Effects of nearby boundaries on bubble Rayleigh lifespan and load response

Bubble–structure interaction studies rarely consider nearby moving boundaries. This study extends these works by numerically analyzing large (∼10 mm) bubbles near a moving sphere and a fixed elastic–plastic plate, and the resulting elastic–plastic structural response of the plate. The Rayleigh lifespan is defined as the time from bubble initiation to its first complete collapse, and the structural response encompasses the elastic–plastic energy transfer and deformation. The focus is on how boundary distribution and motion affect the Rayleigh lifespan, bubble morphology, and structural response. A multi-material Euler method with remapping was employed. Its reliability was verified through comparisons with previous experiments and analytical solutions, and grid-independence tests were performed. Results show that boundary configurations strongly affect bubble deformation and energy release. Increased boundary interference and reduced sphericity accelerate collapse, shortening the Rayleigh lifespan. For moving boundaries, a critical velocity range relative to the bubble center was identified. Exceeding this range causes the bubble to lose coherence and split into multiple smaller bubbles. The structural response is closely linked to bubble dynamics, including internal energy transfer and effective strain. Shortened collapse time enhances local flow momentum but limits the conversion of elastic energy into plastic deformation, weakening the plate's structural response. These findings clarify the influence of nearby boundaries on bubble dynamics and provide theoretical guidance for predicting underwater bubble-induced loads and designing protective structures.