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The Willam-Warnke yield criterion 〔Willam, K. J. and Warnke, E. P. (1975). ''Constitutive models for the triaxial behavior of concrete.'' Proceedings of the International Assoc. for Bridge and Structural Engineering , vol 19, pp. 1- 30.〕 is a function that is used to predict when failure will occur in concrete and other cohesive-frictional materials such as rock, soil, and ceramics. This yield criterion has the functional form : where is the first invariant of the Cauchy stress tensor, and are the second and third invariants of the deviatoric part of the Cauchy stress tensor. There are three material parameters ( - the uniaxial compressive strength, - the uniaxial tensile strength, - the equibiaxial compressive strength) that have to be determined before the Willam-Warnke yield criterion may be applied to predict failure. In terms of , the Willam-Warnke yield criterion can be expressed as : where is a function that depends on and the three material parameters and depends only on the material parameters. The function can be interpreted as the friction angle which depends on the Lode angle (). The quantity is interpreted as a cohesion pressure. The Willam-Warnke yield criterion may therefore be viewed as a combination of the Mohr-Coulomb and the Drucker-Prager yield criteria. == Willam-Warnke yield function == In the original paper, the three-parameter Willam-Warnke yield function was expressed as : where is the first invariant of the stress tensor, is the second invariant of the deviatoric part of the stress tensor, is the yield stress in uniaxial compression, and is the Lode angle given by : where : The quantities and describe the position vectors at the locations and can be expressed in terms of as : The parameter in the model is given by : The Haigh-Westergaard representation of the Willam-Warnke yield condition can be written as : where : 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「Willam-Warnke yield criterion」の詳細全文を読む スポンサード リンク
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