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A sandwich-structured composite is a special class of composite materials that is fabricated by attaching two thin but stiff skins to a lightweight but thick core. The core material is normally low strength material, but its higher thickness provides the sandwich composite with high bending stiffness with overall low density. Open- and closed-cell-structured foams like polyethersufone polyvinylchloride, polyurethane, polyethylene or polystyrene foams, balsa wood, syntactic foams, and honeycombs are commonly used core materials. Sometimes, the honeycomb structure is filled with other foams for added strength. Open- and closed-cell metal foam can also be used as core materials. Laminates of glass or carbon fiber-reinforced thermoplastics or mainly thermoset polymers (unsaturated polyesters, epoxies...) are widely used as skin materials. Sheet metal is also used as skin material in some cases. The core is bonded to the skins with an adhesive or with metal components by brazing together. == History == A summary of the important developments in sandwich structures is given below.〔(EconHP Holding – History without Flash /index.php ). Econhp.de. Retrieved on 2012-09-06.〕 * 230 BC Archimedes describes the laws of levers and a way to calculate density. * 25 BC Vitruvius reports about the efficient use of materials in Roman truss roof structures. * 1493 Leonardo da Vinci discovers the neutral axis and load-deflection relations in three-point bending. * 1570 Palladio presents truss beam constructions with diagonal beams to prevent shear deformations. * 1638 Galileo Galilei describes the efficiency of tubes versus solid rods. * 1652 Wendelin Schildknecht reports about sandwich beam structures with curved wooden beam reinforcements. * 1726 Jacob Leupold documents tubular bridges with compression-loaded roofs. * 1786 Victor Louis uses iron sandwich beams in the galleries of the Palais-Royal in Paris. * 1802 Jean-Baptiste Rondelet analyses and documents the sandwich effect in a beam with spacers. * 1820 Alphonse Duleau discovers and publishes the moment of inertia for sandwich constructions. * 1830 Robert Stephenson builds the Planet locomotive using a sandwich beam frame made of wood plated with iron *1940 The de Havilland Mosquito was built with sandwich composites; a balsa-wood core with plywood skins. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sandwich-structured composite」の詳細全文を読む スポンサード リンク
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