Two-dimensional linear friction damper consists of concave conical lever and disc (Investigation of fundamental property by simplified model)

Abstract

A passive vibration isolation system consisting of a friction damper is advantageous at cost, a maintenance, etc. However, the conventional damper of constant friction force has performance limitations; the isolation performance declines and the residual displacement becomes large when the friction force is large, while the resonant peak becomes large when the friction force is small. It is known that above drawbacks are avoided when the friction force varies in proportion to the relative displacement. Recently, authors proposed a simple linear friction damper mechanism that consists of a cylindrical block and a tilt lever supported with a pivot or a leaf spring. When the cylindrical block moves and pushes the tilt lever, the normal and friction forces at the contact surface vary proportionally to the displacement of the cylindrical block. However, the mechanism is limited to one-dimensional motion. This paper proposes the extended mechanism that can be applied to the motion moving in two dimensions by combining the conical lever and the disc. The conical lever consists of the concave cone supported with the universal joint at the apex side and the tilting movement is constrained by the restoring spring. The rounded edge of the disc is set up to contact the inside flank of the concave cone. When the disc moves in arbitrary direction in the planar floor and pushes the conical lever, the normal and friction forces at the contact portion vary depending on the displacement of the disc. Fundamental property of the proposed mechanism is investigated by the simplified numerical simulation and the experiment.