Kitkavaimennus

Kitkavaimennus, in mechanical engineering, refers to damping that arises from friction between contacting surfaces within a system. The damping effect converts part of the system’s kinetic energy into heat as surfaces slide against each other or repeatedly alternate between sticking and slipping. This type of dissipation is typically nonlinear and can vary with load, temperature, lubrication, and wear.

Mechanisms and forms. Frictional damping includes dry (Coulomb) friction, where energy is lost during sliding, and micro-slip at interfaces that can produce hysteresis. In lubricated joints, the friction force can depend on velocity (the Stribeck effect) and may combine with viscous components. The result is often a nonlinear damping behavior, with potential stick-slip phenomena at low relative velocities and reduced damping at higher speeds, depending on the interface conditions.

Modeling and behavior. Friction damping is frequently implemented or observed as a non-ideal, velocity-dependent damper. It does not require a external power source and can be robust, but its performance is sensitive to surface finish, lubrication state, temperature, and wear. Because of its nonlinear nature, predicting damping ratios and resonant responses requires empirical testing or detailed interface models.

Applications. Friction damping is used in various domains, including engine mounts and vibration isolators, mechanical couplings, and dampers in rotating machinery. In civil engineering, friction-based dampers and friction pendulums are employed to reduce structural vibrations during earthquakes. Friction dampers are valued for simplicity and reliability but may require maintenance to control wear and lubrication.

Considerations. Designers must account for wear, lubrication maintenance, temperature rise, and potential noise or stick-slip vibrations. The effectiveness of kitkavaimennus can change over the component’s life, necessitating periodic assessment and possible tuning or replacement.