Additively manufactured all-metallic metamaterial solutions for protection of electronic systems in autonomous vehicles

Project started July 2022.

Structures in military ground vehicles must protect personnel and critical electronic components from impact and severe vibrations. While the absence of personnel in autonomous vehicles presents an opportunity for more aggressive mission profiles (e.g., faster driving on challenging terrain), the corresponding increase in vibration and impact loads poses challenges to the delicate electronic components. As in unmanned vehicles electronic failure almost always implies loss of the asset, the development of next-generation structures and materials for vibration isolation and impact protection becomes paramount.

Metamaterials are engineered material systems typically consisting of the repetition of a topologically optimized porous unit cell along three dimensions. The resulting cellular material can be optimized for multiple functionalities and achieve combination of properties not available in existing monolithic materials. Over the past decade, optimal metamaterial designs for specific strength and stiffness, active cooling, impact protection and vibration isolation have all been demonstrated. These different functionalities were explored individually, each utilizing different topological concepts and constituent materials. Here we will explore a fully integrated all-metallic lightweight solution to provide mechanical integrity, vibration isolation, impact protection and active cooling of electronic components for autonomous ground vehicles. The proposed system will consist of a highly engineered additively manufactured aluminum metamaterial. We expect that the proposed solution will increase the performance of electronic packages for autonomous ground vehicle while reducing the overall mass and volume of the system.

The success of the proposed technology hinges on two fundamental research questions: (1) Can one design an all-metallic metamaterial that provides stiffness and strength, impact protection and vibration damping, while serving as an active cooling platform? (2) What are the manufacturability limitations to additively fabricate it in a suitable alloy using LPBF? These fundamental questions make this clearly a basic research program. The proposed research project has 5 key objectives:

1. Explore the range of impact mitigation that can be provided by an additively manufactured metallic metamaterial design with a non-convex elastic energy landscape, resulting from isolated regions of negative stiffness behavior during deformation;
2. Explore the frequency and amplitude ranges of vibration damping that can be provided by an additively manufactured metallic metamaterial design that possesses a periodic network of internal resonances;
3. Explore the ability of these cellular metamaterial designs to provide active cooling through their internal porosity at minimum pressure drop;
4. Identify the additively manufacturable metallic alloy that provides optimal combinations of mechanical and thermal properties to maximize multi-objective performance, and explore the optimal processing parameters and printability limits for Laser Powder Bed Fusion;
5. Identify an all-metallic additively manufactured metamaterial that has optimal combinations of impact mitigation, vibration isolation, active cooling, mechanical integrity and low mass and volume.

#3.24, #3.A96