Nonlinear displacement analysis of advanced propeller structures using NASTRAN

摘要: SUMMARYThe steady state displacements of a rotating advanced turboprop, SR3, werecomputed using the geometrically nonlinear capabilities COSMIC NASTRANRigid Format 4 and MSC NASTRAN Solution 64. Displacements were computed forrotational speeds up to lO 000 rpm. The results showed that complete non-linear analysis is required. Neither linear elastic nor one stepdifferential stiffness adequate. inaccuracy these linearanalyses increased with increases in rotational speeds.A modified Newton-Raphson algorithm used by 64 anIteratlve scheme Rigid employed forpredicting geometrlcally response SR3. was run twoways: (l) constant centrifugal body force from undeform-ed blade, (2) Field corrected each iteration for changesin blade's position. does not possess this load updatingcapability. When updating feature used, thetwo programs generated similar tip deflections rotations. loadupdating capability tlp displacement varied slg-nlflcantly between 4.The SR3 turboprop blade has been shown behave fashion under loading. This becomesincreasingly important at higher speeds. Also, since NASTRANSolution can correct changes position, Itis more desirable tool predicting behavior thanCOSMIC 4.INTRODUCTIONIncreasing concern improving aircraft fuel efficiency broughtabout renewed interest propeller propulsion systems. Improved multl-bladedpropellers, termed turboprops, have potential reduced fuelconsumption while maintaining performance levels modern turbofans.These turboprops thin, flexible, swept blades complex structuralproperties. Extensive research both analytical experimental techniqueshas continues be conducted researchers In field betterunderstand structural aerodynamic complicated blades.An area investigate computation de-flections blades. Previous experience demonstratedthat techniques are inaccurate