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Vibration Characteristics of Washing Machine Dehydration and Effects of Vibration Reduction Devices

ㆍProduct: Top Loading Washing Machine

ㆍAnalysis Goal: Reproduction of vibration characteristics of a washing machine and comparison of characteristics of vibration reduction devices (suspension, fluid balancer)

Download PDF File "Simulation of Washing Machine for Vibration Analysis" (Click)

Washing machines generate large vibrations and noise when washing and spin-drying. These vibrations and noise are crucial factors in washing machine development because they have a significant influence on customer satisfaction. Various vibration reduction devices such as suspension and fluid balancers are used in washing machines.

A virtual washing machine model with 4 suspension elements was created and simulated in RecurDyn to analyze its vibration characteristics. The effects of the suspension types and the structural shape of fluid balancer was compared. The simulation accurately reproduced the vibration phenomenon of washing machine, and the results were in good agreement with physical tests. This virtual washing machine model for vibration simulation is expected to be used for improving washing machine design in virtual environments and solving problems in the future.

Process of Washing Machine Modeling and Simulation

① Precise modeling of the dynamics of suspension used in washing machines

② Correlation between the physical tests and simulation of the suspension

③ Simulation of entire washing machine and analysis of its vibration characteristics

④ Modeling a fluid balancer through co-simulation with CFD

⑤ Investigation of the effects of washing machine vibration reduction devices such as suspension and fluid balancers and the mechanisms of vibration generation

RecurDyn Washing Machine Simulation Model

Key Technologies for Analysis

• Mathematical modeling of nonlinear characteristics for washing machine suspension (friction, pneumatic, viscoelasticity)

• Efficient modeling and optimization using parametric modeling

• Reduction of modeling time using subsystems

• Particle-based CFD using Particleworks

• Integrated RecurDyn and Particleworks simulation (co-simulation between MBD and CFD)

• Post-processing for vibration characteristics analysis (FFT, Campbell Diagram, etc.)

Toolkits for the Simulation and Optimization of Washing Machine Vibration

• RecurDyn/Professional

• RecurDyn/AutoDesign

• Particleworks Interface

Customer Challenges

• An accurate simulation model for washing machine vibration evaluation

• Vibration evaluation for various weights and eccentric conditions of laundry

• Nonlinear characteristics of suspension

• Simulation technologies for washing machine vibration evaluation that include the effects of fluid balancers are required.

• Identification of vibration during dehydration

• Demand for both reducing modeling and analysis time

Solutions

• Mathematical representation of nonlinear various suspension characteristics using Function Expressions

• Model simplification and time saving through suspension subsystem and parametric modeling

• Improvement of analysis accuracy through comparison between actual tests and analysis results for nonlinear characteristics of suspension

• Obtaining optimal values for suspension model parameters using AutoDesign

• Implementation of washing machine model for vibration analysis reflecting various conditions

• Vibration evaluation including a fluid balancer through co-simulation with particle-based CFD

• Validation of simulation results with vibration measurements using laser sensors

• Validation of simulation results of fluid balancer with measurements using high speed camera

Washing Machine Simulation using MBD and CFD

Outcomes

• Washing Machine Simulation results of a suspension model that matched with measurement results well (error < 6%)

• Simulation results of dehydration vibration were in good agreement with experimental results (R2 > 90%)

• The vibration characteristics and mechanism of the washing machine for various suspension types were identified.

• The relationship between the vibration mechanism of washing machine and the type and structural shape of the fluid balancer was identified and the fluid behavior could be visualized

• Reduction of analysis time through model optimization (more than 40% compared to existing models)

Other Applications Related to Washing Machine Simulation

◀ Automatic washing machine simulation

ㆍVibration reduction simulation using 4 suspension elements

◀ Washing machine simulation using RecurDyn and Particleworks

ㆍCo-simulation of multibody dynamics model and CFD model

ㆍLaundry modeling using flexible bodies in RecurDyn

◀ Modeling and vibration control of a front-load washing machine using MR fluid damper

ㆍVerification of bearing model between tub and drum of a front-load washing machine

ㆍSimulation of suspension consisting of two springs and MR damper