The invention relates to the technical field of structural design, and discloses a topology and size joint optimization design method and
system for a hierarchical
composite structure, and the method comprises the following steps: dividing a structural domain into a plurality of hierarchical sub-domains, defining the size constraint range of each sub-domain, and distributing a multi-phase material for each sub-domain; grid
discretization processing is carried out on the structural domain, a topological design variable is given to each discrete unit, acoustic unit modeling is carried out on the
sound field domain,
sound pressure boundary conditions are defined, and
coupling boundary conditions are applied to the interface of the
sound field domain and the structural domain; solving an acoustic-structure
coupling equation based on a
finite element method, calculating an objective function and constraint conditions, analyzing the sensitivity of the objective function to topological variables by adopting an adjoint method, and iteratively updating the topological design variables through an optimization
algorithm until a convergence criterion is met; and on the basis of a
topological optimization result, constructing a neural
network agent model of an input layer, a
hidden layer and an output layer, and carrying out
global optimization on sub-domain size parameters by adopting a
genetic algorithm so as to minimize a target function.