Traditional engineering focuses on solving problems, using a repetitive process of designbuild-test, studying in detail the problems associated with interactions of the factors involved.
Design consists of a hierarchical sequence of steps. It begins with ideas, missions and concepts, takes successively firmer shape until the configuration can be frozen, continues with the practical considerations about hardware, and leads to a set of manufacturing instructions and airworthiness documentation. As this process evolves design freedom decays rapidly while knowledge about the object of design is increasing.
Over the last few years the design practice has undergone fundamental changes in methods and purposes; there has been an increased emphasis on integrating the disciplines into the design at an earlier time and the attention to product quality and development costs has been dramatically increased.
The traditional deterministic approach, in which uncertainties of design variables are either unaccounted far or accounted far by the safety factors, is gradually being improved by the robust design, capable of accounting far the random nature of the design characteristics, and of pursuing objectives like robustness and reliability.
A robust design is not simply strong, flexible and efficient. We can say we have a robust design when it can withstand a wide range of changing client and manufacturing conditions. It also provides a method far designing products and processes that are minimally impacted by external forces, such as environment, client use, or manufacturing conditions. A robust design provides a more efficient, costeffective way to improve products and processes.
In addition, the Multidisciplinary Design Optimisation (MDO) techniques has supported the design of complex coupled engineering systems, exploiting the interactions among different phenomena.
Examples far MDO and Robust Design applications applied to Avio low pressure turbine components are given. Here modeFRONTIER workflow manager and multi-objective algorithms have been used far LPT flow-path optimisation, rotar stage robust design analysis, biade cooling analysis and LPT casing robustness assessment. |
