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Lightweight Sandwich Structures Eyed for Micro-Drones

MALIBU, CALIF.—HRL Laboratories says it created a material structure suitable for micro-drones. Researchers at HRL said they have “ utilized a self-propagating photopolymer waveguide process to form ultra-thin sandwich structures that could provide a platform from micro-unmanned aerial vehicles.”

According to Dr. Christopher Roper, HRL senior research staff engineer and co-author of “Enabling Ultra-Lightweight Structures: Microsandwich Structures with Microlattice Cores,” published in APL Materials, “Sandwich structures improve the performance of weight-sensitive vehicles like airplanes and helicopters because they’re lighter than solid materials.”

Roper said that, because traditional methods of making sandwich structures do not scale down to the thickness and densities need for micro-drones, “The HRL researcher team was challenged to do more with less.” HRL said its researchers demonstrated a fabrication process for making microsandwich structures with areal densities from 0.04 g/cm2 down to 0.005 g/cm2 – roughly the thickness of a quarter, but 97 to 99.6 percent lighter.

“These low densities are impossible with traditional sandwich structure fabrication techniques because the weight of adhesive would be greater than the weight of the facesheet and core it was holding together,” Roper said. Instead, researchers employed HRL’s photopolymer waveguide microlattice material so that the microlattice core did double duty as both the adhesive and the core.

Roper noted that microsandwich structures could potentially be used in the wings or propellers of insect-like robots or other micro-UAVs. “Micro-drones could facilitate scientific research or enable infrastructure inspections,” he said. “After a natural disaster, they could even travel through hard-to-reach areas to search for survivors.”