Microstructure and in-situ tensile strength of propodus of mantis shrimp.

Effects of microstructure and phase component on mechanical property of spearer propodus of mantis shrimp were investigated. The spearer propodus consisted of three layers including epicuticle (outer layer), exocuticle (middle layer), and endocuticle (inner layer). The outer layer was composed of fluorapatite, which was treated as permeability barrier to environment. The compact middle layer and inner layer were constituted of chitin-protein fibers, which exhibited the layered spiral structure. Under the in-situ tensile test environment, spearer propodus owned high mechanical strength, which bore maximum tensile fore of 320 N. In the in-situ tensile process, cracks extended along with zigzag lines on spearer propodus surface. The middle layer and inner layer resisted the damage of force via the fracture and pulling of fibers. The crack deflection and delamination phenomena were the mechanical property mechanisms of spearer propodus of mantis shrimp. The investigations provided typical bionic models for the design and preparation of bionic structure materials, bionic anti-impact materials, and bionic soft materials in engineering fields.