A thicker panel can be lighter. Here’s what the core actually does.
A sandwich is a system: the skins resist bending, the core separates and stabilizes them, and the bond transfers load. Choosing only the fiber misses most of the design.
Start with supports, not a material menu
A 600 mm unsupported span and a 200 mm span are very different problems, even if the panel outline is identical. Record where the part is supported, which edges can rotate, and whether the load is spread out or introduced through a small footprint. A screw, a foot or a bracket needs a local load path; it does not become a uniform pressure just because the surrounding panel is large.
Give each component its own job
LEMKER’s guide is useful here: it treats the skin, core and adhesive as interdependent choices rather than calling one ingredient “best.” It also discusses failure modes beyond skin strength. That is the right foundation for a panel configurator. [1, printed pp. 5–7]
| Component | What to establish |
|---|---|
| Skins | Actual cured laminate properties along the load direction, thickness and schedule. Fiber data alone are insufficient. |
| Core | Grade, thickness, shear direction and local load demands. A density label alone is insufficient. |
| Bond | Compatible materials, surface preparation, cure and inspection. A stiffness calculation assumes the bond works. |
Why more core can help, and why it can stop helping
Separating the skins increases their moment arm. That can make increasing core thickness an efficient way to reduce bending deflection. But total movement also includes core shear deformation. A calculation that only improves the bending term can look encouraging while missing the remaining movement. The calculator shows these contributions separately using the cited beam approximation. [2, pp. 11–13, 27]
There is no universal “37 times stiffer at almost the same weight” promise here. LEMKER’s comparison illustration is for a particular aluminum/honeycomb concept. Our carbon/glass skins, foam cores, bonding resin and finishes have their own mass and stiffness. We calculate the selected section rather than applying a marketing multiplier. [1, printed p. 6]
A mounting hole changes the question
Average core shear says little about a bolt crushing foam or an insert pulling out. Core compression, skin bearing, fastener preload, isolation and load spreading need separate checks. Hardpoints and inserts should be selected with a controlled detail and an inspection plan. Closeouts also need a defined purpose: covering an edge, sealing it and carrying a structural load are different requirements.
Use comparison data carefully
The LEMKER guide explicitly flags interpolated and extrapolated foam values. Those plots can help explain tradeoffs, but they cannot establish properties for another supplier’s exact core grade or qualify a finished panel. We keep these comparisons out of the quoting and structural property library until a traceable, applicable source is available. [1, printed pp. 9–11]
What the first calculation does
The design wizard screens a narrow, uniform sandwich beam with equal skins. It covers ideal simple supports or a cantilever, and either a distributed load or a line load across the entire width. Inputs and sources travel with the downloaded calculation. It does not analyze arbitrary panel geometry, bonding, wrinkling, buckling, impact or attachments.
For a wide plate, curved section, local patch, cutout or point attachment, use an analysis that represents those details. A quoted panel and a drawing package remain separate from structural approval.
Open the design wizard Configure a part
Sources and scope
- Ryan C. Hagan, Composite Sandwich Panels: Engineering Principles, Component Selection, and Our Design Philosophy, LEMKER Products, September 12, 2024. Printed pp. 5–11 (PDF pp. 6–12). Educational manufacturer publication; its chosen materials and comparisons are not PlyDrop product specifications.
- Hexcel Composites, HexWeb Honeycomb Sandwich Design Technology, AGU 075b, December 2000. Calculator equations and load coefficients: pp. 11–13, 27. Worked example used for numerical verification; not a material qualification or an assertion of standards compliance.
Sources checked October 26, 2026. This article is an independent synthesis. No endorsement, manufacturing relationship or permission to reuse either publisher’s figures is implied.