| Geometric nonlinearity is a typical characteristic of high-aspect-ratio wing. The traditionalaeroelastic analysis method based on the assumption of small disturbance is no longer applicable. It isnecessary to have nonlinear aeroelastic analysis.This paper based on the multidisciplinary design optimization platform ISIGHT integrated withNASTRAN and MATLAB,presents a nonlinear aeroelastic analysis method for the high-aspect-ratiowing.They can be composed of the following steps:1) given the flight conditions for the nonlinearstatic aeroelastics deformation calculation, the static equilibrium position of high-aspect-ratio wing isobtained through iteration.2) linearize the system and carry out the linearized model analysis at thislocation. According to the selected type of analysis(static divergence or flutter),output the date.3) takethe date output by the previous step into NASTRAN′aeroelastic solving sequence through DMAPlanguage.4) compare the dynamic pressure value obtained in the3) and previous step.Settingconvergence indicator,the nonlinear aeroelastic characteristics of wing are obtained through iteration.The examples show that this method can effectively account for the impact of geometric nonlinearityon the aeroelastic characteristics of wing,and can realize the automatic solution.This method has agood engineering applicability. By using the method,two different examples of the static aeroelasticanalysis and flutter analysis are presented.This paper further discuss the impact of geometricnonlinearity on the flutter speed of wing at different initial angle of attack.Using the above method and combining ISIGHT′optimization function,the paper realize thenonlinear aeroelastic tailoring of the high-aspect-ratio wing without changing the weight of the wingstructure.The skin ply angle are the design variables and the nonlinear flutter velocity are theoptimization objective. The example shows that the composite laminate angle have a great impact onthe nonlinear flutter speed. |
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