Laboratoire Interdisciplinaire de Physique, CNRS-Université de Grenoble, 140 av de la Physique, 38402 Saint Martin d'Hères, France.
J Acoust Soc Am. 2011 Mar;129(3):1231-9. doi: 10.1121/1.3543943.
Thin solid shell contrast agents bubbles are expected to undergo different volume oscillating behaviors when the acoustic power is increased: small oscillations when the shell remains spherical, and large oscillations when the shell buckles. Contrary to bubbles covered with thin lipidic monolayers that buckle as soon as compressed: the solid shell bubbles resist compression, making the buckling transition abrupt. Numerical simulations that explicitly incorporate a shell bending modulus give the critical buckling pressure and post-buckling shape, and show the appearance of a finite number of wrinkles. These findings are incorporated in a model based on the concept of effective surface tension. This model compares favorably to experiments when adjusting two main parameters: the buckling tension and the rupture shell tension. The buckling tension provides a direct estimation of the acoustic pressure threshold at which buckling occurs.
当壳保持球形时会发生小的振荡，而当壳发生屈曲时会发生大的振荡。与覆盖着薄脂质单层的气泡不同，后者一旦被压缩就会发生屈曲：固壳气泡抵抗压缩，使屈曲转变突然发生。明确包含壳弯曲模量的数值模拟给出了临界屈曲压力和屈曲后的形状，并显示出有限数量的皱纹的出现。这些发现被纳入基于有效表面张力概念的模型中。通过调整两个主要参数，该模型与实验相比表现良好：屈曲张力和破裂壳张力。屈曲张力提供了一个直接的估计，即在哪个声压阈值下会发生屈曲。
