Importance analysis based on universal grey operation for an aircraft landing gear retraction system

2021 ◽  
pp. 1-11
Author(s):  
Feng Zhang ◽  
Mingying Wu ◽  
Xinting Hou ◽  
Xinhe Wang ◽  
Cheng Han ◽  
...  
Keyword(s):  
Failure Probability ◽  
Oil Pollution ◽  
Landing Gear ◽  
Weak Links ◽  
System Failure ◽  
Aircraft Landing ◽  
Interval Operation ◽  
Importance Analysis ◽  
Grey Number ◽  
And Performance

In order to improve the reliability and performance of landing gear retraction systems, this paper presents two importance analysis methods based on universal grey operation. According to the system principle and fault mechanisms, the fault tree of the retraction system was first established. The uncertainties of the bottom events were then described using the universal grey number to obtain the universal grey representation of the system failure probability. And compared with the traditional interval operation, the results show that universal grey operation can solve the problem of interval expansion with uncertainty. Importance analyses of the bottom events were then conducted based on the probability importance and the key importance. By comparing the two important indices of the bottom events, the larger the value is, the higher the importance is. It was found that the occurrence of the bottom events “pipeline oil leakage,” “pump motor damage,” and “oil pollution” had the greatest impact on system failure probability, thus determining the key weak links affecting system failure and indicating the most effective targets for improvement.

scholarly journals Fault Tree Interval Analysis of Complex Systems Based on Universal Grey Operation

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Feng Zhang ◽  
Shiwang Tan ◽  
Leilei Zhang ◽  
Yameng Wang ◽  
Yang Gao
Keyword(s):  
Failure Probability ◽  
System Reliability ◽  
Fault Tree ◽  
Landing Gear ◽  
Aircraft Landing ◽  
Interval Operation ◽  
Aircraft Landing Gear ◽  
Grey Number ◽  
Conversion Rules ◽  
Interval Enlargement

The objective of this study is to propose a new operation method based on the universal grey number to overcome the shortcomings of typical interval operation in solving system fault trees. First, the failure probability ranges of the bottom events are described according to the conversion rules between the interval number and universal grey number. A more accurate system reliability calculation is then obtained based on the logical relationship between the AND gates and OR gates of a fault tree and universal grey number arithmetic. Then, considering an aircraft landing gear retraction system as an example, the failure probability range of the top event is obtained through universal grey operation. Next, the reliability of the aircraft landing gear retraction system is evaluated despite insufficient statistical information describing failures. The example demonstrates that the proposed method provides many advantages in resolving the system reliability problem despite poor information, yielding benefits for the function of the interval operation, and overcoming the drawback of solution interval enlargement under different orders of interval operation.

Improved uncertain method for safety analysis of aircraft landing gear

2021 ◽  
pp. 095441002110005
Author(s):  
Xintian Liu ◽  
Shuanglong Geng ◽  
Xueguang Yu ◽  
Jiachi Tong ◽  
Yansong Wang
Keyword(s):  
Number Theory ◽  
Mixed Method ◽  
Landing Gear ◽  
Interval Method ◽  
Truncation Method ◽  
Manufacturing Tolerance ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
Practical Engineering ◽  
Grey Number

There are various uncertain factors in most practical engineering applications, such as input loads, structural sizes, manufacturing tolerance, and initial and boundary conditions. The interval method and grey number theory are common methods to deal with uncertainty. In this article, the interval truncation method and grey number theory are improved. And a mixed method is proposed to represent the confidence interval of output result based on the improved interval truncation method and improved grey number theory. The proposed methods’ feasibility is verified by a stepped bar; the methods are applied to the analysis of aircraft landing gear safety uncertainty.

