Washing Machine Vibration Isolation
Dr. James Ferguson
Over the last few decades there have been many advances in home construction and appliances that are placed in homes. An important advancement in home construction is the manufactured I-joist used in flooring. Appliances have been advanced through front load washing machines. A local company to Boise, iLevel Manufacturing, is one particular producer of engineered lumber, and has received many complaints due to front load washing machines located on the second story of residential buildings. These front load machines tend to vibrate more than ordinary machines, and although manufactured I-joist can support a vertical load better than sawed lumber, they do not have enough lateral stiffness to be able to resist these vibrations. The design team has met with iLevel to find a solution to this problem. Two paths were taken, one to solve problems in existing homes and the other to prevent this problem from occurring in future homes. In vibration analysis, there is a vibration source (the washing machine), a vibration path (the washing machine feet and the floor), and a vibration responder (the home and everything contained within it). To address problems in existing homes, the vibration path was addressed. The design team has developed a concept of vibration isolating pads that will be placed under each corner of the washing machine to isolate the vibrations before they reach the responder. The vibrations have been analyzed through a series of mathematical models in order to select the appropriate isolation pad. For future home construction, the vibration responder was addressed. The design is to stiffen the floor through a series of joist blocking, smaller joist spacing, and heavier wood products. These models have both shown reduced transmitted vibrations through testing.