Solid contacts involving soft materials are important in mechanical engineering or biomechanics. Experimentally, such contacts have been shown to shrink significantly under shear, an effect which is usually explained using adhesion models. Here we show that quantitative agreement with recent high-load experiments can be obtained, with no adjustable parameter, using a non-adhesive model, provided that finite deformations are taken into account. Analysis of the model uncovers the basic mechanisms underlying anisotropic shear-induced area reduction, local contact lifting being the dominant one. We confirm experimentally the relevance of all those mechanisms, by tracking the shear-induced evolution of tracers inserted close to the surface of a smooth elastomer sphere in contact with a smooth glass plate. Our results suggest that finite deformations are an alternative to adhesion, when interpreting a variety of sheared contact experiments involving soft materials.

涉及软材料的固体接触在机械工程或生物力学中很重要。实验证明，这种接触在剪切作用下会明显收缩，这种作用通常用粘附模型来解释。在这里，我们表明，如果考虑到有限变形，则可以使用非粘性模型获得与最近的高负荷实验的定量一致性，而无需调整参数。对模型的分析揭示了各向异性剪切引起的面积减小的基本机理，其中局部接触提升是主要的机理。我们通过跟踪插入在与光滑玻璃板接触的光滑弹性体球体表面附近的示踪剂的剪切诱导演化，通过实验证实了所有这些机制的相关性。