Ivar KJELBERG
                                                                                                                                                    COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
                                                         
                            
                         
                                                
    
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                                                Posted:
                            
                                2 decades ago                            
                            
                                7 ott 2009, 08:58 GMT-4                            
                        
                        
                                                    Hi
it depends what you are trying to do, I'm not sure I get it correct, but if you do not use the thermal expansion "alpha", with a little care you can use it for a non linear "swelling" by defining a function and set your alpha (normal material expansion) to this function. This is the way the material detabase define non-linear material.
There are quite some text in the help/documentation about interpolated data functions
Does it help ? Hope so
Good luck
Ivar                                                
                                                
                            Hi
it depends what you are trying to do, I'm not sure I get it correct, but if you do not use the thermal expansion "alpha", with a little care you can use it for a non linear "swelling" by defining a function and set your alpha (normal material expansion) to this function. This is the way the material detabase define non-linear material.
There are quite some text in the help/documentation about interpolated data functions
Does it help ? Hope so
Good luck
Ivar                        
                                                
                                                                                                            
                                             
                        
                        
                                                
    
        Please login with a confirmed email address before reporting spam
     
    
 
                                                Posted:
                            
                                2 decades ago                            
                            
                                7 ott 2009, 09:38 GMT-4                            
                        
                        
                                                    Hello,
I did consider including this swelling in my expansion coefficient, but I would have to include logical statements, which would change the equation dependent on some other variable I have in my model. 
e.g.
alpha = (if stage=1 then a + b*T + c*T^2, if stage=2 then d+ e*T + f*T^2)
this is to ensure the volume does not decrease with temperature, the same way it increased, giving a hysterisis graph of material swelling.                                                
                                                
                            Hello,
I did consider including this swelling in my expansion coefficient, but I would have to include logical statements, which would change the equation dependent on some other variable I have in my model. 
e.g.
alpha = (if stage=1 then a + b*T + c*T^2, if stage=2 then d+ e*T + f*T^2)
this is to ensure the volume does not decrease with temperature, the same way it increased, giving a hysterisis graph of material swelling.