COMSOL Multiphysics^® 5.6 Release Highlights

Nonlinear Structural Materials Module Updates

For users of the Nonlinear Structural Materials Module, COMSOL Multiphysics^® version 5.6 brings plasticity and damage improvements, as well as new hyperelastic material models. Browse these features and more below.

Plasticity Improvements

A new node, Set Variables, is available as an attribute under the Plasticity and Porous Plasticity nodes in the Solid Mechanics, Shell, Layered Shell, Membrane, and Truss interfaces. This feature makes it possible to assign values or expressions to plastic variables based upon Boolean conditions, for both the Small plastic strains and Large plastic strains options. You can see this functionality demonstrated in the Plastic Strain Mapping model.

The COMSOL Multiphysics version 5.6 UI with the Set Variables node settings shown and a meshed model shown to the right.

Mapping of plastic strains from a triangular mesh in Component 1 to the quadrilateral mesh in Component 2 using the Set Variables node.

Large-Strain Plasticity in Layered Shell Interface

The Linear Elastic Material in the Layered Shell interface now includes the possibility to model Large-Strain Plasticity. The same set of yield functions and isotropic hardening models as in the Solid Mechanics interface are available.

It is now possible to add Plasticity to the Hyperelastic Material node in the Layered Shell interface. The new subnode uses the Large-Strain Plasticity formulation. The same set of yield functions and isotropic hardening models are available as in the Hyperelastic Material node for the Solid Mechanics interface. The Layered Shell interface requires the Composite Materials Module.

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Porous Plasticity Improvements

The Large plastic strains option is available to all the material models under the Porous Plasticity node. The formulation uses a multiplicative decomposition of deformation gradients, giving a good approximation at high compressive strains. You can see this functionality demonstrated in the Powder Compaction of a Flanged Component model. Also, the Capped Drucker-Prager model is available as an attribute under the Linear Elastic Material and Nonlinear Elastic Material nodes.

The COMSOL Multiphysics version 5.6 UI with the Porous Plasticity settings shown with the Porous Plasticity section expanded and a rotational flange model in the Graphics window.

The Porous Plasticity node settings in COMSOL Multiphysics^® version 5.6 with the Large plastic strain option and the Capped Drucker-Prager material model selected.

Nonlinear Elastic Material Improvements

A new material model called Shear data is added to the Nonlinear Elastic Material node. The new material model is similar to the Uniaxial data model, but it is intended for simulations where shear stress vs. shear angle data is available. In the Uniaxial data material model, the Hardening data can now be taken from the Material Library.

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Viscoelasticity Improvements

Two more built-in viscoelastic models are added to the Nonlinear Elastic Material: the Maxwell and Generalized Kelvin models. For frequency domain analyses, you can add fractional derivatives for all the built-in viscoelastic models.

When using a Viscoelasticity subnode under the Hyperelastic Material node, a new leaner implementation for the Generalized Maxwell and Standard Linear Solid models for large-strain viscoelasticity is available, giving significant speedups. You can see this functionality demonstrated in the Impact Analysis of a Golf Ball model.

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New Hyperelastic Material Models

Three new hyperelastic material models are added: the Extended Tube model for modeling rubber-like materials, and the Delfino and anisotropic Fung material models to simulate large deformations in biological tissue. Additionally, all of the Hyperelastic Material models available in the Solid Mechanics interface are now available in the Layered Hyperelastic Material node in the Shell interface. If the Composite Materials Module is available, the material models can also be used in multilayered shells, and the individual layers can have different material models.

The COMSOL Multiphysics version 5.6 UI with the Hyperelastic Material model settings shown and a sea urchin blastula model in the Graphics window.

A spherical sea urchin blastula modeled with the new hyperelastic Delfino material model. The plot shows the ratio between the deformed and undeformed radius for varying internal pressure and different material parameters.

Nonlinear Material Models in the Layered Shell Interface

The Linear Elastic Material node in the Layered Shell interface now includes the possibility to model Large Strain Plasticity. You can also add Plasticity to the Hyperelastic Material node in the Layered Shell interface. The Plasticity subnode uses the Large Strain Plasticity formulation, which gives a good approximation for high strain levels. Note that both the Nonlinear Structural Materials Module and Composite Materials Module are needed for this functionality. If the Composite Materials Module is available, the material models can also be used in multilayered shells.

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Damage in Layered Shells

All the Damage models available in the Solid Mechanics interface are now available for the Layered Linear Elastic Material node in the Shell interface, as well as for the Linear Elastic Material node in the Layered Shell interface. The Layered Shell interface requires the Composite Materials Module.

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Damage Improvements

There are several improvements to the Damage feature including a new phase-field-based damage model for crack propagation. The news includes:

New viscous regularization method for time-dependent analysis
Polynomial strain softening and Multilinear strain softening available for the damage evolution laws for Scalar damage and Mazars damage for concrete
New Phase field damage model, available in the Linear Elastic Material node in the Solid Mechanics interface
Damage feature available in the Layered Linear Elastic Material node of the Shell interface
Damage feature available in the Linear Elastic Material node of the Layered Shell interface
A new model: Brittle Fracture of a Holed Plate

Evolution of the crack phase field during loading of a holed plate.

Shape Memory Alloy Improvements

There are several improvements to the Shape Memory Alloy feature:

The user inputs for the Shape Memory Alloy material models are now available as material properties
For the Lagoudas model, you can enter the material data in terms of transition temperatures or transition stresses
The Souza–Auricchio model is modified to account for the reference temperature instead of the martensite finish temperature
The radius of the elastic domain is entered instead of the initial yield stress
Both the Lagoudas and Souza–Auricchio SMA models are now available in the Truss interface

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New Default Plots

New default contour plots, showing the inelastic strains, have been added for the Plasticity, Porous Plasticity, Viscoplasticity, Creep, Viscoelasticity, and Shape Memory Alloy features. Many of the Application Library models reflect this change.