Quantitative Assessment of Dynamic Stability Characteristics for Jet Transport in Sudden Plunging Motion

Abstract The main objective of this article is to present a training program of loss control prevention for the airlines to enhance aviation safety and operational efficiency. The assessments of dynamic stability characteristics based on the approaches of oscillatory motion and eigenvalue motion modes for jet transport aircraft response to sudden plunging motions are demonstrated in this article. A twin-jet transport aircraft encountering severe clear-air turbulence in transonic flight during the descending phase will be examined as the study case. The flight results in sudden plunging motions with abrupt changes in attitude and gravitational acceleration (i.e. the normal load factor). Development of the required thrust and aerodynamic models with the flight data mining and the fuzzy-logic modeling techniques will be presented. The oscillatory derivatives extracted from these aerodynamic models are then used in the study of variations in stability characteristics during the sudden plunging motion. The fuzzy-logic aerodynamic models are utilized to estimate the nonlinear unsteady aerodynamics while performing numerical integration of flight dynamic equations. The eigenvalues of all motion modes are obtained during time integration. The present quantitative assessment method is an innovation to examine possible mitigation concepts of accident prevention and promote the understanding of aerodynamic responses of the jet transport aircraft.

Download Full-text

Fuzzy Logic-Based Aerodynamic Modeling with Continuous Differentiability

Mathematical Problems in Engineering ◽

10.1155/2013/609769 ◽

2013 ◽

Vol 2013 ◽

pp. 1-14 ◽

Cited By ~ 3

Author(s):

Ray C. Chang

Keyword(s):

Fuzzy Logic ◽

Atmospheric Turbulence ◽

Model Development ◽

Unsteady Aerodynamics ◽

Least Square Method ◽

Least Square ◽

Transport Aircraft ◽

Fuzzy Logic Algorithm ◽

Modeling Process ◽

Data Points

This paper presents a modeling method based on a fuzzy-logic algorithm to establish aerodynamic models by using the datasets from flight data recorder (FDR). The fuzzy-logic aerodynamic models are utilized to estimate more accurately the nonlinear unsteady aerodynamics for a transport aircraft, including the effects of atmospheric turbulence. The main objective in this paper is to present the model development and the resulting models with continuous differentiability. The uncertainty and correlation of the data points are estimated and improved by monitoring a multivariable correlation coefficient in the modeling process. The latter is increased by applying a least square method to a set of data points to train a set of modeling coefficients. A commercial transport aircraft encountered severe atmospheric turbulence twice at transonic flight in descending phase is the study case in the present paper. The robustness and nonlinear interpolation capability of the fuzzy-logic algorithm are demonstrated in predicting the degradation in performance and stability characteristics of this transport in severe atmospheric turbulence with sudden plunging motion.

Download Full-text

Flight Load Design of Nacelle of Carrier-Based Propeller Transport Aircraft

Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University ◽

10.1051/jnwpu/20203861249 ◽

2020 ◽

Vol 38 (6) ◽

pp. 1249-1256

Author(s):

Kaichao Ma ◽

Changhong Tang ◽

Jianye Zhang ◽

Xiaofei Niu ◽

Qingzhi Fan

Keyword(s):

Aerodynamic Force ◽

Normal Load ◽

Inertial Force ◽

Design Criteria ◽

Load Factor ◽

Aerodynamic Load ◽

Inertial Load ◽

Transport Aircraft ◽

Design Loads ◽

Cfd Method

The carrier-based propeller transport aircraft has a compact layout, where the large nacelle in size and weight is sensitive to propeller slipstream, and thus calls for sophisticated flight load design studies, which are still insufficient considering domestic experience. In detail, the design methods on aerodynamic load, inertial load, gyrostatic moment, as well as studies on design criteria and maneuver simulation technology are shown for a reference aircraft. The design range applied to this nacelle's flight load is firstly determined by understanding and selecting the design criteria. The typical loadcases of the nacelle are derived from aircraft maneuver simulation. The data of pressure distribution under a series of propeller slipstream strengths is obtained by CFD method. The Design Loads and Design Loadcases of the nacelle are calculated and selected. The effects of the propeller slipstream are compared in an example of the increment on aerodynamic load in a maneuver. The results show that the Design Loads of the nacelle are obtained from the abrupt pitching maneuver under the maximum normal load factor (Nz), the yawing maneuver under the Design Dive Speed(VD), and the maximum propeller pull under the maximum landing weight; the transverse loads of the nacelle are dominated by the aerodynamic load, and the normal loads are dominated by the inertial load, in which the inertial force exceeds the aerodynamic force by 4 times under the extreme circumstances. In some manoeuvres or status, the total aerodynamic force of the whole nacelle is increased by above 90% due to propeller slipstream; the front part of the nacelle which is close to the propeller sees a much bigger increment.

