Bovine pericardium, a tissue commonly used to make artificial heart valves, fulfills two fundamental mechanical requirements: a low modulus to ensure opening and closing in cyclic pulsatile flow and a high fatigue threshold to prevent crack growth. The tissue consists of a soft matrix and crimped fibers. Inspired by this architecture, we develop a composite of a soft polymer matrix and a knitted fabric. When the stretch is small to modest, the knitted fabric is easily stretched, so that the composite is soft. When the stretch is large, the knitted fabric is stiff and strong, so that the composite resists fatigue crack growth. The mechanical behavior of the composite is comparable to that of bovine pericardium. The composite has an exceptionally long fatigue life, enduring 25 million cycles of pulsatile flow, two orders of magnitude longer than the polymer matrix. This soft and fatigue-resistant composite may find broad applications in biomedicine.

中文翻译：

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一种模拟心脏瓣膜的柔软且抗疲劳的材料


牛心包是一种常用于制造人工心脏瓣膜的组织，满足两个基本的机械要求：低模量以确保在循环脉动流中打开和关闭，以及高疲劳阈值以防止裂纹扩展。该组织由柔软的基质和卷曲的纤维组成。受这种架构的启发，我们开发了一种由柔软的聚合物基体和针织面料组成的复合材料。当拉伸从小到适度时，针织面料很容易拉伸，因此复合材料柔软。当拉伸力大时，针织物坚硬而坚固，使复合材料抵抗疲劳裂纹的扩大。该复合材料的机械性能与牛心包相当。该复合材料具有极长的疲劳寿命，可承受 2500 万次脉动流循环，比聚合物基体长两个数量级。这种柔软且抗疲劳的复合材料可能在生物医学中得到广泛的应用。