Floating Titanium Lattice Could Outperform Steel and Plastic in Marine Use

Australian engineers at RMIT University have created a strong, lightweight titanium material that floats in water even after severe damage, revealing a promising new material for marine infrastructure. The 3D-printed titanium lattice, made of hollow interconnected struts filled with foam, withstands seawater exposure and is stronger than the stainless steel or high-density plastic currently used in jetties, buoys and floating sensors. Researchers say it is the first reported demonstration of a floating metal-hybrid lattice metamaterial.

 

Details of the Breakthrough

 

Australian engineers have created a novel material. It is a strong, lightweight titanium material. It floats in water even after severe damage. This reveals a promising material for marine use. RMIT University led the research.

The material has a distinctive structure. It is a 3D-printed titanium lattice. It consists of hollow interconnected struts. These are filled with foam. This combination gives the material its properties.

 

Overcoming the Buoyancy Challenge

 

The research solved a fundamental problem. Metallic lattices can be extremely light. Their density can be below one-tenth of water. However, their open spaces let water in. This has caused such structures to sink.

The researchers developed a clever solution. They filled only the hollow struts with foam. This uses polyurethane foam. The result allows water to flow through the structure. Yet it remains buoyant despite this.

 

The Skeletal Density Measure

 

The team developed a new predictive tool. It is called skeletal density. This predicts whether open structures will float. Conventional density includes all open space. This space can fill with water.

The new measure works differently. It considers only water-excluding parts. These are the titanium walls and sealed channels. This gives engineers a simple design rule. If skeletal density is below the liquid, it floats.

 

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The Performance Advantages

 

The material offers notable strength. It was 70 percent stronger than alternatives. These are stainless steel and high-density plastic. The comparison was at the same overall density. This demonstrates a significant strength advantage.

The material also resists corrosion well. It performed well in seawater testing. After two weeks, it lost only 0.15 percent of its mass. Its strength declined by less than 1 percent. This shows strong resistance to seawater.

 

Resilience After Damage

 

The material remains buoyant when damaged. It stayed afloat after significant damage. This included cracking and connection failures. It even survived the fracture of a lattice layer. It sank only after severe crushing.

The foam is key to this resilience. Sealed cells in the foam trap gas. This prevents water flooding the struts. The foam acts as a distributed barrier. This helps the structure stay afloat after damage.

 

Applications and Next Steps

 

The team demonstrated a practical application. They created a 3D-printed marine buoy. It remained stable in a turbulent tank. This held even when rotated up to 45 degrees. It needed no sealed casing or extra flotation.

The research points to broader potential. Next steps include scaling up the parts. Long-term marine testing is also planned. The structure is highly tailorable too. Other applications could include energy absorption and thermal management.