org/10.1155/2009/732803.
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An adaptive landing gear is a landing gear (LG) capable of active adaptation to particular landing conditions by means of controlled hydraulic force. The objective of the adaptive control is to mitigate the peak force transferred to the aircraft structure during touch-down, and thus to limit the structural fatigue factor. This paper investigates the ultimate limits for improvement due to various strategies of active control. Five strategies are proposed and investigated numerically using a~validated model of a real, passive landing gear as a reference. Potential for improvement is estimated statistically in terms of the mean and median (significant) peak strut forces as well as in terms of the extended safe sinking velocity range. Three control strategies are verified experimentally using a laboratory test stand.
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Huang, Longlong, Kun Zhao, Junbiao Liang, Victor Kopiev, Ivan Belyaev, and Tian Zhang. "A Numerical Study of the Wind Speed Effect on the Flow and Acoustic Characteristics of the Minor Cavity Structures in a Two-Wheel Landing Gear ." Applied Sciences 11, no. 23 (November 26, 2021): 11235. http://dx.doi.org/10.3390/app112311235.
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The landing gear is widely concerned as the main noise source of airframe noise. The flow characteristics and aerodynamic noise characteristics of the landing gear were numerically simulated based on Large Eddy Simulation and Linearized Euler Equation, and the feasibility of the simulation model was verified by experiments. Then the wind speed effect on the flow and acoustic characteristics of the minor cavity structures in a two-wheel landing gear were analyzed. The results show that the interaction of vortices increases with the increase of velocity at the brake disc, resulting in a slight increase in the amplitude of pressure fluctuation at 55 m·s−1~75 m·s−1. With the increase of speed, the obstruction at the lower hole of torque link decreases, and many vortical structures flow out of the lower hole and are dissipated, so that the pressure fluctuation amplitude of 75 m·s−1 almost does not increase relative to 55 m·s−1. The contribution of each part in the landing gear to the overall noise is as follows: shock strut > tire > torque link > brake disc. At the speed of 34 m·s−1~55 m·s−1, the contribution of each component to the total noise increases with the increase of speed, and the small components such as torque link and brake disc contribute more to the total noise. At the speed of 55 m·s−1~75 m·s−1, the increase of overall noise mainly comes from the main components such as shock strut and tire, and the brake disc and torque link contribute very little to the overall noise. It provides a reference for the further noise reduction optimization design of the landing gear.
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Mu, Yongfei, Jie Li, Wutao Lei, and Daxiong Liao. "The effect of doors and cavity on the aerodynamic noise of fuselage nose landing gear." International Journal of Aeroacoustics 20, no. 3-4 (March 15, 2021): 345–60. http://dx.doi.org/10.1177/1475472x211003297.
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The aerodynamic noise of landing gears have been widely studied as an important component of the airframe noise. During take-off and landing, there are doors, cavity and fuselage around the landing gear. The noise caused by these aircraft components will interfere with aerodynamic noise generated by the landing gear itself. Hence, paper proposes an Improved Delayed Detached Eddy Simulation (IDDES) method for the investigation of the flow field around a single fuselage nose landing gear (NLG) model and a fuselage nose landing gear model with doors, cavity and fuselage nose (NLG-DCN) respectively. The difference between the two flow fields were analyzed in detail to better understand the influence of these components around the aircraft’s landing gear, and it was found that there is a serious mixing phenomenon among the separated flow from the front doors, the unstable shear layer falling off the leading edge of the cavity and the wake of the main strut which directly leads to the enhancement of the noise levels. Furthermore, after the noise sound waves are reflected by the doors several times, an interference phenomenon is generated between the doors. This interference may be a reason why the tone excited in the cavity is suppressed.
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Pritchard, Jocelyn. "Overview of Landing Gear Dynamics." Journal of Aircraft 38, no. 1 (January 2001): 130–37. http://dx.doi.org/10.2514/2.2744.
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Long, Shuang Li, Hong Nie, and Xin Xu. "Aeroacoustic Study on a Simplified Nose Landing Gear." Applied Mechanics and Materials 184-185 (June 2012): 18–23. http://dx.doi.org/10.4028/www.scientific.net/amm.184-185.18.
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Simulation analysis and experiment research are performed on the aeroacoustic noise of a landing gear component in this paper. Detached Eddy Simulation (DES) is used to produce the flow field of the model. The Ffowcs-Williams/Hawkings (FW-H) equation is used to calculate the acoustic field. The sound field radiated from the model is measured in the acoustic wind tunnel. A comparison shows that the simulation results agree well with the experiment results under the acoustic far field condition. The results show that the noise radiated from the model is broadband noise. The directivity of the noise source is like a type of dipole. The wheel is the largest contributor and the strut is the least contributor to the landing gear noise. The results can provide some reference for low noise landing gear design.
