Traditional strain analysis assumes that a particle deforms affinely with its matrix and that the magnitude and geometry of particle deformation are representative of the bulk strain. However, there are forces, lumped together under the terms of competency or viscosity contrast, which oppose particle deformation. For small weak particles, surface tension may also be important in resisting particle deformation. We performed analogue model experiments to investigate the effect of surface tension on the deformation of a weak viscous particle (bubble or droplet) enclosed in a viscous matrix. The experiments were performed using a ring-shear apparatus allowing large magnitudes of plane strain, simple shear. The results demonstrate the controlling influence of capillary number on particle deformation. The particles did not continuously elongate with increasing shear strain but achieved a steady-state value dependent on capillary number. Because capillary number represents the ratio of shear stresses, which deform particles, to the surface (interfacial) stresses restraining elongation, there should be a strong dependence of particle strain on the deformed particle size and bulk strain rate. The most important geological implications of this study are in the field of melt segregation in deforming anatectic systems.

传统的应变分析假设粒子与其基体仿射变形，并且粒子变形的大小和几何形状代表了整体应变。然而，在能力或粘度对比的条件下，有一些力集中在一起，它们反对粒子变形。对于小的弱颗粒，表面张力在抵抗颗粒变形方面也可能很重要。我们进行了模拟模型实验，以研究表面张力对封闭在粘性基质中的弱粘性粒子（气泡或液滴）变形的影响。使用允许大平面应变、简单剪切的环形剪切装置进行实验。结果表明毛细管数对颗粒变形的控制影响。颗粒不会随着剪切应变的增加而连续伸长，而是达到取决于毛细管数的稳态值。因为毛细管数表示使颗粒变形的剪切应力与抑制伸长的表面（界面）应力之比，所以颗粒应变对变形颗粒尺寸和体应变率有很强的依赖性。这项研究最重要的地质意义在于变形深熔系统中的熔体偏析领域。颗粒应变对变形颗粒尺寸和体积应变率有很强的依赖性。这项研究最重要的地质意义在于变形深熔系统中的熔体偏析领域。颗粒应变对变形颗粒尺寸和体积应变率有很强的依赖性。这项研究最重要的地质意义在于变形深熔系统中的熔体偏析领域。