Numerical analysis of multiple friction contacts in bladed disks

Mohammad Afzal, Ines Lopez Arteaga, Leif Kari

Research output: Contribution to journalArticleAcademicpeer-review

6 Citations (Scopus)

Abstract

The damping potential of multiple friction contacts in a bladed disk is investigated. Friction contacts at tip shrouds and strip dampers are considered. It is shown that friction damping effectiveness can be potentially increased by using multiple friction contact interfaces. Friction damping depends on many parameters such as rotational speed, engine excitation order and mode family and therefore it is not possible to damp all the critical resonances using a single kind of friction contact interface. For example, a strip damper is more effective for the low nodal diameters, where blade/disk coupling is strong. The equations of motion of the bladed disk with multiple friction contacts are derived in the frequency domain for a cyclic structure with rotating excitations. A highly accurate method is used to generate the frequency response function (FRF) matrix. Furthermore, a finite element contact analysis is performed to compute the normal contact load and the contact area of the shroud interface at operating rotational speed. The multiharmonic balance method is employed in combination with the alternate frequency time domain method to find the steady state periodic solution. A low-pressure turbine bladed disk is considered and the effect of the engine excitation level, strip mass, thickness and the accuracy of FRF matrix on the nonlinear response curve are investigated in detail.

Original languageEnglish
Pages (from-to)224-237
Number of pages14
JournalInternational Journal of Mechanical Sciences
Volume137
DOIs
Publication statusPublished - 1 Mar 2018

Keywords

  • Alternate frequency time domain method
  • Cyclic symmetry
  • Friction damping
  • Multiharmonic balance method
  • Shroud contact
  • Strip damper

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