Numerical analysis of multiple friction contacts in bladed disks
(English)In: International Journal of Mechanical Sciences, ISSN 0020-7403, E-ISSN 1879-2162Article in journal (Other academic) Submitted
The damping potential of multiple friction contacts in a bladed disk, tip shroud and strip damper is investigated, showing 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 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 and 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 approximate 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.
Friction damping, Shroud contact, Strip damper, Cyclic symmetry, Alternate frequency time domain method, Multiharmonic balance method.
Research subject Engineering Mechanics
IdentifiersURN: urn:nbn:se:kth:diva-202994OAI: oai:DiVA.org:kth-202994DiVA: diva2:1080749
FunderSwedish Energy Agency, 26159
QC 201703132017-03-102017-03-102017-03-13Bibliographically approved