Overview of Z-mat

The product includes over 75K lines of C++ material models providing the most flexible set of constitutive equations on the market. Many models are highly modular allowing the user to combine different "material model building bricks" to construct a new model dynamically. Many thousands of combinations are possible with application for metals, polymers, crystals, porous inelasticity (densification and damage), continuum damage mechanics, soil and rocks, and anisotropic materials. NW Numerics and the Z-set partners are adding to the capabilities all the time, often in direct response to our existing or prospective users.

It is important to note that Z-mat is not just a material model user routine, but a whole suite of software with tools for simulating basic stress-strain behavior efficiently, fitting material coefficients to experimental data, interfacing with FEA software, and doing post processing. With all the complex capabilities, NW Numerics backs the software with exceptional (essentially consulting level) technical support standard with the software.

The figure below shows schematically some of the ways that Z-mat works with ABAQUS (and applies to the other ports as well), including separate input for the material, scripts for running ABAQUS, the Z-mat constitutive library along with user extensions, and the extra Z-set modules such as simulation and optimization. Note that we are beginning to incorporate some Z-mat interface capabilities in Zmaster. Much more work on this is slated for the Z-set 8.2 release in late 2001.

While the existing capabilities in Z-mat are extensive and have helped many companies and research groups improve the accuracy of their material models, Z-mat is also an idea development platform. User additions may be combined with the standard Z-mat library to make a permanent customized site library of material model routines. There is no limit to the number or type of additions in the library, so one may create for example a whole new series of flow laws to be used in combination with the supplied behavior models. Also, user-behavior models may use the generic objects defined in the library (e.g. elasticity matrices, isotropic hardening, criteria, etc) to fabricate a complex set of options for the new behavior. These capabilities are due to the use of advanced object-oriented techniques in the design of the library, and greatly expand the usefulness of different codes Fortran user development interface.