Nonlinear Aeroelastic Analysis of Joined Wing Aircraft
NONLINEAR AEROELASTIC ANALYSIS OF JOINED-WING AIRCRAFT
ABSTRACT Joined-wing aircraft are being designed for ‘sensorcraft’ configuration. Joined wings lead to multiple load paths and constraints. The focus of this work is to understand the nonlinear structural as well as aeroelastic behavior of joined wings. The paper presents a formulation for the nonlinear aeroelastic analysis of joined wings. Results are presented for two joined wings configurations. Overall, the joined wings are found to be stiffer than single wing configuration. The ‘non-planar’ joined wing is found to be stiffer than the ‘planar’ joined wing. The structural dynamic characteristics of the joined wings are also presented. The bending modes are similar to the cantilevered beam modes while the torsional vibrations are restricted to the unconstrained part of the main wing. The structural analysis showed negligible nonlinear effects for static deformation as well as for structural dynamics characteristics.
KEY-WORDS: Jointed wing, wing defection.
INTRODUCTION
In recent years there has been a push towards the design and development of uninhabited aerial vehicles (UAVs). UAVs are being designed for various missions including atmospheric sensing, border monitoring, military reconnaissance and combat (UCAV). It is expected that UAVs would not only take over multiple conventional roles in civilian as well as military service, but also undertake new unconventional missions in the future. One example of an unconventional a mission is the ‘sensorcraft.’ Sensorcraft is being designed for longrange, high-altitude, intelligence, surveillance and reconnaissance (ISR). Sensorcraft is a joined-wing design aimed at providing an unobstructed field of view around the vehicle.1 Weisshaar and Lee2 present the history of joined-wing aircraft. The paper also presents aeroelastic tailoring studies. Livne3 presents a literature survey of the present status of technical development. Aeroelastic
ABSTRACT Joined-wing aircraft are being designed for ‘sensorcraft’ configuration. Joined wings lead to multiple load paths and constraints. The focus of this work is to understand the nonlinear structural as well as aeroelastic behavior of joined wings. The paper presents a formulation for the nonlinear aeroelastic analysis of joined wings. Results are presented for two joined wings configurations. Overall, the joined wings are found to be stiffer than single wing configuration. The ‘non-planar’ joined wing is found to be stiffer than the ‘planar’ joined wing. The structural dynamic characteristics of the joined wings are also presented. The bending modes are similar to the cantilevered beam modes while the torsional vibrations are restricted to the unconstrained part of the main wing. The structural analysis showed negligible nonlinear effects for static deformation as well as for structural dynamics characteristics.
KEY-WORDS: Jointed wing, wing defection.
INTRODUCTION
In recent years there has been a push towards the design and development of uninhabited aerial vehicles (UAVs). UAVs are being designed for various missions including atmospheric sensing, border monitoring, military reconnaissance and combat (UCAV). It is expected that UAVs would not only take over multiple conventional roles in civilian as well as military service, but also undertake new unconventional missions in the future. One example of an unconventional a mission is the ‘sensorcraft.’ Sensorcraft is being designed for longrange, high-altitude, intelligence, surveillance and reconnaissance (ISR). Sensorcraft is a joined-wing design aimed at providing an unobstructed field of view around the vehicle.1 Weisshaar and Lee2 present the history of joined-wing aircraft. The paper also presents aeroelastic tailoring studies. Livne3 presents a literature survey of the present status of technical development. Aeroelastic
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