buckling example

Author: mkraska

Linear/L-Plate/PS3.png

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+# Buckling and modal analysis with preload
+Tested with CGX/CCX 2.10
+
++ Modal analysis with preload
++ Eigenvalue buckling analysis
++ Shell edge load
+
+File                      | Contents    
+ :-------------           | :-------------
+ [pre.fbl](pre.fbl)       | Preprocessing script for CGX     
+ [modal.inp](modal.inp)   | CCX input
+ [shapes.fbl](shapes.fbl) | CGX script for postprocessing (mode shape movies)
+
+
+
+## Model Description
+The model is a flat L-shaped plate.
+
+<img src="mesh.png" width="400" title="mesh">
+
+Boundary conditions
++ UY=0, UZ=0 at the upper edge (red)
++ UX=0, UZ=0 at the left edge (green)
++ UZ=0 at the lower (blue) and right (magenta) edges
++ Line load in y-direction (1 N/mm)
+
+<img src="RFv.png" width="400" title="Reactions and loads">
+<img src="PS3.png" width="400" title="Minimum principal stress">
+
+Set the appropriate values for the parameters in `par.run.fbd` and run the simulation using
+```
+> param.py par.run.fbd
+> cgx -b run.fbl
+```
+## Solution
+
+If you want to run the analysis separately:
+```
+> ccx solve.inp
+```
+The analysis consists of 3 steps:
++ Static step, application of preload for the modal analysis
++ Frequency step, modal analysis with preload
++ Buckle step.
+
+## Postprocessing
+
+### Vibration mode shapes
+These are displayed using `ds <n> a` to get a sinusoidal animation
+```
+> cgx -b vmodes.fbd
+```
+<img src="v1.gif" width="400"><img src="v2.gif" width="400">
+
+### Buckling mode shapes:
+These are displayed with
+```
+anim real
+scal d 200
+ds <n> a
+```
+to get a single-sided animation:
+```
+> cgx -b bmodes.fbd
+```
+<img src="b1.gif" width="400"><img src="b2.gif" width="400">

Linear/L-Plate/README.md

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+read solve.frd new
+
+rot -z
+rot c -60
+rot d 60
+zoom 1.5
+tra r 20
+view elem
+anim real
+scal d 200
+movi frames 11
+ds -2 a
+sys mv movie.gif b1.gif
+movi frames 11
+ds -1 a
+sys mv movie.gif b2.gif
+movi frames 11
+ds -0 a
+sys mv movie.gif b3.gif