Cervenka Consulting Forums — MODEL OF BEAM WITH FRP

Re: MODEL OF BEAM WITH FRP

2010-10-06T21:28:14Z

Hello,

one more suggestion when using interface elements:

- never use zero for cohesion and ft, but rather put some small value such as for instance 0.01.
- never use zero for friction

This helps for robust numerical results.

Regards

Jan Cervenka

Re: MODEL OF BEAM WITH FRP

2010-09-06T07:42:56Z

Please follow the paragraph "I have problems when using the Interface (GAP) material on contacts" from our "Known problems" page http://www.cervenka.cz/products/atena/known-problems for the Interface Material settings.

However, if you have no information about the concrete-epoxy interface, I would recommend first running the analysis with "perfect connection" instead of GAP material, and only switch later if you see the results are too high due to not capturing the debonding.

Regarding the epoxy stregth, you could
a) keep the elastic model and only check in posptocessing that the stress does not exceed the strength
b) switch to Bilinear von Mises material with ideal plasticity (0 hardening modulus). However, if the epoxy behaviour is more brittle than plastic, you still may have to check in postprocessor
c) if you have more material data (e.g., direct compression and/or tension test on an epoxy sample), you may choose a more advanced material model, calibrated by modelling the material test.

MODEL OF BEAM WITH FRP

2010-09-05T11:02:46Z

Sir,

I am trying to make a model for beam with FRP at bottom in ATENA 3D

I am using shell/plate element for FRP, by defining as 3D Elastic material, and then using 3D interface as gap material between concrete and FRP

For 3D interfaceI am using default values, because manufactures provides E and f values for epoxy.

Is this a write prosedure?

How to use the values of strengh and modulas of elasticity of epoxy in the model?

please explain

Thanking you