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Luong, Quoc Viet, Dae-Sung Jang, and Jai-Hyuk Hwang. "Intelligent Control Based on a Neural Network for Aircraft Landing Gear with a Magnetorheological Damper in Different Landing Scenarios." Applied Sciences 10, no. 17 (August 28, 2020): 5962. http://dx.doi.org/10.3390/app10175962.
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A typical oleo-pneumatic shock-absorbing strut (classic traditional passive damper) in aircraft landing gear has a metering pin extending through the orifice, which can vary the orifice area with the compression and extension of the damper strut. Because the metering pin is designed in a single landing condition, the traditional passive damper cannot adjust its damping force in multiple landing conditions. Magnetorheological (MR) dampers have been receiving significant attention as an alternative to traditional passive dampers. An MR damper, which is a typical semi-active suspension system, can control the damping force created by MR fluid under the magnetic field. Thus, it can be controlled by electric current. This paper adopts a neural network controller trained by two different methods, which are genetic algorithm and policy gradient estimation, for aircraft landing gear with an MR damper that considers different landing scenarios. The controller learns from a large number of trials, and accordingly, the main advantage is that it runs autonomously without requiring system knowledge. Moreover, comparative numerical simulations are executed with a passive damper and adaptive hybrid controller under various aircraft masses and sink speeds for verifying the effectiveness of the proposed controller. The main simulation results show that the proposed controller exhibits comparable performance to the adaptive hybrid controller without any needs for the online estimation of landing conditions.
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TIAN, Siyuan, Peixun YU, Junqiang BAI, Xiaofeng REN, Anyu BAO, and Xiao HAN. "Analysis of aerodynamic and aeroacoustics of full scale landing gear." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 40, no. 5 (October 2022): 953–61. http://dx.doi.org/10.1051/jnwpu/20224050953.
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The aerodynamic noise of a landing gear is an important source of airframe noise. The analysis of its noise characteristics plays an important role in the design of a low-noise landing gear. Based on the FL-52 acoustic wind tunnel test technology, the coupled scale adaptive model and the acoustic disturbance equation, the results on aerodynamic noise of a full-scale landing gear model are analyzed. The high-fidelity model includes transverse strut, torsion arm, piston rod, wheel and other parts. The characteristics of static pressure distribution, power spectrum density of pulsating pressure, aerodynamic noise source distribution and directivity of overall sound pressure level are analyzed. The noise characteristics of the far-field microphone are compared with the local microphone installed in the wheel cavity. In this way, we characterize the directivity of pure tone in the wheel cavity and understand its contribution to the far-field noise. The results show that the aerodynamic noise of the landing gear can be quantified accurately by the hybrid numerical method. The pure tone has two frequencies inside and outside the wheel of the landing gear: 560 Hz and 960 Hz. The peak of the loudest sound pressure level reaches 136 dB, and the pure tone radiates to the surface of the non-separation area of the wheel of the landing gear. However, the wall pressure spectrum of the points located in the turbulence region shows a wide-frequency characteristic, and there is no obvious pure tone. From the point of view of the far-field noise directivity, the forward noise of the landing gear is larger than the rear noise, and there is a small overall sound pressure level area at the points of 65 and 110 degrees respectively. When the monitoring points are far away, the far-field noise of the landing gear shows the characteristics of wide frequency, and no obvious pure tone appears. The method can provide the technical support for predicting the aeroacoustics of a landing gear and designing a low-noise land gear.
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Li, Yuan, Jason Zheng Jiang, Simon A. Neild, and Huailei Wang. "Optimal Inerter-Based Shock–Strut Configurations for Landing-Gear Touchdown Performance." Journal of Aircraft 54, no. 5 (September 2017): 1901–9. http://dx.doi.org/10.2514/1.c034276.
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Bakulin, V. N., S. V. Borzykh, and V. V. Voronin. "Space vehicle landing dynamics at failure of landing gear." Russian Aeronautics (Iz VUZ) 59, no. 1 (January 2016): 23–28. http://dx.doi.org/10.3103/s1068799816010049.
