Overview
- The RMIT-led team published results on Thursday confirming laboratory validation of a hollow, 3D‑printed titanium lattice whose struts are filled with polyurethane foam and that floated in freshwater for more than two months.
- The researchers introduced 'skeletal density' as a simple design rule that counts only solid walls and sealed foam channels to predict flotation when water can pass through large external openings.
- Compression tests showed the hybrid lattice was about 70% stronger than stainless steel or high‑density polyethylene at the same overall density, giving it a higher strength-to-weight ratio for marine structures.
- Short-term seawater trials in Port Phillip Bay produced just 0.15% mass loss and under 1% strength loss after two weeks, and damage tests showed the structure remained buoyant after cracking and layer fractures, only sinking after severe crushing.
- The team demonstrated a 3D‑printed buoy that stayed stable in a turbulent seawater tank and now plans to scale up parts, run long-term marine and deep‑sea trials, and study costs, long-term corrosion and biofouling before commercial use.