黏性耗散决定软物质中气泡形态与失效行为

中文摘要 AI 辅助

空化现象，即流体和软物质中气泡的生长，在组织损伤、超声治疗和材料失效中起着核心作用，然而黏弹性耗散对气泡动力学的影响仍不清楚。本文研究了具有相同弹性模量但不同黏性耗散的聚丙烯酰胺水凝胶中的空化行为。我们观察到显著的对称性破缺转变：弹性凝胶在破裂前迅速形成椭球形空腔，而黏弹性凝胶则维持大的近球形气泡。修正的瑞利-普莱塞特框架表明，黏性应力抑制形状不稳定性并延迟对称性破缺，而弹性应力加速空腔变形。有限元模拟独立验证了这些发现。德博拉数（De）进一步捕捉了材料弛豫与空腔生长之间的竞争，较高的De与以弹性生长为主相关，较低的De则与更大的弛豫相关。综合来看，我们的结果确立了黏性耗散作为关键稳定机制，控制软材料中气泡形态与失效行为。这些结果对理解生物组织中空化介导的损伤、优化治疗性超声以及推进水凝胶在工程和食品加工应用中的力学表征具有直接意义。

英文摘要

Cavitation, the growth of bubbles in fluids and soft matter, plays a central role in tissue damage, ultrasound therapies, and material failure, yet the influence of viscoelastic dissipation on bubble dynamics remains unclear. Here, we investigate cavitation in polyacrylamide hydrogels with identical elastic moduli but different viscous dissipation. We observe a striking symmetry breaking transition: elastic gels rapidly develop ellipsoidal cavities before rupture, whereas viscoelastic gels sustain large, nearly spherical bubbles. A modified Rayleigh Plesset framework shows that viscous stresses suppress shape instabilities and delay symmetry breaking, whereas elastic stresses accelerate cavity deformation. Finite element simulations independently validate these findings. The Deborah number (De) further captures the competition between material relaxation and cavity growth, with higher De associated with predominantly elastic growth and lower De with greater relaxation. Together, our results establish viscous dissipation as a key stabilizing mechanism that governs bubble morphology and failure in soft materials. These results have direct implications for understanding cavitation-mediated damage in biological tissues, optimizing therapeutic ultrasound, and advancing mechanical characterization of hydrogels for engineering and food processing applications.

发表机构

• Indian Institute of Science, Bangalore（印度科学研究所）
• Indian Institute of Technology Guwahati（印度技术学院古瓦哈提分校）

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