Discussion Forum

Hi,

I am just started with the use of comsol, I improved/corrected my model many times, but there is one problem I can't solve.

I am trying to model a ultrasonic transducer to get its frequency response. For this I am using the Acoustic-Piezoelectric interaction, Frequency domain. I added the geometry, materials, crystal orientation, boundary conditions and solved the problem.

However in the geometry is used the "form union" finalization. Which I think means that all the domains are 'glued' together. However, looking at the physical point of view, the frequency response of the transducer is influenced by the elasticity of the bolt, since the whole structure is bolted together. This means if using a form union finishing method, the top part of the bolt becomes part of the layers it clamps and is unable to stretch. I tried forming an assembly, but i can't get the boundary conditions right. So nothing happens than except for the deformation of the crystals.

I also tried to cheat my way out of this by adding a small crevice where the bolt should not be attached, but this messes up the mesh.

Anyone knows how to wash this big as we say in the Netherlands? Any modeling tips for this anyway?
BTW this is what I am trying to make:
www.mpi-ultrasonics.com/images/figure1-piezoelectric-transducer.gif