Comment on 'NASA investigation of a claimed 'Overlap' between two gust response analysis methods'

1992 ◽  
Vol 29 (4) ◽  
pp. 741-742 ◽  
Author(s):  
Bernard Etkin
Keyword(s):  
Response Analysis ◽  
Analysis Methods ◽  
Gust Response

NASA investigation of a claimed 'overlap' between two gust response analysis methods

1990 ◽  
Vol 27 (7) ◽  
pp. 605-611 ◽  
Author(s):  
Boyd Perry ◽  
Anthony S. Pototzky ◽  
Jessica A. Woods
Keyword(s):  
Response Analysis ◽  
Analysis Methods ◽  
Gust Response

Vibration behavior of an overhead conductor under updraft winds

2021 ◽  
pp. 107754632110058
Author(s):  
Qi Zhou ◽  
Liangtao Zhao ◽  
Chong Zheng ◽  
Feng Tu
Keyword(s):  
Induced Response ◽  
Response Analysis ◽  
Response Factor ◽  
Structural Dynamic ◽  
Resonance Response ◽  
Structural Dynamic Characteristics ◽  
Strong Winds ◽  
American Society ◽  
Gust Response Factor ◽  
Gust Response

At present, the wind-induced response analysis of an overhead conductor is mainly based on the action of horizontal normal wind. However, for crossing hillsides or extremely strong winds, such a conductor will bear the action of updraft wind, which will change the geometry of the conductor and make its structural dynamic characteristics nonlinear to some extent. In this work, the in-plane and out-of-plane two-dimensional nonlinear equations were established under the action of self-weight and updraft wind. Furthermore, the improved equations of conductor tension and sag were obtained, and the wind-induced vibration response was further investigated. The results showed that the updraft wind caused the nonlinearity of the tension and sag of the overhead conductor, and the nonlinear geometric change significantly affected its resonance response, which exceeded 25% if the wind speed was 50 m/s. In addition, because the proportion of the resonance response in the total wind-induced response was different, the influence of the wind attack angle calculated using the gust response factor method on the gust response factor was slightly larger than that calculated using the the American society of civil engineers method.

scholarly journals Gust Response Analysis of a Turbine Cascade

2003 ◽  
Vol 20 (2) ◽  
Author(s):  
Rama Subba Reddy Gorla ◽  
Tondapu Seetharama Reddy ◽  
Dhanireddy Ramalinga Reddy ◽  
Anatole P. Kurkov
Keyword(s):  
Response Analysis ◽  
Turbine Cascade ◽  
Gust Response

Log-Logistic Analysis of Herbicide Dose-Response Relationships

1995 ◽  
Vol 9 (2) ◽  
pp. 218-227 ◽  
Author(s):  
Steven S. Seefeldt ◽  
Jens Erik Jensen ◽  
E. Patrick Fuerst
Keyword(s):  
Dose Response ◽  
Logistic Model ◽  
Response Analysis ◽  
Analysis Method ◽  
Weed Science ◽  
Response Curves ◽  
Herbicide Resistant ◽  
Logistic Analysis ◽  
Analysis Methods ◽  
The Difference

Dose-response studies are an important tool in weed science. The use of such studies has become especially prevalent following the widespread development of herbicide resistant weeds. In the past, analyses of dose-response studies have utilized various types of transformations and equations which can be validated with several statistical techniques. Most dose-response analysis methods 1) do not accurately describe data at the extremes of doses and 2) do not provide a proper statistical test for the difference(s) between two or more dose-response curves. Consequently, results of dose-response studies are analyzed and reported in a great variety of ways, and comparison of results among various researchers is not possible. The objective of this paper is to review the principles involved in dose-response research and explain the log-logistic analysis of herbicide dose-response relationships. In this paper the log-logistic model is illustrated using a nonlinear computer analysis of experimental data. The log-logistic model is an appropriate method for analyzing most dose-response studies. This model has been used widely and successfully in weed science for many years in Europe. The log-logistic model possesses several clear advantages over other analysis methods and the authors suggest that it should be widely adopted as a standard herbicide dose-response analysis method.

Kriging-Based Aeroelastic Gust Response Analysis at High Angles of Attack

AIAA Journal ◽  
2020 ◽  
Vol 58 (9) ◽  
pp. 3777-3787 ◽  
Author(s):  
Wrik Mallik ◽  
Daniella E. Raveh
Keyword(s):  
Response Analysis ◽  
High Angles Of Attack ◽  
Gust Response

scholarly journals Gust Load Alleviation including Geometric Nonlinearities Based on Dynamic Linearization of Structural ROM

2019 ◽  
Vol 2019 ◽  
pp. 1-20
Author(s):  
Chao An ◽  
Chao Yang ◽  
Changchuan Xie ◽  
Yang Meng
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Kernel Functions ◽  
Structural Deformation ◽  
Control Technique ◽  
Feedback Signal ◽  
Response Analysis ◽  
Geometric Nonlinearities ◽  
Gust Load Alleviation ◽  
Gust Response

This paper describes a framework for an active control technique applied to gust load alleviation (GLA) of a flexible wing, including geometric nonlinearities. Nonlinear structure reduced order model (ROM) and nonplanar double-lattice method (DLM) are used for structural and aerodynamic modeling. The structural modeling method presented herein describes stiffness nonlinearities in polynomial formulation. Nonlinear stiffness can be derived by stepwise regression. Inertia terms are constant with linear approximation. Boundary conditions and kernel functions in the nonplanar DLM are determined by structural deformation to reflect a nonlinear effect. However, the governing equation is still linear. A state-space equation is established in a dynamic linearized system around the prescribed static equilibrium state after nonlinear static aeroelastic analysis. Gust response analysis can be conducted subsequently. For GLA analysis, a classic proportional-integral-derivative (PID) controller treats a servo as an actuator and acceleration as the feedback signal. Moreover, a wind tunnel test has been completed and the effectiveness of the control technology is validated. A remote-controlled (RC) model servo is chosen in the wind tunnel test. Numerical simulation results of gust response analysis reach agreement with test results. Furthermore, the control system gives GLA efficacy of vertical acceleration and root bending moment with the reduction rate being over 20%. The method described in this paper is suitable for gust response analysis and control strategy design for large flexible wings.

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