Can you anyone help me regarding element birth and death technique. My questions 1) what is the value of Stiffness multiplication for transient thermal analysis in element birth and death analysis.
2) is it required to activate the previous elements which is already done the simulation along with the new elements which I'm going to solve. The example I have 10 load steps in that solved the 1 step, Now I am applying a load to the 2 step in this I need to activate the 1step elements as well as 2step elements also?
Hi,
all the necessary information is provided in "Understanding Element Birth and Death" in the "ANSYS Advanced Analysis Guide":
1) Elements are "killed", i.e. deactivated, by multiplying their stiffness (or conductivity, or other analogous quantity) by a severe reduction factor (ESTIF command). This factor is set to 1.0E-6 by default, but can be given other values.
2) Element loads associated with deactivated elements are zeroed out of the load vector. Similarly, mass, damping, specific heat, and other such effects are set to zero for deactivated elements. An element's strain is also set to zero as soon as that element is killed. When an element is reactivated, i.e. "born", its stiffness, mass, element loads, etc. return to their full original values. Elements are reactivated with no record of strain history (or heat storage, etc.). Thermal strains are computed for newly-activated elements based on the current load step temperature and the reference temperature. Thus, newborn elements with thermal loads may not be stress-free as intended.
Regards
ANSYS - DEFAULT 1.0E-6 MULTIPLIER.
It is possible to activate any set elements.
These things achieved with in *Do loop by simple logic formula.
Hi
The Nastran trick for killing elements is simply by adding elements with negative Youngs modulus to the elements you wish to kill.
/Claes
Does anyone know how the element birth and death in ABAQUS works? I am trying to develop a model for metal powder bed in AM for ABAQUS, so initially I have properties of the metal powder that will be submitted to a laser scan, melt, and solidify into a part with different properties.
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