Learning Forum

[rahultk1]

I need to find degree of rotation between two vertebraes. Previous queries were all asked  for workbench. In the classic version, how do we measure it ? My elements are solid185

[sk_cheah]

You could try a Google search for "ansys euler angle". A possible way is to define a coordinate using NWPLAN  & CSWPLA from 3 nodes, then extract the angles via *GET, par, CDSY, N, ANG, xy for example for THXY rotation. With two coordinates, you could work on getting the relative rotation matrix via dot product described here. 

 

Kind regards, 
Jason

[rahultk1]

 Hi Jason,

Thanks for the prompt reply. I followed your advice and defined a local CWS on top of a vertebrae, and after extracting using *GET, the angles are showing same before and after the simulation. Maybe i am not able to grasp properly and i use GUI, still a novice learner yet. Below are the codes and a sample pic of the model. 

NWPLAN,-1,  157797,  157800,  157798

CSWPLA,11,2,1,1,

*get, par, CDSY, 11, ang, xy

*get, par, CDSY, 11, ang, yz

*get, par, CDSY, 11, ang, zx

[sk_cheah]

Your code needs to be modified a bit to capture all 3 different angles.

*get, parXY, cdsy, 11, ang, xy
*get, parYZ, cdsy, 11, ang, yz
*get, parZX, cdsy, 11, ang, zx

Next, you could try UPGEOM to have the nodes be at their deformed position before applying the same method. 

 

Kind regards,
Jason

[rahultk1]

Hi Jason,

sorry, that too didn't work. I am getting the same values.

 

.

[sk_cheah]

Did you solve your model and use UPGEOM before extracting the angles again? Below is a sample code that shows initial rotation of 45 degrees and final rotation of 50 degrees. 

!%%  Example of extracting angles with NWPLAN & UPGEOM



/filname, file ! defined for RST file name later

tol=0.01

*dim, cs0, array, 3,1 ! stores 3 node numbers for axis

*dim, rot0, array, 3,1 ! rotation angles before

*dim, rot1, array, 3,1 ! rotation anglse after



! simple block

/prep7

block, -0.5,0.5, -0.5,0.5, 1,2

mp, ex, 1, 1e9

mp, dens, 1, 1

et, 1, 185

esize, 0.25

vmesh, all

et,2,21, 0      ! mass 21 for pivot point

r,2, tol,tol,tol, tol,tol,tol

*get, nmax, node, 0, count

type, 2

real, 2

n, nmax+1, 0, 0, 0.5

e, nmax+1



! node numbers used to define coordinates

nsel, s, loc, z, 2-tol, 2+tol

nsel, r, loc, x, -0.5-tol, -0.5+tol

nsel, r, loc, y, -0.5-tol, -0.5+tol

*get, cs0(1), node, 0, num, min

nsel, s, loc, z, 2-tol, 2+tol

nsel, r, loc, x, 0.5-tol, 0.5+tol

nsel, r, loc, y, -0.5-tol, -0.5+tol

*get, cs0(2), node, 0, num, min

nsel, s, loc, z, 2-tol, 2+tol

nsel, r, loc, x, -0.5-tol, -0.5+tol

nsel, r, loc, y, 0.5-tol, 0.5+tol

*get, cs0(3), node, 0, num, min



! face that connects to pivot point

nsel, s, loc, z, 1-tol, 1+tol

cm, botface, node

alls



! rotate block

local, 11, 0, 0, 0, 0.5

local, 12, 0, 0, 0, 0.5, 0,45,0  ! rotates 45deg about X axis

csys, 11

vtran, 12, all,,,,0,1 ! moves block to new coordinate



! connects face to pivot point

et, 3, 173, ! conta173

et,4,170    ! targe170

keyo,4,2,1               ! Don't fix the pilot node

keyo,4,4,0               ! Activate all DOF's due to large deformation

keyo,3,12,5              ! Bonded Contact

keyo,3,4,2               ! Rigid CERIG style load

keyo,3,2,2               ! MPC style contact

cmsel, s, botface

esln

type, 3

real, 3

esurf



type, 4

real, 3

tshap, pilo

e, nmax+1



! get angles before solution

alls

nwplan, 100, cs0(1), cs0(2), cs0(3)

cswpla, 100, 0

*get, rot0(1), cdsy, 100, ang, xy

*get, rot0(2), cdsy, 100, ang, yz

*get, rot0(3), cdsy, 100, ang, zx



! display angles as originally prescribed

*stat, rot0



! solves with another 5 degrees added

/solu

csys,0

antype, static

alls

nlgeom, on

d, nmax+1, ux, 0

d, nmax+1, uy, 0

d, nmax+1, uz, 0

d, nmax+1, rotz, 0

d, nmax+1, rotx, 0.087266462599716 ! rotate by x axis again (0.08726 radians = 5degrees)

d, nmax+1, roty, 0

solve



/post1

set, last

*get, substepnum, active, 0, set, sbst

/prep7

alls

upgeom, 1, 1, substepnum, file, rst     ! updates geometry

nwplan, 101, cs0(1), cs0(2), cs0(3)

cswpla, 101, 0

*get, rot1(1), cdsy, 101, ang, xy

*get, rot1(2), cdsy, 101, ang, yz

*get, rot1(3), cdsy, 101, ang, zx



! display angles after rotation

*stat, rot1

 

Kind regards,
Jason

[rahultk1]

Hi Jason,

Thanks for the code. I could solve my problem. I didn't defined another co-ordinate system after solving. Therefore,it was showing the same values.

regards

Rahul