Experimental and numerical study on the flexural mechanical properties of bioinspired composites with suture structures

Abstract

Composite structures inspired by the suture line in the beak of woodpeckers, which is composed of stiff material (mimicking keratin) and compliant material (mimicking collagen), are proposed in this article. The flexural mechanical properties as well as the deformation and failure modes are investigated combining experiments and simulations, which are also compared with conventional laminated structures. First, three-point bending test is performed to characterize mechanical properties such as flexibility, stiffness, strength, and energy dissipation. Experimental results confirm that the suture structure affects the flexural properties significantly. Then, a finite element (FE) model is established to present the strain and stress fields inside the composite beams. The strain distribution demonstrates a shear mechanism in suture structures to dissipate energy, while the stress distribution reveals that the soft layers act as shock absorbers to release stress transmitted through the structure. At last, the failure mode and toughening mechanism of the composite structures is discussed. The mechanism responsible for the mechanical performance of biological structures can be generalized to design architectures with customized mechanical performances.

Keywords:

• Suture structures
• composite beams
• flexural mechanical properties
• toughening mechanism
• energy dissipation

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.

Additional information

Funding

This work is supported by the National Natural Science Foundation of China (Grant No. 11972049 and No. 12002050). The supports from National Key Laboratory Foundation of Science and Technology on Materials under Shock and Impact (Grant No. 6142902200401), Opening fund of State Key Laboratory of Nonlinear Mechanics, and State Key Laboratory of Explosion Science and Technology (Beijing Institute of Technology) are also acknowledged.