Topology optimization of composite shell damping structures based on improved optimal criteria method

Aiming at the damped composite shell structure in topology vibration reduction optimization, a topology vibration reduction optimization model is constructed by taking the finite element of the damped layer as the design variable and the volume ratio, modal frequency and mode shape as the optimization constraintshe model of the structure modal loss factor is designed with the multi-modal weight coefficient as the optimization objective function. The form of the interpolation model limit to a variable density method, the general function of the sensitivity of the optimized objective is derived. Due to existence of the positive and negative sets of this sensitivity, the design variables of the non-convex objective function has negative values or optimal solution of this optimization function is the local extremum. With the improved global sensitivity optimization criterion, the iteration method for composite shell damping structures is derived, ensur that each iteration is a set of global design variables. Based on the finite element method, the improved criterion programming is written, and the optimal analysis of topological vibration reduction is carried out on the damped composite shell structure. The results indicate that hen the volume of constrained damping layer is reduced to 50% of the total coverage, the mode loss factor of the shell structure is increased or decreased by 10%, which has the purpose of lightweight design to improve the vibration reduction The number of iterations required by each order objective function and topology configuration is small, the middle density area is smaller, and the multi-order is better than the single-order modal optimization function, which is easy to obtain the effective vibration reduction of global optimization. © 2020, Press of Chinese Journal of Aeronautics. All right reserved.