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.
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.
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.
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.
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.
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.
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.
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.
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
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
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.
New Tutorial Models
COMSOL Multiphysics® version 5.6 brings several new tutorial models to the Nonlinear Structural Materials Module.
Impact Analysis of a Golf Ball
Application Library Title:
golf_ball_impact
Brittle Fracture of a Holed Plate
Application Library Title:
holed_plate_fracture
Plastic Strain Mapping
Application Library Title:
plastic_strain_mapping
Powder Compaction of a Rotational Flanged Component
Application Library Title:
compaction_of_a_rotational_flange