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Concrete-Epoxy Interaction Guide

This document provides guidance on defining a cohesive interaction property in Abaqus to model the bond between concrete and FRP sheets. It outlines the steps to: 1) define the interaction property with a bilinear traction-separation curve, 2) calculate stiffness parameters for the normal and shear directions, and 3) define damage initiation and evolution criteria based on tensile strength and fracture energies of the materials. The interaction is created by selecting the stiffer FRP sheet as the master surface and the softer concrete as the slave surface.

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Soumya Gorai
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202 views9 pages

Concrete-Epoxy Interaction Guide

This document provides guidance on defining a cohesive interaction property in Abaqus to model the bond between concrete and FRP sheets. It outlines the steps to: 1) define the interaction property with a bilinear traction-separation curve, 2) calculate stiffness parameters for the normal and shear directions, and 3) define damage initiation and evolution criteria based on tensile strength and fracture energies of the materials. The interaction is created by selecting the stiffer FRP sheet as the master surface and the softer concrete as the slave surface.

Uploaded by

Soumya Gorai
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Cohesive Interaction

Prepared by
Prof. Dr. Ibrahim M. Metwally
Concrete Structures Research Institute

Housing & Building National Research Center,

87, El-Tahrir St., Dokki, Giza 11511-P.O. Box: 1770 Cairo, Egypt.

Emails : ibrahimhbrc@gmail.com &


dr_ibrahimmetwally@yahoo.com

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Cohesive Surface

1) Define Interaction Property

Press create interaction property


Choose: contact & continue

2) Define Cohesive Behaviour


Mechanical ------Cohesive Behaviour

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Bilinear Traction Separation Constitutive Curve

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1
K nn
tc t epoxy

Ec E epoxy
tc = Concrete thickness, mm Usually, take tc = 5 mm
tepoxy = Epoxy or adhesive thickness, mm Usually, take tepoxy = 1 mm
Ec = Young's modulus of concrete, MPa
Eepoxy = Young's modulus of adhesive, MPa

The approximate value of Knn = 1700

Gepoxy
K ss K tt 1000(0.16 0.47)
t epoxy
Gepoxy = Shear modulus of epoxy or adhesive in GPa, Usually, take
Gepoxy = 0.665 GPa

tepoxy = Epoxy or adhesive thickness, mm Usually, take tepoxy = 1 mm

OR

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K ss K t t
tc t epoxy

Gc Gepoxy
Gc = Shear modulus of concrete in MPa Usually, take Gc= 10800 MPa
Gepoxy = Shear modulus of epoxy or adhesive in MPa Usually, take
Gepoxy= 665 MPa

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3) Define Damage of the Interface

Mechanical ------Damage
Initiation

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To Calculate these stresses as follows:

Normal Only = Tensile strength of concrete (fct)= 0.33 f c MPa


Shear-1 Only = Shear-2 Only = max

max 1.46Gepoxy 0.165 f ct1.033


Gepoxy= Epoxy or adhesive shear modulus in GPa Usually, take Gepoxy=
0.665 GPa
fct = Tensile strength of concrete, MPa

OR

bf bf
max 1.5 f ct 2.25
/ 1.25
bc bc

bf = FRP plate width, mm
bc = Concrete width, mm

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Evolution

Normal Fracture Energy = 0.09 mJ/mm2


1st Shear Fracture Energy = 2nd Shear Fracture Energy range from 0.3 to
1.5 mJ/mm2 . Usually take = 0.9 mJ/mm2

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4) Create Interaction

Press Create Interaction

Select Master & Slave Surfaces as follows:


Master surface is the surface of the material which has
biggest Young's modulus, is FRP sheet.
Slave surface is the surface of the material which has
lowest Young's modulus, is concrete

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