Bending moment for Billy

Billy is DAVE’s the lifting barge.

DAVEs shear and bending calculations use the same core are the static equilibrium solver. Therefore all forces are included. This includes the tanks, buoyancy, loads due to the crane and tie-back wires.





from DAVE import *
Equilibrium-core version = 2.1
default resource folders:
Blender found at: C:\Program Files\Blender Foundation\Blender 2.93\blender.exe

Import Billy

s = Scene()
s.import_scene("res: billy.dave", containerize=False, prefix="")
Loading c:\python\miniconda3\envs\book\lib\site-packages\DAVE\resources\billy.dave
Loading c:\python\miniconda3\envs\book\lib\site-packages\DAVE\resources\100x30x8_barge.dave
Loading c:\python\miniconda3\envs\book\lib\site-packages\DAVE\resources\crane block 4p.dave
c:\python\miniconda3\envs\book\lib\site-packages\DAVE\ UserWarning: BallastSystem.new_tank is outdated and may be removed in a future version.
  "BallastSystem.new_tank is outdated and may be removed in a future version."

Ballast billy to 5m draft

s["ps_outer2"].fill_pct = 40
s["sb_inner2"].fill_pct = 100.0
s["sb_outer2"].fill_pct = 100.0
s["ps_inner3"].fill_pct = 100.0
s["ps_outer3"].fill_pct = 100.0
s["sb_inner3"].fill_pct = 100.0
s["sb_outer3"].fill_pct = 100.0
s["ps_inner4"].fill_pct = 100.0
s["ps_outer4"].fill_pct = 100.0
s["sb_inner4"].fill_pct = 100.0
s["sb_outer4"].fill_pct = 100.0
s["ps_inner5"].fill_pct = 100.0
s["ps_outer5"].fill_pct = 100.0
s["sb_inner5"].fill_pct = 100.0
s["sb_outer5"].fill_pct = 100.0
s["ps_inner6"].fill_pct = 100.0
s["ps_outer6"].fill_pct = 61
Solved to 4.340e-05 kN

Define the distribution of the self-weight of billy (not present in the default model at the time of writing).

Distribute the self-weight evenly over its length, from x=0 to x=100

s['Billy'].footprint = [(0,0,0),(100,0,0)]

And request the bending moment calc

lsm = s['Billy'].give_load_shear_moment_diagram()
embedWindow(verbose=True): could not load ipyvtk_simple try:
> pip install -U git+
../_images/Bending moment on Billy_11_1.png

For a better readable plot use the .pdf export:

lsm.plot(filename = r'c:\temp\bendingmoment.pdf')
lsm.plot_simple(figsize=(10,6), dpi=100);
../_images/Bending moment on Billy_13_0.png

It is also possible to add the moment and shear-lines to the 3d view produces with “show”. This is done by generating vtk actors for the moment and shear lines and by then adding them to the show function.

from DAVE.visual import create_momentline_actors, create_shearline_actors

moment_axis, moment_line = create_momentline_actors(s['Billy'], scale_to=10)
shear_axis, shear_line = create_shearline_actors(s['Billy'], scale_to=10)
from DAVE.jupyter import *

show(s, camera_pos=(50,-20,0),lookat='y', zoom_fit=True, painters='X-ray',
     additional_actors=(moment_axis, moment_line, shear_line))
No actors created for node Billy Ballast system
number of points changed, creating new
../_images/Bending moment on Billy_16_2.png