Research on Dynamic Load Coefficient Based on the Airfield Pavement Roughness

2011 ◽  
Vol 97-98 ◽  
pp. 386-390 ◽  
Author(s):  
Xian Min Zhang ◽  
Li Li Sun ◽  
Chun Fei Hu ◽  
Zhi Chao Sun
Keyword(s):  
Analytical Solution ◽  
Dynamic Load ◽  
Aircraft Landing ◽  
Pavement Roughness ◽  
Vibration Model ◽  
Allowable Level ◽  
Aircraft Landing Gear ◽  
Dynamics And Vibration ◽  
The Impact ◽  
The Relationship

It applies flight dynamics and vibration principle to create vibration model of aircraft landing gear considering aircraft tire damping, and get the equation of analytical solution based on the impact on airfield pavement roughness. It studies the relationship between dynamic load coefficient and time and speed and roughness. For a special aircraft, it gives the allowable level for pavement roughness based on the influence of pavement and passengers comfort.

AN ANALYSIS OF THE DAMAGE TOLERANCE OF LIGHT AIRCRAFT LANDING GEAR

2013 ◽  
Vol 37 (4) ◽  
pp. 1147-1159 ◽  
Author(s):  
Pu-Woei Chen ◽  
Shu-Han Chang ◽  
Jyun-Yuan Siao
Keyword(s):  
Life Cycle ◽  
Damage Tolerance ◽  
Life Time ◽  
Initial Crack ◽  
Landing Gear ◽  
Finite Element Software ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
The Relationship

This study uses the finite element software, FRANC2D, and the life-time analysis software, AFGROW, to perform simulation analyses of the damage tolerance of the landing gear of light aviation vehicles. This study explores the effect that the initial crack positions and different materials have on the life cycle of landing gear under long-term loads. This study also compares the relationship between stress intensity factors and crack growth for four types of aluminum alloys, titanium alloy and alloy steel. The relationship between residual strength and life cycle, in the presence of existing cracks, is also investigated.

Effect of the Impact Load on the Main Welding Outer Cylinder of Large Aircraft Landing Gear

2013 ◽  
Vol 567 ◽  
pp. 169-173
Author(s):  
Hong Feng Wang ◽  
W.W. Song ◽  
J.L. Wang ◽  
Dun Wen Zuo ◽  
X.L. Duan
Keyword(s):  
Life Prediction ◽  
Impact Load ◽  
Outer Cylinder ◽  
Element Model ◽  
Landing Gear ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
The Impact ◽  
Important Basis ◽  
Large Aircraft

Analysis about the cause of the main failure and the forces of the main welding outer cylinder of the recent large aircraft landing gear were given. The impact load for main welding outer cylinder in the process of the taking off and landing was calculated of 580MPa. Finite element model of the main welding outer cylinder was then established and the influence of the impact loading to the main welding outer cylinder was analyzed. The results showed that crack was most likely take place on the top of the outer cylinder, and then on the two welds. The crack expanded in an S shape. This study could provide an important basis for the safety of the aircraft landing gear inspection and service life prediction.

scholarly journals A Supervised Neural Network Control for Magnetorheological Damper in an Aircraft Landing Gear

2021 ◽  
Vol 12 (1) ◽  
pp. 400
Author(s):  
Quoc-Viet Luong ◽  
Bang-Hyun Jo ◽  
Jai-Hyuk Hwang ◽  
Dae-Sung Jang
Keyword(s):  
Neural Network ◽  
Mr Damper ◽  
Landing Gear ◽  
Network Control ◽  
Neural Network Control ◽  
Hybrid Controller ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
Drop Tests ◽  
The Impact

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.

scholarly journals Effects of Spring and Damper Elements in Aircraft Landing Gear Dynamics

2020 ◽  
Vol 8 (5) ◽  
pp. 4265-4269
Keyword(s):  
Shock Absorber ◽  
Impact Force ◽  
Landing Gear ◽  
Damping Coefficient ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
Spring Coefficient ◽  
Mass Spring ◽  
The Impact

In this study a typical Aircraft Landing Gear with shock absorber was modeled a Mass-Spring-Damper System. Basic components of the system were explained. The equations of the model was presented. Aircraft Landing Gear was also modeled in Matlab/Simulink for a given set of aircraft parameters. A case study for an Aircraft Landing Gear was solved and results were presented. Results included the variation of spring (k1 and k2 ) and damping coefficient (b) in a given interval to show their effects on the impact force and displacement of landing gear as main outputs to consider. Effect of damping coefficient (b) on impact force was found to be highest (3.76%), spring coefficient (k1 ) effect is moderate (2.29%), and spring coefficient (k2 ) is lower (0.97%), for a change of ±10% of coefficients.

