Discussion Forum

Hi,

I need to apply an experiment. In the experiments, there will be a soft deformable object. It is on a flat surface. The soft object will be pushed from different places on its surface to see relation between the force and the deformation.
I will try the same experiment with different force measurements, pushing position, material properties(softness) and shape of objects. I attached the file that I created the experiment. The experiment consists a flat surface and a cube on top of it.

This experiment will be the simulation of the experiments where a robot manipulator pokes a soft object on the surface.

I am new in FEM simulations and COMSOL. I watched a couple of tutorials and read the chapters in manual that looks relevant according to me. But I couldn't come up with an answer.
Here are my questions:
1- First question is about the surface. First, I created a surface from block geometry. But I couldn't manage to establish a contact with the soft object and the surface. So instead I created block with harder material (iron) and put my soft object on top of that. Now the contact can be computed. But I don't understand why surface doesn't work to compute the contact.
2. The simulation works only when I fix a part of the soft object. But I don't want to do that. I want the object to be free and to observe the behaviour of it without making any assumptions on the fixation of the object. But if I do not fix it, the relative error becomes greater than the relative tolerance.
3. I am applying the forces on points. But I want to apply it on a continuous surface such as 2cm by 2cm surface in the middle upper layer for instance. How can I do that?

Sorry if I am not using the correct terminology. I just want to simulate realistic deformations of a free object under a constant force which is applied on a particular region on a flat surface such as table etc. Like poking a teddy bear from different positions while it is laying on a table.

Best regards,
Püren