Abstract:Among the materials used in outlet structures of hydraulic engineering, elastic materials have a very broad application as anti-cavitation materials. It has clear practical significance and theoretical value to study the interaction between cavitation bubbles and different material surfaces and explore the anti-cavitation mechanism of elastic materials. By carrying out ultrasonic cavitation erosion experiments of materials with different elasticity, we analyze the cavitation erosion characteristics of different elastic materials from the macro and micro perspectives, and investigate the factors affecting the anti-cavitation properties of materials. The elastic materials used in this study include 216–1 silica gel, 216–2 silica gel, 218–1 silica gel, 218–2 silica gel, polyurethane, soft polyvinyl chloride, rigid polyvinyl chloride, phenolic laminate, low-density polyethylene, high-density polyethylene, polyamide and other materials, and the corresponding tensile elastic modulus ranges from 1 to 4 660 MPa. The main conclusions are as follows: 1) The materials with an elastic modulus of 1～11 MPa have no erosion mass loss under ultrasonic cavitation. In addition, the surface of the elastic material has only small texture changes and no crack or hole on the morphologies, which demonstrates their good anti-cavitation characteristics. 2) With the increase of elastic modulus, the cavitation erosion characteristics of different elastic materials have shown obvious differences, indicating that the correlation between the anti-cavitation properties of materials and their elastic modulus decreases, rather the anti-cavitation properties of materials are related to the material density, structure, etc. The larger density and densely structured materials have less erosion mass loss and change of surface roughness, while lower densely structured materials have more erosion mass loss and increased surface roughness, and the cavitation erosion is more likely to occur at the defects on the surface of the materials.