Defining Material Activation

You can specify how eigenstrains or thermal parameters are applied to the model for element activation.

The steps below are based on use of the default (Built-in) schema for material activation that is embedded in the app. You can use a custom schema instead by choosing User defined as the source. A custom schema redefines the interface (dialog box) to work with a user subroutine that exposes only the options required for your process. In this case, your material activation options might be different from those described.

This task shows you how to:

Defining Trajectory-Based Material Activation
Defining Pattern-Based Material Activation
Defining Thermal Pattern-Based Material Activation

Defining Trajectory-Based Material Activation

You can activate elements with a supplied event series. This option is only available in the eigenstrain workflow.

Before you begin: To understand the entries and definitions required, review the Abaqus user subroutines and keywords for use with additive manufacturing.

From the Additive Manufacturing section of the action bar, click Material Activation .
Select the part.
The part indicates the predefined volume (part or mesh) that is filled with material, layer by layer, to become a real part as the additive manufacturing process is completed.
Select Follow deformation to have inactive elements—elements within the mesh of the part volume that do not yet contain enough material to be activated—follow the model deformation.
If there is significant model deformation and inactive elements do not follow the deformation, they can distort because of their connection to the motion of the active elements. When the inactive elements are activated, the distortion can cause problems with the simulation.
Optional: Edit the Eigenstrain time constant.
The eigenstrain time constant ramps up the selected eigenstrain at element activation. Applying the strains gradually can aid in solution convergence, especially when there is plasticity. The default constant is two times the initial time increment in the static step.
Optional: Select the Additive manufacturing library.
This step is required only if you have created more than one library in the current simulation. Otherwise the application automatically selects the single library.
Switch the Simulation method to trajectory based.
Specify Stack direction.
- X
- Y
- Z
Specify a bead height.
Specify a bead width.
Specify a deposition position.
- Above
- Below
For each laser rule listed in the table, specify the eigenstrain to apply in the analysis when this rule is active.
Select Full or Partial activation.
Full activation uses only the Max volume fraction to activate an entire mesh element when it is filled to at least the specified amount. Partial activation partially activates elements based on the Activation Threshold and fully activates them at the Max volume fraction.
Enter the Activation Threshold as a fraction.
The activation threshold applies partial activation. For example, you could partially activate an element at 0.05 (5%) fill to begin simulating that area of the part.
Enter the Max volume fraction.
The maximum volume fraction applies to both full and partial activation. The maximum volume fraction is the amount of fill at which an element is treated as completely filled with material. For example, you could treat all elements with at least 0.90 as filled.

Defining Pattern-Based Material Activation

You can activate elements with a user-defined eigenstrain pattern. This option is available only in the eigenstrain workflow.

From the Additive Manufacturing section of the action bar, click Material Activation .
Select the part.
The part indicates the predefined volume (part or mesh) that is filled with material, layer by layer, to become a real part as the additive manufacturing process is completed.
Select Follow deformation to have inactive elements—elements within the mesh of the part volume that do not yet contain enough material to be activated—follow the model deformation.
If there is significant model deformation and inactive elements do not follow the deformation, they can distort because of their connection to the motion of the active elements. When the inactive elements are activated, the distortion can cause problems with the simulation.
Optional: Edit the Eigenstrain time constant.
The eigenstrain time constant ramps up the selected eigenstrain at element activation. Applying the strains gradually can aid in solution convergence, especially when there is plasticity. The default constant is two times the initial time increment in the static step.
Optional: Select the Additive manufacturing library.
This step is required only if you have created more than one library in the current simulation. Otherwise the application automatically selects the single library.
Switch the Simulation method to pattern based.
Specify the Axis system definition for the build direction.
Specify the Slice Thickness to define the thickness of each layer.
Select a how the start and end times are applied with the Time Selector.
- Total time
- Step time
Enter the start time for the beginning of the element activation, if the activation starts after the step or analysis begins.
Enter the end time for when the element activation ends, if the activation ends before the step or analysis completes.
Select the Activation technique.
- Sweep to activate elements sequentially across a layer over the course of the increment.
- Layer by layer to activate all elements in a layer at the same time.
Optional: Check One slice per increment to adjust the analysis incrementation such that a single layer is activated in a single increment.
Enter data in the table to apply a strain pattern patch from the eigenstrain library to the model. You can select a patch, specify its bounding box, and add a rotation angle.
Select Full or Partial activation.
Full activation uses only the Max volume fraction to activate an entire mesh element when it is filled to at least the specified amount. Partial activation partially activates elements based on the Activation Threshold and fully activates them at the Max volume fraction.
Enter the Activation Threshold as a fraction.
The activation threshold applies partial activation. For example, you could partially activate an element at 0.05 (5%) fill to begin simulating that area of the part.
Enter the Max volume fraction.
The maximum volume fraction applies to both full and partial activation. The maximum volume fraction is the amount of fill at which an element is treated as completely filled with material. For example, you could treat all elements with at least 0.90 as filled.

Defining Thermal Pattern-Based Material Activation

You can activate elements with a user-defined thermal parameter pattern. This option is available only in the thermal-mechanical pattern workflow.

From the Additive Manufacturing section of the action bar, click Material Activation .
Select the part.
The part indicates the predefined volume (part or mesh) that is filled with material, layer by layer, to become a real part as the additive manufacturing process is completed.
Select Follow deformation to have inactive elements—elements within the mesh of the part volume that do not yet contain enough material to be activated—follow the model deformation.
If there is significant model deformation and inactive elements do not follow the deformation, they can distort because of their connection to the motion of the active elements. When the inactive elements are activated, the distortion can cause problems with the simulation.
Optional: Edit the Expansion time constant.
The expansion time constant ramps up the thermal strain at element activation. Applying the strains gradually can aid in solution convergence, especially when there is plasticity. The default constant is two times the initial time increment in the static step.
Optional: Select the Additive manufacturing library.
This step is required only if you have created more than one library in the current simulation. Otherwise the application automatically selects the single library.
Switch the simulation method to pattern-based.
Specify the Axis system definition for the build direction.
Specify the Slice thickness to define the thickness of each layer.
Select a how the start and end times are applied with the Time Selector.
- Total time
- Step time
Enter the Start time for the beginning of the element activation, if the activation starts after the step or analysis begins.
Enter Recoater time to describe how long the roller takes to traverse the powder bed.
Select the Activation technique.
- Sweep to activate elements sequentially across a layer over the course of the increment.
- Layer by layer to activate all elements in a layer at the same time.
Optional: Enter the Number of layers per increment to adjust the analysis incrementation such that the specified number of layers are activated in a single increment.
Enter data in the table to apply a strain pattern patch from the eigenstrain library to the model. You can select a patch, specify its bounding box, and add a rotation angle.
Select Full or Partial activation.
Full activation uses only the Max volume fraction to activate an entire mesh element when it is filled to at least the specified amount. Partial activation partially activates elements based on the Activation Threshold and fully activates them at the Max volume fraction.
Enter the Activation Threshold as a fraction.
The activation threshold applies partial activation. For example, you could partially activate an element at 0.05 (5%) fill to begin simulating that area of the part.
Enter the Max volume fraction.
The maximum volume fraction applies to both full and partial activation. The maximum volume fraction is the amount of fill at which an element is treated as completely filled with material. For example, you could treat all elements with at least 0.90 as filled.