PSI - Issue 47

Fatima Gugouch et al. / Procedia Structural Integrity 47 (2023) 952–958 Fatima Gugouch/ Structural Integrity Procedia 00 (2019) 000–000

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Fig. 6. Curve of MTBF according to the fraction of life

The Fig. 6 shows that the MTBF represents a linear function according to the harmfulness of damage as the case of the level of loading applied in fatigue. The availability, which is a quantity as a function of the latter and of the maintainability represented by the Mean Time To Repair (MTTR) Eq. (4), will have a downward trend under the same conditions, impacted by the skill level maintenance and quality of intervention staff.

MTBF MTTR MTBF 

 (%)

Avail

(4) The Fig.7 illustrates the evolution of availability as a function of the fraction of life. We note that the level of maintainability control has a direct impact on the availability of CPVC pipes.

Fig. 7. Evolution of availability as a function of the quality of maintainability of CPVC pipes.

5. Conclusion A study of the damage and reliability of the CPVC specimens subjected to thermomechanical tests led to the establishment of the bathtub curves which takes advantage of the damage and reliability curves. In addition, the evolution of MTBF in proportion to the harmful effect, representing the level of loading, has been plotted. Therefore, the three stages in the life of the equipment have been determined to know when exactly it will maintain or disassemble a part and by knowing the level of maintainability, availability is obtained.