Dear Reader,

Good day to you! I will be reflecting quite briefly today about Mantis Shrimp.

The reason is because today is my birthday and I am in a bit of a celebratory mood but just wanted to take time to write this newsletter.

This newsletter edition will be solely about a Technical Reflection on the subject of Mantis Shrimp.

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Technical Reflection

The Relationship between Mantis Shrimp and Biocomposites

Just over two years ago, I never heard about Mantis Shrimp until someone asked me a question on the CM Videos YouTube channel about Bouligand structures and how to model them. I then started researching into it and the key paper I read discussed the relationship between Mantis Shrimp and the Bouligand structure. More about the bouligand structure later!

Mantis Shrimp

This mantis shrimp is a marine crustacean which means it belongs to the crabs, lopsters, shrimp, banacles, crayfish, krill and similar types of marine animal's family. It is characterized by hard exoskeletons, segmented bodies and jointed appendages. The mantis shrimp is known specifically for its remarkable eyesight, vibrant colours and incredible hunting abilities. It is in the later ability of hunting prowess that I am keen to talk about this marine animal.

Hunting capability of mantis shrimp

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The video above shows a typical mantis shrimp while hunting... and it can strike with such spring-loaded impact loads that it is one of the fiercest marine creatures. It packs a punch and can attack other creatures twice its size. The distinctive thing that makes them special is the use of its club which it uses to hit its preys so aggresively.

What has the mantis shrimp got in common with biocomposites

The subject of this newsletter is on the connection between a mantis shrimp and a biocomposite. The answer lie in the mantis shrimp club which it uses to fight. This club is made from a natural biocomposite which has a bouligand structure. It is made up of laminates that are oriented at specific angular off-sets in a multidirectional arrangement as would an angular ply laminate. Below is a typical image of the bouligand structure in the mantis shrimpt club.

This bouligand structure is a biocomposite with fibres and matrix constituents. It is arranged in this cyclical positioning of different laminates. It is so designed that unlike other laminated composites, onset and evolution of failure is suppressed due to the complex architecture. As a result, bouligand structures tend to show higher damage tolerance and impact load absorption capabilities. This is why it is able to apply such high impact loads without the consequent failure of the biocomposite.

Computational modelling of impact loading of mantis shrimp

I made two videos about the strategies for modelling of mantis shrimp club material. I used a micromechanical consideration showing how to develop using a Python script the architecture of the bouligand structure. The image above of the cross-sectional view of the bouligand structure came from that video making exercise. In the end, I identified a suitable RVE of the bouligand structure and then used that to undertake numerical modelling of the bouligand structure. If you have not seen the video, then consider watching it below. The first is about the domain creation.

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In order to understand how to islolate an RVE of the bouligand structure, impose adequate boundary conditions and using FEA generate the mechanics of the bouligand structure, especially under compressive loading which the the loading sequence it experiences when the club punches a prey. Here is the video that shows this numerical modelling exercise.

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Conclusions

I quite enjoy this sort of computational modelling exercise. This is because there is so much beauty in nature that we can learn a lot from it to inspire the design of bespoke next-generation materials especially with the advances already seen from additive manufacturing. Understanding the secret in nature, especially in the area of biocomposites and bio-inspired material development can only lead to resilient material designs such as this naturally occuring mantis shrimp bouligand structure. Please let me know what you think about it all and if you have further insights that will be beneficial to this sort of discussion.

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That is where I want to stop this week. I will get back to you later in the week with further computational modelling reflections, Question of the Week, Quote for the week and some Behind the Scene news about CM Videos.

I wish you all a wonderful week.

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