GeomSect_001 Case4 Vertical plane non-parallel to XYZ coordinate system planes

 

The data file for this exercise is located in GeomSect_001/Exercices/Case4/Data. Look for ! TODO  text in the datafile and follow the instructions.

 

In this example the section plane is rotated to perform a vertical section in a plane non-parallel to any of the ZX nor YZ planes. This is performed by defining a Coordinate_system defining the rotation.

 

In the International Society of Biomechanics web page an Excel Spreadsheet developed by Neil Crawford to calculate direction cosines for a X, Y, Z sequential 3D rotation can be downloaded. The instructions are included in the spreadsheet. Note that rotation should be performed using the tilt-twist input in the spreadsheet following the sequence:

1Define the sequential rotation in the input cells (B3 to B5)

2Look at the tilt-twist values provided in cells M3 to M5

3Change the input of the B3 to B5 for the tilt-twist values

4Copy the resulting direction cosines matrix in cells Q20 to S22

 

Data File

 

 

* Coordinate_system  NUM=1  

! ---------------------------------

Direction_cosines   IDM=3  JDM=3

0.9397        0.3420        0.0000

0.0000        0.0000        1.0000

0.3420        -0.9397        0.0000

 

 

* Geometry_section_surface  

! ---------------------------------

 Section_type          "XY_local"

 Generation_type    "Section"

 Reference_location     IDM=3

   4250.0  1000.0  2000.0

 Coordinate_system        1

 Output_level             3

 Groups   IDM=4

   "formation0"

   "formation1"

   "formation2"

   "formation3"                

 

1A coordinate system to describe the rotation for sectioning is defined. In the present case the direction cosines correspond to a sequential rotation of:

a.-90º along X axis

b.0º along Y axis

c.20º along Z axis

d.Note that the final input in cells (B3, B4, B5) for the til-twist method has been (-90, -20, 0).

2Section_type is set to "XY_local" (flat and initially parallel to XY plane).

3Generation_type is set to "Section" (a .geo file containing the sectioned geometry and a datafile will be generated).

4Reference location is defined to be at the center of the geometry.

5Coordinate system 1 is assigned to the sectioning in order to rotate the section.

 

 

Results

The result files for the project are in directory: GeomSect_001\Case4\Results.   Note that the output section 2D geometry is oriented within plane XY as 2D problems in ParaGeo must be oriented in that plane.  

 

 

GeomSect_001_Case4_results

3D geometry showing the section plane (left). Sectioned geometry (right)