kitkälämmitys

Kitkälämmitys, or friction heating, is the generation of heat from the conversion of mechanical work into thermal energy at the interface of contacting bodies that move relative to each other. The heat production results from friction during sliding or rolling, and the rate of heat generation can be approximated by P ≈ μ N v in dry sliding, where μ is the coefficient of friction, N is the normal load, and v is the relative velocity.

Key factors influencing kitkälämmitys include the coefficient of friction, normal load, sliding speed, contact area, material properties, and whether the contact is dry, lubricated, or in a boundary regime. Lubrication generally reduces heat generation, while dry or high-friction contacts can produce rapid temperature rises. Excessive heating may cause surface damage, wear, or distortion, whereas controlled heating can be beneficial in certain processes.

Applications and examples vary widely. In vehicles, friction between brake pads and discs converts kinetic energy into heat, warming components and surroundings. In manufacturing, friction heating can aid forming, preheating, or surface treatments, and deliberate friction-based methods such as friction welding or friction stir processing rely on local heat generation at interfaces to join or modify materials. In geology, natural frictional heating occurs in fault zones during earthquakes and rock deformation.

Measurement and control rely on temperature sensing and modeling. Thermocouples, infrared cameras, and tribological simulations help assess heat generation and distribution, guiding design choices in lubrication, cooling, and material selection to manage kitkälämmitys effectively.