What's New

R2022x FD01 (FP.2205)

Unsymmetric Iterative Linear Equation Solver

The unsymmetric iterative linear equation solver can now solve problems with strongly unsymmetric modeling features; for example, models with a high contact friction coefficient and some material models that cause an unsymmetric system matrix.

The iterative linear equation solver can solve strongly unsymmetric problems using a newly developed Krylov iterative solver (FGMRES) and unsymmetric preconditioners. The new unsymmetric iterative linear equation solver can solve strongly unsymmetric problems that the iterative solver using symmetric preconditioners cannot solve. It can also solve weakly unsymmetric problems faster than the iterative solver using symmetric preconditioners.

Benefits: This capability improves the iterative solver performance for models with strongly unsymmetric modeling features.

Variable Bead Width and Bead Orientation in Additive Manufacturing Processes

For thermomechanical analyses of FDM- and LDED-type additive manufacturing processes, you can define material deposition and moving heat sources with varying bead sizes and orientations. You can also define material removal.

Previously, the bead width and orientation for material deposition and a moving heat source in an additive manufacturing simulation were fixed. Now you can simulate complex additive manufacturing and welding operations using parameter tables to specify arbitrary three-dimensional motions of the toolpath with varying bead orientations and bead widths.

In addition, you can now use element progressive activation to specify material removal. The material removal functionality also supports varying bead width and bead orientation. This allows you to define complex three-dimensional cutting operations.

Benefits: The ability to vary both the bead width and bead orientation in FDM- and LDED-type processes expands the range of additive manufacturing simulations you can perform.

For more information, see Thermomechanical Analysis of FDM- and LDED-Type Additive Manufacturing Processes Machining and Material Removal Process

Stress Intensity Factor–Based Fatigue Crack Growth Laws

Stress intensity factor–based fatigue crack growth laws are now available for enriched elements.

Previously, fatigue crack growth laws were based only on the strain energy release rates. You can now specify a mode-mix formula for computing the effective stress intensity factor based on the following:

The Irwin mixed-mode fracture criterion.
A tabular form to support multiple piecewise linear log-log (crack growth rate versus effective stress intensity factor range of a load cycle) segments.
A user-defined crack growth criterion using user subroutines in a fatigue crack growth analysis.

The stress intensity factor–based laws are not available for crack propagation or debonding along initially partially bonded surfaces where the strain energy release rate–based laws are more relevant and should continue to be used.

Benefits: Stress intensity factor–based fatigue crack growth laws expand the modeling capabilities available in Abaqus/Standard.

For more information, see Linear Elastic Fatigue Crack Growth Analysis Modeling Discontinuities as an Enriched Feature Using the Extended Finite Element Method

Contour Integrals with Second-Order Tetrahedral Elements Based on the Conventional Finite Element Method

You can now use second-order tetrahedral elements for fracture mechanics studies based on the conventional finite element method.

You must specify a small radius within which rings of elements are identified in a model for fracture mechanics studies. A refined mesh is required to define the rings of elements around the crack front, especially in a region near the external free surfaces.

You can now request field output for the contour integral for fracture mechanics studies based on the conventional finite element method.

Benefits: Contour integrals with second-order tetrahedral elements based on the conventional finite element method expand the simulation capabilities for fracture mechanic studies.

For more information, see Contour Integral Evaluation

Adjoint Sensitivities for a Static Analysis in Abaqus/Standard

Enhancements for adjoint sensitivities include new design responses, shape sensitivities for additional element types, a new user subroutine for user-defined element design response, and a set of additional stress-based element design responses.

You can now request design responses and adjoint sensitivities for Neuber and Glinka plasticity correction measures, which approximately account for the effects of plasticity in structural design optimization studies based on linear analyses with a purely elastic material response. This capability is useful in design applications where plasticity effects are important, but a full nonlinear analysis that includes plasticity is too expensive computationally. You can utilize this approximate approach during the initial phases of a design cycle to select one or more candidate designs for more detailed analysis.

You can request adjoint shape sensitivities for a wider class of elements that include hybrid, modified, modified-hybrid, axisymmetric continuum, axisymmetric continuum with twist, and membrane elements. This extends the class of design applications for which the adjoint sensitivities, computed by Abaqus, can be used as part of a design optimization workflow involving either Tosca or an external optimizer. For example, axisymmetric hybrid elements are often used for applications such as door seals made out of almost incompressible elastomers.

