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Hello,

I want to analyse the mechanical behaviour of a spring, that is being piezoelectrically activated. With one piezo this wasnt any problem, as i would just use 5V as electrical potential, and run a simple FrequencyDomain analysis.
But in my case the Piezos need to be phaseshifted like:
U1=U0*sin(2pi*f*t)
U2=U0*sin(2pi*f*t+pi/4)
I tried to use waveforms as global definitions and used them for my electrical potential like "wv1(t[1/s])" (found that hint on another thread), which seems to work in the first place, as the entry wont turn red/yellow.
Trying to simulate, i get this error:
--------------------------
Failed to evaluate variable.
- Variable: t
- Geometry: 1
- Boundary: 52 67
Failed to evaluate variable.
- Variable: comp1.pzd.V0
- Defined as: wv2((t/unit_s_cf))
Failed to evaluate expression.
- Expression: comp1.pzd.V0-comp1.V
-------------------------

I tried looking for solutions on the forum, but couldnt find any useable (or im just searching for the wrong topics, as im very new on comsol). I mean this is a very basic problem:
Two phaseshifted oscillations on something... it probably hardly matters in that case if its voltage, force or whatever..

Thanks Andreas