Kulumiskoormus

Kulumiskoormus is a term used in tribology and materials engineering to describe the effective load associated with wear under sliding or rolling-contact conditions. In practice, it denotes the portion of contact load that drives material removal and surface damage during a wear process, and it is often considered in relation to other variables such as sliding speed, lubrication, and temperature. The concept is particularly used when characterizing the wear resistance of coatings and surface treatments and in the development of predictive wear models.

Definition and measurement: Kulumiskoormus can be defined in multiple ways depending on test convention. It may refer to the maximum normal load at which a specified wear rate is observed, or to the average contact load during a wear test that yields a target wear rate. In laboratory testing, wear tests such as pin-on-disk or ball-on-disk provide data to estimate kulumiskoormus, with the load expressed as force (newtons) or as contact pressure (megapascals) when the contact area is known. The wear rate is typically reported as volume loss per sliding distance or per time.

Relation and applications: Kulumiskoormus is influenced by material hardness, counterface material, lubrication regime, surface roughness, and temperature. It is used to compare wear performance across materials and coatings and to inform design decisions for components subjected to sliding contact, such as bearings, gears, and seals. In predictive maintenance, knowledge of kulumiskoormus supports life estimates under expected operating loads and lubricants.

Etymology and usage: The term combines Estonian kulumis, meaning wear, with koormus, meaning load, reflecting its origin in Estonian technical literature. It is used primarily in Estonian-speaking contexts but appears in broader tribology discussions when translating wear-load concepts.