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plasticity material properties

Posted 7 mars 2013, 10:13 UTC−5 Materials, Structural Mechanics Version 4.2, Version 4.2a, Version 4.3, Version 4.3a 2 Replies

uday
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Hi ,

i try to solve one structural mechanics problem. In my case, i want to give yield stress level and isotropic tangent modulus properties to my model.i found one similar tutorial (snap hook) in comsol. they used yield stress level and isotropic tangent modulus.they used isotropic tangent modulus as constant value.but they used following equation as yield stress to the model.

S_yield_hook*(1+1e3*flc2hs(1-X/0.0025[m],0.25))


S_yield_hook - is yield stress of hook material

But i could not understand the below term
(1+1e3*flc2hs(1-X/0.0025[m],0.25))

can anybody help me??

2 Replies Last Post 7 mars 2013, 10:41 UTC−5
Henrik Sönnerlind COMSOL Employee

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Posted: 1 decade ago 7 mars 2013, 10:24 UTC−5
Hi,

In the modelling instructions (page 8) this is described as

"The increase in the yield stress near the hook tip and thus near the contact surface
will help to avoid spurious plastic deformations that might occur due to the
computational errors during iterations in the contact force calculations."

Regards,
Henrik
Hi, In the modelling instructions (page 8) this is described as "The increase in the yield stress near the hook tip and thus near the contact surface will help to avoid spurious plastic deformations that might occur due to the computational errors during iterations in the contact force calculations." Regards, Henrik
Nagi Elabbasi Facebook Reality Labs
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Posted: 1 decade ago 7 mars 2013, 10:41 UTC−5
If your question was about the meaning of the expression, here is a description based on the COMSOL documentation: “flc2hs is a smoothed Heaviside function with a continuous second derivative without overshoot”. The expression used increases the yield stress by a factor of 1000 for X less than 2.5[mm] and does it using a smooth transition. It’s done for the reason Henrik described above.

Nagi Elabbasi
Veryst Engineering
If your question was about the meaning of the expression, here is a description based on the COMSOL documentation: “flc2hs is a smoothed Heaviside function with a continuous second derivative without overshoot”. The expression used increases the yield stress by a factor of 1000 for X less than 2.5[mm] and does it using a smooth transition. It’s done for the reason Henrik described above. Nagi Elabbasi Veryst Engineering

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