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A geodesic dome is a spherical or hemispherical thin-shell structure (lattice-shell) based on a network of geodesics (great circles) on the surface of a sphere or a hemisphere. The geodesics intersect to form triangular elements, which have local, triangular rigidity, and so distribute the structural stress throughout the geodesic sphere. The design of a geodesic dome begins with an icosahedron (20-side form) inscribed onto a hypothetical sphere, each triangular face of the icosahedron then is filled with “tiles” that are smaller triangles; the triangle vertices then are projected upon the sphere. The end-points of the links of the completed sphere are the projected end-points on the surface of the sphere. When fitted exactly, the sub-triangle edge-lengths assume different values, which thus requires links of many sizes to form the structure (spherical or hemispherical). To minimize the number of different values for the edge-lengths, the design is simplified, and the resultant geodesic dome is a compromise of triangles with the vertices lying approximately on the sphere, so that the triangle-edges form approximate geodesic paths over the surface of the geodesic dome. ==History== The first dome that could be called "geodesic" in every respect was designed after World War I by Walther Bauersfeld,〔(First Geodesic Dome: Planetarium in Jena 1922 ) incl. patent information 〕 chief engineer of the Carl Zeiss optical company, for a planetarium to house his planetarium projector. The dome was patented, constructed by the firm of Dykerhoff and Wydmann on the roof of the Zeiss plant in Jena, Germany, and opened to the public in July 1926. Some 20 years later, R. Buckminster Fuller named the dome "geodesic" lattice of interlocking icosahedrons that could be skinned with a protective cover. Although Fuller was not the original inventor, he developed the intrinsic mathematics of the dome, thereby allowing popularization of the idea — for which he received U.S. patent 2,682,235 〔() 〕 29 June 1954.〔For a more detailed historical account, see the chapter "Geodesics, Domes, and Spacetime" in Tony Rothman's book ''Science à la Mode'', Princeton University Press, 1989.〕 The geodesic dome appealed to Fuller because it was extremely strong for its weight, its "omnitriangulated" surface provided an inherently stable structure, and because a sphere encloses the greatest volume for the least surface area. The dome was successfully adopted for specialized uses, such as the 21 Distant Early Warning Line domes built in Canada in 1956, the 1958 Union Tank Car Company dome near Baton Rouge, Louisiana designed by Thomas C. Howard of Synergetics, Inc. and specialty buildings like the Kaiser Aluminum domes (constructed in numerous locations across the US, e.g., Virginia Beach, VA), auditoriums, weather observatories, and storage facilities. The dome was soon breaking records for covered surface, enclosed volume, and construction speed. Beginning in 1954, the U.S. Marines experimented with helicopter-deliverable geodesic domes. A 30-foot wood and plastic geodesic dome was lifted and carried by helicopter at 50 knots without damage, leading to the manufacture of a standard magnesium dome by Magnesium Products of Milwaukee. Tests included assembly practices in which previously untrained Marines were able to assemble a 30 foot magnesium dome in 135 minutes, helicopter lifts off aircraft carriers, and a durability test in which an anchored dome successfully withstood a day-long 120 MPH propeller blast from the twin 3,000 horsepower engines of an anchored airplane without damage. The dome was introduced to a wider audience as a pavilion for the 1964 World's Fair in New York City designed by Thomas C. Howard of Synergetics, Inc. This dome is now used as an aviary by the Queens Zoo in Flushing Meadows Corona Park after it was redesigned by TC Howard of Synergetics, Inc. Another dome is from Expo 67 at the Montreal World's Fair, where it was part of the American Pavilion. The structure's covering later burned, but the structure itself still stands and, under the name ''Biosphère,'' currently houses an interpretive museum about the Saint Lawrence River. A dome appeared in the 1967 James Bond film ''You Only Live Twice'', inspiring the production designer of Austin Powers ''The Spy Who Shagged Me'' to use a dome for Dr Evil's moon base. During the 1970s, the Cinesphere dome was built at the Ontario Place amusement park in Toronto, Canada. In 1975, a dome was constructed at the South Pole, where its resistance to snow and wind loads is important. On October 1, 1982, one of the most famous geodesic domes, Spaceship Earth at the EPCOT Center in Walt Disney World (Bay Lake, Florida), opened. The building and the ride inside of it are named with one of Buckminster Fuller's famous terms, Spaceship Earth, a world view expressing concern over the use of limited resources available on Earth and encouraging everyone on it to act as a harmonious crew working toward the greater good. The building is Epcot's icon, and is also included in the park's logo. In the year 2000 the world's first fully sustainable geodesic dome hotel, EcoCamp Patagonia, was built in Chilean Patagonia〔() 〕 opening the following year in 2001. The hotel's dome design is key to resisting the region's strong winds and is based on the dwellings of the indigenous Kaweskar people. 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「Geodesic dome」の詳細全文を読む スポンサード リンク
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