5. SKL-1 clip

This part of the study was aimed at assessing the loss of mechanical performance of the clip SKL-1 depending on the degree of use. New clips, clips used under normal and extraordinary conditions, and clips subjected to different deterioration treatments were used. To simulate in-service conditions, a compressive load of 15 kN was applied for 10 s, and the sample was unloaded to 0.5 kN; this sequence was repeated nine more times. Figure 18 shows the experimental curves obtained from the clips previously described. The comparison of responses was carried out using clips subjected to the following different conditions:


Optimization of Components of Superstructure of High-Speed Rail: The Spanish Experience DOI: http://dx.doi.org/10.5772/intechopen.80013

Figure 19. Detail of the last load cycle on clip.


The difference between the first cycle and the rest of them was analyzed. The used clip was the only one in which this difference did not occur, since it behaved elastically from the first cycle. The clips that had not been previously tightened show a first cycle with higher compliance and permanent deformation. In addition, in the case of the salt chamber clip without coating, the flexibility is greater than in the new one, possibly due to the loss of net section because of the corrosion process. In all cases, the following cycles do not show plastic deformations. Figure 19 shows a detail of the last 10 load cycles applied to the four clips.

The highest stiffness corresponds to the clip used, and the greatest flexibility to the clip subjected to the salt chamber without coating. As for the new clip and the salt chamber with coating, the difference between them is negligible, showing a behavior in an intermediate situation between the previous ones.
