Thermomechanical Analysis of FDM- and LDED-Type Additive Manufacturing Processes

Special-purpose techniques and user subroutines are available for FDM- and LDED-type additive manufacturing processes. These internal built-in user subroutines are accessed by starting names and types with "ABQ_" as described below.

This page discusses:

See Also
Progressive Element Activation
In Other Guides
Sequential thermomechanical analysis of a directed energy deposition build
Defining Moving or Stationary Nonuniform Heat Flux in User Subroutine UMDFLUX
Accessing Abaqus Table Collections
Accessing Abaqus Event Series Data
*EVENT SERIES
*EVENT SERIES TYPE
*TABLE COLLECTION
*PARAMETER TABLE
*PARAMETER TABLE TYPE
*PROPERTY TABLE
*PROPERTY TABLE TYPE

ProductsAbaqus/Standard

In a fusion deposition modeling (FDM)-type additive manufacturing process, the raw material is injected through a nozzle onto a platform. The nozzle traces the cross-section pattern for each layer with the raw material. Materials are typically deposited layer-upon-layer until the build is complete. The raw material can be deposited in a molten state and then hardens as it cools. In some processes, such as laser direct energy deposition (LDED), the raw material is injected in a powdered form and then heated in place by a laser beam.

Specifying Progressive Element Activation

The deposition of raw material from a moving nozzle is simulated using progressive element activation in a structural or a thermal analysis. The cross-section of the nozzle and the bead of the material being deposited are assumed to be rectangular (see Figure 1). The following steps are required to define the deposition process completely:

  • Define the motion of the nozzle in an event series.
  • Create a table collection with a name that begins with "ABQ_AM". The table collection must contain a parameter table of type "ABQ_AM_MaterialDeposition" and a parameter table of type "ABQ_AM_MaterialDeposition_Bead".
  • In the parameter table of type "ABQ_AM_MaterialDeposition", include a reference to the event series for the nozzle motion, and set the deposition process type to "Bead".
  • In the parameter table of type "ABQ_AM_MaterialDeposition_Bead", define the process parameters, such as the height and width of the bead.
  • Refer to the table collection in the progressive element activation.

Abaqus activates elements automatically according to the specified nozzle trajectory.

Figure 1. Progressive element activation for FDM and LDED processes.

A dedicated collection of parameter table, property table, and event series types is available to include all of the definitions required by special-purpose techniques for additive manufacturing. You can use the abaqus fetch utility to obtain the file containing all of the type definitions of parameter tables, property tables, and event series required by the special-purpose techniques for additive manufacturing as follows:

abaqus fetch job=ABQ_am_special_purpose_types.inp

Input File Usage

Use the following options to define element activation for an FDM- or LDED-type process:

EVENT SERIES, NAME=event series name, TYPE="ABQ_AM_MaterialDeposition"
data lines to define the motion of the nozzle
TABLE COLLECTION, NAME="ABQ_AM.table_collection_name"
PARAMETER TABLE, TYPE="ABQ_AM_MaterialDeposition" 
event series name, "Bead"
PARAMETER TABLE, TYPE="ABQ_AM_MaterialDeposition_Bead"
"Z", bead height, bead width, activation offset, "Below"
PARAMETER TABLE, TYPE="ABQ_AM_MaterialDeposition_Advanced"
"Full" or "Partial", min volume fraction threshold for partial activation, 
max volume fraction threshold for partial activation, 
volume fraction threshold for full activation, update orientation, element subdivision order
...
ELEMENT PROGRESSIVE ACTIVATION, NAME=activation name, ELSET=element set name
...
STEP
STATIC or HEAT TRANSFER
...
ACTIVATE ELEMENTS, ACTIVATION=activation name
"ABQ_AM_table collection name"
...

Specifying Progressive Element Activation for a Material Bead with Variable Size and Orientation

You can simulate the deposition of a raw material bead from a moving nozzle using progressive element activation in a structural or a thermal analysis. The height, width, and orientation of the rectangular cross-section of the bead of the deposited raw material can vary with time.

The following steps are required to define the deposition process completely:

A dedicated collection of parameter table, property table, and event series types is available to include all of the definitions required by special-purpose techniques for additive manufacturing. You can use the abaqus fetch utility to obtain the file containing all of the type definitions of parameter tables, property tables, and event series required by the special-purpose techniques for additive manufacturing as follows:

abaqus fetch job=ABQ_am_special_purpose_types.inp

Input File Usage

Use the following options to define element activation for an FDM- or LDED-type process:

EVENT SERIES,  NAME=event series name, TYPE="ABQ_AM_MaterialDeposition_5AxisStrategy_VariableCrossSection"
t1, x1, y1, z1, 1, Z11x, Z11y, Z11z, h1, w1 
t2, x2, y2, z2, 1, Z12x, Z12y, Z12z, h2, w2 
...
TABLE COLLECTION, NAME="ABQ_AM_table_collection_name"
PARAMETER TABLE, TYPE="ABQ_AM_MaterialDeposition" 
event series name, "Bead"
PARAMETER TABLE, TYPE="ABQ_AM_MaterialDeposition_Bead"
"X", "Y", or "Z", bead height, bead width, activation offset, "Below" , "Middle", or "Above"
PARAMETER TABLE, TYPE="ABQ_AM_MaterialDeposition_5AxisStrategy"
"false", 2, 3, 4
PARAMETER TABLE, TYPE="ABQ_AM_MaterialDeposition_VariableBeadSize"
5, 6
PARAMETER TABLE, TYPE="ABQ_AM_MaterialDeposition_Advanced"
"Full" or "Partial", min volume fraction threshold for partial activation, 
max volume fraction threshold for partial activation, 
volume fraction threshold for full activation, update orientation, element subdivision order
...
ELEMENT PROGRESSIVE ACTIVATION, NAME=activation name, ELSET=element set name
...
STEP
STATIC or HEAT TRANSFER
...
ACTIVATE ELEMENTS, ACTIVATION=activation name
"ABQ_AM_table collection name"
...

Specifying a Moving Heat Source

For information on specifying a moving heat source for FDM- and LDED-type additive manufacturing processes, see Specifying a Concentrated Moving Heat Source, Specifying a Moving Heat Source with a Goldak Distribution, and Specifying a Moving Heat Source with a Uniform Distribution.

The toolpath-mesh intersection module can attach only a single element set to each event series. If you define an event series to activate a bead of material and use the same event series to define the path of a heat source, the heat source applies only to the elements in the bead. To apply the heat source to additional elements, you should define two separate event series, one for the material deposition and one for the moving heat source.