Updated in September 2017
Prepared by Aleksandr Cherniaev - Univerity of Waterloo, Canada
GENERAL NOTES FROM LS-DYNA SUPPORT: Composite models || Define Composites || Cohesive materials || Cohesive Elements || History Variables || AOPTs
GENERAL OVERVIEW OF MODELING TECHNIQUES: Recent developments in reinforced polymer modelling in LS-DYNA || Single-Slide Overview || Single-Graph Overview
DELAMINATION MODELING: Best Practices (Aerospace Group) || Tiebreak Contacts (DYNA Support) || Tied Contact With Failure (Presentation) || Cohesive Contact Delamination Modeling (Paper) || Delamination Using CZI Elements and Tiebreak Contact (Paper) || Adhesives Modeling (Presentation)
TABLE 1 - MATERIAL MODELS SUITABLE FOR POLYMER MATRIX COMPOSITES
| MAT # | Name | Brief Description | Elements | Comments | Additional References |
|---|---|---|---|---|---|
| *MAT_002 | *MAT_OPTIONTROPIC_ELASTIC | This material is valid for modeling the elastic-orthotropic behavior of materials. | Shell, TShell, Solid | ||
| *MAT_021 | *MAT_ORTHOTROPIC_THERMAL_{OPTION} | A linearly elastic, orthotropic material with orthotropic thermal expansion. | |||
| *MAT_022 | *MAT_COMPOSITE_DAMAGE | An orthotropic material with optional brittle failure for composites. | Include a delamination failure criterion when used with solid elements. | ||
| *MAT_023 | *MAT_TEMPERATURE_DEPENDENT_ORTHOTROPIC | An orthotropic elastic material with arbitrary temperature dependency. | |||
| *MAT_040 | *MAT_NONLINEAR_ORTHOTROPIC | This model allows the definition of an orthotropic nonlinear elastic material based on a finite strain formulation with the initial geometry as the reference. Failure is optional with two failure criteria available. Optionally, stiffness proportional damping can be defined. In the stress initialization phase, temperatures canbe varied to impose the initial stresses. | Shell, Solid | ||
| *MAT_054-055 | *MAT_ENHANCED_COMPOSITE_DAMAGE (input) | Enhanced versions of the composite model material type 22. Arbitrary orthotropic materials (e.g., unidirectional layers in composite shell structures can be defined). Various types of failure. | STRENGTH reduction factors after failure initiation; Crashfront elements softening. | A B C D E Single-Element | |
| *MAT_058 | *MAT_LAMINATED_COMPOSITE_FABRIC (input) | Damage mechanics-based model. Depending on the type of failure surface, this model may be used to model composite materials with unidirectional layers, complete laminates, and woven fabrics. Current version includes strain rate effects for both strength and stiffness parameters. | Shell, TShell (1,2) | The main difference to MAT_054 lies in the smooth increase of damage; no sudden change in meterial behavior occurs, which appears to be physically more correct. | A B C D E Theory |
| *MAT_059 | *MAT_COMPOSITE_FAILURE_{OPTION}_MODEL | Shell, Solid, SPH | Include a delamination failure criterion when used with solid elements. | A | |
| *MAT_086 | *MAT_ORTHOTROPIC_VISCOELASTIC | Allows the definition of an orthotropic material with a viscoelastic part. | Shell | Elastic constants are the only input. Does not support specification of a material angle, beta, for each through-thickness integration point of a shell. | |
| *MAT_104 | *MAT_DAMAGE_1 | A continuum damage mechanics (CDM) model which includes anisotropy and viscoplasticity. | Shell, TShell, Solid | ||
| *MAT_108 | *MAT_ORTHO_ELASTIC_PLASTIC | Combines orthotropic elastic plastic behavior with an anisotropic yield criterion. | Shell | ||
| *MAT_114 | *MAT_LAYERED_LINEAR_PLASTICITY | A layered elastoplastic material with an arbitrary stress versus strain curve and an arbitrary strain rate dependency can be defined. This material must be used with the user defined integration rules, see *INTEGRATION-SHELL, for modeling laminated composite and sandwich shells where each layer can be represented by elastoplastic behavior with constitutive constants that vary from layer to layer. Individual layers are isotropic | Shell | Lamination theory is applied to correct for the assumption of a uniform constant shear strain through the thickness of the shell. Unless this correction is applied, the stiffness of the shell can be grossly incorrect leading to poor results. Generally, without the correction the results are too stiff. | |
