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22 Jul 2008  -  Belgium

The new version of Digimat

© E-Xstream

Digimat is a nonlinear multi-scale material and structure modelling platform. Digimat centralizes the modelling technologies and products developed at e-Xstream engineering. 

Details:

Digimat-MF is the Mean-Field homogenization software used to predict the nonlinear constitutive behaviour of multi-phase composite materials.
New capabilities in 3.1:
¤ Improved homogenization methods for elasto-viscoplastic composites: The homogenization methods based on the incremental linearization were improved in order to better homogenized composites made of an elasto-viscoplastic matrix reinforced by elastic fibers. This improvement ensures a proper saturation of the composite stress level at high strain rate.
¤ Elasto-viscoplastic material model at finite strain (Leonov-EGP model): Elasto-viscoplasticity at finite strain is now available by using the Leonov-EGP material model. That material model involves strain rate and temperature dependences as well as ageing. It can be mixed in composites with other finite strain material models (i.e. hyperelastic material models).
¤ Creep model based on hyperbolic sinus law: A creep model using a hyperbolic sinus relation between the viscous stress and the plastic strain rate was introduced. It particularly helps to reproduce stress saturation at different strain rates.
¤ Prediction of initial elastic stiffness for non-linear composites: The user has now access to the composite elastic stiffness, compliance and engineering modulii when using non-linear small strain material models.
¤ Extension of Lemaitre-Chaboche damage model: Elastoplastic material model including continuous damage (Lemaitre-Chaboche model) was enhanced with two new material parameters. Theses two new material parameters enable to define a critical damage threshold as well as to tune the relation linking damage to plastic deformation evolution.
¤ Other improvements:
- Improved post processing in order to display, in a hierarchical way, the results coming from different material scales and/or analyses;
- Automatic revalidation of phases when changing its related material properties;
- Improvement of the orientation distribution function reconstruction;
- Definition of the targeted strain rate within the loading definition.

Digimat-FE is the homogenization software based on the nonlinear Finite Element modeling of realistic Representative Volume Element (RVE) of material microstructure. Digimat-FE allows you to describe the microstructure of your composite as well as the material properties of its constituents in order to generate the FE model of the composite’s RVE.
New capabilities in 3.1:
¤ Microstructure geometry export to ANSYS Workbench: Export of the RVE geometry to ANSYS workbench within a single STEP geometry file.
¤ Automatic computation of optimal RVE size as a function of the underlying microstructure: Depending over the RVE microstructure (i.e. fiber orientation and shape) an optimal RVE size is computed and proposed to the user. This enables an automatic generation of non cubic RVE while having particular fiber orientations (e.g. fully aligned or planar orientations). The main objective is to reduce the size of the FE model to solve.
¤ Periodic boundary condition: Periodic boundary conditions can be used to apply any mechanical loading on any RVE having a periodic microstructure. The periodic boundary conditions do not require a periodic mesh in order to be used.
¤ Robustness improvement and iterative meshing in Abaqus/CAE: The RVE meshing operations performed in ABAQUS/CAE are now iterative. If a meshing operation doesn’t succeed, a new mesh seeding is automatically assigned to the geometric entities which fail to be meshed, and meshing is restarted.
¤ Support of hyperelastic material model in the interface to Abaqus: Hyperelastic material model can now be used in Digimat-FE and exported to ABAQUS as any other Digimat material model.
¤ Definition of fiber coating with constant thickness: Fiber coating with constant thickness can be defined in addition to coating having the same aspect ratio as its underlying fiber.
¤ Other improvements:
- Access to the partially generated RVE when generation failed or is stopped due to user request;
- Improved RVE display;
- Display of the RVE during the generation process;
- Graphical user interface improvement to automatically show inclusion shape during its definition.

Digimat to CAE
A product which centralizes all capabilities related to interfaces between Digimat and major injection moulding and structural FEA software to enable seamless nonlinear multi-scale analyses of composite materials and structures.
New capabilities in 3.1:
¤ Improved CPU performance: Digimat interfaces to structural FEA software were optimized in order to improve the CPU performance. These improvements are particularly important
when using Digimat to LS-DYNA interface.
¤ Parallelization of the Digimat to Abaqus interfaces: Parallel Digimat-Abaqus (Standard and Explicit) jobs can now be solved using multiple cores/CPUs sharing the same memory on a single node.
¤ Use of Digimat thermoelastic materials in an ANSYS thermomechanical analysis.
¤ Stiffness update delay method for improved CPU performance: A stiffness update delay method allowing the user to choose to delay the material stiffness update for a given number of time increments was implemented in Digimat interfaces to explicit structural FEA software. This method reduces the CPU time required to solve strongly coupled Digimat/FEA analysis. This is particularly the case when the material stiffness can be considered constant during a certain number of small explicit time steps. This method is available in Digimat interfaces to Abaqus/Explicit and LS-DYNA.
¤ Other improvements:
- Assignation, in the graphical user interface, of orientation files when defining aspect ratio distribution.

MAP
2D & 3D mapping software used to transfer fiber orientation, residual stresses and temperature between dissimilar injection molding and structural FEA meshes.
New capabilities in 3.1:
¤ Computation of local and global error indicators: Error indicators can be computed locally (error field displayed on the mesh) and globally (statistical information on the data before and after mapping).
¤ Management of element sets for partial mapping: Element sets are now managed as defined in the imported mesh files. It allows the user to perform the mapping from any element set defined in the donor mesh to any element set defined in the receiver mesh.
¤ Support of new mesh file format: LS-DYNA, PAM-Crash as well as REM3D mesh file format are now supported.
¤ Support of new orientation file format: Moldex3D and REM3D orientation file format are now supported.
¤ Support of 1st order hexahedron and wedge elements in donor mesh.
¤ Support of 1st order wedge elements in receiver mesh.
¤ Support of 2nd order hexahedron and tetrahedron elements in the receiver mesh.
¤ Other improvements:
- Improved user friendliness.
- Improved stability when dealing with several meshes and data files.
- Mesh and data file deletion in analysis tree.

MICROSS
Accurate and easy to use software for the micromechanical modeling of composite sandwich structure.
New capabilities in 3.1:
¤ Sandwich lay-up definition: The core and skin definitions are now positioned at the same level within the analysis tree.
¤ Improved stability when doing successive analyses.
¤ Clearer html report for multi-layer skins
¤ Other improvements :
- Correction in the loader of honeycomb cell definition files;
- Correction in the definition of transversely isotropic material.

Source : e-Xstream