Operands ========= The POST_K_BETA operator can be used for axisymmetric or three-dimensional models. In the figures below we show a diagram of a tank slice with the presence of an elliptical defect (negative and positive offset) or a semi-elliptical defect. Offset elliptical defect in the base metal .. image:: images/Shape1.gif .. _RefSchema_Shape1.gif: .. image:: images/Cadre2.gif .. _RefSchema_Cadre2.gif: Offset elliptical defect in the coating .. image:: images/Cadre3.gif .. _RefSchema_Cadre3.gif: Semi-elliptical defect located under the coating Operand MAILLAGE ----------------- Mesh-type concept. Operand MATER_REV ------------------ Name of the material-type concept defining the material constituting the coating. Needed to recover: * Young's modulus, for calculating influence coefficients (semi-elliptic defect), * Elastic limits, for the plastic correction of stress intensity factors. Operand EPAIS_REV ------------------ Coating thickness. Needed for: * The calculation of stress intensity factors in the case of the influence coefficients method (semi-elliptical defect) * The correction of stress intensity factors by edge factors and for plastic correction. Operand MATER_MDB ------------------ Name of the material-type concept that defines the material that makes up the base metal. Necessary to recover the Young's modulus, for the calculation of the influence coefficients (semi-elliptical defect). Operand EPAIS_MDB ------------------ Thickness of the base metal, necessary for the correction of stress intensity factors by the method of coefficients of influence (semi-elliptical defect). Keyword FISSURE --------------- Keyword factor for the geometric characterization of the defect. It can only be used once. Operand FORM_FISS ~~~~~~~~~~~~~~~~~~~ .. csv-table:: "Defect shape:", "'ELLIPSE 'for an elliptical defect," "", "'SEMI_ELLIPSE 'for a semi-elliptic defect," Operand DECALAGE ~~~~~~~~~~~~~~~~~~ This operand is only used in the case of a 'ELLIPSE' shape defect. From the coating/base metal interface, it makes it possible to offset the crack in the: * Coating: DECALAGE negative, * Base metal: DECALAGE positive or zero. Operand PROFONDEUR ~~~~~~~~~~~~~~~~~~~~~ Radial dimension of the defect. Operand LONGUEUR ~~~~~~~~~~~~~~~~~~ Second dimension of the defect (axial or orthoradial depending on the orientation of the defect). Operand ORIENTATION ~~~~~~~~~~~~~~~~~~~~~~ .. csv-table:: "Characterization of the orientation of the defect:", "'CIRC 'for a circumferential defect," "", "'LONGI 'for a longitudinal defect." Keyword K1D ----------- Keyword factor for characterizing the thermomechanical transient. The repetition of this keyword is possible. Operands TABL_MECA_REVet TABL_MECA_MDB ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ **Shape defect** 'ELLIPSE' **with negative offset:** For this type of defect, the two tables TABL_MECA_REVet TABL_MECA_MDB are mandatory, they provide the transient of the stresses experienced by the tank during the history of the loading, respectively on the coating side (from the point A of the defect to the interface) and on the base metal side (from the interface to the point B of the defect). **Shape defect** 'ELLIPSE' **with positive offset:** For this type of defect, table TABL_MECA_MDB is mandatory, it provides the transient of the stresses experienced by the tank during the history of loading, respectively on the coating side (from point A of the defect) and on the base metal side (at point B of the defect) and on the base metal side (at point B of the defect). **Shape defect** 'SEMI_ELLIPSE' **:** For this type of defect, table TABL_MECA_MDB is mandatory, it provides the transient of the stresses experienced by the tank during the history of the loading, respectively on the coating side (from point A of the defect: interface between the coating and the base metal) and on the base metal side (at point B of the defect). The common parameters required for these tables are: * 'INST' [R], * 'SIXX' [R] (in 3D with 'LONGI'), * 'SIYY' [R] (in 3D with 'LONGI' or in 2D with 'CIRC'), * 'SIXY' [R] (in 3D with 'LONGI'), * 'SIZZ' [R] (in 2D with 'LONGI' or in 3D with 'CIRC'). The required parameters specific to: * TABL_MECA_REVsont: * 'COOR_X' [R], * 'COOR_Y' [R] * TABL_MECA_MDBsont: * 'ABSC_CURV' [R] The reader is invited to consult the documentation for commands POST_RELEVE_T [:ref:`U4.81.21 `] and MACR_LIGN_COUPE [:ref:`U4.81,13 `] for more information on the meaning of the parameters. In the case of a form defect 'SEMI_ELLIPSE' the macro command MACR_LIGN_COUPE must be used with the keywords TYPE =' SEGMENT 'and NB_POINTS =5. The influence coefficient method requires the evaluation of a degree 5 polynomial representing the evolution of the stress normal to the segment representing the crack [:ref:`R7.02.10 `]. The macro command MACR_LIGN_COUPE allows the user to define the places where the stress is detected and this is independent of the mesh used during the thermo-mechanical study. Operand TABL_THER ~~~~~~~~~~~~~~~~~~~ Table providing the thermal transient in the tank during the history of loading from tip A to tip B. The required parameters of this table are: * 'INST' [R], * 'ABSC_CURV' [R], * 'TEMP' [R]. The reader is invited to consult the documentation for commands POST_RELEVE_T [:ref:`U4.81.21 `] and MACR_LIGN_COUPE [:ref:`U4.81.13 `] for more information on the meaning of the parameters. Operand INTITULE ~~~~~~~~~~~~~~~~~~ Title to specify the group of nodes in question. Operand TITRE -------------- Title attached to the concept produced by this operand [:external:ref:`U4.03.01 `].