Optimization Of Laminated Plates Based On The Direct Multisearch Method

Composite laminated plate materials are widely used in aerospace,automobile,shipbuilding and other fields.Laminated plates have been studied by many scholars both at home and abroad in recent years,due to its strong designed good mechanical properties.With the development of engineering technology,the requirement of environmental comfort increased gradually,and laminated plates structure problem of the vibration and noise reduction is concerned.And the structural strength has always been the hot spot of the concerned problems.Therefore,the laminated plate vibration frequency,strength and the radiation sound power were studied.First of all,the fundamental frequency of laminated plates was studied.Natural frequency and modal of laminated plates was deduced based on first-order shear deformation theory with finite element method.Compared with other theories,the accuracy of the model is verified.And we judged the strength of the laminated plates with Tsai-Hill criterion.The impact of fiber orientation angles and the ratio of elastic modular have been discussed.Results showed that the fundamental frequency of symmetric and antisymmetric laminated plates is higher than one-way laid.The elastic modulus ratio is greater,the larger of the natural frequency.The influence of laying way and elastic modulus ratio on laminated plates' strength is obvious.Secondly,the forced vibration of the damping laminated plates has been discussed.The acoustic radiation mode coefficient and the radiation sound power were solved based on the acoustic radiation modal theory.The impact of fiber orientation angles,the ratio of elastic modulus,the ratio of width to thickness were studied in different boundary conditions.The results showed that,the symmetric and antisymmetric laminated plates have the same influence on the radiation sound power,but lower than the one-way laid sometimes.The influence of elastic modulus ratio on sound power is not obvious.Finally,the principle of direct multisearch method was introduced and compared with genetic algorithm.It showed that direct multisearch method is fast and has high precision.The optimization of fundamental frequency and sound power,fundamental frequency and strength,strength and sound power were discussed as well as fundamental frequency,strength and sound power.Results showed that the influence of boundary conditions is obvious for the fundamental frequency but not obvious for sound power while in the optimization of fundamental frequency and sound power.In the optimization of fundamental frequency and strength,Pareto results is mainly distributed in two range as the layer angle is variable,and Pareto results is almost linear distribution as the elastic modulus ratio is variable.The Failure index's order of magnitude is 10-3 in the optimization of strength and sound power.It is excellent to optimize fundamental,strength and sound power for the failure index is almost 0.1.