General Mechanical

General Mechanical

FINITE ELEMENT ANALYSIS OF BOND INTERACTION OF FRP REBARS IN CONCRETE

    • owaissiddiqui12
      Subscriber

      Good evening, 


      I am finding issues on carrying out analysis of my FRP-concrete pull out tests which will give me an idea for the bond stress-slip curves. I already do have the experimental values from which i applied a max displacement to the rebar. I have my boundary conditions all set and my mesh too refined. On analysis, i am getting Von-mises stress abnormally high and not in range with what i get from experimental values. I believe the main issue is modeling the contact between FRP and concrete. i have 3 embeddment lengths of 100mm, 150mm and 200mm. Concrete cylinder is of 200mm length and 100mm diameter with strength of 36.12 MPa experimentally.


      Properties of GFRP are below:


      Tensile Strength – 760 MPa


      Modulus of Elasticity – 40 GPa   


      Poisson’s Ratio = 0.29


      I have modelled the GFRP as an e-glass material with orthotropic elastic behaviour and all other properties calculated accordingly in all directions. 


      The issue i have is with my contact. Selecting the most appropriate frictional constant. or the normal stiffness factor? how should i make my values as accurate as close to the experimental values?


      I am not being able to obtain a linear pattern of the Von-mises stresses which i also believe is the Bond stresses. 


      Can someone please help me out on this?

    • peteroznewman
      Subscriber

      You will need much smaller elements around the rod.


    • owaissiddiqui12
      Subscriber

      Sir, I have reduced the mesh sizing to about 3mm however, I am still getting a lot of variation between results. Can you give me an idea of how to model the most realistic contact between FRP and concrete.? what would be the best value for Friction constant, or even normal stifness or even if I am getting any parameters wrong. Do you have an idea of how to calculate orthotropic properties of FRP? 

    • owaissiddiqui12
      Subscriber

      Also, I am using static structural, and since i am applying maximum displacement from experimental values, how can i generate a proper bond stress-slip curve in ansys?

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