Decreasing bladed disk response with dampers on a few blades. Part II: Nonlinear and blade-blade dampers applications

This two part paper focuses on the optimum placement of a limited number of dampers, i.e. fewer than the number of blades, on a bladed disk to induce the smallest possible amplitude of blade response with or without involuntary, random mistuning. Intentional mistuning is also considered as an option to reduce the amplitude of blade response and the pattern of two blade types (referred to as A and B blades) is then part of the optimization effort in addition to the location of the dampers on the disk. This second part of the investigation focuses on the application of the optimization algorithms developed in Part I to nonlinear dampers, more specifically friction dampers, as well as to the consideration of blade-blade dampers, linear or nonlinear (underplatform dampers). Additionally, the optimization of blade-only and blade-blade linear dampers will be extended to include uncertainty/variability in the damper properties that arise during the manufacturing and/or inservice. It is found that the optimum achieved without considering such uncertainty/variability is robust with respect to it.