In addition, you can now define your own element design response, based on either the stress or the plastic strain tensor, through a new user subroutine. This capability significantly expands the scope of element-response based designs and allows you to define, for example, various failure measures as responses and to set constraints on such measures.

Finally, you can now request response and adjoint sensitivities for both the maximum and the minimum principal stress and the signed von Mises stress. The maximum principal stress is an important measure for design applications involving nominally brittle materials, while the signed von Mises stress is utilized in civil engineering applications involving concrete as well as some fatigue applications using metals.

The Neuber and Glinka design responses can be helpful during the design phases of automobile parts. The figure below highlights a panel of a full body-in-white model (courtesy of the Public Finite Element Model Archive of the National Crash Analysis Center at George Washington University). A Tosca-Abaqus design optimization workflow minimizes the effects of the material plasticity for the panel under different loading conditions by carrying out a purely linear elastic multiple load case analysis while minimizing the Neuber effective plastic strain.

Benefits: Enhancements for adjoint sensitivities expand the modeling capabilities for Abaqus/Standard.

For more information, see Adjoint Design Sensitivity Analysis

Adjoint Shape/Bead Sensitivities for a Transient Dynamic Analysis in Abaqus/Standard

You can now request design responses for implicit transient dynamic analyses and the corresponding adjoint sensitivities with respect to shape and bead design variables.

You can output the design response and corresponding adjoint sensitivities from Abaqus for use in your own design modification approaches. The figure below shows both the initial (left) and the optimized (right) design of a plate, based on a combined Tosca-Abaqus design optimization workflow. The optimized design results in 65% lesser deflection under a given transient load compared to the initial design. Thereby, it yields an increase in the dynamic stiffness of the structure by almost a factor of three.

Benefits: This capability expands the coverage of the adjoint transient dynamic sensitivities and benefits workflows such as concept design for crashworthiness, design for dynamics of machinery and compliant flexible dynamic mechanisms, and the behavior of electronic equipment in drop tests.

For more information, see Adjoint Design Sensitivity Analysis

R2022x GA

Eliminated Substructure Library .sup File

A major redesign of the substructure functionality is introduced in this release.

The major changes are as follows:

The substructure library .sup file is eliminated. The substructure .sim file is now the main file of the substructure database.
You must regenerate all previously generated substructures.
The redesign does not change the overall substructure workflow and results. All of the models that use the regenerated substructures run in the same manner as before and provide the same output.
With the elimination of the .sup file, the concept of a “substructure library” as a container for multiple substructures is obsolete. As a result, each substructure database becomes a fully independent set of files generated using the substructure name. You can copy, rename, and delete these files.
The options related to substructure libraries are removed: *SUBSTRUCTURE COPY, *SUBSTRUCTURE DELETE, and *SUBSTRUCTURE DIRECTORY.
The other substructure-related options (*SUBSTRUCTURE GENERATE and *ELEMENT) still support the traditional library-id naming convention for the substructure but with a different meaning: library is now a prefix in the substructure name, id is a suffix, and the resulting substructure name is libraryZn. This convention guarantees backward compatibility with existing input files.
New parameters are available for the *SUBSTRUCTURE GENERATE and *ELEMENT options that allow you to specify the substructure name, which is used to name the substructure database files. The name value can be any valid name, including libraryZn.
- *SUBSTRUCTURE GENERATE, NAME=name
  Using the new NAME parameter is the preferred method to name a substructure.
- *ELEMENT, TYPE=SUBSTR, FILE=name
  Using TYPE=SUBSTR is the preferred type setting for substructure elements.

Benefits: Elimination of the .sup file simplifies the substructure functionality, file management, and naming conventions, while ensuring backward compatibility in future releases.

For more information, see Using Substructures Generating Substructures

Battery Electrochemical Simulation

The new fully coupled thermal-electrochemical-structural procedure is intended for the analysis of battery electrochemistry applications.

Using an extended three-dimensional Porous Electrode Theory (PET) Newman model, the fully coupled analysis solves simultaneously for the following highly coupled fields: displacements, temperature, electric potentials in the solid and electrolyte phases, ion concentration in the electrolyte, and concentration in the solid particles in the electrodes. You can use nonuniform and uniform meshes. Only brick elements are supported, which prove to be sufficient for all commercial cell designs, including all cylindricals, pouches, and prismatics.

Benefits: You can use the fully coupled thermal-electrochemical-structural procedure to simultaneously analyze mechanical effects in conjunction with the thermal-electrochemical fields.

For more information, see Fully Coupled Thermal-Electrochemical-Structural Analysis