A method to predict the non-linear vibratory response of bladed disc system with shrouded dampers

Gu, Wei; Zhou, Xu; Liu, Y

doi:10.1177/0954406211424671

Cited by 13 publications

(9 citation statements)

References 21 publications

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“…Therefore, in order to prevent high vibration amplitude, the best option is to add external sources of damping, e.g., in the form of dry friction devices [1,4]. Dry friction can be incorporated into the blade design, in the form of shrouds [5][6][7][8], interlocked contact surfaces [9], lacing wires or zigzag pins. Alternatively, external devices such as solid dampers (available in several designs, namely cylindrical, curved flat, wedge damper, etc.…”

Section: Introductionmentioning

confidence: 99%

Forced Response Prediction of Turbine Blades with Flexible Dampers: The Impact of Engineering Modelling Choices

2017

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This paper focuses on flexible friction dampers (or "strips") mounted on the underside of adjacent turbine blade platforms for sealing and damping purposes. A key parameter to ensure a robust and trustworthy design is the correct prediction of the maximum frequency shift induced by the strip damper coupling adjacent blades. While this topic has been extensively addressed on rigid friction dampers, both experimentally and numerically, no such investigation is available as far as flexible dampers are concerned. This paper builds on the authors' prior experience with rigid dampers to investigate the peculiarities and challenges of a robust dynamic model of blade-strips systems. The starting point is a numerical tool implementing state-of-the-art techniques for the efficient solution of the nonlinear equations, e.g., multi-harmonic balance method with coupled static solution and state-of-the-art contact elements. The full step-by-step modelling process is here retraced and upgraded to take into account the damper flexibility: for each step, key modelling choices (e.g., mesh size, master nodes selection, contact parameters) which may affect the predicted response are addressed. The outcome is a series of guidelines which will help the designer assign numerical predictions the proper level of trust and outline a much-needed experimental campaign.

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Section: Introductionmentioning

confidence: 99%

Forced Response Prediction of Turbine Blades with Flexible Dampers: The Impact of Engineering Modelling Choices

2017

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“…Petrov [21] used the finite element method to analyze the influence of parameters such as the friction coefficient, contact surface stiffness (normal and tangential coefficients), clearances, interferences, and the normal stresses at the contact interfaces on the vibration response of the blade. Gu et al [22][23][24] proposed a three-dimensional numerical friction contact model to investigate the nonlinear vibration of a damped blade through the FE model. Zucca et al [25] computed the actual contact area on the shroud surface and the distribution of normal static loads through the FE model.…”

Section: Introductionmentioning

confidence: 99%

Study on the Damping Mechanism of the Shrouded Blade considering Contact Features

Qiao

et al. 2019

Shock and Vibration

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A dynamic model of the rotating shrouded blade is established, considering the shroud mass, the Coriolis force, and the centrifugal stiffening effect. And a macroslip model of dry friction with variable normal load is established to simulate the separation-contact-stick-slip state of the shroud. The Lagrangian equation is utilized to solve the differential motion equation, and the Galerkin method is used for discretization. The influence of shroud structure’s parameters such as rotational speed, contact angle, friction coefficient, clearance, and shroud position on the damping effect of the shroud is reviewed by means of amplitude-frequency response and energy through the Newmark-β numerical method. The results demonstrate that the damping effect of the shroud by contact is more obvious than by friction and the amplitude-frequency curve of the shrouded blade shows a strong hard nonlinear phenomenon.

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“…14,32 In order to do this, the Fourier coefficients of the nonlinear displacements X¯N are turned to temporal displacements X N ( t ) by inverse fast Fourier transform (IFFT). Then, a state-of-the-art 3D contact model (Figure 1) 33,34 is used to compute periodic contact forces. Finally, the periodic nonlinear forces F N ( t ) are turned to Fourier coefficients by FFT and introduced in the balance equations.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of free interface-based reduction techniques for nonlinear forced response analysis of shrouded blades

Mashayekhi

Zucca

Nobari

2019

Proceedings of the Institution of Mechanical Engineers, Part C:

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The efficient dynamic stress assessment of turbine blades is of prime importance in turbomachinery design. An accurate prediction of forced response level of shrouded blades requires a very detailed finite element model in addition to a nonlinear solver. In order to perform nonlinear forced response analysis of blades at an affordable computational cost, applying a model order reduction technique is essential. The appeal for component mode synthesis methods in dimension reduction of structures with friction contacts is due to the possibility of retaining a subset of physical degrees of freedom (e.g. the contact degrees of freedom) in the set of generalized coordinates. In this paper, a reduction method recently developed for nonlinear forced response analysis of structures with local nonlinearity is evaluated and compared with two classical component mode synthesis reduction techniques. All three methods have the same projection basis, which includes residual flexibility attachment modes and free interface modes, but different implementation. The response is computed in the frequency domain using multiharmonic balance method and periodic contact forces are modeled with a node-to-node 3D friction contact model. In order to demonstrate the efficiency of the three formulations, a rod and a simplified shrouded turbine blade are considered as case studies.

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A method to predict the non-linear vibratory response of bladed disc system with shrouded dampers

Cited by 13 publications

References 21 publications

Forced Response Prediction of Turbine Blades with Flexible Dampers: The Impact of Engineering Modelling Choices

Forced Response Prediction of Turbine Blades with Flexible Dampers: The Impact of Engineering Modelling Choices

Study on the Damping Mechanism of the Shrouded Blade considering Contact Features

Evaluation of free interface-based reduction techniques for nonlinear forced response analysis of shrouded blades

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