Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Adding a Point Load Without a Geometrical Point

Please login with a confirmed email address before reporting spam

Hello, I'm a new learner about COMSOL. Now I'm modeling a bending beam and want to simulate its stress. I create a 3D model and build a block(cuboid) suppose it's a beam. Then I fix one side of block, and add force on another side(opposite fixed side). Now I want to add force on this side in different point (suppose I select ten points) to see the stress. I try to use Points in Physics, but it only can be selected on block's eight corners. Could someone please help me to solve this? Thank you very much.


3 Replies Last Post 5 juin 2018, 09:47 UTC−4
Henrik Sönnerlind COMSOL Employee

Please login with a confirmed email address before reporting spam

Posted: 6 years ago 1 juin 2018, 01:57 UTC−4
Updated: 6 years ago 1 juin 2018, 02:00 UTC−4

Hi Ben,

A Point Load can only be applied to a geometrical point, so you will to add more points to your geometry.

There is however a way to add a load at an arbitrary location (not necessarily even a mesh node). This requires using some more advanced features. In the attached example model, look for

Definitions->Domain Point Probe
Solid Mechanics->Weak Contribution

Regards,
Henrik

P.S. To make it easier for others to find this solution, I will change the title of your thread.

-------------------
Henrik Sönnerlind
COMSOL
Hi Ben, A **Point Load** can only be applied to a geometrical point, so you will to add more points to your geometry. There is however a way to add a load at an arbitrary location (not necessarily even a mesh node). This requires using some more advanced features. In the attached example model, look for Definitions->Domain Point Probe Solid Mechanics->Weak Contribution Regards, Henrik P.S. To make it easier for others to find this solution, I will change the title of your thread.


Please login with a confirmed email address before reporting spam

Posted: 6 years ago 4 juin 2018, 16:15 UTC−4

Hello Henrik,

Thanks for helping me. Your attachments are really helpful. But when I compute, it has an error. I think it's the expression of point probe. Could you please help me to check this? I attached my screenshot.

Hello Henrik, Thanks for helping me. Your attachments are really helpful. But when I compute, it has an error. I think it's the expression of point probe. Could you please help me to check this? I attached my screenshot.


Henrik Sönnerlind COMSOL Employee

Please login with a confirmed email address before reporting spam

Posted: 6 years ago 5 juin 2018, 09:47 UTC−4
Updated: 6 years ago 5 juin 2018, 09:47 UTC−4

Hi,

The Point Probe Expression should be the displacement component in the direction of the load. In my example, the Y-direction displacement 'v' was used.

More generally speaking (in case someone would like to add a heat source, for example), it should be the degree of freedom which is energetically conjugate to the prescribed 'load' or 'point source'.

Regards,
Henrik

-------------------
Henrik Sönnerlind
COMSOL
Hi, The Point Probe Expression should be the displacement component in the direction of the load. In my example, the Y-direction displacement 'v' was used. More generally speaking (in case someone would like to add a heat source, for example), it should be the degree of freedom which is energetically conjugate to the prescribed 'load' or 'point source'. Regards, Henrik

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.