$$$$ VOLU NOTICE CHAT 11/09/12 21:18:33 7124 DATE 11/09/12 Operateur VOLUME Voir aussi : ---------------- The VOLU operator may be used in different cases : --------------------- | 1st possibility | --------------------- GEO1 = SURF1 VOLU ; Description : ____________ The VOLU operator constructs the mesh GEO1 (MAILLAGE type) of the volume situated inside the envelope SURF1 (MAILLAGE type). --------------------- | 2nd possibility | --------------------- GEO1 = SURF1 VOLU | (N1) ('DINI' DENS1) ('DFIN' DENS2) | ... | 'PROG' LR1 | |'TRAN' VEC1 | ... |'ROTA' FLOT1 AXEI1 AXEJ1 | ; |'GENE' LIG1 | | SURF2 | Description : _____________ The VOLU operator constructs the volume generated by the translation or the rotation of a surface. Contents : _________ SURF1 : surface (MAILLAGE type) N1 : number of generated layers (ENTIER type) 'TRAN' : key word indicating that the volume is generated by a surface SURF1 translation, followed by : VEC1 : vector of translation (POINT type) 'ROTA' : key word indicating that the volume is generated by a surface SURF1 rotation, followed by : FLOT1 : angle of rotation (FLOTTANT type) AXEI1 | : points (POINT type) defining the rotation axis AXEJ1 | 'GENE' : key word indicating that the volume is generated by a translation parallel to a generatrix, followed by : LIG1 : generatrix line (MAILLAGE type) SURF2 : if no key word is specified, the constructed volume connects SURF1 to SURF2 (MAILLAGE type) the two objects SURF1 and SURF2 must be homeomorphic DENS1 | : densities associated with the surface SURF1 and the DENS2 | vector VEC1 (option 'TRAN'), or with the axis AXEI1 AXEJ1 (option 'ROTA'), with the line LIG1 (option 'GENE'), or else with the surface SURF2 LR1 : a LISTREEL object defining the positions of the newly created nodes (see the note for more details) Notes : ________ If SURF1 is already a volume, the operation is applied to the face 2 of SURF1 ; its result is SURF1 plus the generated elements. The same is true for SURF2 and its possible face 1. If N1 is not specified, the number of generated layers and their thicknesses will be computed in relation to the densities used. If N1 is specified and positive, N1 layers of equal thickness will be generated. If N1 is negative, N1 layers will be generated, and their thickness will be computed in relation to the densities used. If the densities associated with the surface SURF1 and the vector VEC1 or with the points AXEI1 and AXEJ1 or else with the surface SURF2 are inaccurate, they may be increased. The accurate value of the initial density will be mentioned after the 'DINI' key word, that of the final will be mentioned after the 'DFIN' key word. When the PROG (followed by a LISTREEL object) is used, the middle nodes will be created using the following rule. The two extremities of the volume to be created are homeomorphic (SURF1 and SURF2 or the TRANslated or ROTAted copy of SURF1). Hence, each node of the first one has its equivalent on the second surface. If LR1 = {r1,...,rn}, for each pair of equivalent nodes we define a linear map L: [r1,rn] ---> interval(P1,P2) (or arc between P1 and P2 in case of ROTA option) such that L(r1)=P1 and L(rn)=P2. The middle nodes will be positioned at L(r2), L(r3), ... If LR1 contains n values, (n-1) layers of elements will be created. WARNING !!! No tests are made on the contents of LR1. If the progression of values in LR1 is not monotonic, overlapping elements will be generated. --------------------- | 3rd possibility | --------------------- GEO1 = SURF1 VOLU SURF2 PO1 PO2 (N1) ('DINI' DENS1) ('DFIN' DENS2) Description : _____________ The VOLU operator enables the user to joint two meshes. These two meshes must be a grid though they may have different numbers of lines and rows. The total number of rows must be even, same for the total number of lines. Comments : __________ SURF1: The mesh must contain elements of QUA4 or QUA8 type. It must be a grid. SURF2: The mesh must contain the same type of elements as SURF1. It must be a grid. PO1 : point at the corner of SURF1 (POINT type). PO2 : point at the corner of SURF2 to be connected to PO1. The parameters have the same meaning as before, but there is a small change regarding N1 : If N1 is not specified, only one layer will be generated. If N1 is specified and positive, N1 layers of equal thickness will be generated. If N1 is negative, an error will occur. Note : ______ The solution is not unique if both the number of lines and rows increase or decrease simultaneously. In this case, the process has 2 steps. First the number of rows is increased and then the number of lines. Lines and rows depend on the choice of the corner. --------------------- | 4rd possibility | --------------------- GEO1 = SURF1 VOLU | EPAI | PO1 | MCHPO1 | Description : _____________ Transformation of a middle surface to a volume. From a mesh, composed only of QUA4, and from an thickness ( or a field of thicknesses) the operator generate a volumic mesh (CUB8) around the surface's one. PO1 gives the direction from internal surface to external surface. Comments : __________ SURF1: The mesh must contain elements of QUA4. EPAI : real value representing the thickness MCHPO1 : object of type CHPOINT representing the node's field of thicknesses PO1 : vector oriented from interior to exterior (see note) Note : ______ the object GEO1 contains two references which are the two internal and external surfaces. To obtain these surfaces, the FACE operator must be used (SINT= GEO1 FACE 1)
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