I am modeling RC beam externally reinforced with FRP sheets in ANSYS apdl. I want to know how can we make interface debonding model between the Concrete and the FRP. From my search I found it can be done using cohesive zone model (CZM) in ANSYS. But how to consider the matrix and fiber while modelling in the ANSYS. The RC beam will be modeled for both shear and flexural strengthening.
There are basically two approaches for the debonding analysis between FRP and concrete. i.e. Use of interface element or without use of interface element. If you dont want to use interface element, the debonding is simulated by modelling the cracking and failure of concrete elements adjacent to adhesive layer. But you can use interface element with proper bond-slip relation for FRP-Concrete interface.
In addition to the contact element available in ANSYS, there are two elements which they can simulate debonding. COMBIN14 and COMBIN39. First one is a linear and the second one is a non-linear element. You can connect between the concrete and FRB sheet by using one of these elements to represent the adhesive material. You can also use BIRTH and DEATH feature in ANSYS to simulate the accurance of debonding...
The best way in Ansys is using interface element. which is a contact element available in the software
- How can I model a RC beam externally reinforced with FRP sheet with interface debonding in ANSYS apdl? please i want help in this subjuct
- How can I model a RC beam externally reinforced with FRP sheet with interface debonding in ANSYS apdl? please i want help in this subjuct
the debonding can be modeled using contact element with czm now I am using target 169 and contact 172 with czm element to represent 2d debonding between concrete and CFRP. the problem that I have now is in that the real model failed at 14 KN but my model fails at 2KN . any suggestions to over com this problem?
Thanks for your answer
There are so many reasons for the failure, such as material property, boundary condition, mesh size, and of course contact parameters. As we all know, Contact element always creates convergence problem. In my case, i have used spring element to consider the bond-slip, however in both cases, proper bond-slip law should be used.
can anyone please help me in FRP wrapping of RC beams, the bonding connection and modelling. please
Hi
To model debonding using surface-based cohesive behavior, you must define:
•contact pairs and initially bonded crack surfaces;
•the traction-separation behavior;
•the damage initiation criterion; and
•the damage evolution.
•You may also, specify viscous regularization to facilitate solution convergence in Abaqus/Standard.
and attached file can help you.
In addition to what's said. The normal/tangential stiffness of the contact region affects the debonding force. If stiffness increased the debonding force will also increased and vice versa.
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