FEM analysis in excellent cushion characteristic of ostrich (Struthio camelus) toe pads

• Published in: PloS one 2019-05, Vol.14 (5), p.e0216141-e0216141
• Main Authors: Zhang, Rui, Ling, Lei, Han, Dianlei, Wang, Haitao, Yu, Guolong, Jiang, Lei, Li, Dong, Chang, Zhiyong
• Format: Article
• Language: English
• Subjects: Acceleration; Animals; Biocompatible Materials - metabolism; Biological products; Biology; Biology and Life Sciences; Biomaterials; Biomechanics; Biomedical materials; Camelus - metabolism; Camelus - physiology; Common ostrich; Composite materials; Education; Energy absorption; Engineering; Finite Element Analysis; Finite element method; Foot diseases; Impact loads; Laboratories; Mechanical properties; Medicine and Health Sciences; Multilayers; NMR; Nuclear magnetic resonance; Pathogenesis; Physical Sciences; Pressure distribution; Residual stress; Soft tissues; Strain; Struthio camelus; Struthioniformes - metabolism; Struthioniformes - physiology; Toe; Toes - physiology; Vibration; Vibration control; Viscoelasticity; Zoology
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0216141

African ostrich (Struthio camelus) is the largest and fastest extent bipedal animal. The ostrich mainly relies on the 3rd toe to support the entire body under high-speed motion. The short and severe impact concentrated on the limited area would produce tremendous momentary internal stress and strain, which may contribute to the phalanges disloaction, soft tissue damage and the like. The vibration and excessive negative acceleration caused by the ground reaction force also affect the stability of the touching process. Therefore, ostrich toe pads are required to have excellent cushion characteristics. However, current studies often explains the cushion properties by analyzing the macro-microscopic structure of the pad organism, and there is a paucity of research on its biomechanical behaviour. Consequently, from the perspective of multi-layer structure and biomaterial assembly, this study aims to explain the biomechanical characteristics of the ostrich toe pads by FEM (Finite Element Method) analysis. Based on results, we deem that the ostrich toe pad could absorb energy and reduce vibration effectively. Firstly, the multi-layer structure of the pads make the stress and strain decay from outside to inside. Secondly, the minimal response frequency of the pad is 164.22 Hz, making it effectively avoid resonance phenomenon. Finally, the composite material model has the best performance in decreasing the negative acceleration peak value, the impact force peak value and the maximal equivalent stress value at velocities of 0.669 m/s and 1.339 m/s. These results help to further understand the buffer mechanism of the ostrich toe pad, and also have important inter-species reference value for the pathogenesis of human foot soft tissue injury.