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Rośkowicz, Marek, and Piotr Leszczyński. "The Selected Problems of Studies of Aircraft Landing Gear." Research Works of Air Force Institute of Technology 39, no. 1 (December 1, 2016): 91–102. http://dx.doi.org/10.1515/afit-2016-0020.
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Abstract The article portrays the results of experimental studies conducted in the field of static strength test of main landing gear of lightweight aircraft as well as in the area of establishing the pneumatic tyre characteristics of main landing gear. The studies were carried out in compliance with methodologies of performing studies for the purposes of solutions implemented in aviation structures. It was stated that static strength tests of landing gear should not be done with the use of shock absorbers, due to the fact that this element, distinguished by high viscoelastic properties, by being statically loaded, is subject to displacements that do not occur during normal operation of the aircraft. Excessive displacements of shock absorber result in the load distribution in other landing gear elements being incompatible with project assumptions, which in turn leads to this strength test being interrupted, bearing in mind significantly lower loads than anticipated. It was also concluded that in order to determine pneumatic tyre characteristics it is not necessary to carry out tests on the whole landing gear strut, because the results obtained in the compression test of the wheel itself with pneumatic tyre are identical as the results acquired during tests conducted in accordance with methodology. Test preparation process with the use of the wheel itself and its realization is less time-consuming, less expensive and does not entail the necessity to build complex test stands.
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Ni, Xinlei, Qiaozhi Yin, Xiaohui Wei, Peilin Zhong, and Hong Nie. "Research on Landing Stability of Four-Legged Adaptive Landing Gear for Multirotor UAVs." Aerospace 9, no. 12 (November 30, 2022): 776. http://dx.doi.org/10.3390/aerospace9120776.
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Rotorcraft Unmanned Aerial Vehicles (UAVs) often need to take off and land under complex working conditions. The rugged terrains may cause the UAV to tilt during takeoff and landing and even cause rollover and other accidents in severe cases. In this paper, a new four-legged landing gear of multirotor UAVs with a passive cushioning structure is designed, aiming at the landing stability requirement of rotorcraft UAVs in complex terrains. The mathematical model of the landing gear dynamics is established in MATLAB/Simulink, and the drop test simulation is carried out under different landing terrain conditions. By comparing the simulation results of the drop test multibody dynamic model in Simcenter3D dynamics software, the adaptive landing and cushioning capacity of the landing gear and the accuracy of the mathematical model are verified. Combined with the landing stability criterion and control strategy of adaptive landing gear adjustment, the landing stability of adaptive landing gear under different slope angles of landing surface and horizontal velocities is studied. The landing stability boundary under different combinations of these two parameters is found.
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Yu, Jing Wei, Xiao Feng Liu, Hai Long Wang, and Yu Jian Wei. "Dynamic Characteristics of Aircraft Landing Gear." Applied Mechanics and Materials 543-547 (March 2014): 118–21. http://dx.doi.org/10.4028/www.scientific.net/amm.543-547.118.
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Aircraft landing gear can absorb the energy generated and consumed in aircraft landing, taxiing process, thus weakening the vibration of the aircraft, flight safety plays a vital role. This paper established a landing gear dynamics modeling, its mechanical analysis, and through trial and simulation of the dynamic characteristics of the landing gear were studied, with some practical significance.
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Hameed, Asad, Ossama Zubair, Taimur Ali Shams, Zahid Mehmood, Ali Javed, and Zahid Mehmood. "Failure analysis of a broken support strut of an aircraft landing gear." Engineering Failure Analysis 117 (November 2020): 104847. http://dx.doi.org/10.1016/j.engfailanal.2020.104847.
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Wei, Xiaohui, Chenglong Liu, Xiangyao Liu, Hong Nie, and Yizhou Shao. "Improved Model of Landing-Gear Drop Dynamics." Journal of Aircraft 51, no. 2 (March 2014): 695–700. http://dx.doi.org/10.2514/1.c032551.
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KRÜGER, W., I. BESSELINK, D. COWLING, D. B. DOAN, W. KORTÜM, and W. KRABACHER. "Aircraft Landing Gear Dynamics: Simulation and Control." Vehicle System Dynamics 28, no. 2-3 (August 1997): 119–58. http://dx.doi.org/10.1080/00423119708969352.
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Ma, Xiao Cheng, Yue Wang, Ya Lan Jia, Jie Dong, and Hao Gong. "Impact Damage Analysis of Skid Landing Gear of the UAV." Applied Mechanics and Materials 912 (February 17, 2023): 11–18. http://dx.doi.org/10.4028/p-b3m6fc.
