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Heaviside function simulate Acoustic emission signal

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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 2013年2月4日 GMT-5 09:26
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 2013年1月30日 GMT-5 13:10
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
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

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Posted: 1 decade ago 2013年1月31日 GMT-5 12:45
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 2013年2月1日 GMT-5 00:52
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

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Posted: 1 decade ago 2013年2月1日 GMT-5 17:07
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)

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Posted: 1 decade ago 2013年2月4日 GMT-5 09:26
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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