% this is an edited diary file to examine why we get coupling from rotation
about Z to motion in Z – The coupling is from the compressibility of the
cantilever – force along the cantilever makes it longer (or shorter). This moves
the location of the tip which has a large preload. Motion of the preload is like
an effective torque, so the tip moves down (or up).
We see this by changing the stiffness along the blade, and watching the impact
on the stiffness matrix at the K(9,8)=K(8,9) location of the local stiffness of
a single blade.
Note – the step indicators, mistakes, and things not obviously useful were
removed.
cd('C:\Brians_files\model2_7_Folder\designmodel\cg_design_model_1.0');
mkModelETF
modelpath =
ModelConstructor2.7
ans =
C:\Brians_files\model2_7_Folder\designmodel\cg_design_model_1.0
data from file outdata_params_ASI_20cm_GLOB
stage 2 dist from cg to lzmp = -0.2 meters
stage 2 total mass = 1.58e+003 kg
data from file outdata_params_ASI_20cm_GLOB
% now in the function build_cant_spring_set
k
k =
8.8467e+005
0
0
0 -1.0461e+005
0
3.669e+007
0 8.9065e+005
0
0
0 5.3027e+008
0
0
0 8.9065e+005
0
61865
0
-1.0461e+005
0
0
0
23569
0
0
0
0
0
% step through the migrations
K_all
K_all =
Columns 1 through 6
-2.6354e+005
0
0
0 -2.6635e+005
-15.922
0
-15.922 -4.2033e+005
0
3.5872
-0.42672
-78.864
0
0
0
0
0
2.6354e+005
0
0
0 2.6635e+005
15.922
0
15.922 4.2033e+005
0
0
0
0
0
0
0
0
0
Columns 7 through 12
2.6354e+005
0
0
0 2.6635e+005
15.922
0
15.922 4.2033e+005
0
-3.5872
0.42672
78.864
0
0
0
0
0
-2.6354e+005
0
0
0 -2.6635e+005
-15.922
0
3.5872
-0.42672
0.096136
0
0
0
-3.5872
0.42672
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
19801
-78.864 1.2855e-012
0
0
0
0
0
0
2.1135 -3.4453e-014
0
0
78.864 -1.2855e-012
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
-15.922 -4.2033e+005
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
% the -15.922 in K_all(9,8) and K_all(8,9) generates the rotation to Z coupling
% run the code again
mkModelETF
modelpath =
ModelConstructor2.7
ans =
C:\Brians_files\model2_7_Folder\designmodel\cg_design_model_1.0
data from file outdata_params_ASI_20cm_GLOB
stage 2 dist from cg to lzmp = -0.2 meters
stage 2 total mass = 1.58e+003 kg
data from file outdata_params_ASI_20cm_GLOB
('C:\Brians_files\model2_7_Folder\designmodel\ModelConstructor2.7\cantlever\buil
d_cant_spring_set.m', '37')
% now on the cantilever, change the stiffness manually and see what happens
k
k =
8.8467e+005
0
0
0 -1.0461e+005
0
0
3.669e+007
0 8.9065e+005
0
0
0
0 5.3027e+008
0
0
0
0 8.9065e+005
0
61865
0
0
-1.0461e+005
0
0
0
23569
0
0
0
0
0
0
19801
k(2,2) = 100*k(2,2);
k(3,3) = 100*k(3,3);
k
k =
8.8467e+005
0
0
0 -1.0461e+005
0
0
3.669e+009
0 8.9065e+005
0
0
0
0 5.3027e+010
0
0
0
0 8.9065e+005
0
61865
0
0
-1.0461e+005
0
0
0
23569
0
0
0
0
0
0
19801
% see if the local stiffness at the bottom has changed
K_all
K_all =
Columns 1 through 6
-2.6646e+005
0
0
0
0 -2.6648e+005
-0.1593
0.03589
0
-0.1593 -4.2033e+005
-0.0042693
0
0.03589
-0.0042693
0.00096184
-0.52048
0
0
0
0
0
0
0
2.6646e+005
0
0
0
0 2.6648e+005
0.1593
-0.03589
0
0.1593 4.2033e+005
0.0042693
0
0
0
0
-0.52048 8.4843e-015
0
0
0
0
0
0
0.013949 -2.2738e-016
0
0
0.52048 -8.4843e-015
0
0
0
0
0
0
0
0
0
0
0
0
Columns 7 through 12
2.6646e+005
0
0
0 2.6648e+005
0.1593
0
0.1593 4.2033e+005
0
-0.03589
0.0042693
0.52048
0
0
0
0
0
-2.6646e+005
0
0
0 -2.6648e+005
-0.1593
0
-0.1593 -4.2033e+005
0
0
0
0
0
0
0
0
0
% now K_all(8,9) has dropped to -.159, a change of
break
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
100, as we expect
0
0
0
0
0
0
0
0
0
0
0
0
0
0