Mechanical Properties Analysis And Optimization Of Co-Cured And Stiffened Composite Structure With Multilayer Damping Membranes Embedded

Compared with the traditional composite structure with a single-layer damping membrane embedded,Co-cured and Stiffened Composite Structure with Multilayer Damping Membranes Embedded has excellent mechanical properties such as large damping and high rigidity.It has a broad application prospect in the fields of aerospace,shipbuilding,national defense and military industry,bionics,and automobiles.Due to the complexity of the structure,a large number of variables need to be considered in theoretical modeling.At present,there are few literature reports on the research of the mechanical properties and optimization of the structure,which hinders the promotion and application of this structure in the field of aerospace in my country.Therefore,it has important academic significance and practical application value to research dynamic and static mechanical properties,buckling performance and distribution optimization of damping materials for Co-cured and Stiffened Composite Structure with Multilayer Damping Membranes Embedded.Theoretical analysis,numerical simulation and experimental research are combined to study the mechanical properties of Co-cured and Stiffened Composite Structure with Multilayer Damping Membranes Embedded.The static bearing capacity,dynamic characteristics and buckling performance of the structure and its unreinforced structure are compared.The influence of geometric and material parameters on mechanical performance is discussed.Taking the first-order mode loss factor as the objective function and the damping volume fraction as the constraint condition,the layout of the damping material is optimized.The main work and innovation are as follows:(1)Based on the structural geometrical equations,constitutive relations and the theory of segmental displacement,an analytical model for the bending performance of Co-cured and Stiffened Composite Structure with Multilayer Damping Membranes Embedded was established.The deflection function of the structure was derived using the Rayleigh-Ritz method and double trigonometric series.Numerical methods are used to validate the correctness of the theoretical model and theoretical methods,and the effects of various parameters on the structural center deflection were explored with the validated model.(2)A dynamic analytical model of Co-cured and Stiffened Composite Structure with Multilayer Damping Membranes Embedded was established on the basis of first-order shear deformation theory.The complex vibration equations of Co-cured and Stiffened Composite Structure with Multilayer Damping Membranes Embedded are derived by combination of complex modulus theory with composite material mechanics theory.The theoretical solution that satisfies the displacement boundary conditions is obtained by employing Navier method.The experimental platform of modal testing is built.The calculation results were compared with datas of the experimental measurements.The validated model is used to analyze the influence of the geometric and material parameters of the structure on the dynamic characteristics of Co-cured and Stiffened Composite Structure with Multilayer Damping Membranes Embedded.(3)A buckling model of Co-cured and Stiffened Composite Structure with Multilayer Damping Membranes Embedded was established theoretically by using the principle of minimum potential energy and the theory of segmental displacement.The governing equation of the structure is obtained.The critical buckling load of the structure was solved.The finite element method is used to verify the correctness of the theoretical model and theoretical methods,and the effects of various parameters on the critical buckling load were discussed on the basis of the validated model.(4)Based on the modal strain energy method,the sensitivity of modal loss factor for Co-cured and Stiffened Composite Structure with Multilayer Damping Membranes Embedded is derived.An optimization mathematical model is constructed by using the modal loss factor as the objective function and the amount of damping material as the constraint condition.The structural damping film is topologically optimized by using the progressive optimization algorithm.The results lay an important foundation for the wide application of Co-cured and Stiffened Composite Structure with Multilayer Damping Membranes Embedded.