Ivar KJELBERG
                                                                                                                                                    COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
                                                         
                            
                         
                                                
    
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                                                Posted:
                            
                                1 decade ago                            
                            
                                2011/03/24 16:45 GMT-4                            
                        
                        
                                                    Hi
if you are talking about the deformation of a "solid" structure (even thin as a membrane) by some pressure load, then you can get around with only the "solid" or structural module, no need for the full MEMS applications.
the steps are as usual 
1) define the 3D/2D/2d-axi mode most appropriate (fo square rectangles it probably more a 3D or eventually a 2D)
2) select "solid" physics
3) select stationary for pressure load (i.e. eigenfrequencies for modes, but then the pressure is ignored by default)
4) draw your geometry, either as a 2D in a workplane and extrude it, or as 3D block(s)
5) set up the material data (isotropic or crystalline anisotropic Si, my suggestion: start isotropic)
6) define the BC, fixed, the surfaces loaded ...
7) mesh (try a normal default mesh to start with, then perhaps a "finer" and compare)
8) solve (if you apply a large pressure, sometimes it's worth to ramp it up in 5-20 steps with a statioanry solver "continuation" sweep", then you need to define a Parameter i.e. Param with a range of the type range(0,0.1,1), and multiply your load Pressure by Param
9) postprocess (do not forget to add "Deformed" to the surface plot to see the deformation. Check the stress ...
It's the standard procedure as you see in most of the videos you find on the main COSMOL site 
  
--
Good luck
Ivar                                                
                                                
                            Hi
if you are talking about the deformation of a "solid" structure (even thin as a membrane) by some pressure load, then you can get around with only the "solid" or structural module, no need for the full MEMS applications.
the steps are as usual 
1) define the 3D/2D/2d-axi mode most appropriate (fo square rectangles it probably more a 3D or eventually a 2D)
2) select "solid" physics
3) select stationary for pressure load (i.e. eigenfrequencies for modes, but then the pressure is ignored by default)
4) draw your geometry, either as a 2D in a workplane and extrude it, or as 3D block(s)
5) set up the material data (isotropic or crystalline anisotropic Si, my suggestion: start isotropic)
6) define the BC, fixed, the surfaces loaded ...
7) mesh (try a normal default mesh to start with, then perhaps a "finer" and compare)
8) solve (if you apply a large pressure, sometimes it's worth to ramp it up in 5-20 steps with a statioanry solver "continuation" sweep", then you need to define a Parameter i.e. Param with a range of the type range(0,0.1,1), and multiply your load Pressure by Param
9) postprocess (do not forget to add "Deformed" to the surface plot to see the deformation. Check the stress ...
It's the standard procedure as you see in most of the videos you find on the main COSMOL site 
  
--
Good luck
Ivar                        
                                                
                                                                                                            
                                             
                        
                        
                                                
    
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                                                Posted:
                            
                                1 decade ago                            
                            
                                2015/06/04 14:02 GMT-4                            
                        
                        
                                                    Hi,
I'm have an assignment on simulation of MEMS membrane for microphone using Comsol Multiphysics.
I have to set a fixed value of stress to the square with edge clamped membrane. 
After that, i need to analyse how the stress impact on the frequency and displacement,
but i still can figure out how to set a fixed or certain value of residual stress.
If anyone can give any tutorial, i will be very grateful.
Thanks
                                                
                                                
                            Hi,
I'm have an assignment on simulation of MEMS membrane for microphone using Comsol Multiphysics.
I have to set a fixed value of stress to the square with edge clamped membrane. 
After that, i need to analyse how the stress impact on the frequency and displacement,
but i still can figure out how to set a fixed or certain value of residual stress.
If anyone can give any tutorial, i will be very grateful.
Thanks