Multibody dynamic analysis of a washing machine with a rapid change of mass during dehydration

Dehydration is one of the main processes while laundering clothes. The distribution of clothes may not be uniform and can cause an unbalanced mass distribution in washing machines. Recently, many clothes are being made with waterproof materials, which can hold and release water suddenly, causing unusual vibrations during the dehydration process. The purpose of this study was to analyze the vibration of a washing machine during the dehydration process with a rapid decrease of unbalanced liquid mass and to find a design solution for reducing vibrations. A washing machine system rotating on the vertical axis was modeled using ADAMS. A multibody dynamic model was established using experimental data of several components obtained using an MTS test machine. To validate the dynamic model, a comparison of the simulation and experiment of a washing machine during the dehydration process was carried out. For simulating the effects of a rapid decrease of unbalanced liquid, constraint equations were deactivated through several steps with rapidly decreasing time. Higher preload on the upper and lower pivot connectors can help in decreasing the vibration, and in analyzing the dynamic behavior of the washing machine. For decreasing vibration, a pre-load tool was applied in the dynamic model. Effects of pre-load were analyzed by experimental simulation.