PSI - Issue 5

Smail Sahnoun et al. / Procedia Structural Integrity 5 (2017) 1065–1071 Asseya El-amiri et al./ StructuralIntegrity Procedia 00 (2017) 000 – 000

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3.3. Effect of simultaneous variation of rust depth and thickness on surface temperature

Our interest shifts to the case of the large bolt in order to get closer to real cases. To this end, we assumed that the depth and thickness of the rust vary simultaneously. This is why we concurrently varied the depth of the rust layer from 0.5cm to 5.5cm with a pitch of 0.5cm and the diameter from 0.2cm to 2.2cm with a pitch of 0.2 cm as shown in Fig.6. We plotted the variations of the surface temperature of the bolt along the axis A1A2 for each case, which allowed us to observe that temperature evolves exponentialy with respect to depth, taking into account the diameter of the rust Fig.7. From Fig. 7, we notice that the values of the surface temperature of the controlled structures increase with the dimensions of the rust layer. This result is very important in the non-destructive testing of assembly elements.

Fig.6.

Diagram of the simultaneous variation of the depth and the thickness of the hidden rust

Fig.7.

The temperature evolution of the surface with respect to the depth along the axis (A1A2) for the studied cases

4. Conclusion

As part of the safety and security of personnel and rolled metal structures subjected to heavy mechanical or thermal stress, we proposed in this paper a mathematical model based on the numerical three dimensional finite elements method to estimate by infrared thermography the depth, and the thickness of a hidden layer rust between two joint elements in steel anchored in a concrete slab. We have shown that the surface temperature values of the controlled structures increases with the dimensions of the rust layer. This result is very important in the non-destructive testing of assembly elements.