
A new Northwestern study reveals that the patterned grooves on mantis shrimp’s clubs (the flat, reddish-purple appendages shown here) help them resist damage from their own powerful punches. [From the Northwestern press release]
This “phononic” shield may pave the way for next-generation protective gear, from military armor to sports equipment, by mimicking the shrimp’s self-preserving impact strategy.
As the study abstract notes (the full paper is slated for publication on February 7 in Science), this discovery shows that nature has essentially perfected a specialized “acoustic armor” to protect the shrimp’s club from self-inflicted high-frequency damage.
In this work, we explored the phononic properties of the mantis shrimp’s dactyl club using laser ultrasonic techniques and numerical simulations. Our results demonstrate that the dactyl club’s periodic region functions as a dispersive, high-quality graded system, exhibiting Bloch harmonics, flat dispersion branches, ultraslow wave modes, and wide Bragg bandgaps in the lower megahertz range. These features effectively shield the shrimp from harmful high-frequency stress waves generated by cavitation bubble collapse events during impact.
The research team emphasizes that future investigations will focus on translating these biological insights into practical applications. While the current study used 2D simulations to demonstrate the phononic filtering effect, Northwestern Engineering’s Horacio D. Espinosa (co-corresponding author of the study) notes that 3D modeling will be key for understanding how the club’s helical fiber arrangements interact with shockwaves in all dimensions. This could enable engineers to design multilayered composites that replicate both the impact-resistant herringbone pattern and the frequency-filtering Bouligand structure. Additionally, the researchers propose developing submerged testing platforms with advanced sensors to observe how the phononic mechanisms fare underwater. This could pave the way for aquatic robotics or naval armor inspired by these crustaceans. By combining materials science with fluid dynamics, the team aims to create prototype shields that mitigate blast waves in military helmets or vibration-dampening layers for athlete protective gear, potentially revolutionizing impact protection across industries