Ply Orientation Angle by Equation

Altair Forum User

I'm looking to try and vary the angle of a ply, or the angle of an element material orientation based upon distance from the origin.

 

Scenario: I have a disc with a hole in the centre around a cylindrical coordinate system at (0,0,0), I basically want to replicate the idea of bicycle spokes coming out from the hole, if you look at the spoke pattern on a bicycle for a REAR wheel you will note that the spokes are not normal to the hub/hole but are somewhere between the normal and the tangent, the angle they would cross elements closer to the hole will be different than those that are further away from the hole.

 

This will then be layered with plies that are orientated in the circumferential/hoop direction.

 

I realise its very simple to do it when the material axis is actually at the centre (just select radial and theta axes), however can we do it with this offset axis and thus vary the orientation with element position? Or would I have to create concentric rings of element sets and assign different angles to each ring.

Altair Forum User

Hi @George Grant

 

Do you mean something like this where arrows converge near to the hole?

Altair Forum User

Not quite,

 

if I have my material orientation as circumferential about the hole (white arrows), then I can easily do a ply that is circumferential (and one that is radial as you have shown). However, if I then want a ply that has material directions as shown by the black arrows is this possible?

 

The angle at which the 2nd ply is orientated is different for the elements closer to the centre where it is nearly the same as the element orientation, whereas if we go to the elements at the outer diameter then it is nearly perpendicular/normal to the material orientation.

<?xml version="1.0" encoding="UTF-8"?>

 

The angle at which the ply would be orientated is a function of the element centroid and the origin so it can be mathematically calculated, however, I'm not sure if this is possible or how to do it in HM.

 

Altair Forum User

Hi,

 

Well, this is a bit tricky,

 

I will get back to you soon with an efficient way to model the same. 

 

Does the pattern follow any angle?

Altair Forum User

Hi,

 

Is this what you are expecting or at least close to your expectation?

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

This is close and was one way I had thought of doing it, but its not 100% there, ideally as you move outwards from the centre the orientation becomes more radial, so at the centre the orientation is almost circumferential and at the outer diameter its almost radial, if you imagine drawing a line from9 o'clock on the hole to the 12 o'clock on the outer diameter, the ply should be orientated along this line for the elements the line passes through.

 

 

Ways I have thought of doing it are like your pizza slices, or just have element sets in hoops around the centre, as they will all have the same angle relative to their cylindrical axes, I think this may be the best way to do it?

Altair Forum User

OK, let me tell what I have done and maybe you can refine this method to make it fit your requirement:

 

1) I've taken a 1/8th of the disc elements

2) Created a vector and the vector runs from node 1 to node 2 (you can change the angle accordingly)

3) Create a material orientation

4) Rotate the elements to form a circle at the end.

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

So the manual way to do this for me would be to align each 'row' of elements differently, for the top most row orientate them by vector from 1 to a, then the next row down, from 1 to b and so on.

 

However as I want a consistent element orientation (due to the circumferential ply) then I think just creating plies with different angles and applying them to each row of elements. It just needs careful meshing really to make it work well.

 

Any other ideas?

Altair Forum User

Hi,

 

If that is the case you can use nodes or lines to orient the material.

 

I will share a video with you soon.

Altair Forum User

So this is doing it using section surfaces, I'm basically wanting to automate this

 

Altair Forum User

Hi,

 

I am no good at scripting, but you can write your own script for that or please contact your local Altair technical support team for the same. 

 

Altair Forum User

Thank you for your help, definitely got closer to what I want.