Controlling the birth and death times of elements in nonlinear and thermal analyses (Simcenter Samcef)

During the solve of a Simcenter Samcef nonlinear analysis, parts of a structure may need to be added to or removed from a finite element model.

In a Simcenter Samcef structural nonlinear analysis or thermal heat transfer analysis, the Element Birth/Death simulation object lets you define the birth and death times for a specific set of elements.

Once an element is born, the element mass matrix, stiffness matrix, and force vector are added to the mass matrix, stiffness matrix, and force vector of the total element assemblage (until the death time, if any).

Similarly, once an element dies, the element mass matrix, stiffness matrix, and force vector are removed from the total assembled mass matrix, stiffness matrix, and force vectors for all solution times equal to or later than the time of death of the element.

In the Element Birth/Death simulation object, you can define the Element Birth Time value and/or the Element Death Time value.

Limitations on the elements you can select

The Element Birth/Death simulation object is available in the Simcenter Samcef environment with the following limitations on the elements you can select:

• The simulation objects are available for the Structural or Axisymmetric and Other 2D Structural analysis types with a Nonlinear Analysis solution type.Within this configuration, in the Element Birth/Death simulation objects, you can only select the following Simcenter Samcef structural elements:T8, T46, T47, T247 solidsT11, T25 multilayer solidsT15, T26 axisymmetric solids

• The simulation object is also available for the Thermal analysis type with a Heat Transfer solution type.Within this configuration, in the Element Birth/Death simulation object, you can only select the following Simcenter Samcef thermal elements:T39, T103, T105, T106 solids and multilayer solidsT34, T35 axisymmetric solidsT223, T224 thermal shell membranes and multilayer shell membranes

Limitations

• By default, all the elements are alive from the starting time of the computation.

• You can only specify one Element Birth Time value and one Element Death Time value per element.

• When you specify both the Element Birth Time and Element Death Time values for an element, the birth time value must be smaller than the death time value.

• When you specify the Element Birth Time value for an element, by default, this element is deactivated from the starting time of the computation.

Note:

In addition to the birth or death of elements at specific times, you can also enable or disable entities for an entire subcase. For more information, see Enabling or disabling entities (Simcenter Samcef).

Where do I find it?

Application	Pre/Post
Prerequisite	A Simulation file as the work part and the displayed partSimcenter Samcef as the specified solverStructural or Axisymmetric and Other 2D Structural as the specified analysis typeNonlinear Analysis as the specified solution typeThermal as the specified analysis typeHeat Transfer as the specified solution type
Command Finder	Element Birth/Death
Simulation Navigator	Right-click Simulation Objects→New Simulation Object→Element Birth/Death

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Element Birth/Death dialog box (Simcenter Samcef)

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Controlling the birth and death times of elements in nonlinear and thermal analyses (Simcenter Samcef), Simcenter 3D 2021.1 Series

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