Title

An Analytical Approach To Designing Friction Dampers In Turbomachinery Blading

Report Number

WL-TR-91-3078 Volume III, p. JBA-1 thru JBA-14

Creator

Panovsky, Josef

Hendley, David O.

MacKay, Raymond A.

Corporate Author

GE Aircraft Engines, Cincinnati, Ohio and Lynn, Massachusetts

Date

1991

Date Issued

1991-08

Extent

14

Identifier

ADA241313

Format

1 online resource

Abstract

Aircraft engine turbomachinery blading operates in an environment that induces vibration which can lead to failure through high-cycle fatigue. This vibration can often be reduced to acceptable levels by friction dampers, which dissipate energy by capitalizing on the resulting relative motion between the blade and a motionless structure or adjacent vibrating blades. The key to optimizing a given damper design is to determine the dynamic weight at which the maximum energy is dissipated without locking the blade at the damper contact point. As the design of turbomachinery blading
progresses towards higher-loaded stages with more complex geometry, vibratory modes beyond the primary beam bending become more prominent. This pape will discuss the development of an analytical method to predict damper effectlveness for any blade mode. The analysis is based on a component mode method, and includes provisions for modeling stick-slip at the friction contact. Multiple damper contact points can be evaluated, and the damper design can be blade-to-ground or blade-to-blade with arbitrary phase angle. The results of a series of lab tests with simple beam specimens to evaluate the principal damper design variables will be presented along with the corresponding analytical predictions.

Description

Aircraft engine turbomachinery blading operates in an environment that induces vibration which can lead to failure through high-cycle fatigue. This vibration can often be reduced to acceptable levels by friction dampers, which dissipate energy by capitalizing on the resulting relative motion between the blade and a motionless structure or adjacent vibrating blades. The key to optimizing a given damper design is to determine the dynamic weight at which the maximum energy is dissipated without locking the blade at the damper contact point. As the design of turbomachinery blading
progresses towards higher-loaded stages with more complex geometry, vibratory modes beyond the primary beam bending become more prominent. This pape will discuss the development of an analytical method to predict damper effectlveness for any blade mode. The analysis is based on a component mode method, and includes provisions for modeling stick-slip at the friction contact. Multiple damper contact points can be evaluated, and the damper design can be blade-to-ground or blade-to-blade with arbitrary phase angle. The results of a series of lab tests with simple beam specimens to evaluate the principal damper design variables will be presented along with the corresponding analytical predictions.

Distribution Classification

1

Distribution Conflict

No

DTIC Record Exists

No

Illinois Tech Related

No

Photo Quality

Not Needed

Report Availability

Full text available

Type

article

Is Part Of

Proceedings of Damping '91: 13-15 February 1991 San Diego, California (GCA-1 through JCB-17)