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In this paper, by analyzing the structure and material characteristics of skid landing gear, the skid landing gear model is established by using CATIA software. In the explicit dynamic analysis type of ANSYS software, the force comparison between the impact surface of soil material and the impact surface of rigid material is made, combined with the change of momentum and energy in the process of touching the ground. This explains the necessity of landing drones on soft landing surfaces such as soil. In addition, LS-DYNA was used to simulate the dynamics of landing gear, and the strength of landing gear was analyzed according to failure criterion.
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Viet, Luong Quoc, and Jai Hyuk Hwang. "A Semi-Active Controller for an Aircraft Landing Gear Equipped with Magnetorheological Damper." Applied Mechanics and Materials 894 (September 2019): 29–33. http://dx.doi.org/10.4028/www.scientific.net/amm.894.29.
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The magnetorheological (MR) damper is the newest approach to replace the traditional passive damper which cannot change their dynamics in response to different operating conditions of the aircraft landing gear. This paper presents the simulation study of a semi-active controller for a landing gear equipped MR damper. Furthermore, a new method combined skyhook control with force control, called hybrid control, is developed to improve the performance of the MR damper landing gear. Finally, the numerical simulation result of the landing gear using SIMSCAPE-Simulink is discussed.
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Iadicicco, Agostino, Daniele Natale, Pasquale Di Palma, Francesco Spinaci, Antonio Apicella, and Stefania Campopiano. "Strain Monitoring of a Composite Drag Strut in Aircraft Landing Gear by Fiber Bragg Grating Sensors." Sensors 19, no. 10 (May 15, 2019): 2239. http://dx.doi.org/10.3390/s19102239.
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This work reports on the use of Fiber Bragg Grating (FBG) sensors integrated with innovative composite items of aircraft landing gear for strain/stress monitoring. Recently, the introduction of innovative structures in aeronautical applications is appealing with two main goals: (i) to decrease the weight and cost of current items; and (ii) to increase the mechanical resistance, if possible. However, the introduction of novel structures in the aeronautical field demands experimentation and certification regarding their mechanical resistance. In this work, we successfully investigate the possibility to use Fiber Bragg Grating sensors for the structural health monitoring of innovative composite items for the landing gear. Several FBG strain sensors have been integrated in different locations of the composite item including region with high bending radius. To optimize the localization of the FBG sensors, load condition was studied by Finite Element Method (FEM) numerical analysis. Several experimental tests have been done in range 0–70 kN by means of a hydraulic press. Obtained results are in very good agreement with the numerical ones and demonstrate the great potentialities of FBG sensor technology to be employed for remote and real-time load measurements on aircraft landing gears and to act as early warning systems.
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Li, Yuan, Jason Zheng Jiang, Pia Sartor, Simon A. Neild, and Huailei Wang. "Including Inerters in Aircraft Landing Gear Shock Strut to Improve the Touch-down Performance." Procedia Engineering 199 (2017): 1689–94. http://dx.doi.org/10.1016/j.proeng.2017.09.366.
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Krason, W., and J. Malachowski. "Multibody rigid models and 3D FE models in numerical analysis of transport aircraft main landing gear." Bulletin of the Polish Academy of Sciences Technical Sciences 63, no. 3 (September 1, 2015): 745–57. http://dx.doi.org/10.1515/bpasts-2015-0086.
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Abstract Dynamic analyses of a transport aircraft landing gear are conducted to determine the effort of such a complex system and provide capabilities to predict their behaviour under hazardous conditions. This kind of investigation with the use of numerical methods implementation is much easier and less expensive than stand tests. Various 3D models of the landing gear part are defined for the multistage static FE analysis. A complete system of the main landing gear was mapped as a deformable 3D numerical model for dynamic analysis with the use of LS-Dyna code. In this 3D deformable FE model, developed in a drop test simulation, the following matters were taken into consideration: contact problems between collaborating elements, the phenomena of energy absorption by a gas-liquid damper placed in the landing gear and the response of the landing gear during the touchdown of a flexible wheel with the ground. The results of numerical analyses for the selected drop tests and the results from the experiments carried out on a real landing gear were used for verification of FE models and a methodology of the landing gear dynamics analysis. The results obtained from the various simulations of the touchdown have proved the effectiveness of the 3D numerical model and how many problems can be solved in the course of only one numerical run, e.g. geometric and material nonlinearities, a question of contact between the mating components, investigation of the landing gear kinematics, investigation of the energy dissipation problem in the whole system and the stresses influence on the structure behaviour, which can appear in some elements due to overload.
