The first use of honeycomb structures for structural applications had been independently proposed for building application and published already in 1914.
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The problem of bonding a continuous skin to cellular cores led Junkers later to the open corrugated structure, which could be riveted or welded together.
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He described in detail his concept to replace the fabric covered aircraft structures by metal sheets and reasoned that a metal sheet can also be loaded in compression if it is supported at very small intervals by arranging side by side a series of square or rectangular cells or triangular or hexagonal hollow bodies. He proposed and patented the first honeycomb cores for aircraft application in 1915. Hugo Junkers first explored the idea of a honeycomb core within a laminate structure. The three basic techniques for honeycomb production that are still used today-expansion, corrugation and moulding-were already developed by 1901 for non-sandwich applications. For the same purpose, as foundation sheets to harvest more honey, a honeycomb moulding process using a paper paste glue mixture had been patented in 1878. First honeycomb structures from corrugated metal sheets had been proposed for bee keeping in 1890. Paper honeycombs and the expansion production process has been invented in Halle/Saale in Germany by Hans Heilbrun in 1901 for decorative applications. The first paper honeycomb structures might have been made by the Chinese 2000 years ago for ornaments, but no reference for this has been found. and Charles Darwin states in 1859 that "the comb of the hive-bee, as far as we can see, is absolutely perfect in economizing labour and wax”. Robert Hooke discovers in 1665 that the natural cellular structure of cork is similar to the hexagonal honeybee comb. Galileo Galilei discusses in 1638 the resistance of hollow solids: "Art, and nature even more, makes use of these in thousands of operations in which robustness is increased without adding weight, as is seen in the bones of birds and in many stalks that are light and very resistant to bending and breaking”.
The interior ribbing and hidden chambers in the dome of the Pantheon in Rome is an early example of a honeycomb structure. Marcus Varro reports that the Greek geometers Euclid and Zenodorus found that the hexagon shape makes most efficient use of space and building materials. The first man-made honeycomb, according to Greek mythology, is said to have been manufactured by Daedalus from gold by lost wax casting more than 3000 years ago. The hexagonal comb of the honey bee has been admired and wondered about from ancient times. The material takes its name from its visual resemblance to a bee's honeycomb – a hexagonal sheet structure. Honeycomb composites are used widely in many industries, from aerospace industries, automotive and furniture to packaging and logistics.
The strength of laminated or sandwich panels depends on the size of the panel, facing material used and the number or density of the honeycomb cells within it. Man-made honeycomb structures are manufactured by using a variety of different materials, depending on the intended application and required characteristics, from paper or thermoplastics, used for low strength and stiffness for low load applications, to high strength and stiffness for high performance applications, from aluminum or fiber reinforced plastics. Man-made honeycomb structures include sandwich-structured composites with honeycomb cores. Natural honeycomb structures include beehives, honeycomb weathering in rocks, tripe, and bone. They can also be found in many other fields, from packaging materials in the form of paper-based honeycomb cardboard, to sporting goods like skis and snowboards. They are widely used in the aerospace industry for this reason, and honeycomb materials in aluminum, fibreglass and advanced composite materials have been featured in aircraft and rockets since the 1950s. Honeycomb materials are widely used where flat or slightly curved surfaces are needed and their high specific strength is valuable. Man-made honeycomb structural materials are commonly made by layering a honeycomb material between two thin layers that provide strength in tension. A honeycomb shaped structure provides a material with minimal density and relative high out-of-plane compression properties and out-of-plane shear properties. The cells are often columnar and hexagonal in shape. The geometry of honeycomb structures can vary widely but the common feature of all such structures is an array of hollow cells formed between thin vertical walls. Honeycomb structures are natural or man-made structures that have the geometry of a honeycomb to allow the minimization of the amount of used material to reach minimal weight and minimal material cost.