Roll assembly for a fiber-web machine and method of attenuating vibration of a fiber-web machine roll

A method of attenuating the vibration of a roll of a fiber-web machine, the roll having a center, a shell defining a length and a diameter, and having a ratio of shell length to diameter of at least seven, and wherein said roll has a lowest bending eigenfrequency, the method comprising the steps of:

• rotating the roll between two bearing housings, each bearing housing forming part of a bearing assembly, each bearing housing being attached at an end of the roll;
• wherein the rotation of the roll results in vibration of the roll, the vibration of the roll center defining an amplitude of movement of the roll center;
• mounting a mass absorber having a selected natural frequency to each bearing housing;
• mounting the bearing housings to a frame or a foundation of the fiber-web machine so that each bearing housing is supported on the frame or the foundation with a selected spring constant and a selected loss factor η so that the bearing housing vibrates with an amplitude of at least 10% of the amplitude of the movement of the roll center at an eigenmode corresponding to the lowest bending eigenfrequency of the roll.