Study On Dynamic Characteristics Modeling And Structural Parameter Optimization Of A Drum Type Washing Machine

Due to the issue of the structural configuration and the centrifugal forces of the unbalance mass, a drum type washing machine operates with high vibration and noise, which strongly affects its safe operation, service life and the quality of human-machine environment. It is of profound significance, studying on the dynamics characteristics of the washing machine and providing guidance or tools for optimizing design of it, to enhance abilities of independent research and innovation for Chinese products.One of the main parts of the washing machine is a suspension system, also including a cabinet. It is the key to develop a novel suspension system to improve the mechanical structure for achieving the goal of reducing vibration and noise. This paper develops mathematical models for the 1/2 suspension system and whole system, respectively, step by step in order to reveal the dynamics essence and the laws of plane motion of the tub-assembly mass center. Experiment study indicates that the modeling assumption of the tub as a rigid body, with applying the planar model into investigating the suspension system of the drum washing machine, is practicable. As well, simulation of the orbit of the tub centroid is in better agreement with the experimental results, which verifies the model. Then, the virtual prototype for the washing machine is built using the software of ADAMS. Based on the virtual prototype, the method how to update the counterweight and to optimize the structural design is carried out. Furthermore, the paper proposes an objective function characterizing the operation smoothness of the washing machine and its sensitivity curves to design variables.The cabinet is the base framework bearing the suspension system, whose dynamic characteristics directly affects whole performance of the drum washing machine. Using ANSYS, the finite element model for the cabinet is presented. Based on theoretical modes, this paper illustrates the model for testing vibration of the cabinet. The natural frequencies and modal shapes are obtained by finite element analysis and modal experiment, which reveal weak positions of the cabinet. Moreover, the paper proposes rigid-flexible coupled modeling method for the washing machine multibody system, the tub-assembly as rigid and the cabinet as flexible. The vibration behaviour of the cabinet can be furtherly investigated by transient dynamic analysis, which afford an available method which is convenient for improving the cabinet's design and assessing the optimization results of the suspension system by undertaking a parametric investigation.