Multi-Domain Unified Modeling and Simulation for Aircraft Landing Gear Using Modelica

2011 ◽  
Vol 311-313 ◽  
pp. 2457-2460
Author(s):  
Ji Hong Liu ◽  
Ying Zhong Pang ◽  
Yu Ming Zhu
Keyword(s):  
Modeling And Simulation ◽  
Shock Absorber ◽  
Simulation Method ◽  
Heterogeneous Data ◽  
Landing Gear ◽  
Heterogeneous Platforms ◽  
Unified Modeling ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
The Impact

Modern products become more and more complex, the modeling and simulation of them are carried out with different software on heterogeneous platforms, which always caused the heterogeneous data, separated disciplines and cannot obtain the result of unified model correctly. Therefore, a Modelica-based modeling and simulation method for aircraft landing gear is proposed. The landing gear library based on Modelica was established. The unified physical model of landing gear which is composed of structural, thermodynamics and hydromechanics disciplines is constructed. The aircraft landing process, the track of retraction mechanism and the impact work amount of the shock absorber are obtained through multi-domain unified simulation, which provides references for deisgners.

Computer-Aided Multi-Domain Unified Modeling and Simulation for Aircraft Landing Gear

2011 ◽  
Vol 421 ◽  
pp. 392-396
Author(s):  
Yu Ming Zhu ◽  
Hai Cheng Yang
Keyword(s):  
Modeling And Simulation ◽  
Landing Gear ◽  
Domain Modeling ◽  
Complex Product ◽  
Product Systems ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
Model Complex ◽  
Complex Product Systems ◽  
The Impact

In order to model complex product systems and analyze their whole performance to deal with the coupling relationships between multi-domain，aircraft landing gear selected as the object, unified multi-domain modeling and simulation and for complex product systems was studied. The aircraft leading gear is decomposed as structure, and the mathematical models of the landing gear components are established. The model library of the landing gear components was developed using Modelica-based platform and multi-domain unified model of the landing gear was established. The impact work amount, the vertical load and the stroke are selected as the indexes to simulate and analyze the earthquake resistant performance of the shock absorber.

Accent Policy and Accent Modification Enterprises as Potential Indicators of Intercultural Power Relations: A Call for an Updated Research Agenda

2013 ◽  
Vol 3 (1) ◽  
pp. 22-33 ◽  
Author(s):  
Brynne D. Ovalle ◽  
Rahul Chakraborty
Keyword(s):  
International Relations ◽  
Identity Construction ◽  
Social Theory ◽  
Power Relations ◽  
Linguistic Diversity ◽  
Cultural Organization ◽  
Using Data ◽  
The Individual ◽  
The Impact ◽  
The Relationship

This article has two purposes: (a) to examine the relationship between intercultural power relations and the widespread practice of accent discrimination and (b) to underscore the ramifications of accent discrimination both for the individual and for global society as a whole. First, authors review social theory regarding language and group identity construction, and then go on to integrate more current studies linking accent bias to sociocultural variables. Authors discuss three examples of intercultural accent discrimination in order to illustrate how this link manifests itself in the broader context of international relations (i.e., how accent discrimination is generated in situations of unequal power) and, using a review of current research, assess the consequences of accent discrimination for the individual. Finally, the article highlights the impact that linguistic discrimination is having on linguistic diversity globally, partially using data from the United Nations Educational, Scientific and Cultural Organization (UNESCO) and partially by offering a potential context for interpreting the emergence of practices that seek to reduce or modify speaker accents.

