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.
Problem in Global Equations defined variable
Posted Apr 7, 2014, 7:43 p.m. EDT Structural Mechanics 2 Replies
Please login with a confirmed email address before reporting spam
Hi all,
Does anybody know how to fix this? I am simulating a cavity filled with incompressible fluid under external pressure. Following the COMSOL Blog: www.comsol.com/blogs/computing-controlling-volume-cavity/, I used the global equations to define a pressure load "Inner_pressure" to the inner wall of a cavity beam. The global equation is set to find out whatever value of "Inner_pressure" only if it can satisfy the constraint that the cavity's volume is always the same to undeformed state. I tried this method in 2D successfully, but in 3D it has a error like this.
****************************************
Failed to find a solution.
Singular matrix.
There are 1 void equations (empty rows in matrix) for the variable comp1.Inner_pressure.
at coordinates: (0,0,0), ...
Returned solution is not converged.
****************************************
Does anybody know how to fix this? I am simulating a cavity filled with incompressible fluid under external pressure. Following the COMSOL Blog: www.comsol.com/blogs/computing-controlling-volume-cavity/, I used the global equations to define a pressure load "Inner_pressure" to the inner wall of a cavity beam. The global equation is set to find out whatever value of "Inner_pressure" only if it can satisfy the constraint that the cavity's volume is always the same to undeformed state. I tried this method in 2D successfully, but in 3D it has a error like this.
****************************************
Failed to find a solution.
Singular matrix.
There are 1 void equations (empty rows in matrix) for the variable comp1.Inner_pressure.
at coordinates: (0,0,0), ...
Returned solution is not converged.
****************************************
Attachments:
2 Replies Last Post Jun 27, 2017, 2:46 p.m. EDT
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Hi,
In order to compute the volume using the technique from the blog post, the study must be geometrically nonlinear. It is only then that the spatial coordinates reflect the deformed configuration.
Regards,
Henrik
In order to compute the volume using the technique from the blog post, the study must be geometrically nonlinear. It is only then that the spatial coordinates reflect the deformed configuration.
Regards,
Henrik
Please login with a confirmed email address before reporting spam
Posted:
7 years ago
Updated:
7 years ago
Link above is "broken" since it includes comma
Working link is below
www.comsol.com/blogs/computing-controlling-volume-cavity/
Working link is below
www.comsol.com/blogs/computing-controlling-volume-cavity/