Case5 Force-based bed length constraint (Low stiffness)
Contents
The data file for this exercise is located in Rest_001/Exercices/Case5/Data. Look for ! TODO text in the datafile and follow the instructions.
In this exercise the stiffness for the force-based bed-length constrain is as shown below: (see Case4 for full description)
Force-based bed length constraint
Data File |
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* Restoration_data ! --------------------------------- Restoration_surface "Restoration_surface" Operation_type "Translate" Bed_length_constraint_type "Bed_force1" Bed_length_constraint_data IDM=2 /"Stiffness"/ 1E8 /"Maximum Tension"/ 10
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1The Bed_length_constraint_type keyword is set to "Bed_force1" (1D line elements are inserted to the top surface). 2The Bed_length_constraint_data must be provided. In this example the 1D element stiffness is set to 1E8 MPa and the extension yield strength is set to 10 MPa. 3Note that Restoration_data is re-defined in the next stage |
Results
The result files for the project are in directory: Rest_001\Exercises\Case5\Results. Note how the decrease in the stiffness has led to a bit of shortening of the bed length during restoration. In the plot below it can be seen the comparison between Cases 1, 4 and 5 restored geometries after the first restoration step. For a very high stiffness we achieve full preservation of the bed length. A gradual decrease in such stiffness will led to a gradual convergence to the unconstrained top surface bed length case where the final restored bed length is a result of the prescribed vertical displacement, freedom in horizontal direction, inclination of the top surface relative to the restoration surface and the material mechanical properties.
Top surface bed-length (in m) at initial (top) and restored (bottom) configurations.
Comparison of restored geometries for different top surface bed-length constraints.
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