Vibration Characteristic Analysis And Optimization Of Laminated Composite Plates In A Thermal Environment

With used widely in aerospace, marine, automotive and other fields, laminated composite plates are often faced with a variety of harsh and complex working environment, such as high temperature, humidity and noise. These environment presents severe challenges to the durability integrity of laminated plates. The vibration characteristics of laminate structure in a thermal environment is the base of the dynamic response analysis and optimization design and it is analysis of laminated thermosetting vibration characteristic that plays a practical significance. Therefore the paper studies the thermal vibration characteristics and the structure optimization design with the temperature change, main content includes:First of all, the paper analyzes thermal vibration natural frequency and modal vibration mode of laminated plate in a thermal environment with temperature change. Thermal vibration equation are obtained by adopting the composite laminated plate the first-order shear deformation theory and thermal stress by finite element method under the influence of temperature. Results show that the thermal environment of plate vibration problem can be accurately analyzed in the method adopted.Secondly, the influence of elastic modulus and shear modulus and the thermal stress on the thermal vibration characteristics of laminated plates are researched, calculated the temperature when the laminated plate aspect ratio, span angle layer and layer thickness ratio sequence and the influence of boundary condition on thermal vibration frequency. The numerical results show that the temperature rise of laminated plate elasticity modulus and shear modulus, reduce the stiffness matrix of structures, structural natural vibration frequency is reduced; The change of elastic modulus and shear modulus does not change the modal vibration mode of the structure. Thermal stress on the structural natural frequency is greater than the influence of elastic modulus and shear modulus of structural natural frequencies and the effect of increasing thermal stress will change the structure of the modal vibration mode; Different structural parameters of laminated plates, a first order vibration frequency corresponding critical temperature rise of each are not identical. Aspect ratio is smaller, across the thickness ratio, the greater the critical temperature is smaller; Symmetric spread layers of plywood than anti-symmetric spread layers of plywood, the smaller the critical temperature, simply supported boundary layer plywood than clamped boundary layer, the smaller of the critical temperature of plywood.Finally, combined with DSA algorithm for laminated plates with a second order frequency band gap as objective function, layer Angle and temperature for the design variables for optimization calculation. The numerical results show that with the increase of the optimal temperature, the thermal environment of laminated plate is a second-order thermal vibration frequency band gap increased gradually. Clamped boundary a second-order thermal vibration frequency band gap than the frequency of a simply-supported boundary band gap is big. The less layers of laminated plates, aspect ratio, the greater the across the smaller the thickness ratio, a second-order thermal vibration frequency band gap, the greater the preventing resonance effect, the better.