Study On The System Of Composite Synthesis Optimization For Aircraft Structures

The technique of synthesis optimization for aircraft composite structures is the best tool for fully-elaborating the composite designability and increasing the integrated performance of aircraft structures. Combined with modem structural finite element analysis, modern structural optimization algorithms, composite structures mechanics and aeroelastic tailoring of composite wing as well as relative high performance numerical method, a system named the composite synthesis optimization for aircraft structures (COSOAS), has been developed in this paper, which has own independent component of finite element analysis. The characteristic of the composite application has been stressed in the contents of this paper. Firstly, in order to meet the needs of finite element analysis, a new MITC4 laminate element has been developed, which is fit for the composite structures analysis. And based on this element, a system of finite element analysis for composite laminates including static and buckling has come into being. Then because of the character of laminate design in the composite, a conformable model of stacking-sequence synthesis optimization has been generated in this paper for composite through the intermediate design variables and two-level optimization model. Moreover, in the application of aircraft structures design, the composite wing is still to meet the needs of aeroelastic design. Through reading the aerodynamic influence coefficient matrix from the NASTRAN file, this paper generates a static aeroelastic equilibrium equation and divergence eigen-equation, which is needed by the aeroelastic tailoring of composite wing. Through this equation, the aeroelastic tailoring of composite wing and its optimization design have come into being. At last, considering the practical application, the preceding contents have been integrated altogether as a soft system in this paper and the design objective of the composite synthesis optimization for aircraft structures have been realized through the multilevel hybrid optimization model when a specific application of the forward-wing design has been tested.