Ivar KJELBERG
                                                                                                                                                    COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
                                                         
                            
                         
                                                
    
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                                                Posted:
                            
                                1 decade ago                            
                            
                                21 lug 2012, 04:18 GMT-4                            
                        
                        
                                                    Hi
charge you can estimate from voltage and capacitance, but as for power there is a d/dt component missing. Applying a force in stationary does not give any power it's time independent. and the poser depends on the load impedance. You need to define your model fully, i.e. with a CIR and then input some PSD or time varying / harmonic developpment values. 
Sketc it out on a piece of paper before you try to set up the COMSOl model as it will depend on how you decide to masure power, viltage, current, charge ... or whatever. This is true multiphysics ;)
--
Good luck
Ivar                                                
                                                
                            Hi
charge you can estimate from voltage and capacitance, but as for power there is a d/dt component missing. Applying a force in stationary does not give any power it's time independent. and the poser depends on the load impedance. You need to define your model fully, i.e. with a CIR and then input some PSD or time varying / harmonic developpment values. 
Sketc it out on a piece of paper before you try to set up the COMSOl model as it will depend on how you decide to masure power, viltage, current, charge ... or whatever. This is true multiphysics ;)
--
Good luck
Ivar                        
                                                
                                                                                                            
                                             
                        
                        
                                                
    
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                                                Posted:
                            
                                1 decade ago                            
                            
                                23 lug 2012, 01:13 GMT-4                            
                        
                        
                                                    Hi,
In order to obtain charge, you have to couple piezoelectric device physics with CIR. Add capacitance and then plot charge. If you do not do this, you will always get zero charge while you will still get some terminal voltage.
I think power can be plotted directly. Look at the post-processing options. I am sure that Comsol has total power and some gradient of power loss which you can integrate to get full power loss. 
-Sankha                                                
                                                
                            Hi,
In order to obtain charge, you have to couple piezoelectric device physics with CIR. Add capacitance and then plot charge. If you do not do this, you will always get zero charge while you will still get some terminal voltage.
I think power can be plotted directly. Look at the post-processing options. I am sure that Comsol has total power and some gradient of power loss which you can integrate to get full power loss. 
-Sankha