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S. A. R., Sharifah Nadhirah, Jaffar Syed Mohammed Ali, Shaik Dawood M. S. I., and Adib Hamdani R. "Influence of Composite Skin on the Energy Absorption Characteristics of an Aircraft Fuselage." International Journal of Engineering Materials and Manufacture 8, no. 1 (January 20, 2023): 13–20. http://dx.doi.org/10.26776/ijemm.08.01.2023.02.
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In aviation history, accidents during landing are more frequent compared to other phases of flight and in most cases the aircraft is forced to make an emergency belly landing when landing gear malfunctions. This study aims to analyse the energy absorption of a typical composite aircraft fuselage section under such crash belly landing. A finite element model of this composite fuselage section was created and analyzed using LS-Dyna finite element software and the effects of different composite materials on the energy absorption of fuselage section were studied. Four different composite materials that are commonly used in aerospace application were selected for the purpose of the present study namely glass/epoxy, graphite/epoxy, Kevlar/epoxy, and boron/epoxy. An impact velocity of 7 m/s against rigid ground was considered. Results showed that frames and skin contribute the most in energy absorption while the passenger floor and strut contribute the least. Moreover, it was found that fuselage skin made of glass/epoxy absorbed more energy compared to other materials and it had the highest specific energy absorption.
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McComb, Harvey G., and John A. Tanner. "Topics in landing gear dynamics research at NASA Langley." Journal of Aircraft 25, no. 1 (January 1988): 84–93. http://dx.doi.org/10.2514/3.45545.
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Luong, Quoc-Viet, Bang-Hyun Jo, Jai-Hyuk Hwang, and Dae-Sung Jang. "A Supervised Neural Network Control for Magnetorheological Damper in an Aircraft Landing Gear." Applied Sciences 12, no. 1 (December 31, 2021): 400. http://dx.doi.org/10.3390/app12010400.
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This paper adopts an intelligent controller based on supervised neural network control for a magnetorheological (MR) damper in an aircraft landing gear. An MR damper is a device capable of adjusting the damping force by changing the magnetic field generated in electric coils. Applying an MR damper to the landing gears of an aircraft could minimize the impact at landing and increase the impact absorption efficiency. Various techniques proposed for controlling the MR damper in aircraft landing gears require information on the damper force or the mass of the aircraft to determine optimal parameters and control commands. This information is obtained by estimation with a model in a practical operating environment, and the accompanying inaccuracies cause performance degradation. Machine learning-based controllers have also been proposed to address model dependency but require a large number of drop test data. Unlike simulations, which can conduct a large number of virtual drop tests, the cost and time are limited in the actual experimental environment. Therefore, a neural network controller with supervised learning is proposed in this paper to simulate the behavior of a proven controller only with system states. The experimental data generated by applying the hybrid controller with the exact mass and force information, which has demonstrated high performance among the existing techniques, are set as the target for supervised learning. To verify the effectiveness of the proposed controller, drop test experiments using the intelligent controller and the hybrid controller with and without exact information about aircraft mass and force are executed. The experimental results from the drop tests of a landing gear show that the proposed controller maintains superior performance to the hybrid controller without using explicit damper models or any information on the aircraft mass or strut force.
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Chen, Yi, Rongyao Cui, Rongbo Ju, and Qingbo Dou. "Simulation of Nose Landing Gear Shimmy with Flexible Airframe Considered." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 36, no. 2 (April 2018): 388–95. http://dx.doi.org/10.1051/jnwpu/20183620388.
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Shimmy stability of the nose landing gear of an aircraft is studied in this paper. Firstly, Shimmy model was built considering the dynamic characteristics of the airframe. Then the critical damping, critical velocity and frequency range of the shimmy are obtained by introducing relevant parameters into the shimmy model. The research shows that the problem of shimmy is a tire type shimmy caused by insufficient damping of dampers and brings coupled resonance with the vibration mode of the airframe, which can be avoided by increasing the damping of the shimmy. At the same time, the influence of airframe dynamics and tire stiffness on the shimmy characteristics of the landing gear is also studied. With the increase of tire torsion and lateral stiffness, the critical velocity, maximum critical damping value and shimmy frequency of the landing gear increase. However, the elasticity of the airframe makes the frequency of the aircraft landing gear lower and the stable region of the shimmy smaller, so that the phenomenon of shimmy is more likely to occur. Therefore, the influence of airframe dynamic characteristics can not be ignored when studying the shimmy stability of the landing gear of a modern large passenger aircraft.