Rui Micaelo

AbstractThe use of Fibre Reinforced Polymers (FRP) has recently become widespread in the construction industry. However, some drawbacks related to premature debonding of the FRP composites from the bonded substrates have been identified. One of the solutions proposed is the implementation of mechanical anchorage systems. Although some design guidelines have been developed, the actual knowledge continues to be rather limited. Thus, designers and researchers have not yet achieved any consensus on the efficiency of any particular anchor device in delaying or preventing the premature debonding failure mode that can occur in Externally Bonded Reinforcement (EBR) systems. This paper studies the debonding phenomenon of FRP anchoring systems with a linear variable width, with a numerical analysis based on the Distinct Element Method (DEM). Combined systems with constant and variable width are also discussed. The FRP-to-parent material interfaces are modelled with a rigid-linear softening bond–slip law. The numerical results showed that it is possible to attain the FRP rupture force with a variable width solution. This solution is particularly attractive when the bonded length is shorter than the effective bonded length because the strength of the interface can be highly incremented.

The adhesively bonded joints behaviour under cyclic loading is not yet well understood due to its inherent complexity. Numerical approaches appear, therefore, as the easiest way to simulate such mechanical behaviour. In this work, double strap bonded joints with Carbon Fibres Reinforced Polymers (CFRP) and aluminium are numerically simulated and subjected to a cyclic loading history. In the numerical simulation, the Distinct Element Method (DEM) is used and it is assumed cohesive bi-linear bond-slip models with local damage of the interface. The evaluation of the bonded joints under cyclic loading is made by comparing the results with those simulated with a monotonic loading.

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