PSI - Issue 18

Abdeljalil Jikal et al. / Procedia Structural Integrity 18 (2019) 731–741 Abdeljalil JIKAL et al. / Structural Integrity Procedia 00 (2019) 000–000

740 10

curves are coincident with that of the Miner in Stage I. However, they goes up in Stages II and III to be above the Miner’s rule. Moreover, the Miner curve is clearly between that of static damage and that of the unified theory. For this reason, the Miner’s law is the most famous and used model by international codes such as ASME and ISO Majid et al (2017).

1

---------------------------------------------------------------------------------- Increasing loading level

----------------------------------------------------------------------------------

Miner rule D( =2.27) D( =2.09) D( =1.3 Experimental damage Theoretical damage

0.9

0.8

0.7

0.6

0.5

0.4 Damage

0.3

Stage I

Stage III

0.2

Stage II

0.1

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Life fraction 0 i c

Fig. 8. Comparison of the static damage with the damage according to the unified theory and Miner's law.

Conclusion Wire ropes in service are exposed to different damage mechanisms. The corrosion effect is one of these mechanisms, which can cause accelerated damage to cable components and thus lead to sudden and unexpected failure. An experimental study was developed to investigate the influence of corrosion on the mechanical properties of strand, which is extracted from a non-rotating wire rope. In this paper, a new approach based on the calculated forces by the Faupel formula was proposed. This theoretical force can replace the experimental breaking forces of the strands, which were subjected to a tensile test until failure. A modified equation based on a factor  was designed, which depends on the breaking strength behavior of the studied strands. Consequently, in order to calculate the breaking strength afterwards the corresponding damage, it is simple to replace the value of the life fraction in the whole equation (6) or (7), where the parameters max F , r F and c  are constants that depend on the material. Then, through the damage models used, the different stages of the strand’s damage and the critical life fraction that can lead to sudden failure of the wire rope were identified. Stage I is the initiation of the strand failure for the life fraction between � � ���� ���� of damage to the strand, the damage is slowly increasing. Stage II reached for the life fraction between � ����� ���� . In this phase, the damage is progressive and predictive maintenance is essential to industrial user. Stage III, which is characterized by a critical life fraction � � ��� of damage to the strand, which corresponds to twenty four hours of immersion in the acid solution. After that, the progressive damage is suddenly accelerated and the strand break can be brutal for low level of load. The results obtained illustrated that corrosion could lead to a significant decrease in strength and accelerate damage of corroded strands. It also indicated that lifetime decrease linearly with the level of corrosion. References

Judge, R., Yang, Z., Jones, S. W., Beattie, G., 2017. I. Horsfall, Spiral strand cables subjected to high velocity fragment impact, Int. J. Impact Eng., 107, 58-79.