Research On Optimization Method Of The Vibration Parameters For Fiber Reinforced Composites With Laminated Structure

With the development of the aviation technology, the traditional material can't satisfied the requirements of Aero-Engine with high thrust-weight ratio and high reliability, new materials are urged to tackle these problems. Fiber-reinforced materials are prominent for their high strength, high stiffness, and excellent damping performance. More importantly, composite laminates can be designed to satisfy the demand of engineering. Therefore, composite laminates has been widely used in aviation, aerospace and other important field.This thesis concentrates on the following four areas of research of composite laminates:Firstly, the dynamic analysis model is established using finite element method, and the correctness of the model is validated by modal experiment; the dynamical differential equations are formulated and solved by implying Newmark-? and multi-front theory; the response characteristics of laminates are analyzed by exerting simple harmonic excitation and transient excitation.Secondly, the optimization design of variable stiffness laminated plates is research by using the AGA(Adaptive Genetic Algorithm) with elite protection strategy, which are then compared among the optimization results of traditional genetic algorithm; the optimization results of different boundary conditions and different number of design areas are compared; the optimization results of different number layers under the same thickness are discussed. Multi-objective vibration optimization problem is discussed by DC(Direct Comparison) method.Thirdly, by introducing the element stiffness and damping matrices as optimization variables, the MMA(Method of Moving Asymptotes) and DMO(Discrete Material Optimization) is applied to solve variable stiffness plates vibration optimization problems; the convergence characteristics and results of optimization is studied under different interpolation function penalty factors. Lastly, optimizations are made to compare the performance of both algorithm, namely the MMA and the AGA.This optimization study, which for any boundary conditions can obtain layers angle results with high stiffness and damping properties, serves important engineering significance, and the angle information gained could be employed to manufacture laminated plates which can effectively reduce the vibration response of the structure and improve the reliability and lifespan of the machine.