Finite element analysis of the interaction between an AWJ particle and a polycrystalline alumina ceramic

Purpose: Abrasive waterjet cutting involves use of a high pressure, abrasive laden waterjet at transsonic speeds to cut difficult-to-machine materials. The jet-material interaction depends on the nature of the material being cut, such as ductile or brittle. The brittle regime involves the generation and propagation of microcracks due to impact and many theories have been proposed in this regard. We aim to resolve the nature of the generation and propagation of cracks in such phenomena using the finite element analysis methodology. Design/methodology/approach: A 3-dimensional FE model was set up using PATRAN. The alumina ceramic was modelled as a 1-mm cube while a 0.1mm diameter half sphere was used to model a single abrasive particle. The system was imported into ABAQUS and an explicit analysis was performed. The element deletion method was used after invoking a failure criterion to estimate the number of elements removed due to a single impact. The aggregate volume of eroded material was then calculated by multiplying the number of elements removed with the volume of each element. The results of the FEA were compared with the brittle model proposed by Kim & Zeng. Findings: The results of the FEA indicate that mixed-mode failure is the most common form of failure in such interactions. The volume of material removed per impact from the FE results is close to 16% of those predicted by Kim & Zeng's model. Research limitations/implications: The finite element framework presented is idealized for the case of regular cubes based on a set of assumptions. Originality/value: This finite element approach is a good tool to study the nature of interaction between a microscopic particle and a brittle material and accurately predict the erosion mechanisms in such interactions.