On three concepts in robust design optimization: absolute robustness, relative robustness, and less variance

This paper provides a clear perspective on existing several different approaches to robust design optimization of structures. We primarily consider three approaches: the worst-case optimization, the discrepancy (i.e., the maximum gap between the objective values in a nominal case and a possibly occurring case) minimization, and the variance minimization. Some other formulations can also be linked with one of these three approaches. To investigate how the solutions derived by these three approaches differ from each other, we present two numerical examples. This direct comparison clarifies different features of these approaches.