scholarly journals Effect of Joint Clearance on Landing Gear Retraction Failure

Aerospace ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 329
Author(s):  
Sungjoon Cho ◽  
Hwanjeong Cho ◽  
Dooyoul Lee
Keyword(s):  
Sensitivity Analysis ◽  
Geometric Model ◽  
Latin Hypercube Sampling ◽  
Linearization Method ◽  
Landing Gear ◽  
Hydraulic Actuator ◽  
Index Method ◽  
Simple Method ◽  
Failure Data ◽  
Joint Clearances

A simple method of investigating the effect of joint clearances on landing gear retraction failure is presented and applied to the main landing gear with a single sidestay and a hydraulic actuator. A geometric model is presented with assumptions of each link as a rigid body and their relative positions geometrically determined by considering the size of the clearances. We conducted a sensitivity analysis based on a geometric model of the main landing gear. The model was calibrated using the data from the technical order. A Monte Carlo simulation (MCS) was conducted, and whose input was the distance of each clearance based on the experimental design that combined the modified Latin hypercube sampling (LHS) and central composite design (CCD). As a result, we were able to find that the joint had a high potential to operate abnormally. We validated the model by using the actual failure data. Finally, the physical meaning of the sensitivity analysis results was interpreted by comparing them with the values obtained through an amplification index method that is a modified linearization method.

scholarly journals Uncertainty and Sensitivity Analysis of Bifurcation Loci Characterizing Nonlinear Landing-Gear Dynamics

2018 ◽  
Vol 55 (1) ◽  
pp. 162-172 ◽  
Author(s):  
I. Tartaruga ◽  
J. E. Cooper ◽  
M. H. Lowenberg ◽  
P. Sartor ◽  
Y. Lemmens
Keyword(s):  
Sensitivity Analysis ◽  
Landing Gear ◽  
Gear Dynamics ◽  
Uncertainty And Sensitivity Analysis

scholarly journals Development and Evaluation of a Leaf Disease Damage Extension in Cropsim-CERES Wheat

Agronomy ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 120 ◽  
Author(s):  
Georg Röll ◽  
William Batchelor ◽  
Ana Castro ◽  
María Simón ◽  
Simone Graeff-Hönninger
Keyword(s):  
Sensitivity Analysis ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Mean Squared Error ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Extended Model ◽  
Simple Method ◽  
Area Index ◽  
The Impact

Developing disease models to simulate and analyse yield losses for various pathogens is a challenge for the crop modelling community. In this study, we developed and tested a simple method to simulate septoria tritici blotch (STB) in the Cropsim-CERES Wheat model studying the impacts of damage on wheat (Triticum aestivum L.) yield. A model extension was developed by adding a pest damage module to the existing wheat model. The module simulates the impact of daily damage on photosynthesis and leaf area index. The approach was tested on a two-year dataset from Argentina with different wheat cultivars. The accuracy of the simulated yield and leaf area index (LAI) was improved to a great extent. The Root mean squared error (RMSE) values for yield (1144 kg ha−1) and LAI (1.19 m2 m−2) were reduced by half (499 kg ha−1) for yield and LAI (0.69 m2 m−2). In addition, a sensitivity analysis of different disease progress curves on leaf area index and yield was performed using a dataset from Germany. The sensitivity analysis demonstrated the ability of the model to reduce yield accurately in an exponential relationship with increasing infection levels (0–70%). The extended model is suitable for site specific simulations, coupled with for example, available remote sensing data on STB infection.

Modeling bronchial circulation with application to soluble gas exchange: description and sensitivity analysis

1998 ◽  
Vol 84 (6) ◽  
pp. 2070-2088 ◽  
Author(s):  
Thien D. Bui ◽  
Donald Dabdub ◽  
Steven C. George
Keyword(s):  
Sensitivity Analysis ◽  
Gas Exchange ◽  
Pulmonary Circulation ◽  
Blood Flow Rate ◽  
Latin Hypercube Sampling ◽  
Inert Gases ◽  
Phase Iii ◽  
Model Parameters ◽  
Bronchial Circulation ◽  
Wide Range

