radial load

[Giada89]

Bye to all,
I have a question to ask, I find myself with a dense roar that turns on a tree. the wheel produces a radial load on that portion of tree
How do you do this simulation in Patran? Do I have to apply a distributed force or load?
Do you have to proceed first by making a cylindrical coordinate system? and then apply force along the axis r?

thank you in advance for the answers, hello!

 

[Onda]

Good morning,
How is your model done? Can I get a picture?
How can we give you an answer without the most precise indications? ?
at least one hand sketch, understand how you want to set the model.
Thank you.

 

[Giada89]

I don't know if you understand.

I would like to know how to simulate his behavior with Patran

 

[Onda]

Well,
Now you should understand what your model is.
how is the wheel bound to the axis? interference?
Does the axis take only bending cut or even twist?
or is the wheel free on the axis?
You should do a hand sketch with the constraints and forces from which you understand how the axieme works.
mainly if the components are two, you should use contacts.
If you leap from the wheel and models only the axis, you can model the load of the wheel with a force spread over the whole length. this is a fairly push approximation, as the stiffness of the wheel helps the axis, eliminating the wheel the axis sees a greater stress. for a slender axis is an acceptable approximation, but for a short axis like yours, it will make you oversize the axis not by little.

If this approximation is enough, you should make a cylindrical coordinate system, and make a radial load function of the position compared to the axis.
to do this you must create a pcl (function) of the radial coordinate so that it is nothing for half circumference and maximum in the center (direction of the radial force) and that various with sinusoidal law according to the angular coordinate.
all this applies in the form of pressure, where instead of the pressure value put the field created with the pcl.
then evaluate the total value applied and scales the pcl so that the total force is as required.

summing up:
models the axis at the center of the coord 0.
create a cylindrical coordinate system
create a field with pcl function of cylindrical coordinate in order to simulate the bearing load of the wheel on the axis
create a pressure using the field value
evaluate the total value of the applied force and scale the field accordingly
resolving

complicated? A little. above all write field.

 

[Giada89]

Yeah, I'll have to look at some tutorials, but so I have clues.

thanks for the help

 

[Onda]

I'll attach you a field image for contact pressure on a cylindrical axis.
below the expression of the field
0.5 * (sinr('t) + abs ( sinr('t)))
note that I applied the load on all circumference, but with the use of abs I went to put a pressure on all the circumference part having negative breasts.
made this with the utility in lbc you find the total force applied and then the steps changing the coefficient 0.5 at the beginning of the pcl.
the system is an extruded cylinder on x axis. I then defined a cylindrical coordinate system and with this I created the field (see it from the image).
then I selected the elements on which to apply pressure and as pressure value I put the field.
You should succeed. .