| *MAT_116 | *MAT_COMPOSITE_LAYUP | This material is for modeling the elastic responses of composite layups that have an arbitrary number of layers through the shell thickness. A preintegration is used to compute the extensional, bending, and coupling stiffness. | Shell | Resultant formulation (no stresses calculated) | |
| *MAT_117 | *MAT_COMPOSITE_MATRIX | This material is used for modeling the elastic responses of composites where a pre-integration is used to compute the extensional, bending, and coupling stiffness coefficients. 21 coefficients of stiffness matrix are input. Stiffness coefficients given in material coord system . | Shell | Resultant formulation (no stresses calculated) | |
| *MAT_118 | *MAT_COMPOSITE_DIRECT | This material is used for modeling the elastic responses of composites where a pre-integration is used to compute the extensional, bending, and coupling stiffness coefficients. 21 coefficients of stiffness matrix are input. Stiffness coefficients given in element coord system (less storage req'd). | Shell | Resultant formulation (no stresses calculated) | |
| *MAT_132 | *MAT_ORTHOTROPIC_SMEARED_CRACK | This material is a smeared crack model for orthotropic materials with optional delamination failure for brittle composites. | Solid | No strain rete effects. From Ref. A: This is in itself a material card that provides behaviour comparable with cohesive modelling. However, delamination would amount to the erosion of a part of the actual in-plane load carrying material. This would lead to erroneous results in terms of stiffness/strength of a component. Trying to minimise that amount would additionally lead to very small elements through the thickness and would subsequently unacceptably limit the time step. | A |
| *MAT_157 | *MAT_ANISOTROPIC_ELASTIC_PLASTIC | This is Material Type 157. This material model is a combination of the anisotropic elastic material model (MAT_002) and the anisotropic plastic material model (MAT_103_P). Also, brittle orthotropic failure based on phenomenological Tsai-Wu or Tsai-Hill criterion can be defined. | Shell, Solid | Common application - short fiber reinforced plastics | A B C D E |
| *MAT_158 | *MAT_RATE_SENSITIVE_COMPOSITE_FABRIC | Depending on the type of failure surface, this model may be used to model rate sensitive composite materials with unidirectional layers, complete laminates, and woven fabrics. Work reasonably well if the stress increases due to rate affects are up to 15% of the total stress. Updated version of MAT_058 does not have the 15% limitation (see above). | Shell, TShell | ||
| *MAT_161-162 UDelaware | *MAT_COMPOSITE_MSC_{OPTION} | Progressive failure models for composite materials consisting of unidirectional and woven fabric layers. These failure models can be used to effectively simulate fiber failure, matrix damage, and delamination behavior under all conditions - opening, closure, and sliding of failure surfaces. Also take into account the effect of highly constrained pressure on composite failure. MAT_162 includes damage model, which is a generalization of the layer failure model of MAT_161 by adopting the MLT damage mechanics approach, Matzenmiller et al. [1995], for characterizing the softening behavior after damage initiation - the same damage mechanics approach as used for MAT_058 [ACh.]. The failure criteria of fiber, delamination and matrix damage modes are used as damage surfaces in strain space. Damage increases when the strain path intersects the damage surfaces and the strain increment has a non-zero component in the direction normal to the damage surfaces. The model includes a stress-based delamination failure criterion. This approach to predicting interlaminar failure is advantageous in cases when locations of delamination sites (i.e., interlaminar crack initiation surfaces) cannot be anticipated. |
Solid only (single point integration) | Require an additional license from Materials Sciences Corporation
Best applicable to modeling of transverse impact on thick-section composites, where transverse shear damage is important. Only ONE material angle (BETA) per solid element --> a multidirectional laminate must be defined by multiple solid elements through-the-thickness (WOW!). Delamination planes are automatically defined at the interfaces between parts/solid elements with different material angles (BETA). |
A B C D |
