A novel model reduction technique for time-varying dynamic milling process of thin-walled components

In this work, a novel model reduction technique is proposed, which is based on the hybrid coordinate space modal synthesis method and structural dynamics modification method. This technique can be used to construct the corresponding reduced-order model (ROM) to solve some problems, which focus on the updating of time-varying dynamic parameters for thin-walled components in the milling process. These characteristics of the pending workpiece are analyzed, and then the entire workpiece is divided into two substructure parts: constant workpiece and removed material workpiece. The substructure part of the constant workpiece is analyzed by the double-coordinated free interface method, and the substructure part of the removed material workpiece is analyzed by the finite element method (FEM) among them. Afterwards, the two substructure models in the hybrid coordinate space are coupled based on the interface coordination condition, and the ROM can be obtained about the degrees of freedom (DOFs) of thin-walled components. Moreover, the structural dynamics modification method is introduced, which is used to explore the modal characteristics and vibration response characteristics of the ROM, and is performed to update the dynamic parameters for thin-walled components systems in the milling process. Comparing the dynamical parameters obtained by the full-order model (FOM) method and the reference method under the same conditions, the results indicate that the proposed method can be applied to a variety of boundary conditions effectively, its normalized relative frequency difference (NRFD) values are all lower than 5%, and these values are continuously and stably close to 0. Its modal assurance criterion (MAC) values are all higher than 0.99, and its frequency response assurance criterion (FRAC) values are all 1. For the update speed, its maximum growth rate is 97.38%. Accordingly, the proposed method has nice universality and efficiency, which is embodied in the updating of time-varying dynamic parameters of thin-walled components.