Evaluation of Quasi-Static Gust Loads Certification Methods for High-Altitude Long-Endurance Aircraft

Aeroelastic gust loads analysis can be approached using quasi-static, transient, or continuous methodologies. Pratt method is a quasi-static approach that forms the basis for Federal Aviation Regulation Part 23 gust loads certification requirements. This work evaluates the usefulness of Pratt method for unconventional high-altitude long-endurance aircraft. The derivation of Pratt method is reviewed, and all assumptions are identified. Error of a key curve fit equation is quantified directly. A state-of-the-art nonlinear aeroelastic code was upgraded and used to facilitate quantification of application-dependent errors by comparing quasi-static results to results from nonlinear transient analysis. Application-dependent errors are presented in the context of a SensorCraft-inspired joined-wing model and a Helios-aircraft-inspired flying-wing model. Recommendations are made on the usability of Pratt method for aircraft similar to the two high-altitude long-endurance models. It is concluded that Pratt method i...

[1]  Robert A. Canfield,et al.  Joined-Wing Aeroelastic Design with Geometric Nonlinearity , 2005 .

[2]  Dewey H. Hodges,et al.  Geometrically Exact, Intrinsic Theory for Dynamics of Curved and Twisted Anisotropic Beams , 2004 .

[3]  Dario Floreano,et al.  Flying Insects and Robots , 2010 .

[4]  Mayuresh J. Patil,et al.  Nonlinear Gust Response of Highly Flexible Aircraft , 2007 .

[5]  Mayuresh J. Patil,et al.  Utility of Quasi-Static Gust Loads Certification Methods for Novel Configurations , 2011 .

[6]  Jerome C. Hunsaker,et al.  Report on Behavior of Aeroplanes in Gusts , 1915 .

[7]  Robert A. Canfield,et al.  Joined-Wing Sensor-Craft Configuration Design , 2004 .

[8]  John C. Houbolt,et al.  NACA/NASA research related to evolution of U.S. gust design criteria , 1989 .

[9]  M. Patil,et al.  Gust Response of Highly Flexible Aircraft , 2006 .

[10]  Carlos E. S. Cesnik,et al.  Nonlinear Aeroelastic Modeling and Analysis of Fully Flexible Aircraft , 2005 .

[11]  Frederic M. Hoblit,et al.  Gust Loads on Aircraft: Concepts and Applications , 1988 .

[12]  Carlos E. S. Cesnik,et al.  Dynamic Response of Highly Flexible Flying Wings , 2011 .

[13]  Marco Borri,et al.  Composite beam analysis linear analysis of naturally curved and twisted anisotropic beams , 1992 .

[14]  D. Hodges.  A mixed variational formulation based on exact intrinsic equations for dynamics of moving beams , 1990 .

[15]  Paul Scott Zink,et al.  Body Freedom Flutter of High Aspect Ratio Flying Wings , 2005 .

[16]  Mark James Johnson,et al.  Finite-State Airloads for Deformable Airfoils on Fixed and Rotating Wings , 1994 .

[17]  Carlos E. S. Cesnik,et al.  On Timoshenko-like modeling of initially curved and twisted composite beams , 2002 .

[18]  Per-Olof Persson,et al.  A Computational Framework for Fluid Structure Interaction in Biologically Inspired Flapping Flight , 2007 .

[19]  Richard V. Rhode.  Applied Load Factors in Bumpy Air , 1931 .

[20]  Robert A. Canfield,et al.  SENSOR-CRAFT STRUCTURAL OPTIMIZATION AND ANALYTICAL CERTIFICATION* , 2003 .

[21]  Dewey H. Hodges,et al.  Flight Dynamics of Highly Flexible Flying Wings , 2006 .

[22]  David Lucia,et al.  The SensorCraft Configurations: A Non-Linear AeroServoElastic Challenge for Aviation , 2005 .

[23]  Carlos E. S. Cesnik,et al.  Nonlinear Flight Dynamics of Very Flexible Aircraft , 2005 .

[24]  J. R. Fuller.  Evolution and Future Development of Airplane Gust Loads Design Requirements , 1997 .

[25]  D. Peters,et al.  Finite state induced flow models. I - Two-dimensional thin airfoil , 1995 .

[26]  Carlos E. S. Cesnik,et al.  Active Warping Control of a Joined Wing/Tail Airplane Configuration , 2003 .

[27]  Robert A. Canfield,et al.  Optimization process for configuration of flexible joined-wing , 2008 .

[28]  Mark Drela,et al.  INTEGRATED SIMULATION MODEL FOR PRELIMINARY AERODYNAMIC, STRUCTURAL, AND CONTROL-LAW DESIGN OF AIRCRAFT , 1999 .

[29]  Carlos E. S. Cesnik,et al.  Modeling of High Aspect Ratio Active Flexible Wings for Roll Control , 2002 .

[30]  Frederic M. Hoblit.  Gust Loads Fundamentals , 1988 .

[31]  Philip Donely,et al.  Summary of Information Relating to Gust Loads on Airplanes , 1949 .