The steady-state exchange of inert gases across an in situ canine trachea has recently been shown to be limited equally by diffusion and perfusion over a wide range (0.01–350) of blood solubilities (βblood; ml ⋅ ml−1 ⋅ atm−1). Hence, we hypothesize that the exchange of ethanol (βblood = 1,756 at 37°C) in the airways depends on the blood flow rate from the bronchial circulation. To test this hypothesis, the dynamics of the bronchial circulation were incorporated into an existing model that describes the simultaneous exchange of heat, water, and a soluble gas in the airways. A detailed sensitivity analysis of key model parameters was performed by using the method of Latin hypercube sampling. The model accurately predicted a previously reported experimental exhalation profile of ethanol ( R 2= 0.991) as well as the end-exhalation airstream temperature (34.6°C). The model predicts that 27, 29, and 44% of exhaled ethanol in a single exhalation are derived from the tissues of the mucosa and submucosa, the bronchial circulation, and the tissue exterior to the submucosa (which would include the pulmonary circulation), respectively. Although the concentration of ethanol in the bronchial capillary decreased during inspiration, the three key model outputs (end-exhaled ethanol concentration, the slope of phase III, and end-exhaled temperature) were all statistically insensitive ( P > 0.05) to the parameters describing the bronchial circulation. In contrast, the model outputs were all sensitive ( P < 0.05) to the thickness of tissue separating the core body conditions from the bronchial smooth muscle. We conclude that both the bronchial circulation and the pulmonary circulation impact soluble gas exchange when the entire conducting airway tree is considered.

scholarly journals Use of the correlation between input variables in estimating the risk of feedlot finishing of steers and young steers

2014 ◽  
Vol 86 (2) ◽  
pp. 945-954 ◽  
Author(s):  
PAULO S. PACHECO ◽  
JOÃO RESTLE ◽  
LEONIR L. PASCOAL ◽  
FABIANO N. VAZ ◽  
RICARDO Z. VAZ ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Stochastic Dominance ◽  
Net Present Value ◽  
Latin Hypercube Sampling ◽  
Risk Estimate ◽  
Present Value ◽  
Random Input ◽  
Financial Indicator ◽  
Input Variables ◽  
Diet Intake

The objective of this study was to evaluate the risk of feedlot finishing of steers (22.8 months) and young steers (15.2 months), using or not a correlation between the random input variables (data collected from 2004 to 2010) in the simulation of the Net Present Value (NPV) financial indicator. The animals were fed a diet containing roughage:concentrate ratio of 60:40 for 34 and 143 days, respectively, until they had reached a predetermined slaughter weight of 430 kg. For the NPV simulation, Latin Hypercube sampling was used, with 2000 interactions. The stochastic dominance analysis, test of differences between pairs of curves of cumulative distributions and sensitivity analysis were carried out. The NPV simulation using the correlation resulted in the best option for risk estimate. The confinement of young steers was the alternative of investment most viable than confinement of steers (NPV ≥ 0 of 80.4 vs. 62.3% in the simulation with correlation, respectively). Sensitivity analysis determined the following items had the greatest impact on the estimate of NPV: prices of fat and thin cattle, initial and final weights, diet costs, minimum rate of attractiveness and diet intake.

scholarly journals Sensitivity analysis on the pollutant trapping efficiencies of a novel sewerage overflow screening device

2016 ◽  
Vol 18 (6) ◽  
pp. 1007-1018
Author(s):  
M. A. Aziz ◽  
M. A. Imteaz ◽  
H. M. Rasel ◽  
M. Samsuzzoha
Keyword(s):  
Sensitivity Analysis ◽  
Sampling Technique ◽  
Latin Hypercube Sampling ◽  
Capture Efficiency ◽  
Industry Standard ◽  
Informed Decisions ◽  
Input Parameters ◽  
Perform Sensitivity Analysis ◽  
Hydro Jet ◽  
Screening Device

A novel ‘Comb Separator’ was developed and tested with the aim of improving sewer solids capture efficiency and reducing blockages on the screen. Experimental results were compared against the industry standard ‘Hydro-Jet™’ screen. Analysing the parameter sensitivity of a hydraulic screen is a standard practice to get better understanding of the device performance. In order to understand the uncertainties of the Comb Separator's input parameters, it is necessary to undertake sensitivity analysis; this will assist in making informed decisions regarding the use of this device. Such analysis will validate the device's performance in urban sewerage overflow scenarios. The methodology includes multiple linear regression and sampling using the standard Latin hypercube sampling technique to perform sensitivity analysis on different experimental parameters, such as flowrate, effective comb spacing, device runtime, weir opening and comb layers. The input parameters ‘weir opening’ and ‘comb layers’ have an insignificant influence on capture efficiency; hence, they were omitted from further analysis. Among the input parameters, ‘effective spacing’ was the most influential, followed by ‘inflow’ and ‘runtime’. These analyses provide better insights about the sensitivities of the parameters for practical application. This will assist device managers and operators to make informed decisions.

