Suction effects of craters under water

Area of Science:

• Biomimetics
• Adhesion Science
• Fluid Dynamics

Background:

• Octopus-inspired cratered surfaces represent a novel class of reusable physical adhesives.
• These surfaces exhibit preload-dependent adhesion and superior performance in wet environments, differentiating them from gecko-inspired designs.
• Existing mechanistic understanding and modeling frameworks for cratered surfaces, especially underwater, remain limited.

Purpose of the Study:

• To investigate and model the suction forces generated by underwater cratered surfaces.
• To validate a predictive framework for suction force-preload relationships in aquatic conditions.
• To compare the performance of liquid-filled versus air-filled craters and analyze the effect of water depth.

Main Methods:

• Development of a theoretical framework to evaluate suction forces in underwater craters.
• Experimental validation using incompressible fluids under varying preload conditions.
• Comparative analysis of liquid- and air-filled craters and assessment of water depth influence.

Main Results:

• The developed framework accurately predicts suction force-preload relationships for underwater craters under small to moderate preloads.
• The model's predictive capability diminishes at large preloads, potentially due to phenomena like liquid vaporization.
• Underwater crater adhesion scales with specimen modulus and shows a non-monotonic dependence on crater aspect ratio.

Conclusions:

• The study provides a validated framework for understanding suction forces in underwater octopus-inspired adhesives.
• Key factors influencing underwater crater adhesion include preload, fluid type, water depth, specimen modulus, and crater geometry.
• This research advances the mechanistic understanding of these bio-inspired adhesives for potential applications in wet environments.