A micro-architectured material as a pressure vessel for green mobility

A shellular is a micro-architectured material formed by a continuous smooth-curved thin shell as a triply periodic minimal surface (TPMS). Owing to its geometry, a shellular supports loads by coplanar (stretching) stresses and achieves very high strength at ultralow density (<10^−2 g/cc). This suggests it can sustain internal pressure via biaxial tension like a balloon. Conventional spherical and cylindrical pressure vessels have long been used but are limited in safety and ability to conform to complex spaces demanded by green mobility (e.g., hydrogen storage). This work proposes a shellular as a pressure vessel. Leveraging its periodic micro-cells and topology, the vessel can be tailored to available volume while promoting leak-before-break safety. We show that, for a given material and pressure, a P-surfaced, cold-stretched, double-chambered shellular with more than 15×15×15 cells can achieve internal volume per total weight surpassing practical bounds of spherical and cylindrical vessels. The large-area thin shell also enables efficient interfacial heat/mass transfer between its two sub-volumes under pressure. Although other ultralight micro-architectures (microlattices, nanolattices, metamaterials) use thin continuous foils, they are not suitable as pressure vessels; despite forming interfaces between sub-volumes, they lack the stretching-dominated TPMS geometry required to sustain pressure differences efficiently.

Yoon Chang Jeong, Seung Chul Han, Cheng Han Wu, Kiju Kang