A novel retractable landing gear of a light amphibious airplane design, synthesis, analysis, and implementation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sinchai Chinvorarat ◽  
Pumyos Vallikul
Keyword(s):  
Impact Load ◽  
Landing Gear ◽  
Drop Test ◽  
Drop Height ◽  
Core Element ◽  
Design Synthesis ◽  
Content Type ◽  
And Performance ◽  
Correct Path ◽  
The Impact

Purpose The purpose of this paper is to present a novel retractable main landing gear for a light amphibious airplane, while the design, synthesis and analysis are given in details for constructing the main landing gear. Design/methodology/approach The constraint three-position synthesis has given the correct path of all linkages that suitably fit the landing gear into the compartment. The additional lock-link is introduced into the design to ensure the securement of the mechanism while landing. Having the telescopic gas-oil shock strut as a core element to absorb the impact load, it enhances the ability and efficiency to withstand higher impact than others type of light amphibious airplane. Findings By kinematics bifurcation analysis, the optimized value of the unlock spring stiffness at 90 N/m can be found to tremendously reduce the extended-retracted linear actuator force from 500 N to 150 N at the beginning of the retraction sequence. This could limit the size and weight of the landing gear actuator of the light amphibious airplane. Practical implications The drop test of the landing gear to comply with the ASTM f-2245 (Standard Specification for Design and Performance of a Light Sport Airplane) reveals that the novel landing gear can withstand the impact load at the drop height determined by the standard. The maximum impact loading 4.8 G occurs at the drop height of 300 mm, and there is no sign of any detrimental or failure of the landing gear or the structure of the light amphibious airplane. The impact settling time response reaches the 2% of steady-state value in approximately 1.2 s that ensure the safety and stability of the amphibious airplane if it subjects to an accidentally hard landing. Originality/value This paper presents unique applications of a retractable main landing gear of a light amphibious airplane. The proposed landing gear functions properly and complies with the drop test standard, ensuring the safety and reliability of the airplane and exploiting the airworthiness certification process.

scholarly journals Mechanism reliability and sensitivity analysis of landing gear under multiple failure modes

2021 ◽  
Vol 39 (1) ◽  
pp. 46-54
Author(s):  
Changcong Zhou ◽  
Mengyao Ji ◽  
Yishang Zhang ◽  
Fuchao Liu ◽  
Haodong Zhao
Keyword(s):  
Failure Probability ◽  
Failure Modes ◽  
Kriging Model ◽  
Landing Gear ◽  
Multiple Failure Modes ◽  
Analysis And Design ◽  
Extension System ◽  
Extension Mechanism ◽  
Assembly Error ◽  
Adaptive Kriging

For a certain type of aircraft landing gear retraction-extension mechanism, a multi-body dynamic simulation model is established, and the time-dependent curves of force and angle are obtained. Considering the random uncertainty of friction coefficient, assembly error, and the change of hinge wear under different retraction times, the reliability model is built including three failure modes of landing gear, i.e. blocking failure, positioning failure and accuracy failure. Based on the adaptive Kriging model, the reliability and sensitivity of retraction-extension system under the condition of single failure mode and multiple failure modes in series are analyzed, and the rule of reliability and sensitivity changing with the number of operations is given. The results show that the system failure probability of landing gear mechanism tends to decrease first and then increase when considering the given information of random factors, and the influences of random factors on the failure probability vary with the number of operations. This work provides a viable tool for the reliability analysis and design of landing gear mechanisms.

scholarly journals 1002 Aerodynamic noise reduction for aircraft landing gear

2009 ◽  
Vol 2009 (0) ◽  
pp. 321-322
Author(s):  
Kazuhide Isotani ◽  
Kenji Hayama ◽  
Akio Ochi ◽  
Toshiyuki Kumada
Keyword(s):  
Noise Reduction ◽  
Landing Gear ◽  
Aerodynamic Noise ◽  
Aircraft Landing ◽  
Aircraft Landing Gear

Reduction of Aircraft Tyre Wear by Pre-Rotating Wheel Using ANSYS Mechanical Transient

2016 ◽  
Vol 17 ◽  
pp. 89-100 ◽  
Author(s):  
Abdurrhman A. Alroqi ◽  
Wei Ji Wang
Keyword(s):  
Landing Gear ◽  
Slip Ratio ◽  
Aircraft Landing ◽  
Tyre Wear

Heavy aircraft main landing gear tyres skid immediately after touchdown as result of the high slip ratio between the tyres and runway, which lead to tyre wear and smoke. In this paper, the tyre wear is modelled on the Archard theory using ANSYS mechanical transient, to reveal the wheel’s dynamic and the tyre tread wear. The wheel’s dynamic and the amount of wear are calculated for initially static and for pre-spun wheels in order to find the effectiveness of the technique of pre-spinning the wheel, as suggested by many patents since the early days of airplane use, in order to eliminate aircraft landing wear and smoke.

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