Download Full-text

Quantitative Assessment Method of Green Power Development Level Based on Multidimensional Coordination Index

2020 10th International Conference on Power and Energy Systems (ICPES) ◽

10.1109/icpes51309.2020.9349637 ◽

2020 ◽

Author(s):

Nan Li ◽

Tianwen Zheng ◽

Haining Zhang ◽

Libo Jiang ◽

Wenbao Hu ◽

...

Keyword(s):

Quantitative Assessment ◽

Assessment Method ◽

Power Development ◽

Development Level ◽

Green Power

Download Full-text

Quantitative Assessment Method for Supporting Scenario Workshops toward Sustainable Consumption and Production

Procedia CIRP ◽

10.1016/j.procir.2021.01.004 ◽

2021 ◽

Vol 98 ◽

pp. 49-54

Author(s):

Sota Onozuka ◽

Yusuke Kishita ◽

Mitsutaka Matsumoto ◽

Michikazu Kojima ◽

Yasushi Umeda

Keyword(s):

Quantitative Assessment ◽

Sustainable Consumption ◽

Assessment Method ◽

Sustainable Consumption And Production

Download Full-text

A validation research on fuzzy logic-AHP-based assessment method of operator’s situation awareness reliability

Safety Science ◽

10.1016/j.ssci.2018.10.007 ◽

2019 ◽

Vol 119 ◽

pp. 344-352 ◽

Cited By ~ 1

Author(s):

Pengcheng Li ◽

Xiaofang Li ◽

Li Zhang ◽

Licao Dai

Keyword(s):

Fuzzy Logic ◽

Situation Awareness ◽

Assessment Method ◽

Validation Research

Download Full-text

A quantitative assessment method of seismic geometries based on random sampling theory

10.1190/igcbeijing2014-018 ◽

2014 ◽

Author(s):

Du Juan ◽

Wang Huazhong ◽

Wang Xiongwen

Keyword(s):

Random Sampling ◽

Quantitative Assessment ◽

Sampling Theory ◽

Assessment Method

Download Full-text

OPTIMIZATION OF LONG-RANGE TRAJECTORY FOR AN UNPOWERED FLIGHT VEHICLE

Vietnam Journal of Science and Technology ◽

10.15625/2525-2518/57/6a/14012 ◽

2020 ◽

Vol 57 (6A) ◽

pp. 43

Author(s):

Tuan Hung Pham ◽

Duc Cuong Nguyen ◽

Duc Thanh Nguyen

Keyword(s):

Long Range ◽

Numerical Experiments ◽

Optimization Problem ◽

Normal Load ◽

Load Factor ◽

Flight Vehicle ◽

Maximum Range ◽

Normal Acceleration

This report presents problems of optimization of long-range trajectory for an unpowered flight vehicle at subsonic and transonic speed. The results may be recommended to have a new long range trajectory. The optimization problem is solved by numerical experiments while the normal load factor (normal acceleration) is used as optimization variables with compliance to flight constraints. The focus problem of this study is the investigation of the possibility of trajectory expansion according to the criteria of the maximum range in the first stage of the trajectory.

Download Full-text

Underground Risk Index Assessment and Prediction Using a Simplified Hierarchical Fuzzy Logic Model and Kalman Filter

Processes ◽

10.3390/pr6080103 ◽

2018 ◽

Vol 6 (8) ◽

pp. 103 ◽

Cited By ~ 12

Author(s):

Muhammad Fayaz ◽

Israr Ullah ◽

Do-Hyeun Kim

Keyword(s):

Fuzzy Logic ◽

Kalman Filter ◽

Fuzzy Inference ◽

Risk Index ◽

Significant Risk ◽

Assessment Method ◽

Logic Model ◽

Membership Functions ◽

Inference System ◽

Fuzzy Logic Model

Normally, most of the accidents that occur in underground facilities are not instantaneous; rather, hazards build up gradually behind the scenes and are invisible due to the inherent structure of these facilities. An efficient inference system is highly desirable to monitor these facilities to avoid such accidents beforehand. A fuzzy inference system is a significant risk assessment method, but there are three critical challenges associated with fuzzy inference-based systems, i.e., rules determination, membership functions (MFs) distribution determination, and rules reduction to deal with the problem of dimensionality. In this paper, a simplified hierarchical fuzzy logic (SHFL) model has been suggested to assess underground risk while addressing the associated challenges. For rule determination, two new rule-designing and determination methods are introduced, namely average rules-based (ARB) and max rules-based (MRB). To determine efficient membership functions (MFs), a module named the heuristic-based membership functions allocation (HBMFA) module has been added to the conventional Mamdani fuzzy logic method. For rule reduction, a hierarchical fuzzy logic model with a distinct configuration has been proposed. In the simplified hierarchical fuzzy logic (SHFL) model, we have also tried to minimize rules as well as the number of levels of the hierarchical structure fuzzy logic model. After risk index assessment, the risk index prediction is carried out using a Kalman filter. The prediction of the risk index is significant because it could help caretakers to take preventive measures in time and prevent underground accidents. The results indicate that the suggested technique is an excellent choice for risk index assessment and prediction.

Download Full-text