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Photoelasticity is an experimental method to determine the stress distribution in a material. The method is mostly used in cases where mathematical methods become quite cumbersome. Unlike the analytical methods of stress determination, photoelasticity gives a fairly accurate picture of stress distribution, even around abrupt discontinuities in materials. The method is an important tool for determining critical stress points in a material, and is used for determining stress concentration in irregular geometries. ==History== The photoelastic phenomenon was first described by the Scottish physicist David Brewster〔D. Brewster, Experiments on the depolarization of light as exhibited by various mineral, animal and vegetable bodies with a reference of the phenomena to the general principle of polarization, Phil. Tras. 1815, pp.29-53.〕 .〔D. Brewster, On the communication of the structure of doubly-refracting crystals to glass, murite of soda, flour spar, and other substances by mechanical compression and dilation, Phil. Tras. 1816, pp.156-178.〕 Photoelasticity developed at the beginning of the twentieth century with the works of E.G.Coker and L.N.G. Filon of University of London. Their book ''Treatise on Photoelasticity'' published in 1930 by the Cambridge Press became a standard text on the subject. Between 1930 and 1940 many other books in Russian, German and French appeared on the subject. At the same time much development occurred in the field. Great improvements were achieved in the technique and the equipment was simplified. With the improvement in technology the scope of photoelasticity was extended to three-dimensional state of stress. Many practical problems were solved using photoelasticity, and it soon became popular. A number of photoelastic laboratories were established in educational institutions and industries. With the advent of digital polariscope using light-emitting diodes, continuous monitoring of structures under load became possible. This led to the development of dynamic photoelasticity. Dynamic photoelasticity has contributed greatly to the study of complex phenomena such as fracture of materials. 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「Photoelasticity」の詳細全文を読む スポンサード リンク
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