Nagi Elabbasi
                                                                                                                                                    Facebook Reality Labs
                                                         
                            
                         
                                                
    
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                                                Posted:
                            
                                1 decade ago                            
                            
                                12 mars 2015, 17:05 UTC−4                            
                        
                        
                                                    Dear Gaurav,
It’s not the easiest way but you can implement the viscoelastic material in COMSOL as ODEs (Ordinary Differential Equations). That gives you total control over the rheological network structure of the viscoelastic material. You have to derive the equations though. I will be presenting a paper showing how to do this in more details at the NAFEMS World Congress 2015 in June in San Diego.
Nagi Elabbasi
Veryst Engineering                                                
                                                
                            Dear Gaurav,
It’s not the easiest way but you can implement the viscoelastic material in COMSOL as ODEs (Ordinary Differential Equations). That gives you total control over the rheological network structure of the viscoelastic material. You have to derive the equations though. I will be presenting a paper showing how to do this in more details at the NAFEMS World Congress 2015 in June in San Diego.
Nagi Elabbasi
Veryst Engineering                        
                                                
                                                                                                            
                                             
                                            
                            
                                                                                        
                                Henrik Sönnerlind
                                                                                                                                                    COMSOL Employee
                                                         
                            
                                                                                                                                                
                         
                                                
    
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                                                Posted:
                            
                                1 decade ago                            
                            
                                13 mars 2015, 03:06 UTC−4                            
                        
                        
                                                    Hi,
You can also do like this: Separate the second Maxwell unit into the spring and the damper. By some algebra, you can move the spring into the Generalized Maxwell material by changing the material properties.
Now you have a modified Generalized Maxwell material in series with only a damper. But a damper is a special case of pure creep, so you can then add a Creep node with either 
a)  Norton creep with exponent n=1
or 
b) Deviatoric creep
to simulate that part.
Regards,
Henrik                                                
                                                
                            Hi,
You can also do like this: Separate the second Maxwell unit into the spring and the damper. By some algebra, you can move the spring into the Generalized Maxwell material by changing the material properties.
Now you have a modified Generalized Maxwell material in series with only a damper. But a damper is a special case of pure creep, so you can then add a Creep node with either 
a)  Norton creep with exponent n=1
or 
b) Deviatoric creep
to simulate that part.
Regards,
Henrik                        
                                                
                                                                                                            
                                             
                                            
                                                
    
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                                                Posted:
                            
                                1 decade ago                            
                            
                                14 mars 2015, 08:59 UTC−4                            
                        
                        
                                                    Thankyou for the reply .                                                 
                                                
                            Thankyou for the reply .                         
                                                
                                                                                                            
                                             
                                            
                                                
    
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                                                Posted:
                            
                                1 decade ago                            
                            
                                14 mars 2015, 09:00 UTC−4                            
                        
                        
                                                    Thank you for the suggestion .                                                 
                                                
                            Thank you for the suggestion .                         
                                                
                                                                                                            
                                             
                                            
                                                
    
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                                                Posted:
                            
                                9 years ago                            
                            
                                10 mai 2016, 08:10 UTC−4                            
                        
                        
                                                    Dear Dr. Elabbasi,
I am currently studying the modeling of viscoelastic material  using COMSOL and like to do it without the structural module. 
I was wondering whether you could share the paper that you model the viscoelastic material using ODEs node.
Thank you very much,
--
Bhagya  
                                                
                                                
                            Dear Dr. Elabbasi,
I am currently studying the modeling of viscoelastic material  using COMSOL and like to do it without the structural module. 
I was wondering whether you could share the paper that you model the viscoelastic material using ODEs node.
Thank you very much,
--
Bhagya  
                        
                                                
                                                                                                            
                                             
                        
                        
                            
                                                                                        
                                Nagi Elabbasi
                                                                                                                                                    Facebook Reality Labs
                                                         
                            
                         
                                                
    
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                                                Posted:
                            
                                9 years ago                            
                            
                                10 mai 2016, 11:05 UTC−4                            
                        
                        
                                                    Sorry Bhagya this is a client model that I cannot share beyond what was presented in the conference I mentioned above and at last year’s COMSOL Conference in Boston: 
www.comsol.com/paper/download/257801/elabbasi_presentation.pdf.                                                
                            Sorry Bhagya this is a client model that I cannot share beyond what was presented in the conference I mentioned above and at last year’s COMSOL Conference in Boston: https://www.comsol.com/paper/download/257801/elabbasi_presentation.pdf.