This paper is categorized into two parts. （1） A frame work to design the aircraft wing structure and （2） analysis ofa morphing airfoil with auxetic structure. The developed design frame work in the first part is u...This paper is categorized into two parts. （1） A frame work to design the aircraft wing structure and （2） analysis ofa morphing airfoil with auxetic structure. The developed design frame work in the first part is used to arrive at the sizes of the various components of an aircraft wing structure. The strength based design is adopted, where the design loads are extracted from the aerodynamic loads. The aerodynamic loads acting on a wing structure are converted to equivalent distributed loads, which are further converted point loads to arrive at the shear forces, bending and twisting moments along the wing span. Based on the estimated shear forces, bending and twisting moments, the strength based design is employed to estimate the sizes of various sections of a composite wing structure. A three dimensional numerical model of the composite wing structure has been developed and analyzed for the extreme load conditions. Glass fiber reinforced plastic material is used in the numerical analysis. The estimated natural frequencies are observed to be in the acceptable limits. Furthermore, the discussed design principles in the first part are extended to the design of a morphing airfoil with auxetic structure. The advantages of the morphing airfoil with auxetic structure are （i） larger displacement with limited straining of the components and （ii） unique deformation characteristics, which produce a theoretical in-plane Poisson＇s ratio of -1. Aluminum Alloy AL6061-T651 is considered in the design of all the structural elements. The compliance characteristics of the airfoil are investigated through a numerical model. The numerical results are observed to be in close agreement with the experimental results in the literature.展开更多
A simplified adaptive wing, which deflects its leading edge and trailing edge flaps to vary its shape, is calculated to investigate the potential aerodynamic gains and compared with a biobjective optimization (BO) win...A simplified adaptive wing, which deflects its leading edge and trailing edge flaps to vary its shape, is calculated to investigate the potential aerodynamic gains and compared with a biobjective optimization (BO) wing in the present paper. In subsonic-transonic flights the deflection angle of a flap is determined through optimization using a deterministic method. In supersonic flight the flaps are not deflected due to the requirement of having a minimum drag. For comparison the aerodynamic characteristics of a BO airfoil and wing is calculated. A parallel genetic algorithm is used in BO. Euler equations served as governing equations in flow field calculation. Numerical results in both 2D (airfoil) and 3D (wing) cases show that aerodynamic performances of the two design airfoils and wings are much better than those of the original ones, with the adaptive design one the best. Keywords simplified adaptive wing - biobjective optimization - airfoil and wing design展开更多
本文将基于弹性体变形思想的FFD(Free Form Deformation,自由变形)方法引入飞机气动外形优化设计中,为气动优化设计提供了一种快速、有效的参数化方法和自动网格生成方法.对FFD方法的原理进行分析,归纳了FFD方法的特点;将FFD方法应用于...本文将基于弹性体变形思想的FFD(Free Form Deformation,自由变形)方法引入飞机气动外形优化设计中,为气动优化设计提供了一种快速、有效的参数化方法和自动网格生成方法.对FFD方法的原理进行分析,归纳了FFD方法的特点;将FFD方法应用于几何外形参数化和空间网格自动生成中,建立了基于FFD方法和遗传算法的翼型优化设计系统以及基于FFD方法、遗传算法和Kriging代理模型的翼根整流包优化设计系统;分别对NACA0012翼型和DLRF4翼身组合体翼根整流包进行减阻优化设计,优化结果得到了显著的减阻成效,证明了FFD方法在气动优化设计中有很好的应用效果.展开更多
文摘This paper is categorized into two parts. （1） A frame work to design the aircraft wing structure and （2） analysis ofa morphing airfoil with auxetic structure. The developed design frame work in the first part is used to arrive at the sizes of the various components of an aircraft wing structure. The strength based design is adopted, where the design loads are extracted from the aerodynamic loads. The aerodynamic loads acting on a wing structure are converted to equivalent distributed loads, which are further converted point loads to arrive at the shear forces, bending and twisting moments along the wing span. Based on the estimated shear forces, bending and twisting moments, the strength based design is employed to estimate the sizes of various sections of a composite wing structure. A three dimensional numerical model of the composite wing structure has been developed and analyzed for the extreme load conditions. Glass fiber reinforced plastic material is used in the numerical analysis. The estimated natural frequencies are observed to be in the acceptable limits. Furthermore, the discussed design principles in the first part are extended to the design of a morphing airfoil with auxetic structure. The advantages of the morphing airfoil with auxetic structure are （i） larger displacement with limited straining of the components and （ii） unique deformation characteristics, which produce a theoretical in-plane Poisson＇s ratio of -1. Aluminum Alloy AL6061-T651 is considered in the design of all the structural elements. The compliance characteristics of the airfoil are investigated through a numerical model. The numerical results are observed to be in close agreement with the experimental results in the literature.
文摘A simplified adaptive wing, which deflects its leading edge and trailing edge flaps to vary its shape, is calculated to investigate the potential aerodynamic gains and compared with a biobjective optimization (BO) wing in the present paper. In subsonic-transonic flights the deflection angle of a flap is determined through optimization using a deterministic method. In supersonic flight the flaps are not deflected due to the requirement of having a minimum drag. For comparison the aerodynamic characteristics of a BO airfoil and wing is calculated. A parallel genetic algorithm is used in BO. Euler equations served as governing equations in flow field calculation. Numerical results in both 2D (airfoil) and 3D (wing) cases show that aerodynamic performances of the two design airfoils and wings are much better than those of the original ones, with the adaptive design one the best. Keywords simplified adaptive wing - biobjective optimization - airfoil and wing design
文摘本文将基于弹性体变形思想的FFD(Free Form Deformation,自由变形)方法引入飞机气动外形优化设计中,为气动优化设计提供了一种快速、有效的参数化方法和自动网格生成方法.对FFD方法的原理进行分析,归纳了FFD方法的特点;将FFD方法应用于几何外形参数化和空间网格自动生成中,建立了基于FFD方法和遗传算法的翼型优化设计系统以及基于FFD方法、遗传算法和Kriging代理模型的翼根整流包优化设计系统;分别对NACA0012翼型和DLRF4翼身组合体翼根整流包进行减阻优化设计,优化结果得到了显著的减阻成效,证明了FFD方法在气动优化设计中有很好的应用效果.