| *MAT_215 | *MAT_4A_MICROMEC | A micromechanical material that distinguishes between a fiber/inclusion and a matrix material, developed by 4a engineering GmbH. Intended for short and long fiber thermoplastics. | Explicit only: Shell, TShell, Solid | A B C | |
| *MAT_219 | *MAT_CODAM2 (input) | This material model is the second generation of the UBC Composite Damage Model (CODAM2) developed at the University of British Columbia. The model is a sub-laminate-based continuum damage mechanics model for fiber reinforced composite laminates made up of transversely isotropic layers. The material model includes an optional non-local averaging and element erosion. This model does not intend to predict the details of damage in the laminate. Rather, by assuming the effective strain-softening behaviour of the layers, the goal is to capture the overall response of the laminate in a structure. | Shell, TShell, Solid | Strain-only (no strength) input. Multiple non-standard experiments are required for parameters' identification for this model. Not all possible layups/stacking sequences can be represented as a result of "sublaminate approach" employed in this model. No strain-rate sensitivity |
A B C |
| *MAT_221 | *MAT_ORTHOTROPIC_SIMPLIFIED_DAMAGE | An orthotropic material with optional simplified damage and optional failure for composites can be defined.The elastic behavior is the same as MAT_022. Nine damage variables are defined such that damage is different in tension and compression. These damage variables are applicable to Ea, Eb, Ec, Gab, Gbc and Gca. In addition, nine failure criteria on strains are available. When failure occurs, elements are deleted (erosion). Failure depends on the number of integration points failed through the element. | Solid | ||
| *MAT_261 | *MAT_LAMINATED_FRACTURE_DAIMLER_PINHO | An orthotropic continuum damage model for laminated fiber-reinforced composites. It is based on a physical model for each failure mode and considers non-linear in-plane shear behavior. | Shell, TShell (3,5), Solid | MAT_261_vs_MAT_262 | A Pinho1 Pinho2 |
| *MAT_262 | *MAT_LAMINATED_FRACTURE_DAIMLER_CAMANHO (input) | An orthotropic continuum damage model for laminated fiber-reinforced composites. It is based on a physical model for each failure mode and considers a simplified non-linear in-plane shear behavior. The intraply failure mechanisms occurring in the longitudinal and transverse directions of a ply are represented by a set of scalar damage variables. Damage activation functions based on the LaRC04 failure criteria are used to predict the different failure mechanisms occurring at the ply level. | Shell, TShell (3,5), Solid | A B C Camanho1 Camanho2 LaRC03 LaRC04 |
TABLE 2 - MATERIAL MODELS SUITABLE FOR DRY FABRICS AND FORMING SIMULATIONS
| MAT # | Name | Brief Description | Elements | Comments | Additional References | *MAT_034 | *MAT_FABRIC | The fabric model is a variation on the layered orthotropic composite model of material 22. Especially developed for airbag materials. | Membrane | DRY FABRIC |
|---|---|---|---|---|---|
| *MAT_034M | *MAT_FABRIC_MAP | This is Material Type 34 in which the stress response is given exclusively by tables. | DRY FABRIC | ||
| *MAT_214 | *MAT_DRY_FABRIC | This material model can be used to model high strength woven fabrics, such as Kevlar49, with transverse orthotropic behavior for use in structural systems where high energy absorption is required. The major applications of the model are for the materials used in propulsion engine containment system, body armor and personal protections. | DRY FABRICS | ||
| *MAT_234 | *MAT_VISCOELASTIC_LOOSE_FABRIC | The model is a mechanism incorporating the crimping of the fibers as well as the trellising with reorientation of the yarns and the locking phenomenon observed in loose fabric. The equilibrium of the mechanism allows the straightening of the fibers depending on the fiber tension. The contact force at the fiber cross over point determines the rotational friction dissipating a part of the impact energy. The stress-strain relationship is viscoelastic based on a three-element model. The failure of the fibers is strain rate dependent. *DAMPING_-PART_MASS is recommended to be used in conjunction with this material model. This material is valid for modeling the elastic and viscoelastic response of loose fabric used in body armor, blade containments, and airbags. | DRY FABRICS | ||
