An efficient solution method based on wave propagation method
multi-harmonic balance method and Receptance method was developed to solve the problem with overlarge degrees of freedom and computational complexity in calculating the nonlinear vibration response of continuous covered blades with damped shroud. According to the cyclic symmetry property of blade
the vibration analysis of a whole blade can be reduced to one of its basic sector using wave propagation method and the nonlinear friction force can be solved from the displacement of the basic sector and friction contact model; the differential equations in time domain of the reduced basic sector can be transformed into algebraic equations in frequency domain by multi-harmonic balance method. The orthogonality of normalized modes is used to decouple the vibration equation of blade in frequency domain and the local nonlinear characteristics of the blade system are used to condense the linear DOFs in non-contact interfaces. So that the scale of nonlinear iteration can be effectively reduced and the computation efficiency is improved. The results showed that the relative error obtained with the developed method was 0.33% and the calculation time was reduced to 10%
which verifies the accuracy and efficiency of the proposed method. The nonlinear vibration response of a real shrouded blade was investigated by this method.
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