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ANALYSIS, DESIGN AND EXPERIMENTAL VALIDATION OF A SIMPLIFIED COMPOSITE STRUCTURE FOR A BOX WING AND A METHOD FOR ITS PRODUCTION. Plamen Roglev Technical University Sofia – Branch Plovdiv plroglev@mail.bg. ISCM 2012 Stade, Germany.
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ANALYSIS, DESIGN AND EXPERIMENTAL VALIDATION OF A SIMPLIFIED COMPOSITE STRUCTURE FOR A BOX WING AND A METHOD FOR ITS PRODUCTION Plamen Roglev Technical University Sofia – Branch Plovdiv plroglev@mail.bg ISCM 2012 Stade, Germany
Design objectivesimple and efficient composite wing structure for an experimental UAV
The joined-wing / box-wing promises many structural, aerodynamic and aeroelastic advantages
Bleriot III Lee-Richards Joined-wing configurations have been proposed since the earliest days of aviation
Wolkovitch first investigated the joined-wing in more detail
Numerical analysisSpanwise aerodynamic load distributionVortex Lattice Method Program -VLMpc
Approximation of the distribution of the lift coefficient along the span
Condition III- Positive Low Angle of Attack Condition IV- Negative Low Angle of Attack Structural behaviour investigationVon Mises Stress distribution for an isotropic shell
Von Mises Stress distribution of Model 1’rear wing with no dihedral
The joined wing type proposed by WOLKOVITCH(Model 3) leads to divergency and should be avoided
Influence of the distribution of the load carrying material in the section of the wing: variants studied
WINGS WITH MATERIAL DISTRIBUTION ACCORDING TO WOLKOWITCH AT LOAD FACTOR 3 WINGS WITH EVEN MATERIAL DISTRIBUTION AT LOAD FACTOR 4 EXPERIMENTAL COMPARISON
The specimen with Wolkovitch type distribution failed at a load factor 3.2 The specimen with even distribution failed at a load factor 4.7 The failure occurred first at the middle of the rear wing and than at its root The type of failure was of local buckling of the compressed skin The best variant for the material distribution in the section of the wings for a simplified construction is the even distribution. Experimental results
Technological scheme SKIN PRODUCTION SKIN AND CORE BONDING CONTROL SURFACES CUTTING FRONT AND REAR WINGS JOINING CORE SHAPING PAINTING
Production method advantages • High-temperature cure resin can be used which produces laminate more resistant to compression • No finishing sanding and filling • A lighter and stronger laminate is achieved • Short cycle time of production
Acknowledgments I would like to thank Dr. Dimo Zafirof As. Professor at Technical University Sofia – Branch Plovdiv and Dr. Hristian Panayotov for the precious assistance they provided during this study
References 1. Gay D., Hoa S., Tsai S. - Composite Materials Design And Applications, CRC 2003 2.Gallman J., Smith S., Kroo I. - Optimization of Joined-Wing Aircraft, JOURNAL OF AIRRCRAFTVol. 30, No. 6, Nov.-Dec. 1993 3.Kroo I. - Nonplanar Wing Concepts for Increased Aircraft Efficiency, 2005 4.Wolkovitch J. - The Joined Wing – an Overview, AIAA, 1985 5.Zafirov D. I. Joined Wing UAV with Ducted Fan. UAV World Conference, Frankfurt/Main 2009 6.Zafirov, D., Joined Wings Thrust Vectored UAV Flight Envelope. AIAA Papers, AIAA-2010-7509, AIAA Atmospheric Flight Mechanics Conference, Toronto, 2010 7.Панайотов, Х., Д. Зафиров Изследване на аеродинамични характеристики на съчленено крило по метода на дискретните вихри ЮНС “10 години катедра Въздушен транспорт” 01-03 октомври 2003