近日，美国哈佛大学Bertoldi, Katia团队报道了在软硬摩擦界面处发出的尖锐声响。相关论文于2026年2月25日发表在《自然》杂志上。

无论是橡胶底鞋在硬木地板上摩擦，还是粉笔划过黑板、自行车刹车制动，或是带着人工髋关节行走，尖锐的摩擦声总是如影随形地伴随在我们日常生活的方方面面。学界普遍认为，当两个刚体相互滑动时，摩擦系数随滑动速度增加而减小会诱发自激的"黏滑振荡"，从而产生尖锐声响。然而，在较大界面的滑动过程中可能涉及裂纹或滑移脉冲的扩展。当软体在硬体表面滑动时，这种区别更为显著——此时大形变与材料性质差异会导致"张开滑移脉冲"，使界面发生分离。此前的研究主要关注无尖锐声响产生的慢速滑动过程。尽管软-硬界面的尖锐声响被认为与黏滑振荡有关，但其机理尚不明确。

研究组通过实验探究了可产生尖锐声响的软-硬界面滑动过程。高速摄像与声学分析表明，张开脉冲以接近软材料剪切波速的速度传播，在不同材料间引发局域滑移。在平面样品中，这些脉冲呈现不规则形态，产生宽频声发射。引入薄表面脊约束脉冲传播，产生一个与滑块第一剪切模式相匹配的稳定重复频率，并以该频率发出尖锐声响。这些发现揭示了双材料摩擦过程中一种结构驱动的断裂稳定机制：几何约束抑制了竞争模态，将原本不规则的二维动力学行为转化为相干的一维脉冲序列，为从工程表面到地质断层的摩擦断裂研究提供了新视角。

附：英文原文

Title: Squeaking at soft–rigid frictional interfaces

Author: Djellouli, Adel, Albertini, Gabriele, Wilt, Jackson, Tournat, Vincent, Weitz, David, Rubinstein, Shmuel, Bertoldi, Katia

Issue&Volume: 2026-02-25

Abstract: Squeaking is a constant companion in various aspects of our daily lives, whether we slide rubber-soled shoes across hardwood floors1, scrape chalk on a blackboard2, engage the brakes on a bicycle3 or walk with a hip replacement4,5. When two rigid bodies slide over each other, squeaking is widely understood to result from self-excited stick–slip oscillations, triggered by a decrease in the friction coefficient with increasing slip velocity6,7,8,9,10. However, sliding of extended interfaces can involve crack or slip-pulse propagation11,12,13,14,15,16,17,18,19,20,21. This distinction is amplified when a soft body slides on a rigid one, in which large deformations and material mismatch can cause detachment by opening slip pulses22,23,24,25,26,27. Previous studies focused mainly on slow sliding17,26,28,29,30,31,32,33,34, in which pulses are slow and squeaking is absent. Although squeaking at soft–rigid interfaces has been linked to stick–slip oscillations35,36,37, the mechanisms remain unclear. Here we experimentally investigate soft–rigid interfaces sliding at velocities that produce squeaking. High-speed imaging and acoustic analysis show that opening pulses propagate at approximately the shear wave speed of the soft material, mediating local slip across diverse materials. In flat samples, these pulses are irregular and generate broadband acoustic emissions. Introducing thin surface ridges confines pulse propagation, yielding a consistent repetition frequency matching the first shear mode of the sliding block and squeaking at that frequency. These findings show a structure-driven mechanism that stabilizes rupture in bimaterial friction. Geometric confinement suppresses competing modes, transforming irregular two-dimensional dynamics into coherent one-dimensional pulse trains, offering new insights into frictional rupture from engineered surfaces to geological faults.

DOI: 10.1038/s41586-026-10132-3

Source: https://www.nature.com/articles/s41586-026-10132-3