Designing soft robots that have greater toughness and better resistance to damage propagation while at the same time retaining their properties of compliance is fundamentally important for soft robotics applications. This study's main contribution is proposing a framework for nonlinear multimaterial architectural design of soft structures to increase their toughness and delay damage propagation. What are the limits when combining significantly different materials in one structure that will delay crack propagation while significantly maintaining postdamage toughness? Through this study, we observed that there is a very dynamic interplay when combining significantly different materials in one structure; this interplay could weaken or strengthen the multimaterial structure's toughness. In biological evolutionary terms, the Pangolin, Seashell, and Arapaima have found their answer for deflecting the crack and maintaining strength in their bodies. How does nature put these multimaterial structures together? Our research led us to find that the multimaterial toughness limits depend largely on the following parameters: components' relative morphology, architecture, spatial distribution, surface areas, and Young's Modulus. We found that a linear geometry, when it comes to morphology and/or architecture relative to surface area in multimaterial design, significantly reduces total toughness and fails to delay crack propagation. In contrast, incorporating geometric nonlinearities in both morphology and architecture significantly maintains higher total toughness even after damage, and significantly delays crack propagation. We believe that this study can open the door to further research and ultimately to promising and wide applications in soft robotics.

中文翻译：

---

非线性多材料架构可提高软材料的韧性并延迟损伤传播。

设计具有更高韧性和更好的抗损伤传播能力的软机器人，同时保留其顺从性对于软机器人应用至关重要。这项研究的主要贡献是提出了软结构非线性多材料建筑设计的框架，以提高其韧性并延迟损伤传播。当在一种结构中组合显着不同的材料以延迟裂纹扩展同时显着保持损伤后韧性时，有哪些限制？通过这项研究，我们观察到，当在一个结构中组合显着不同的材料时，会产生非常动态的相互作用；这种相互作用可能会削弱或增强多材料结构的韧性。从生物进化的角度来看，穿山甲、贝壳和巨骨舌鱼已经找到了偏转裂缝并保持身体力量的答案。大自然是如何将这些多材料结构组合在一起的？我们的研究发现，多材料的韧性极限很大程度上取决于以下参数：组件的相对形态、结构、空间分布、表面积和杨氏模量。我们发现，当涉及多材料设计中相对于表面积的形态和/或结构时，线性几何形状会显着降低总韧性，并且无法延迟裂纹扩展。相比之下，在形态和结构中纳入几何非线性，即使在损坏后也能显着保持较高的总韧性，并显着延迟裂纹扩展。我们相信这项研究可以为进一步研究打开大门，并最终为软机器人技术带来有希望和广泛的应用。