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Heaviside function simulate Acoustic emission signal

Posted Jan 30, 2013, 11:02 a.m. EST Version 4.2a 5 Replies

Nuno Gueiral
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Hello,

I need to apply a Heaviside function difference to simulate a Acoustic emission burst signal. Can help, how can I do this? What model should I use? I'm new working with COMSOL.

Thanks,

Nuno Gueiral
5 Replies Last Post Feb 4, 2013, 9:26 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Jan 30, 2013, 1:10 p.m. EST
Hi

the Heavyside functions of 3.5 are now readily available as Definitions - Functions : such as step, or rectangle or ramp ... , all with smoothing

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Good luck
Ivar
Hi the Heavyside functions of 3.5 are now readily available as Definitions - Functions : such as step, or rectangle or ramp ... , all with smoothing -- Good luck Ivar
Nuno Gueiral
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Posted: 1 decade ago Jan 31, 2013, 12:45 p.m. EST
Hello,

I'm using de COMSOL 4.2a version.

Best regards,
Gueiral
Hello, I'm using de COMSOL 4.2a version. Best regards, Gueiral
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Feb 1, 2013, 12:52 a.m. EST
Hi

in v4 look under Model - Definitions - Functions, and check the step, rect or ramp functions, these have Heavyside smoothing included

--
Good luck
Ivar
Hi in v4 look under Model - Definitions - Functions, and check the step, rect or ramp functions, these have Heavyside smoothing included -- Good luck Ivar
Stevie89
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Posted: 1 decade ago Feb 1, 2013, 5:07 p.m. EST
Hi

The ramp function worls perfectly fine, but if your lazy like me and u use the Heaviside function often, its easier to use COMSOL's inbuilt Heaviside function


flc1hs(X,scale)



Hi The ramp function worls perfectly fine, but if your lazy like me and u use the Heaviside function often, its easier to use COMSOL's inbuilt Heaviside function flc1hs(X,scale)
Nuno Gueiral
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Posted: 1 decade ago Feb 4, 2013, 9:26 a.m. EST
Hello,

Tank you Stevie for your answer.
I need to insert in COMSOL a function or a expression like this:
f is a impact force
f = F_max [flch2(t,t_rise )-flch2(t-t_width ,t_fall )]
where
F=max( F )/ S_max ( N / m 2 )
and
S_max=pi*(2.5e-3/2)^2

F : maximum force (2-5N)

and I don't know how? Could you help me?

Best Regards

Nuno
Hello, Tank you Stevie for your answer. I need to insert in COMSOL a function or a expression like this: f is a impact force f = F_max [flch2(t,t_rise )-flch2(t-t_width ,t_fall )] where F=max( F )/ S_max ( N / m 2 ) and S_max=pi*(2.5e-3/2)^2 F : maximum force (2-5N) and I don't know how? Could you help me? Best Regards Nuno

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