Fig.1

Power turbine rotor model and unit node division

Fig.2

Rotor system coordinate system

Fig.3

Assembly of coefficient matrices for single rotor systems

Fig.4

Power turbine rotor model and unit node division

Table 1

Comparison of critical speed and calculated time results

Fig.5

Comparison of vibration mode calculation results

Fig.6

Dynamic neighborhood relations

Fig.7

Flow chart of IPSO algorithm

Table 2

Comparison of test results of optimization algorithms

Fig.8

Comparison of test results of optimization algorithms

Fig.9

Campbell diagram of power turbine rotor

Fig.10

Vibration mode diagrams of power turbine rotor

Fig.11

Unbalance response of the rotor in X-direction at node 67

Fig.12

Bistable characteristics of rotor induced by dampers

Table 3

Design objectives of helicopter power turbine rotor system

Fig.13

Two critical speed setting methods

Table 4

Dynamic design schemes of helicopter power turbine rotor system

Fig.14

Critical speed exclusion zone

Fig.15

Flow chart of rotor system optimization based on IPSO

Fig.16

Change of fitness with number of iterations

Table 5

Comparison of two optimization solutions

Fig.17

Comparison of maximum unbalance response amplitude of rotor

Table 6

Damper optimization results

Fig.18

Variable speed power turbine rotor test bed

Fig.19

Schematic diagram of sensors layout of rotor tester

Table 7

Parameters of sensors

Table 8

Comparison between calculated and actual measured values of critical speed of experimental rotor system

Fig.20

Comparison of measured and calculated results of vibration mode under two schemes

Fig.21

Single peak amplitude and variable speed range of rotor vibration

Fig.22

Comparison of maximum amplitude test results of rotor tester before and after optimization