9.2.2 Transferring results between Abaqus/Explicit and Abaqus/Standard
Products: Abaqus/Standard Abaqus/Explicit Abaqus/CAE
References
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“Transferring results between Abaqus analyses: overview,” Section 9.2.1 *IMPORT *IMPORT ELSET *IMPORT NSET *IMPORT CONTROLS *INSTANCE
“Transferring results between Abaqus analyses,” Section 16.6 of the Abaqus/CAE User's Manual
Overview
Abaqus provides the capability to import a deformed mesh and its associated material state from Abaqus/Standard into Abaqus/Explicit and vice versa. In addition, new model information can be specified during the import analysis. This capability is useful for problems that involve several analysis stages. For example, in manufacturing processes the preloading can be analyzed using Abaqus/Standard
and the subsequent forming operation can be simulated using Abaqus/Explicit. Finally, the springback of the material can be performed in Abaqus/Standard.
For this capability to work, the same release of Abaqus/Explicit and Abaqus/Standard must be run on computers that are binary compatible.
Information about how to transfer results between Abaqus analyses is provided in “Transferring results between Abaqus analyses: overview,” Section 9.2.1.
Specifying new data in an import analysis
Additional model definitions such as new elements, nodes, surfaces, etc. can be defined during the import analysis. Initial conditions can also be specified during the import analysis.
New model definitions
New nodes, elements, and material properties can be added to the model in an import analysis once import has been specified. Nodal coordinates must be defined in the updated configuration, regardless of whether or not the reference configuration is updated on import (see “Updating the imported configuration” in “Transferring results between Abaqus analyses: overview,” Section 9.2.1). The usual Abaqus input can be used. Imported material definitions can be used with the new elements (which will need new section property definitions).
Nodal transformation
Nodal transformations (“Transformed coordinate systems,” Section 2.1.5) are not imported; transformations can be defined independently in the import analysis. Continuous displacements, velocities, etc. are obtained only if the nodal transformations in the import analysis are the same as those in the original analysis. Use of the same transformations is also recommended for nodes with boundary conditions or point loads defined in a local system.
Specifying geometric nonlinearity in an import analysis
By default, Abaqus/Standard uses a small-strain formulation (i.e., geometric nonlinearity is ignored) and Abaqus/Explicit uses a large-deformation formulation (i.e., geometric nonlinearity is included). For each step of an analysis you can specify which formulation should be used; see “Geometric nonlinearity” in “General and linear perturbation procedures,” Section 6.1.2, for details.
The default value for the formulation in an import analysis is the same as the value at the time of import. Once the large-displacement formulation is used during a given step in any analysis, it will remain active in all the subsequent steps, whether or not the analysis is imported.
If the small-displacement formulation is used at the time of import, the reference configuration cannot be updated.
Specifying initial conditions for imported elements and nodes
Initial conditions (“Initial conditions in Abaqus/Standard and Abaqus/Explicit,” Section 30.2.1) can be specified on the imported elements or nodes only under certain conditions. Table 9.2.2–1 lists the initial conditions that are allowed depending on whether or not the material state is imported (see “Importing the material state” in “Transferring results between Abaqus analyses: overview,” Section 9.2.1). The reference configuration can be updated or not, as desired.
Table 9.2.2–1Valid initial conditions.
Initial condition Hardening Relative density Rotational velocity Material state imported? No No Yes or No Solution-dependent state variables No Stress Velocity Void ratio
No Yes or No No Procedures
Results can be imported into Abaqus/Explicit only from a general analysis step involving static stress analysis, dynamic stress analysis, or steady-state transport analysis in Abaqus/Standard. Results transfer from linear perturbation procedures (“General and linear perturbation procedures,” Section 6.1.2) is not allowed.
Abaqus/Standard offers several analysis procedures that can be used in an import analysis. These procedures can be used to perform an eigenvalue analysis, static or dynamic stress analysis, buckling analysis, etc. See “Procedures: overview,” Section 6.1.1, for a discussion of the available procedures.
For springback analysis of a formed component the first step in the Abaqus/Standard analysis usually consists of a static analysis procedure so that the initial out-of-balance forces can be removed gradually from the system. The removal of these forces is performed automatically by Abaqus/Standard during the first static analysis step, as described below. If the first step in the Abaqus/Standard analysis is not a static step (such as a dynamic step), the analysis proceeds directly from the state imported from the Abaqus/Explicit analysis.
Achieving static equilibrium when importing into Abaqus/Standard
When the current state of a deformed body in an explicit dynamic analysis is imported into a static analysis, the model will not initially be in static equilibrium. Initial out-of-balance forces must be applied to the deformed body in dynamic equilibrium to achieve static equilibrium. Both dynamic forces (inertia and damping)