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Flight Simulator Research and Technologies
Published in Mark S. Young, Michael G. Lenné, Simulators for Transportation Human Factors, 2017
Barbara G. Kanki, Peter M. T. Zaal, Mary K. Kaiser
However, there was still the question of whether pilot inputs caused or exacerbated the rudder hardover. Of particular concern was whether the initial extreme movements of the aircraft caused spatial disorientation, leading the pilot(s) to input improper commands (rather than control reversal by the rudder system). Examining this question in a simulator was challenging because most transport simulators are designed primarily to reproduce vehicle motions typical of normal flight. The extreme yaw and roll rates recovered from the FDR of Flight 427 could not be recreated on a Boeing 737 simulator with a hexapod motion platform.
Missile Systems Engineering
Published in Anna M. Doro-on, Handbook of Systems Engineering and Risk Management in Control Systems, Communication, Space Technology, Missile, Security and Defense Operations, 2023
The control effectiveness with regard to pitching moment per unit deflection is likely the least of all three key control surfaces. The body plus wing configuration can have control reversal under specific flight or loading cases, particularly, the center of gravity ahead of wing of pressure. The wing downwash on the rearward surfaces provides a majority range on the resultant control effectiveness of the overall model configuration. Despite the trim angle of attack may be nearly lesser, but the net hinge moment of the wing control is relatively at the maximum.
Human Performance
Published in Gawron Valerie Jane, Human Performance and Situation Awareness Measures, 2019
Strengths and limitations – Corwin et al. (1989) reported that control input activity was a reliable and valid measure. Griffith et al. (1984) were unable to compute control reversal rates for throttle and rudder pedal activity due to minimal control inputs. Further, there were no significant differences among display configurations for pitch-axis control reversal rate. There were, however, significant differences among the same display configurations in the roll-axis control reversal rate.
Equivalent beam modeling scheme based on three-dimensional structure with blade element concept
Published in Advanced Composite Materials, 2020
Commercial codes based on the BEMT, such as Flex5 and GH Bladed, usually simplify the blade structure using the modal reduction method with the blades regarded as a beam element which adopts a certain group of the mode shapes and frequencies. This approach turns out to be quite accurate and expeditious in predicting the wind turbine dynamic response [6]. The BEMT analyses require a number of properties of the blade, including the stiffness, mass, and the moment of inertia in terms of the span length [7]. One of the critical steps in blade analysis is to obtain the beam properties from the three-dimensional representation of the blade. The flexible beams of rotor blades undergo elastic deformations in the process of bending and torsion. Under normal operating conditions, their deformations are allowed to go beyond the limits of the linear beam theories. Thus, moderately large nonlinear deformations need to be taken into account. Numerous state-of-the-art composite blade modeling techniques have been proposed in the past two decades. David and Daniel [8] successfully obtained the moment of inertia for a few structural elements (shear web, spar cap, leading edge, trailing edge, and shell) in the second area from the blade section to deal with the geometrical complexity. The relevant mass is also found under a similar strategy. Zhang [9] presented an analytical method to determine the stiffness of displacements by load. Additionally, various methodologies are introduced how to extract the edge- and flap-wise stiffness and mass per unit length of the blade [10–14]. In addition, Yoon et al. [15] analyzed the effect of control reversal and torsional divergence on a high aspect-ratio wing by using a two-step process involving a two-dimensional (2D) cross-sectional analysis and a one-dimensional (1D) beam analysis combined with a 2D simple aerodynamic model. Su et al. [16] used a coupling of two calculations of wing deformation and aerodynamics. The wing was considered to be a strain-based geometrically nonlinear solid beam, and a study of unsteady aerodynamic loads based on the 2D finite-state inflow was used in the aerodynamic problem. Aeroelastic calculations typically focus on solving the elasticity problem, whereas fixed values are used for aerodynamic forces or are solved using simple methods. Ghafari and Rezaeepazhand [17] studied free vibration analysis of rotating composite beams with arbitrary cross section is presented. The analysis is based on a dimensional reduction method. However, most of the previous methods imposed the loads only at the end of a blade regarded as a linear structure, resulting in limitations associated with nonlinearities. The blade structure is more complex and complicated; the discrepancies between the prediction and reality will become increased. This paper provides a scheme of how to extract structural properties such as edge- and flap-wise stiffness, torsional and extensional rigidity, and mass distribution based on the blade sectional element, which are the characteristics of the blade. This approach is expected to enhance accuracy in identifying the structural characteristics over the original one.