Laser powder bed fusion of mechanically efficient helicoidal structure inspired by mantis shrimp

Abdominal segments are common in crustaceans and are used as biological armor to provide mechanical protection from the surrounding environment. However, little is known about the abdominal segments. Mantis shrimps, a group of crustaceans, evolved abdominal segments that are mechanically robust. Here, we conduct a systematic study of the three-dimensional geometry, material composition, nanoindentation mechanical properties, and microstructural features of mantis shrimp abdominal segments. Inspired by the helicoidally distributed fiber hollow tubes of abdominal segment, a mechanically efficient helicoidal structure is designed and fabricated by laser powder bed fusion (LPBF). The LPBF processed helicoidal structure achieves high forming accuracy (peak deviation = 7.5 μm) and relative density (99.78%). Furthermore, using a combination of compression experiments and finite element simulations, we show that the helicoidal structure exhibits superior specific energy absorption (2.4 times) and plateau stress (2.7 times) to the conventional honeycomb structure and tube structure. The structural optimization results show that the rotation angle and the number of layers have a significant effect on the mechanical properties and the helicoidal structure with a rotation angle of 45° and 3 layers has the best comprehensive energy absorption performance. We demonstrate that the mechanism for this improvement in mechanical properties is the unique twisting stress conduction path of the helicoidal structure under compression. Our results reveal that bio-inspired additive manufacturing paves the way to develop high-performance structures which are in great demand in modern industrial applications.