Cadfil Finite Element Model Types - FEA/FEM types

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Introduction

Of all the filament winding simulation and program generation tools available commercially Cadfil has by far the most extensive and powerful tools for the creation of FEM models. There are many type of output available and many control options to choose from. This web page focuses on output for FEM modelers and solvers that support the (Nastran) bulk data data-deck format. Most FEA systems support this data type to some degree though native systems such as Nastran, Optistruct, SimCentre, Hypermesh, Hyperworks, FEmap etc provide the highest level of support for this data type. All the screen shorts in this section were created with Altair Engineering Hypermesh. Details of specific options can be found in this topic in Cadfil Help system. Cadfil has other output formats such as table data that can be imported into FEM modellers but those features are discussed elsewhere.

Shell Model and Mapped Shell Model (SH)

Shell Model
Cadfil Shell Model (SH)

The shell model can create a fully featured data-deck to run with no-touch in Nastran/Optistruct and other bulkdata based solvers. The model discretisation (division) is fully under the control of the user. The elements are CQUAD4 entries with PCOMP or PCOMPG laminates Each Filament wound layer (FWL) can be represented as 2 or 4 plies (+/- or +/-/-/+ angle), the latter giving a more balanced stress representation. Materials data can come from the Cadfil materials database or can be specified by a user defined include (text) files. Data cards created are MAT1, MAT9, MATORT, MAT8, MAT9, MAT9ORT, MATUSR dependent on the options and materials selected. A pressure load (PLOAD2) can be specified for the shell if required and a distributed load created around the end opening with axial freedom. Boundary conditions for the end opening (SPCx) can be automatically created if required. For Hypermesh HM comments can be added to create components and load collectors to make the model much more user friendly to work with in Hypermesh.

Solver Deck Features
Shell Model (2D) CQUAD, CTRIA
Materials MATxxx
Pressure Load PLOAD2/End load FORCE
Boundary conditions SPCx
Job Control Options
Complete Solver Deck
Hypermesh comments
Material axes, CORD3x
Element Properties PCOMPG/PCOMP/PSHELL

The imported shell option is similarly to the previously described shell model except that the mesh is imported into Cadfil via bulkdata and then the material, laminates etc are applied to it. This is very useful where the mesh has non-standard features, a good example being pressure tanks that have port entries cut into the side walls or domes like in the example shown below. The mesh can have CQUAD4 or CTRIA3 elements. Cadfil creates default (fully fixed) boundary conditions along the edges of all the openings however the user must review/modify these so suit the analysis requirement as Cadfil has no knowledge of how the tank is installed and restrained. Maybe the user wishes to marry the Cadfil model to other models for attached pipework or flanges. Output of loads and boundary conditions is optional.

Material Mapped on Imported Shell Model (SH)
Imported Shell Model (SH)

Cadfil Full 3D Solid Model (FULLSOL)

The full solid model (FULLSOL) is based mostly on 8 node/6 face Brick elements though there at some wedge (CPENTA) elements assigned with a resin property to manage smoother transitions where winding layers end. The model discretisation (division) is fully under the control of the user. Materials data can come from the Cadfil materials database or can be specified by a user defined include (text) files. Element properties are via PCOMPLS/PCOMPS/PSOLID cards are appropriate. One element is defined through thickness of each filament wound layers (FWL) or optionally multiple FWLs where the same winding layer is repeated. Each FWL is identified as a separate components in an Hypermesh assembly if HM comment collectors are specified in the Cadfil parameters. This allows easier manipulation of the model and clear postprocessing of stress/strain results. The mathematics of this type of model can represent through thickness stresses and interlayer stresses more rigorously than shell models. Each PCOMPx can be represented as 2 or 4 plies (+/- or +/-/-/+ angle), the latter giving a more balanced stress representation.

Solver Deck Features
Solid (Brick) Model (3D) CHEXA, CPENTA
Materials MATxxx
Pressure Load PLOAD4
Boundary conditions SPCx
Job Control Options
Complete Solver Deck
Hypermesh comments
Material axes, CORD3x
Element Properties PCOMPS/PCOMPLS/PSOLID
Shell Model
Cadfil Full 3D Solid Model (FULLSOL)
Cadfil Full 3D Solid FEA Model Hypermesh Structure
Cadfil Full 3D Solid Model Hypermesh Structure

Cadfil Cyclic Symmetry Solid Slice Model (CYSYM)

The cyclic symmetry solid model (CYSYM) is like the FULLSOL model based mostly on 8 node/6 face Brick elements and some wedge (CPENTA) elements assigned with a resin property to manage smoother transitions where winding layers end. This is a slice of the full mandrel with cyclic symmetric boundary conditions to link degrees of freedom on the opposite faces. This gives the same results as the FULLSOL model for symmetric load conditions but has onl a frcation of teh analysis time. In Altair this model lends itself to the Multiscale design (MSD) approach with progressive damage as the run time is greatly reduced. As with the FULLSOL model, the model discretisation (divisions) is fully under the control of the user. Materials data can come from the Cadfil materials database or can be specified by a user defined include (text) files. Element properties are via PCOMPLS/PCOMPS/PSOLID cards are appropriate. One element is defined through thickness of each filament wound layers (FWL) or optionally multiple FWLs where the same winding layer is repeated. Each FWL is identified as a separate components in an Hypermesh assembly if HM comment collectors are specified in the Cadfil parameters. This allows easier manipulation of the model and clear postprocessing of stress/strain results. The mathematics of this type of model can represent through thickness stresses and interlayer stresses more rigorously than shell models. Each PCOMPx can be represented as 2 or 4 plies (+/- or +/-/-/+ angle), the latter giving a more balanced stress representation.

Cyclic Symmetry Solid Slice Model
Cadfil Cyclic Symmetry Solid Slice Model (CYSYM)

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Model Features
Solid (Brick) Model (3D) CHEXA, CPENTA
Cyclic Symmetric Boundary conditions
Materials MATxxx
Pressure Load PLOAD4
Boundary conditions SPCx
Job Control Options
Complete Solver Deck
Hypermesh comments
Material axes, CORD3x
Element Properties PCOMPS/PCOMPLS/PSOLID
Cyclic Symmetry Boundary Conditions
Cadfil Cyclic Symmetry Boundary Conditions
Cyclic Symmetry Hypermesh Structure
Cyclic Symmetry Hypermesh Structure

Cadfil Laminated Solid Model (LAMSOL)

The LAminated solid LAMSOL option is made of solid brick elements, this has one element through the thickness with the layer being a laminate stack of all the winding layers. This model has improved physics over a simple shell model in some solvers and analysis types.

Solver Deck Features
Solid (Brick) Model (3D) CHEXA
Materials MATxxx
Pressure Load PLOAD4
Boundary conditions SPCx
Job Control Options
Complete Solver Deck
Hypermesh comments
Material axes, CORD3x
Element Properties PCOMPS/PCOMPLS
Laminated Solid Model (LAMSOL)
Laminated Solid Model (LAMSOL)
Laminated Solid Model  Boundary Conditions
Laminated Solid Model Boundary Conditions

Solid model merged with liner model

It is possible to make a composite model in Cadfil and a liner with inserts model in the FEA preprocessor and then merge the two models. Because the discretisation of the mesh can be controlled by the user the nodes can be made to match in the two models. An example in Hypermesh is show below. A Cadfil example showing the method for contracting this model is available if required.

Laminated Solid Model  Boundary Conditions
Cadfil and external Liner/Insert model Marriage
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Updated: 06 April 2021