What is the main benefit of a sandwich panel with a honeycomb core?

• A. High density
• B. Excellent thermal conductivity
• C. Large bending stiffness with low density
• D. High cost

Answer: (C)

The key idea is that sandwich panels use lightweight hollow cores between stiff face sheets to dramatically boost stiffness without adding much weight. In a honeycomb core, the faces are kept far apart, and the cell walls transfer shear between them. This arrangement makes the panel resistant to bending because the flexural rigidity scales with the separation of the faces and the stiffness of the faces themselves, while the light core keeps the overall weight low. So you get large bending stiffness for a low density, which is the main advantage of honeycomb-core panels. The other traits—being high density, having excellent thermal conductivity, or high cost—don’t capture this primary benefit.