New in Version 4.0

A new graphical user interface, the GIIC (Graphical Interface for Itasca Codes), makes all features in UDEC available by using graphical tools. UDEC command line input is available within the interface. Features in the GIIC help users graphically define the geometry and jointing of the model. Placement of structural support and boundary conditions is easier and more accurate. There is a data base of material properties. Menu access to UDEC's extensive plotting facilities is also provided.

A new option is available in UDEC that allows external zone constitutive models to be written in C++ and compiled as DLL (dynamic link library) files that can be loaded whenever needed. C++ DLL models run nearly as fast as the build in models in UDEC. In addition 19 previously written constitutive models are available as part of this option. This new feature is accessed via the CONFIG cppudm and ZONE model load commands). DLLs written by other users can be accessed via Itasca's web site. As part of the UDM option, joint constitutive models may also be compiled as DLL files. This new feature is accessed via the CONFIG cppudm and JMODEL model load commands). DLLs written by other users (when available) can be accessed via Itasca's web site.

The network key allows a single hardware dongle to be placed at a central location. Individual users may then run UDEC from any computer on the network. Network keys require a special licensing arrangement and installation. Contact Itasca for details.

Individual and groups of blocks may be hidden in UDEC. This can be used for visual effect but is also a very powerful tool in controlling model generation. Most commands such as cutting of joints, zone generation, and property assignment will be limited to visible blocks.

A more robust process for excavate and fill has been implemented in UDEC. In this new procedure, excavated blocks are deleted rather than replaced by a null zone model. When backfill is needed, the BLOCK fill command is used to replace the excavation void with a newly created block. New blocks can be cut and zoned and assigned stresses and material properties. The new block will conform to the displaced geometry of the excavation. The new block may also be trimmed at the top to simulate incomplete filling of the void.

UDEC 4.0 includes a double precision code as well as a single precision code. The double precision version provides more accurate solutions in the cases in which the accumulated value of a variable after many thousands of timesteps is much larger than the incremental change in the variable (e.g. an accumulated value for displacement that is roughly six orders of magnitude greater than the incremental value in a creep calculation). The double precision version is also recommended for models that have coordinates that are large compared to the typical zone or block dimension.

Mixed discretization has been added to UDEC to improve large strain plastic deformation calculations. This feature is implemented by subdividing each of the regular triangular zones in UDEC into quadratic zones.

UDEC can now perform joint fluid flow simulations involving displacement of one fluid by another. Two-phase flow processes have important applications in fields as diverse as the oil industry, agriculture, pollution control, waste disposal, gas storage, and slope stability. In the UDEC formulation, the two fluids are considered immiscible and slightly compressible (i.e., spatial variations of densities are neglected).

With UDEC 4.0 data can be passed rapidly between two or more Itasca codes running on the same machine. All other Itasca codes also have this capability. One possible application would be embedding PFC2D particles inside an excavation in UDEC thus providing an efficient boundary condition for the ball assembly. The data transmission between codes is invoked by the SOCKET IO FISH functions that allow large arrays of data to be exchanged with a single command.

A new command SOLVE fos has been added to allow the calculation of a factor of safety in the model. The shear strength reduction method for determining the factor has been implemented. The user has control over specific zone and joint properties to be reduced in the calculation.