engleski

SLIDING WEAR SIMULATIONS IN FOAM-EXTEND

The presence of wear is a well-known reason for the failure of mechanical components in mechanical systems. Wear was rarely studied in detail using numerical analysis and was usually accounted for in the design stage of components by relying on complex and financially demanding experiments or engineering experience. With modern system design moving towards increased efficiency and optimisation, certain machine elements are expected to operate under conditions (e.g. mixed-mode lubrication or direct surface-to-surface contact) where understanding the wear phenomena becomes of great importance. Wear can be defined as the removal of material from one or both solid surfaces in contact, when the surfaces are in relative contact (sliding, rolling or impact motion). Surface interaction at asperities is thought of as the main mechanism behind the occurrence of wear. Adhesive wear is identified as the most common type of wear [1]. In adhesive wear the sliding contact between surfaces leads to the formation of cold welds at asperity junctions and shearing action leads to breaking of the cold welds and formation of fragments. These fragments may be transferred to the original surface or may form loose wear particles. The Archard wear model is recognised as having a high general applicability and is widely used in wear research [2]. Archard’s wear model may be used to calculate the depth of the worn material using the real contact area, contact load, hardness of the materials in contact and the experimentally determined wear coefficient [3, 4]. A numerical framework based on the Archard wear model and the Finite Area Method (FAM) [5] is presented as a viable tool for calculating wear of contacting rough surfaces in relative motion. The elastoplastic contact model presented in [6] is modified to be compatible with the implemented wear model and is used to resolve the contact between rough surfaces. The resulting wear algorithm is implemented in foam-extend and is capable of calculating parameters relevant in wear analysis of surfaces under dry contact conditions, while being able to consider the evolution of contact due to wear. The wear algorithm is used in numerical simulations of relevant test cases, such as the simulation of a spherically tipped pin sliding over a disc. The results show that acceptable accuracy may be achieved for numerical simulations of wear for contacting surfaces in relative motion. The algorithm will be developed further, as to take into account the presence of lubricant and to be applicable to real rough surface topologies.

Sliding Wear, Finite Area Method, FVM, foam-extend

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