Conceptos de probabilidad y estadística en análisis de fallas de componentes mecánicos

• Main Author: Héctor Hernández
• Format: Article
• Language: English
• Published: Universidad Nacional de Colombia 1996-05-01
• Series: Ingeniería e Investigación
• Subjects: ingeniería mecánica; probabilidad de fallas
• Online Access: https://revistas.unal.edu.co/index.php/ingeinv/article/view/24815

When a mechanical component fails, somehow or other, the applied load becomes equal or greater than the fail load. Taking in mind this principle and considering the statistical variability of both, applied stress and strength, the concept of failure probability is catched. Assuming that both strenght and stress have a normal distribution, then failure probability increases with: (a) the reduction of the difference between mean value of strenght and stress, (b) the increase of strenght and stress variance. Defects introduced by manufacturing and defects introduced into service such as voids, pits, inclusions or cracks can increase the failure probability and decrease the reliability. This is due to the' increase in the overlapping between the two distributions, of stress and strenght. This depends on failure mode such as plastic collapse, britle fracture and failure by fatigue. When the failure mode is by slow crack growth, reliability can be improved by using of nondestructive inspection methods to detect subcritical crack sizes.