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Dynamic and resonance response analysis for a turbine blade with varying rotating speed

Wang D., Hao Z., Chen Y., Zhang Y.

Journal of Theoretical and Applied Mechanics

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2018

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Vol. 56 nr 1

31--42

EN

A coupling model between turbine blades with a varying rotating speed and oncoming vortices is constructed, where the coupling of the structure and the fluid is simulated by the van der Pol oscillation. Partial differential governing equations of motions for the coupled system are obtained and discretized by using the Galerkin method. The 1:2 subharmonic resonance and the 1:1 internal resonance are investigated with the multiple scale method and first-order averaged equations are then derived. Nonlinear responses and bifurcation characteristics are studied by a numerical integration method. Stability of bifurcation curves is determined by utilizing the Routh-Hurwitz criterion. The effect of system parameters including the detuning parameter, steady-state rotating speed, amplitude of periodic perturbation for the rotating speed and freestream velocity on vibration responses are investigated.

2

A novel dynamical model for GVT nonlinear supporting system with stable-quasi-zero-stiffness

Hao Z., Cao Q.

Journal of Theoretical and Applied Mechanics

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2014

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Vol. 52 nr 1

199--213

EN

In this paper, a dynamical model of a spring-mass system with a single degree of freedom is proposed, which can be designed as a nonlinear supporting system for GVT of large scale aircraft and vibration isolation owing to stable-quasi-zero-stiffness (SQZS). The SQZS structure is constructed by a positive stiffness component and a pair of inclined linear springs providing negative stiffness, which is typical for an irrational restoring force due to geometrical configuration. The unperturbed analysis demonstrates complex equilibrium bifurcations and stabilities for this peculiar system, based upon which parameter optimizations are performed for SQZS and the maximum interval of low frequency. Furthermore, the dynamics analysis of the perturbed system near the optimized parameters reveals complicated behaviour of KAM structures, period doubling, chaos crisis, coexistence of multiple solutions, intermittency chaos, chaos saddle, etc. All those presented herein provide a better understanding for the complicated dynamics of SQZS nonlinear system.

3

A reconstruction method of generalized sampling based on generalized inverse

Zhaoxuan Z., Houjun W., Zhigang W., Hao Z.

Metrology and Measurement Systems

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2010

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Vol. 17, nr 2

163-171

EN

This paper considers the problem of reconstructing a class of generalized sampled signals of which a special case occurs in, e.g., a generalized sampling system due to non-ideal analysis basis functions. To this end, we propose an improved reconstruction system and a reconstruction algorithm based on generalized inverse, which can be viewed as a reconstruction method that reduces reconstruction error as well. The key idea is to add an additional channel into a generalized sampling system and apply the generalized inverse theory to the reconstruction algorithm. Finally, the approach is applied, respectively, to an oscilloscope, which shows the proposed method yields better performance as compared to the existing technique.