Frequency response analysis of the bladed disk system with the mistuned in mass and stiffness

Ideally, bladed disk systems are tuned and all blades are identical but, in practice there always exist small, random differences among the blades. In designing bladed disks, all the blades on each stage are generally assumed to be identical, and this is called a tuned bladed disk. However, due to manufacturing tolerances, variations in material properties and wear in service, each blade on a disk is almost always slightly different to the others. These small differences, collectively called mistuning. It is well known that even a small amount of mistuning can induce a large forced response known as mode localization. In this study a representative model for the bladed disk system is presented and equation of motion derived. Then the response of tuned system was obtained. Afterward, frequency response of mistuned system with genetic algorithm for mistuned blade in mass was studied. Also maximum frequency response of the system for mistuned blade in stiffness was calculated. The result indicated the slightly mistuning in system can increase the response of the system. The worst response of mistuned system is 5.563 times greater than the response of the tuned system. Increase in frequency response of the system is undesirable and should be considered in the initial design of these systems.