生物材料表现出复杂的结构-性质关系,这是自然界经过数百万年的进化而设计的。解开这些关系背后的基本物理原理对于创造具有先进功能的生物材料和结构至关重要。蛋壳是一个非凡的例子,它具有精心设计的结构来平衡权衡,因为它提供了机械保护,同时仍然易于孵化。在这项研究中,我们通过实验和模拟相结合,研究了鸡蛋壳在各种加载条件下的基本机械设计原理。蛋壳的独特几何形状和结构在实现机械韧性和易于孵化之间的出色平衡中起着关键作用。阐明了蛋壳膜的作用以调节蛋壳的机械性能以进一步增强这种平衡。此外,基于这些设计原则,提出了基于力学的三指标模型,建议最佳的蛋壳厚度设计,以提高在各种不同大小的禽类物种中的生存能力。生存能力-设计关系对于开发用于运动安全设备和包装行业的改进结构材料具有巨大潜力。重要声明:在这项研究中揭示了生物材料中复杂的结构-性质关系的基本物理原理,以特别关注鸡蛋壳为例。通过对其机械设计的调查,我们揭示了蛋壳几何形状和结构在实现韧性和易于孵化之间的平衡的关键作用。具体来说,观察到裂纹静止效应,使蛋壳从内部比从外部更容易破裂。此外,我们探索蛋壳膜对这种平衡的影响,有助于增强蛋壳的机械性能。第一次,我们提出了一个三指数模型,揭示了控制蛋壳厚度演变的基本原理。该模型提出了针对多种鸟类的最佳厚度设计,以提高卵子的生存能力为目标。这些发现可以指导具有先进功能的改进结构材料的开发,在广泛的应用中实现更高的安全性和效率。
Biological materials exhibit complex structure-property relationships which are designed by nature\'s evolution over millions of years. Unlocking the fundamental physical principles behind these relationships is crucial for creating bioinspired materials and structures with advanced functionalities. The eggshell is a remarkable example with a well-designed structure to balance the trade-off as it provides mechanical protection while still being easy for hatching. In this study, we investigate the underlying mechanical design principles of chicken eggshells under various loading conditions through a combination of experiments and simulations. The unique geometry and structure of the eggshell play a critical role in achieving an excellent balance between mechanical toughness and ease of hatching. The effects of eggshell membranes are elucidated to tune the mechanical properties of the eggshell to further enhance this balance. Moreover, a mechanics-based three-index model is proposed based on these design principles, suggesting the optimal eggshell thickness design to improve survivability across a broad range of avian species with varying egg sizes. The survivability-design relationships hold great potential for the development of improved structural materials for applications in sports safety equipment and the packaging industry. STATEMENT OF SIGNIFICANCE: The fundamental physical principles underlying the complex structure-property relationships in biological materials are uncovered in this study, with a particular focus on chicken eggshells as a prime example. Through the investigation of their mechanical design, we reveal the critical role of eggshell geometry and structure in achieving a balance between toughness and ease of hatching. Specifically, the crack resting effect is observed, making the eggshell easier to break from the inside than from the outside. Additionally, we explore the influence of eggshell membranes on this balance, contributing to the enhancement of the eggshell\'s mechanical properties. For the first time, we propose a three-index model that uncovers the underlying principles governing the evolution of eggshell thickness. This model suggests optimal thickness designs for diverse avian species, with the goal of enhancing egg survivability. These findings can guide the development of improved structural materials with advanced functionalities, enabling greater safety and efficiency in a wide range of applications.