A simulation called dynamic when some of parameter are variably in line with time alteration or can be said time based simulation. For example box positions in dynamic motion simulation post, are categorized as time based simulation because its change collateral with time increases. If your simulation are contains displacement, velocity, acceleration or any variable that depend on time so it’s your dynamic simulation.
How about Finite Element Analysis, what kind of FEA simulation are categories as dynamic? For example in Stress simulations post, are categorized as static FEA since no time based variable are involve, how about the video that obviously shows stress vary with time? No, its only animation with using load factor and there are no stress output data generated by Msc.Visual Nastran 4D that depend of time. The main distinction parameters to grouping our analysis in static or dynamic field are equivalent stress with von misses theory (svm):
Remark:
To gain comprehension and knows the different more clearly to identify a Finite Element Analysis category, I will explain each below:
STATIC FEA
Finite Element Analysis described as static if meet the condition where yield strength of material are greater than generated stress (svm≤syield), as an effect for exposing external load in object or model. So if we said our visual display consist of frame by frame in proportion with time, any deformation or shape transformation as calculation result that performed previous frame are neglected in the next frame so our model assume recover instantly or never been receive any load before, this assumption are applied because stress works in elastic area of material or usually known as small deformation analysis.
This static FEA regularly used to verify whether current design meet infinite life time work condition or not ,of course combining the stress calculation result with theory of failure that include safety factor in it.
DYNAMIC FEA
In contrary, if generated stresses from external load are passing yield strength so your simulations are categorized as dynamic FEA (svm>syield). Deformation or change shape in analyzed model because of exposed load aren’t neglected so continuously effect especially shape transformation are considerate as calculation variable for next frame depend on time range that decided by user, its known also as Large deformation analysis
These methods are useful to see behavior of our model when work in over load condition, such as collision analysis, crack propagation and etc.
In picture below I made some example a loaded bar tip and hold fix in the other end with frame by frame overview
To decide whether our FEA are static or dynamic can be easily recognize by using Stress-Strain Diagram, in which area they perform analysis
In some mechanical engineer literature, "Static FEA" also mention as "Linear Static FEA" since linear slope in elastic area base on above diagram.
In Vn4D we can collaborated both Motion and Finite Element Analysis in a single simulation environment of course with condition that calculated FEA have to meet linear static FEA requirement, if doesn’t, it will shows error message that says the calculated result doesn’t pass the validation test.
Now we know that Finite Element Analysis also divides in two categories, If linear static FEA can be handled by Msc.Visual Nastran 4D (Vn4D) so how about dynamic FEA? I will explain how to perform Dynamic FEA with software ANSYS-LS DYNA in other post.
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