flac/FLAC3D

FLAC3D 2.10 Modification List (Type PRINT VERSION to check version number.) Changes listed are included in F3210.EXE. Sub-Version Date Description Number 196 04/12/02 Version 2.10 released to users. 197 04/23/02 Flac3D now reads ITASCA system variable from the registry if no environment variable called "ITASCA" is found. Manual file included on the web site explains "Writing User-Defined Constitutive Models." ------------------------------------------------------------------------------ Official Release Version is FLAC3D 2.10.197 on 9A CD ------------------------------------------------------------------------------- 198 05/07/02 Contour plots plot *white* for all values beyond user specified range. By default contour plot automatically determines the whole range and colors all intervals. New command SET GEOMETRY <value> 0.0 (default) This command protects against an illegal geometry error in large-strain mode. The code signals an illegal geomtry error if any tetrahedral sub-zone becomes less than zero. The user input value is the ratio of the volume of a tetrahedral sub-zone to the zone volume. If a value greater than zero is specified for the ratio, then the code will exit cycling and not signal an error. In this way, a run can be made to determine a failure state without a bad geometry error occurring. (Note: Be aware that zone geometry is checked only every 10 steps in large-strain mode, so if the tolerance is set too close to zero, an error may be signaled before exiting at the selected ratio. Also, note that the typical minimum sub-zone volumes are 0.2 of the full-zone volume, so the maximum value selected for the ratio should be less than 0.2 to avoid premature termination of cycling.) 199 05/10/02 Added new FISH intrinsic GP_TFIX(gp_pnt) that fixes the temperature of gridpoint, when thermal option is invoked. This functions the same way as the FIX TEMP <value> RANGE < ... > command. If GP_TFIX(gp_pnt) is queried, it returns the temperature of the gridpoint. This behaves the same way as GP_TEMP FISH function. Informational messages pertaining to creation and deletion of structural element links are now redirected to log file if it is invoked. These messages are no longer echoed to the FLAC3D screen. 200 05/13/02 If GP_TFIX(gp_pnt) is queried, it returns a value of 1 if temperature is fixed at the gridpoint, 0 otherwise. 201 05/20/02 Added new command PLOT BLOCK ZEXTRA <Value> Value corresponds to index of extra variable created in a zone. Corresponding GUI interface has also been added. Corrected problem with SOLVE ELASTIC in some cases when the friction angle is high - the code reported bad plasticity properties. Structural element recover plot item (Stresses, displacement ...) caption now begins with a prefix "SEL " to make the plotitem clear. 202 06/25/02 Added new command GEOM_TEST <RANGE ... > to test any one of the geomteric parameters orthogonality, aspect ratio or face planarity. Also added FISH functions to test any one of the geomteric parameters: orthogonality, aspect ratio or face planarity. To test Orthogonality of a zone use Z_ORTHO(zone_pointer) To test Aspect ratio of a zone use Z_ASPECT(zone_pointer) To test Face planarity of a zone use Z_PLANARITY(zone_pointer) Notes about the geometric parameters -------------------------------------------------- These tests primarily apply to hexahedral elements. The tests compare the hexahedrons to a perfect cube which is the ideal shape for hexahedral meshes. 1) Orthogonality. - For each gridpoint in each zone, compute the determinant of the matrix defined by the three edge vectors, divided by the produce of their lengths. This gives 1.0 for a cube, and approaches zero as pairs of edges approach being coplanar or all three approach being coplanar. Each zone is measured by the worst orthogonality gridpoint. 2) Aspect ratio - For each gridpoint, compute the ratio of the shortest edge length by the longest edge length. This will be 1.0 for a cube. It will approach zero as the zone becomes stretched or flattened. Each zone is measured by the worst aspect ratio gridpoint. 3) Face Planarity - Hexahedrons are composed of 6 quadrilateral faces, just like a cube's square faces, however geometrically it is possible that a quadrilateral polygon in 3D may not have all 4 vertices coplanar. Flac3D allows faces to be nonplanar, but the greater the deviation, the less accurate the solution process will be. There is no clear singular method of measuring planarity. We choose one which compares the volume of a tetrahedron filling the 4 vertices, and the area of the quadrilateral face, computing the area by adding a central point m=(A+B+C+D)/4, and computing the 4 triangle areas ABC, ABD, ACD, BCD. We take the ratio of the cube root of the volume to the square root of the area to get a dimensionless value. This value is zero if planar, and positive if nonplanar. This test can be "scaled" by a constant since there is no fundamental limit on how nonplanar a face can be. (Values should be << 1.0 for a face to be good). Each zone has its six faces tested and the worst value represents the zone. Intrepretation of output of command GEOM_TEST ------------------------------------------------------------------ Average zone values for these tests are meaningless since some meshes might be 90% good and 10% terrible zoning and give the same average as a mesh with all 80% test quality. Therefore we count zones in test value bins (20 in total) from -1.0 to 1.0, with 0.1 intervals. This bin distribution will help identify how many bad zones there are, and how bad. Note that we did not try to determine what is "bad" and only used these tests for re