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Multi-objective vibroacoustic optimization of the double-walled doubly curved composite shells having poroelastic lining in its core in a diffuse field is performed based on Non-dominated sorting Genetic Algorithm-II. To present an analytical model on the basis of multi-objective optimization, the summation of sound transmission loss and transverse displacement along with weight of the structure are considered as two cost functions, which should be optimized in a diffuse field. In fact, the significant achievement of this work is to design an optimization algorithm to improve vibroacoustic fitness and weight of the sandwich doubly curved shells. In the first part of the paper, a general formulation is prepared to analyze the dynamic of the poroelastic composite sandwich structures. Likewise, some validation configurations are presented to confirm the accuracy of the current formulation. Consequently, an optimization algorithm is provided on the basis of considering some appropriate design variables including material and porous types as well as stacking sequences. In this regard, a batch of 19 benchmarks of porous core is investigated. Furthermore, a configuration of optimized points in the Pareto front is plotted in which the simultaneous effects of optimizing the weight and vibroacoustic fitness can be observed. As a result, a new approach is made through optimization of the transverse displacement of the structure as a function of various incidence and azimuth angles in three dimensional configurations with respect to different frequencies.

This study applies shear deformation shallow shell theory to inspect the acoustic behavior of laminated composite infinitely long doubly curved shallow shells subject to a radiating oblique plane sound wave. Herewith, a procedure is developed to investigate sound transmission loss through this shell, clarified as a ratio of incident power to transmitted power in the existence of mean flow. In a further step, displacements are developed as a linear combination of the thickness coordinate to designate an analytical solution based on shear deformation shallow shell theory. Consequently, an exact solution for sound transmission loss is brought forward by combining acoustic wave equations as a result of wave propagation through this shell with doubly curved shell equations of motion. Afterwards, the accuracy of the present formulation (shear deformation shallow shell theory) is determined by comparing the achieved results with those available in the literature and some assumptions associated with the geometric specifications of the plate are investigated. Finally, because of the remarkable achievement of the current formulation results in reduction of noise transmission into such structures, some effective parameters on sound transmission loss are used in numerical results, to solve this problem.