Fredrik W
Mechanical
- Dec 22, 2018
- 1
Hello all,
I'm trying to model a ring of a orthotropic (transverse isotropic) composite material.
First, I've modelled this as a unidirectional composite, i.e. all fibers lie perfectly circumferential. I have used CHexa20 elements. Using a cylindrical glocal coordinate system and Material Orientation Method = Physical Property tab works very well. Using the Check - Material Orientation shows all CSYS for each element as intended, see image1 and the results are smooth between elements, see Image2.
Now, I try one of the other options for Material Orientation Method - Tangent Curve. I choose a circumferential polymer edge as primary and a radial edge as secondary. The resulting Check - Material Orientation show a different result than before, see image3. The radial vector for each element does not align with the global R anymore. In fact, 4 of the elements have the same coordinate system and the remaining 6 have another. The model shown is only 10deg of a circle but i have tried with 90 deg etc. It appears that all elements within an 5 degrees arc have the same Csys, and the Csys for the next element rotates 5 deg between to the next element and is constant for all next elements for the next 5 degrees. I have also checked this in the .dat file to be true. The resulting stress field has some nasty steps in this case the Radial stresses shown, see image4.
The same also happens with other Material Orientation Methods, such as Surface Normal, Element free face proximity and even creating a sin/cos spacial field. All have 5 deg angular resolution on the element Csys
My question is: Why does NX not create the Csys for each element to a higher angular resolution? This is very annoying! It should not be difficult to calculate the exact csys. It does seem that the 5 deg resolution shown corresponds to the visual resolution of circles, but I would be amazed if that was indeed the case. I have tried with "High resolution polygon bodies" which did not help
This was my first post, so hopefully i got all the images correct. Thanks for all your help
-F
I'm trying to model a ring of a orthotropic (transverse isotropic) composite material.
First, I've modelled this as a unidirectional composite, i.e. all fibers lie perfectly circumferential. I have used CHexa20 elements. Using a cylindrical glocal coordinate system and Material Orientation Method = Physical Property tab works very well. Using the Check - Material Orientation shows all CSYS for each element as intended, see image1 and the results are smooth between elements, see Image2.
Now, I try one of the other options for Material Orientation Method - Tangent Curve. I choose a circumferential polymer edge as primary and a radial edge as secondary. The resulting Check - Material Orientation show a different result than before, see image3. The radial vector for each element does not align with the global R anymore. In fact, 4 of the elements have the same coordinate system and the remaining 6 have another. The model shown is only 10deg of a circle but i have tried with 90 deg etc. It appears that all elements within an 5 degrees arc have the same Csys, and the Csys for the next element rotates 5 deg between to the next element and is constant for all next elements for the next 5 degrees. I have also checked this in the .dat file to be true. The resulting stress field has some nasty steps in this case the Radial stresses shown, see image4.
The same also happens with other Material Orientation Methods, such as Surface Normal, Element free face proximity and even creating a sin/cos spacial field. All have 5 deg angular resolution on the element Csys
My question is: Why does NX not create the Csys for each element to a higher angular resolution? This is very annoying! It should not be difficult to calculate the exact csys. It does seem that the 5 deg resolution shown corresponds to the visual resolution of circles, but I would be amazed if that was indeed the case. I have tried with "High resolution polygon bodies" which did not help
This was my first post, so hopefully i got all the images correct. Thanks for all your help
-F