7. Conclusion

The system optimization and reliability methods presented enable us to satisfy the required level of structural reliability and determine the best possible design in terms of cost and quality. The cumulative number of deterministic and random variables makes the reliability optimization problem difficult to converge for very large applications. Various methods for coupling optimization and reliability index evaluation of mechanical structures have been proposed. Finally, three industrial applications of reliability optimization are presented.

The first concerns a SHINSEI USR 60 ultrasonic motor. Characterization of the actual mechanical behavior of motor components is still imperfect. The direct consequence is rapid component wear and limited motor life. To better understand the degradation mechanism, a reliability analysis was carried out. In this context, considering...