| *MAT_235 | *MAT_MICROMECHANICS_DRY_FABRIC | The material model derivation utilizes the micro-mechanical approach and the homogenization technique usually used in composite material models. The model accounts for reorientation of the yarns and the fabric architecture. The behavior of the flexible fabric material is achieved by discounting the shear moduli of the material in free state, which allows the simulation of the trellis mechanism before packing the yarns. This material is valid for modeling the elastic response of loose fabric used in inflatable structures, parachutes, body armor, blade containments, and airbags. | DRY FABRICS | ||
| *MAT_249 | *MAT_REINFORCED_THERMOPLASTIC | This material model describes a reinforced thermoplastic composite material. The reinforcement is defined as an anisotropic hyperelastic material with up to three distinguished fiber directions. It can be used to model unidirectional layers as well as woven and NON-CRIMPED fabrics. The matrix is modeled with a simple thermal elasto-plastic material formulation. For a composite an additive composition of fiber and matrix stresses is used. | Soft tissue (muscles), FORMING with woven and NON-CRIMP FABRICS | A | |
| *MAT_249_UDFIBER | *MAT_REINFORCED_THERMOPLASTIC_UDFIBER | Describes a material with unidirectional fiber reinforcements and considers up to three distinguished fiber directions. Each fiber family is described by a spatially transversely isotropic neo-Hookean (hyperelastic) constitutive law. | Shell, explicit only | Application: Forming with UNIDIRECTIONAL NON-CRIMP FABRICS | A |
| *MAT_293 | *MAT_COMPRF | This material models the behavior of pre-impregnated (prepreg)composite fibers during the high temperature preforming process. In addition toproviding stress and strain, it also provides warp and weft yarn directions and stretchratios after the forming process. The major applications of the model are for materials used in light weight automobile parts. |
TABLE 3 - MATERIAL MODELS SUITABLE FOR COHESIVE MATERIALS
| MAT # | Name | Brief Description | Elements | Comments | Additional References |
|---|---|---|---|---|---|
| *MAT_ADD_COHESIVE | *MAT_ADD_COHESIVE | The ADD_COHESIVE option offers the possibility to use a selection of three dimensional material models in LS-DYNA in conjunction with cohesive elements. Usually the cohesive elements (ELFORM = 19 and 20 of *SECTION_SOLID) can only be used with a small number of material models (41-50, 138, 184, 185, 186, 240). But with this additional keyword, a larger number of standard three dimensional material models can be used that would only be available for solid elements in general. Currently the following material models are supported: 1, 3, 4, 6, 15, 24, 41-50, 81, 82, 89, 96, 98, 103, 104, 105, 106, 107, 115, 120, 123, 124, 141, 168, 173, 187, 188, 193, 224, 225, 252, and 255. | Solid | ||
| *MAT_138 | *MAT_COHESIVE_MIXED_MODE | This model is a simplification of *MAT_COHESIVE_GENERAL restricted to linear softening. It includes a bilinear traction-separation law with quadratic mixed mode delamination criterion and a damage formulation. | |||
| *MAT_184 | *MAT_COHESIVE_ELASTIC | It is a simple cohesive elastic model for use with cohesive element fomulations. | |||
| *MAT_185 | *MAT_COHESIVE_TH | It is a cohesive model with the implementation based on the description of the implementation in the Sandia National Laboratory code, Tahoe [2003]. | |||
| *MAT_186 | MAT_COHESIVE_GENERAL | The material model includes three general irreversible mixed-mode interaction cohesive formulations with arbitrary normalized traction-separation law given by a load curve (TSLC). These three formulations are differentiated via the type of effective separation parameter (TES). The interaction between fracture modes I and II is considered, and irreversible conditions are enforced via a damage formulation (unloading/reloading path pointing to/from the origin). | |||
| *MAT_240 | *MAT_COHESIVE_MIXED_MODE_ELASTOPLASTIC_RATE | This model is a rate-dependent, elastic-ideally plastic cohesive zone model. It includes a tri-linear traction-separation law with a quadratic yield and damage initiation criterion in mixed-mode loading, while the damage evolution is governed by a power-law formulation. |
