Coordination Funds

疲劳失效通常被认为是“突然的”断裂事件，因为在低于准静态强度甚至低于弹性极限的载荷下，在数千或数百万次循环中，损伤没有宏观可见的迹象。疲劳抗力受微观结构特征的影响，如软界面、析出物或颗粒/颗粒大小。这些都增加了韧性、强度或塑性变形能力，从而阻碍了微裂纹的形成和扩展，提高了断裂能。在这里，我们探索了不同合成复合材料中微观结构特征与疲劳之间的相互作用，这些复合材料受到一系列具有显著抗疲劳性的天然材料的启发。我们的研究小组从生物材料的耐疲劳性中寻找灵感，这些材料在长期的自然选择过程中幸存下来，这一主题很少被视为生物灵感的来源。在发言人的协调下，该联盟由四个紧密交织的项目组成，每个项目都由一名“生物”和一名“工程”材料科学家共同领导。这些项目集中在各种不同的、广泛遇到的疲劳载荷、生物、刚性结构和补充工程复合材料上。一方面，我们在一系列生物的、长期循环加载的系统中探索进化生长的疲劳性：珊瑚、牙釉质、鱼骨和木材。我们所有的生物蓝图都共享循环负荷的长期生存，但没有一个生物重建过程可能会用健康的新材料取代疲劳受损的组织。它们进一步跨越了广泛的组成和结构特征。另一方面，我们利用现代添加剂制造和合成方法来构建和模板化复杂的人工纳米复合材料系统。工程材料科学家将使用各种材料成分和制造方法来介绍在生物蓝图中被识别为有利的微结构特征。合作伙伴的方法因材料组成和引入的核心特征而不同。一个重要的方面是项目之间的材料和加工方法的交换，以共同阐明加工对材料性能的影响，以及互补加工方法对不同生物灵感复合材料设计的适用性。我们的首要目标是探索不同长度尺度上的结构特征，以及如何将它们从生物系统转移到工程结构中，以提高疲劳抗力。

Fatigue failures are often experienced as "sudden" fracture events, because damage develops without macroscopically visible signs during thousands or millions of cycles, at loads below the quasistatic strength and often even below the elastic limit. Fatigue resistance is modulated by microstructural features, such as soft interfaces, precipitates, or grain/particle size. These increase toughness, strength or plastic deformability, thus hindering microcrack formation and growth, elevating the fracture energy. Here we explore the interaction between microstructural features and fatigue in different synthetic composites inspired by a range of natural materials with remarkable fatigue resistance. Our research group seeks inspiration from fatigue resistance of biological materials that survived long processes of natural selection, a topic that has rarely been addressed as source of bio-inspiration. Coordinated by the spokesperson, the consortium comprises four tightly interwoven projects, each led jointly by a "biological" and an "engineering" materials scientist. The projects concentrate on diverse, widely encountered fatigue loaded, biological, stiff structures, and complementary engineering composites. On the one hand, we explore evolutionary-grown fatigue resistance in a series of biological, long-term cyclically loaded systems: coral, tooth enamel, fishbone, and wood. All our biological blueprints share long-term survival of cyclic loading, but none of them possesses biological remodeling processes that might replace fatigue damaged tissue by healthy, new material. They further span a wide range of compositional and structural features. On the other hand, we harness modern additive manufacturing and synthesis approaches for structuring and templating intricate artificial nanocomposite systems. The engineering material scientists will use a variety of material compositions and fabrication methods to introduce microstructural features identified as advantageous in the biological blueprints. The approaches of the partners differ by material composition and the introduced core features. An important aspect is the exchange of materials and processing methods between the projects to jointly elucidate the influence of processing on material properties and the applicability of complementary processing methods to the design of different bioinspired composites. Our overarching goal is to explore structural features on different length scales and how they can be transferred from the biological systems into engineering structures to increase fatigue resistance.