Abstract:Composite pretwisted rotating thin walled beams (TWB) can be used as the structural model for composite helicopter and wind turbine blades for the study of aeroelastic response of the blades. In the present study, semi-analytical solution is performed for the free vibration analysis of uniform and asymmetric composite pretwisted rotating TWB. The approximation of the Green-Lagrange strain tensor is adopted to derive the strain field of the system. The Euler–Lagrange governing equations of the dynamic system an… Show more
“…The structural model considered is similar to the model developed in Refs. [10,13,28] in linear form. For a detailed description of the original structural model, the reader is referred to the aforementioned references.…”
Section: Structural Model and Kinematic Relationsmentioning
confidence: 99%
“…The ij Q components are used to transform the stiffness coefficients from the principle axes to the material axes. All the above components are defined explicitly in Ref [13]. The 2D first order force and moment resultants of the cross-section of the TWB are defined in terms of the 3D stresses.…”
Section: Constitutive Relationsmentioning
confidence: 99%
“…(15). Details of force and moment resultants are explicitly defined in our previous study [10,13].…”
Section: Potential Energy Of Wing-engine Systemmentioning
confidence: 99%
“…where F, A, D are the one dimensional beam forces and moment resultants, the resulting stiffness matrix, and generalized strain, respectively. For a single cell thin walled beam, stiffness coefficients ij a are given by the contour integral of the stiffness coefficients as shown in [13]. Potential energy due to engine thrust is given as,…”
Section: Potential Energy Of Wing-engine Systemmentioning
confidence: 99%
“…In order to have slender and lighter wing structure, advanced composite materials with thin walled beams (TWBs) structure has been developed. Application of TWBs in aircraft wings as a load carrying part of the wing and studying their dynamic behavior has been the topic of many researches [8][9][10][11][12][13]. Librescu [9] thoroughly investigated the theoretical foundations of composite TWBs and derived the necessary relations.…”
In the present study, the aeroelastic energy response of a twin-engine composite wing system is optimized based on sequential quadratic programming (SQP) method. The variable stiffness is acquired by constructing laminates of thin wall beam (TWB) with curvilinear fibers having prescribed paths. In order to account the effect of spanwise locations and mass of the engines on the aeroelastic characteristics of TWB, the novel governing equations of motion are obtained using Hamilton's variational principle. The paper aims to exploit desirable fiber paths with improved aeroelastic properties for different twin-engine wing configuration. Ritz based solution methodology is employed to solve the equations with coupled incompressible unsteady aerodynamic model based on Wagner's function. A novel optimization strategy based on the total energy of the aeroelastic system is introduced. The proposed total energy, as a cost function, is minimized in terms of four optimization variables of two engine's locations and wing structure curvilinear fiber angle with two design parameters. The total energy is obtained by integrating responses of kinetic and potential energy in a specific time interval. The minimum total energy is an indication of ideal optimization variables which leads to the optimum flutter performance. Numerical results demonstrate the effectiveness of the optimization variables on the total energy of the aeroelastic system and determine the optimal values of introduced variables in case of minimum total energy and improved aeroelastic characteristics.
“…The structural model considered is similar to the model developed in Refs. [10,13,28] in linear form. For a detailed description of the original structural model, the reader is referred to the aforementioned references.…”
Section: Structural Model and Kinematic Relationsmentioning
confidence: 99%
“…The ij Q components are used to transform the stiffness coefficients from the principle axes to the material axes. All the above components are defined explicitly in Ref [13]. The 2D first order force and moment resultants of the cross-section of the TWB are defined in terms of the 3D stresses.…”
Section: Constitutive Relationsmentioning
confidence: 99%
“…(15). Details of force and moment resultants are explicitly defined in our previous study [10,13].…”
Section: Potential Energy Of Wing-engine Systemmentioning
confidence: 99%
“…where F, A, D are the one dimensional beam forces and moment resultants, the resulting stiffness matrix, and generalized strain, respectively. For a single cell thin walled beam, stiffness coefficients ij a are given by the contour integral of the stiffness coefficients as shown in [13]. Potential energy due to engine thrust is given as,…”
Section: Potential Energy Of Wing-engine Systemmentioning
confidence: 99%
“…In order to have slender and lighter wing structure, advanced composite materials with thin walled beams (TWBs) structure has been developed. Application of TWBs in aircraft wings as a load carrying part of the wing and studying their dynamic behavior has been the topic of many researches [8][9][10][11][12][13]. Librescu [9] thoroughly investigated the theoretical foundations of composite TWBs and derived the necessary relations.…”
In the present study, the aeroelastic energy response of a twin-engine composite wing system is optimized based on sequential quadratic programming (SQP) method. The variable stiffness is acquired by constructing laminates of thin wall beam (TWB) with curvilinear fibers having prescribed paths. In order to account the effect of spanwise locations and mass of the engines on the aeroelastic characteristics of TWB, the novel governing equations of motion are obtained using Hamilton's variational principle. The paper aims to exploit desirable fiber paths with improved aeroelastic properties for different twin-engine wing configuration. Ritz based solution methodology is employed to solve the equations with coupled incompressible unsteady aerodynamic model based on Wagner's function. A novel optimization strategy based on the total energy of the aeroelastic system is introduced. The proposed total energy, as a cost function, is minimized in terms of four optimization variables of two engine's locations and wing structure curvilinear fiber angle with two design parameters. The total energy is obtained by integrating responses of kinetic and potential energy in a specific time interval. The minimum total energy is an indication of ideal optimization variables which leads to the optimum flutter performance. Numerical results demonstrate the effectiveness of the optimization variables on the total energy of the aeroelastic system and determine the optimal values of introduced variables in case of minimum total energy and improved aeroelastic characteristics.
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