VIBRATION ANALYSIS OF MISTUNED BLADED-DISK ASSEMBLIES - INVERSE APPROACH

This paper deals with the development or a general analysis method tha t aims at solving the inverse response problem where some of the key s tructural parameters are determined from knowledge of the system's res ponse. This proposed method of analysis was applied to the specific ca se of a 12-bladed disk to determine the range of individual blade cant ilever frequency scatter so that all blade responses lay below an allo wable maximum level. This scatter or manufacturing tolerance was compu ted statistically, and the analysis was verified using a direct Monte Carlo simulation. The relationship between the allowable response incr ease due to mistuning and the corresponding manufacturing tolerances w as also investigated, and the presence of a critical mistuning thresho ld was noted. The existence and the nonuniqueness of the inverse solut ion is discussed in some detail. A number of numerical problems are id entified, and routes for their avoidance are suggested. Finally, a com parison of the direct and inverse analysis methods for bladed-disk mis tuning studies is presented and the suitability of the inverse method to bladed-disk design is discussed.