5. 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-scale applications. Various methods for coupling optimization and reliability index evaluation of mechanical structures have been proposed. Finally, an industrial application on the optimization and reliability of an ultrasonic motor was presented. Characterization of the actual mechanical behavior of the components of the SHINSEI USR 60 motor is still imperfect. The direct consequence is rapid component wear and limited motor life. To better understand the mechanism of wear degradation, we carried out a reliability analysis. In this context, taking into account...