methods-preventing-blade-vibrations-1Friction dampers:-"Piston rings"- Inserts between the blades (e.g. cowbells)Pottant with highinner damping:(e.g. silicon gum)Friction damping at thecontact surfaces:(e.g. blade roots)Material removal tomistune and/or removethe vibration-sensitivearea:- Chord shortening- Cutting off cornerOuter dampingbandage:- Elastomer- Fiber-reinforced syntheticsBlade material with highinner damping, e.g.:- Fiber technical materials, e.g. MMC and fiber- reinforced synthetics, CFC in hot parts- Dispersion hardened (ODS)- Memory metalsDamping foilsdamping coatings:- Lacquers- Enamels- "Active" coatings (e.g. Piezo, memory)Damping housingmaterials:e.g. Fiber-reinfocedsynthetics and MMCThere are many different methods for preventingdangerous blade vibrations.Configuring the blading to prevent resonancesand forced excitementsStiffening, thickeningIncreasingblade spacingStiffening innershroudSuitable rubbingsystemsAvoiding dangerous flow disturbancesin the in- and outlflow Avoiding effects that have a negative influence onthe flow, such as high roughness and large clearance gaps, through: FOD, erosion, foulingLining masseswith highdamping