High strength and damage-tolerance in echinoderm stereom as a natural bicontinuous ceramic cellular solid
Abstract
Due to their low damage tolerance, engineering ceramic foams are often limited to non-structural usages. In this work, we report that stereom, a bioceramic cellular solid (relative density, 0.2–0.4) commonly found in the mineralized skeletal elements of echinoderms (e.g., sea urchin spines), achieves simultaneous high relative strength which approaches the Suquet bound and remarkable energy absorption capability (ca. 17.7 kJ kg−1) through its unique bicontinuous open-cell foam-like microstructure. The high strength is due to the ultra-low stress concentrations within the stereom during loading, resulted from their defect-free cellular morphologies with near-constant surface mean curvatures and negative Gaussian curvatures. Furthermore, the combination of bending-induced microfracture of branches and subsequent local jamming of fractured fragments facilitated by small throat openings in stereom leads to the progressive formation and growth of damage bands with significant microscopic densification of fragments, and consequently, contributes to stereom’s exceptionally high damage tolerance.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 14, 2022
- Source ID
- 10.1038/s41467-022-33712-z
Entities
People
- Hongshun Chen
- Ling Li
- Liuni Chen
- Ting Yang
- Yunhui Zhu
- Zhifei Deng
- Zian Jia
- Ziling Wu
Organizations
- Air Force Office of Scientific Research
- National Science Foundation