A Sensitivity Analysis of Two Mesoscale Models: COAMPS and WRF

2020 ◽  
Vol 148 (7) ◽  
pp. 2997-3014
Author(s):  
Caren Marzban ◽  
Robert Tardif ◽  
Scott Sandgathe
Keyword(s):  
Sensitivity Analysis ◽  
Spatial Structure ◽  
Latin Hypercube Sampling ◽  
Forecast Model ◽  
The United States ◽  
Model Parameters ◽  
Analysis Methodology ◽  
Trigger Function ◽  
Multivariate Multiple Regression

Abstract A sensitivity analysis methodology recently developed by the authors is applied to COAMPS and WRF. The method involves varying model parameters according to Latin Hypercube Sampling, and developing multivariate multiple regression models that map the model parameters to forecasts over a spatial domain. The regression coefficients and p values testing whether the coefficients are zero serve as measures of sensitivity of forecasts with respect to model parameters. Nine model parameters are selected from COAMPS and WRF, and their impact is examined on nine forecast quantities (water vapor, convective and gridscale precipitation, and air temperature and wind speed at three altitudes). Although the conclusions depend on the model parameters and specific forecast quantities, it is shown that sensitivity to model parameters is often accompanied by nontrivial spatial structure, which itself depends on the underlying forecast model (i.e., COAMPS vs WRF). One specific difference between these models is in their sensitivity with respect to a parameter that controls temperature increments in the Kain–Fritsch trigger function; whereas this parameter has a distinct spatial structure in COAMPS, that structure is completely absent in WRF. The differences between COAMPS and WRF also extend to the quality of the statistical models used to assess sensitivity; specifically, the differences are largest over the waters off the southeastern coast of the United States. The implication of these findings is twofold: not only is the spatial structure of sensitivities different between COAMPS and WRF, the underlying relationship between the model parameters and the forecasts is also different between the two models.

Reliability Sensitivity Analysis for Rack-and-Pinion Steering Linkages

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Xianzhen Huang ◽  
Yimin Zhang
Keyword(s):  
Sensitivity Analysis ◽  
Linearization Method ◽  
Link Length ◽  
Statistical Parameters ◽  
Kinematic Accuracy ◽  
Analysis Methodology ◽  
Direct Linearization ◽  
Reliability Sensitivity ◽  
Reliability Sensitivity Analysis ◽  
Planar Linkages

In this paper, a reliability sensitivity analysis methodology for the kinematic accuracy of rack-and-pinion steering linkages (RPSLs) is developed. The direct linearization method is applied to obtain the kinematic accuracy errors of planar linkages due to link-length variations. The RPSL widely used in many types of vehicles is chosen as an example to propose an analytical model for reliability analysis of the kinematic accuracy of planar linkages. Furthermore, reliability sensitivity analysis of planar linkages, which is the main focus of this paper, is used to compute the reliability sensitivity of the kinematic accuracy of steering linkages with respect to the statistical parameters (e.g., mean, standard deviation, or higher moments) of the basic errors of random variables. Finally, the practicality and efficiency of the proposed method are demonstrated by a numerical example.

Application of the Average Rank Time Method in Parameter Estimation for Fixed-Time Censoring Experiment

2014 ◽  
Vol 556-562 ◽  
pp. 4146-4150
Author(s):  
Shu Meng ◽  
Gui Xiang Shen ◽  
Ying Zhi Zhang ◽  
Shu Guang Sun ◽  
Qi Song
Keyword(s):  
Parameter Estimation ◽  
Likelihood Function ◽  
Fixed Time ◽  
Model Optimization ◽  
Application Process ◽  
Index Method ◽  
Average Rank ◽  
Failure Data ◽  
Two Parameters ◽  
Mutually Independent

In this paper, the parameter estimation problem of products which are mutually independent and whose life belongs to two parameters Weibull distribution in fixed-time censoring experiment is discussed. And the rank of failure data is corrected by average rank time method, when the censoring experiments appeared. It is found that the method not only achieves the same effect for likelihood function theory, but also has the characters of high precision, simple process, no programming calculation, when model optimization is done by correlation index method. Finally, take field test data of a machine tool as an example to introduce the specific application process of this method, in order to verify the effectiveness and practical applicability.

A Mechatronic Active Force Control System for Real Time Test Loading of an Aircraft Landing Gear

2009 ◽  
Author(s):  
Giovanni Jacazio ◽  
Gualtiero Balossini
Keyword(s):  
Control System ◽  
Real Time ◽  
Force Control ◽  
Landing Gear ◽  
High Rate ◽  
Active Force ◽  
Hydraulic Actuator ◽  
Active Force Control ◽  
Complex Adaptive ◽  
Force Control System

This paper describes an electronically controlled active force control system that was recently developed to provide real time loading for the tests of a landing gear. As the landing gear moves during the test, a force is generated on the landing gear in order to ensure that its dynamics is identical to that that would occur during its operation in an actual flight. Since landing gear deployment and retraction can occur at different environmental and flight conditions, the load profile that must be developed by the force control system depends on the simulated flight condition and is determined by an appropriate landing gear model. To attain accurate force control, a system was setup comprised of a servovalve controlled hydraulic actuator, force and position sensors, and a high rate digital controller implementing a complex adaptive control law. An excellent accuracy of the load control was eventually achieved for all load profiles occurring on the landing gear.

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