Equation loading

Casper Kruger
Casper Kruger Altair Community Member
edited March 2022 in Community Q&A

Hi 

 

I am trying to add a varying load on the radius of a drum. I created the cylindrical UCS and assigned the pressure load with an equation, but it returns zero pressure along the wall. The images below shows what I need and what I am seeing. 

What axis corresponds to the angle in the equation? Do i just add the pressure directly into the equation?  

image

image

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Best Answer

  • Brett Ramsey_20633
    Brett Ramsey_20633 New Altair Community Member
    edited March 2022 Answer ✓
    Casper Kruger said:

    Brett, That is correct. I got it to work when I set my cylindrical axis with r and t inplane to the cylinder, why is that? 

    Why did you select x-axis as your vector?

     

    image

    I sent up the coordinate system as I would in all cylindrical systems r is the radius, theta is the angle, and z is the out plane from those two. Setting this up differently would just mean that your x, y, and z would correspond to different r, theta, and/ or z. 

    As for why, the x-axis is the vector plays into how I set up my CS. The "x-axis" in my cylindrical system is my r ie normal to the cylinder. 

     

Answers

  • Brett Ramsey_20633
    Brett Ramsey_20633 New Altair Community Member
    edited February 2022

    The r, theta, and z coordinates correspond x, y, and z still.

    image

    This should give you the intended results. That should fix your problem, you may also need to play with your element normals to get the desired load directions. That can be done in the elements tab in the Normals ribbon. 

    image

    Hope this helps

  • Casper Kruger
    Casper Kruger Altair Community Member
    edited February 2022

    Hi Brett,

     

    I tried your suggestion and it created a strange pressure distribution. I displayed the desired pressure distribution below, but I can not get HW to replicate this. 

     

    I tried all the axis, as well as the global and local UCS, But I can not get the pressure to distribute over the surface along the length. The normals are all pointed inwards. I tried swopping this, but no luck. 

    Is the angle in rads or deg?

    image

    image

  • Brett Ramsey_20633
    Brett Ramsey_20633 New Altair Community Member
    edited February 2022

    image

    From my understanding, this is what you are looking for based on the diagram from the original posting. 

  • Casper Kruger
    Casper Kruger Altair Community Member
    edited February 2022

    Brett, That is correct. I got it to work when I set my cylindrical axis with r and t inplane to the cylinder, why is that? 

    Why did you select x-axis as your vector?

     

    image

  • Brett Ramsey_20633
    Brett Ramsey_20633 New Altair Community Member
    edited March 2022 Answer ✓
    Casper Kruger said:

    Brett, That is correct. I got it to work when I set my cylindrical axis with r and t inplane to the cylinder, why is that? 

    Why did you select x-axis as your vector?

     

    image

    I sent up the coordinate system as I would in all cylindrical systems r is the radius, theta is the angle, and z is the out plane from those two. Setting this up differently would just mean that your x, y, and z would correspond to different r, theta, and/ or z. 

    As for why, the x-axis is the vector plays into how I set up my CS. The "x-axis" in my cylindrical system is my r ie normal to the cylinder. 

     

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