Reliability-based design optimization of load-sharing systems

This research aims at developing computationally efficient method for the design optimization of load-sharing systems. In the case of designing a mechanical system with some reliability requirements, especially parallel or mixed systems, the current system reliability evaluation method assumes component's failure probability being constant. For real world applications, this may not be true, as the failure of one component will increase the failure probability for the remaining components when the system load gets redistributed. Primary applications include aerospace systems, bridges, automobiles, etc. In our approach, we consider the dynamic nature of component's failure probability in a load-sharing system. The failure of components are not independent to each other and the first failure may equal-likely happen on any component. The limit-state functions of components are built upon the Stress-Strength Interference theory. We use the Sequential Optimization and Reliability Assessment (SORA) method that decouples optimization from reliability analysis. The advantage of this method is that it allows flexibility in the use of optimization and reliability analysis methods. This methodology also allows the user to decide the optimal number of components required for the system with the given load characteristics. Finally, numerical examples are provided to verify the methodology.