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how to define ramp load using time dependent solver

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Hi,
im currently using comsol v4 for my project. My project is to simulate a piezoresistive device which consist of pvdf layer embedded in a silicone block for sensor application.
I am able to came out with the model and run it using -1N of static boundary load. The problem is now that i wanted to produce a graph of voltage versus time..thus i need to use the time dependent solver. But i did not manage to get the graph that i want. I want to either use ramp load or sine load for boundary load. I only manage to came out with von misses stress vs arc length where the legends are 0s to 6s. i have tried to follow www.comsol.com/community/forums/general/thread/4498/ but still cannot get the result.

i have used F=1[N/m^2] + (6-1)[N/m^2]/(6[s])*t in boundary load. I really need the graph..and im new in comsol as im trying to learn it slowly. I would be very grateful if anyone can help me solve this problem.
Thank you.

2 Replies Last Post 18.05.2014, 22:07 GMT-4

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Posted: 1 decade ago 16.05.2014, 03:58 GMT-4
Do you have have any 'memory' effects like inertia or the voltage building up over a finite time span after the load has been applied? If not and you expect the voltage to be generated immediately when you apply the load, you could simply calculate the voltage as a function of load (V = V(P)). If you then apply a time dependent load P=P(t) you can simply calculate V(t) = V(P(t)).
Do you have have any 'memory' effects like inertia or the voltage building up over a finite time span after the load has been applied? If not and you expect the voltage to be generated immediately when you apply the load, you could simply calculate the voltage as a function of load (V = V(P)). If you then apply a time dependent load P=P(t) you can simply calculate V(t) = V(P(t)).

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Posted: 1 decade ago 18.05.2014, 22:07 GMT-4
Dear Pieter Westerik,

Thank you so much for the reply.
Now i dont have any 'memory' effects like inertia or the voltage building. In my project the vibration of the pvdf due to dynamic load will produce voltage as output result.
Urm..I'll try to do it as you advised and i'll inform u either i get the result or not.. :)
Dear Pieter Westerik, Thank you so much for the reply. Now i dont have any 'memory' effects like inertia or the voltage building. In my project the vibration of the pvdf due to dynamic load will produce voltage as output result. Urm..I'll try to do it as you advised and i'll inform u either i get the result or not.. :)

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