Relationship between space and time characteristics of cavitation impact pressures and resulting pits in materials

Cavitation erosion studies require a well-defined measure of the aggressiveness of the subject cavitation field. One proposed method of cavitation field strength evaluation is to use pitting tests on a selected material sample subjected to the cavitation field. These relatively short duration tests record pits or permanent deformations from individual cavitation events during the cavitation incubation period. The pitting test results are dependent on the load and the material used in the tests and a good understanding of the pit formation mechanism is required to correlate the loads with the deformations. In this study, finite element numerical simulations are conducted to examine the response of several selected materials to imposed loads representing cavitation events. The magnitude, duration, and spatial extent of the loads are varied, and the effects of these on the material deformations are studied. Next, the effects of material properties, such as yield stress, Young’s modulus, and plastic modulus on the pitting characteristics are elucidated. Material responses are found to be drastically different between metals and compliant materials and to depend significantly on load duration and spatial extent in addition to the magnitude.