Business: Making Cents of Coding Systems: Billing for Professional Services

2010 ◽  
Vol 20 (1) ◽  
pp. 3-8
Author(s):  
Dee Adams Nikjeh
Keyword(s):  
Professional Services ◽  
Speech Language Pathology ◽  
Coding Systems ◽  
Language Pathology ◽  
Program Funding ◽  
Fee Schedule ◽  
Procedure Codes ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

Abstract Administrators and supervisors face daily challenges over issues such as program funding, service fees, correct coding procedures, and the ever-changing healthcare regulations. Receiving equitable reimbursement for speech-language pathology and audiology services necessitates an understanding of federal coding and reimbursement systems. This tutorial provides information pertaining to two major healthcare coding systems and explains the relationship of these systems to clinical documentation, the Medicare Physician Fee Schedule and equitable reimbursement. An explanation of coding edits and coding modifiers is provided for use in those occasional atypical situations when the standard use of procedural coding may not be appropriate. Also included in this tutorial is a brief discussion of the impact that the Medicare Improvements for Patients and Providers Act of 2008 (HR 6331 Medicare Improvements for Patients and Providers Act [MIPPA], 2008) has had on the valuation of speech-language pathology procedure codes.

The Need to Belong and the Relationship Between Loneliness and Health

2014 ◽  
Vol 22 (4) ◽  
pp. 194-201 ◽  
Author(s):  
Freda-Marie Hartung ◽  
Britta Renner
Keyword(s):  
Individual Differences ◽  
Social Isolation ◽  
Social Situation ◽  
First Year ◽  
Health State ◽  
Need To Belong ◽  
First Year University ◽  
Perceived Social Isolation ◽  
The Impact ◽  
The Relationship

Humans are social animals; consequently, a lack of social ties affects individuals’ health negatively. However, the desire to belong differs between individuals, raising the question of whether individual differences in the need to belong moderate the impact of perceived social isolation on health. In the present study, 77 first-year university students rated their loneliness and health every 6 weeks for 18 weeks. Individual differences in the need to belong were found to moderate the relationship between loneliness and current health state. Specifically, lonely students with a high need to belong reported more days of illness than those with a low need to belong. In contrast, the strength of the need to belong had no effect on students who did not feel lonely. Thus, people who have a strong need to belong appear to suffer from loneliness and become ill more often, whereas people with a weak need to belong appear to stand loneliness better and are comparatively healthy. The study implies that social isolation does not impact all individuals identically; instead, the fit between the social situation and an individual’s need appears to be crucial for an individual’s functioning.

Investigating the Relationship Between Self-Esteem and Stigma Among Young Adults With History of Suicide Attempts

Crisis ◽  
2016 ◽  
Vol 37 (4) ◽  
pp. 265-270 ◽  
Author(s):  
Meshan Lehmann ◽  
Matthew R. Hilimire ◽  
Lawrence H. Yang ◽  
Bruce G. Link ◽  
Jordan E. DeVylder
Keyword(s):  
Young Adults ◽  
Suicide Attempts ◽  
Self Esteem ◽  
High Risk Population ◽  
High Functioning ◽  
People With Mental Illness ◽  
History Of ◽  
The Individual ◽  
The Impact ◽  
The Relationship

Abstract. Background: Self-esteem is a major contributor to risk for repeated suicide attempts. Prior research has shown that awareness of stigma is associated with reduced self-esteem among people with mental illness. No prior studies have examined the association between self-esteem and stereotype awareness among individuals with past suicide attempts. Aims: To understand the relationship between stereotype awareness and self-esteem among young adults who have and have not attempted suicide. Method: Computerized surveys were administered to college students (N = 637). Linear regression analyses were used to test associations between self-esteem and stereotype awareness, attempt history, and their interaction. Results: There was a significant stereotype awareness by attempt interaction (β = –.74, p = .006) in the regression analysis. The interaction was explained by a stronger negative association between stereotype awareness and self-esteem among individuals with past suicide attempts (β = –.50, p = .013) compared with those without attempts (β = –.09, p = .037). Conclusion: Stigma is associated with lower self-esteem within this high-functioning sample of young adults with histories of suicide attempts. Alleviating the impact of stigma at the individual (clinical) or community (public health) levels may improve self-esteem among this high-risk population, which could potentially influence subsequent suicide risk.

Sign in / Sign up

Export Citation Format

Share Document