Biomimetic approach to gradient-helicoidal laminates for impact-resistant applications

Composite-based battery enclosure is considered to be an effective solution to protect the automotive battery cells from physical impacts. Conventional lay-up design schemes employed for enhancing the impact resistance of composite laminates have been proven inadequate due to their inability to realize the prevention mechanism against asymmetric damage modes. Inspired by the gradient arrangement of Bouligand structure observed in the exoskeletons of crustaceans, such as Mantis Shrimp and American Lobster, this work applies the gradient-helicoidal (GH) design strategies to the fabrication of high-performance composite laminates. Notably, the out-of-plane mechanical responses show that the GH configurations possess enhanced performances compared with the traditional quasi-isotropic laminates. The difference in the regional arrangement of structural parameters alters the mechanical characteristics and damage mechanisms of GH configurations. Specifically, the GH-I configuration mimicking the dactyl of Mantis Shrimp successfully resists the damage initiation in specific regions under the short duration impact loading, which is reflected in a 52% improvement of the threshold force for critical impact damage compared to the inverted counterpart inspired by lobster cuticle (GH-II). It is a further proof of the predation strategy adopted by Mantis Shrimp, which implements a quick dynamic strike to smash the preys, resulting in a requirement for impact resistance. With prolonged exposure to out-of-plane loading, the GH-II configuration exhibits a 46% and 25% increase in load-bearing capacity and energy dissipation, respectively, developing the typical crushing mechanism of lobster claws that fully exploits the damage tolerance of local structures. These findings reveal the underlying mechanics of biological paradigms and convey that the GH design is a potentially feasible approach to achieve win–win progress in matching the demands of automotive battery enclosures, whether it is the requirement to reduce structural damage for impact resistance or to provide load-carrying support for the heavy battery pack.

Graphical abstract