An Adaptive Perturbation Scheme for the Analysis of Mistuned Bladed Disks

1995 ◽  
Author(s):  
Chung-Chih Lin ◽  
Marc P. Mignolet
Keyword(s):  
Steady State ◽  
Forced Vibration ◽  
Perturbation Technique ◽  
Computational Effort ◽  
Vibration Response ◽  
Perturbation Scheme ◽  
Bladed Disks ◽  
Steady State Analysis ◽  
At Will

In this paper, a novel perturbation technique is introduced for the determination of the forced vibration response of mistimed bladed disks. The proposed technique is adaptive in the sense that the level of approximation can be varied at will to accommodate any specificities of the tuned system and/or of the existing mistuning. This versatility of the proposed approach not only guarantees the reliability of the computed response but also leads to an excellent compromise between accuracy and computational effort. Numerical results are presented that demonstrate both the reliability of the computed response and the computational saving obtained by relying on the suggested perturbation technique as opposed to a straightforward steady state analysis.

An Adaptive Perturbation Scheme for the Analysis of Mistuned Bladed Disks

1997 ◽  
Vol 119 (1) ◽  
pp. 153-160 ◽  
Author(s):  
C.-C. Lin ◽  
M. P. Mignolet
Keyword(s):  
Steady State ◽  
Forced Vibration ◽  
Perturbation Technique ◽  
Computational Effort ◽  
Vibration Response ◽  
Perturbation Scheme ◽  
Bladed Disks ◽  
Steady State Analysis ◽  
At Will

In this paper, a novel perturbation technique is introduced for the determination of the forced vibration response of mistuned bladed disks. The proposed technique is adaptive in the sense that the level of approximation can be varied at will to accommodate any specificities of the tuned system and/or of the existing mistuning. This versatility of the proposed approach not only guarantees the reliability of the computed response but also leads to an excellent compromise between accuracy and computational effort. Numerical results are presented that demonstrate both the reliability of the computed response and the computational saving obtained by relying on the suggested perturbation technique as opposed to a straightforward steady-state analysis.

A multibody dynamic model for predicting operational load spectra of dual clutch transmissions

2021 ◽  
Vol 263 (2) ◽  
pp. 4132-4143
Author(s):  
Murat Inalpolat ◽  
Enes Timur Ozdemir ◽  
Bahadir Sarikaya ◽  
Hyun Ku Lee
Keyword(s):  
Steady State ◽  
Dynamic Model ◽  
Forced Vibration ◽  
Linear Time ◽  
Vibration Response ◽  
Operating Conditions ◽  
Mode Shapes ◽  
Time Step ◽  
Gear Mesh ◽  
Multibody Dynamic

In this paper, a generalized nonlinear time-varying multibody dynamic model of dual clutch transmissions (DCT) is presented. The model consists of clutches, shafts, gears and synchronizers, and can be used to model any DCT architecture. A nonlinear clutch model is used to determine the transmitted power to the transmission at any speed and clutch temperature. The clutch can be a single- or multi-plate clutch and can operate in a wet or dry-clutch configuration. A combined kinematic and powerflow simulation enables calculation of gear, shaft, bearing and clutch quasi-static loads as well as gear mesh frequencies following a duty cycle as the input. For the corresponding Linear-Time-Invariant (LTI) system model, natural frequencies and mode shapes are obtained by solving the eigenvalue problem. The modal summation technique is used to determine the steady state forced vibration response of the system. For the corresponding NTV system, Newmark's time-step marching based integration is used to determine both the steady state and transient forced vibration response of the system. The DCT model is exercised using a common transmission architecture operating at several different operating conditions. The resulting impact of changing operational conditions on gear and bearing loads as well as dynamic transmission error spectra are demonstrated.

A new approach for steady state analysis of three-phase SEIG feeding single-phase load

2019 ◽  
Vol 38 (1) ◽  
pp. 46-67 ◽  
Author(s):  
Tarek Zine Eddine Benhacine ◽  
Ali Nesba ◽  
Said Mekhtoub ◽  
Rachid Ibtiouen
Keyword(s):  
Steady State ◽  
Single Phase ◽  
Conventional Approach ◽  
Operating Point ◽  
Resolution Method ◽  
Modified Model ◽  
Steady State Analysis ◽  
Content Type ◽  
Three Phase

Purpose This paper aims to deal with a modified-based approach for the evaluation of the steady state performances of three-phase self-excited induction generator (SEIG) feeding single-phase load. Design/methodology/approach Using the symmetrical components method, the proposed approach is based on a modified model of unbalanced three-phase SEIG, which is formulated similarly to the well-known model of balanced three-phase SEIG. Owing to this modified model, the determination of the SEIG operating point amounts to the resolution of two semi-decoupled nonlinear equations for two unknowns; the magnetizing reactance and the per-unit frequency. A simple resolution method based on an iterative two-step technique is used. The results obtained by the proposed approach are compared with those given by a conventional approach and are validated experimentally. Findings The proposed approach is as accurate as the conventional approach. Further, for the same accuracy degree, the proposed approach permits to speed up the resolution when compared to the conventional approach, as only few iterations are required for the convergence. The proposed approach was also successfully used for the steady state analysis of SEIG under generalized unbalanced loading conditions. Practical implications The determination of the operating point of the generator is based on a modified model of the generator and a simple iterative resolution method. The calculation technique can be implemented on low resource controller to provide online voltage control of the SEIG. Originality/value The paper contains two main originalities. The first one consists in a modified formulation of the SEIG model under unbalanced loading conditions. The modified formulation permits the use of the well-known model of balanced three-phase SEIG. Unlike previous ones reported in the literature, the proposed model does not require tedious algebraic manipulations. The second originality is the use of two-step technique to solve the equations, which permits to avoid laborious mathematical derivations and manipulating high-order polynomials.

scholarly journals On the Large Amplitude Forced Vibration Analysis of Composite Sectorial Plates

2021 ◽  
Vol 5 (3) ◽  
pp. 83
Author(s):  
Ahmad Saood ◽  
Zain A. Khan ◽  
Mohd T. Parvez ◽  
Arshad H. Khan
Keyword(s):  
Steady State ◽  
Forced Vibration ◽  
Large Amplitude ◽  
Laminated Composite ◽  
Vibration Response ◽  
Arc Length ◽  
Annular Sector ◽  
Sector Plate ◽  
Annular Sector Plate ◽  
State Stress

The nonlinear steady state large amplitude forced vibration response of a laminated composite annular sector plate is presented. The nonlinear governing equation of motion of the laminated composite annular sector plate has been obtained using kinematics of first-order shear deformation theory (FSDT) and employing Hamilton’s principle. The governing equations of motion have been solved in a time domain using a modified shooting method and arc-length/pseudo-arc length continuation technique. The influence of the boundary condition, sector angle, and annularity ratio on the linear as well as nonlinear steady state forced vibration response has been investigated. The strain/stress variation across the thickness of the annular sector plate is presented to explain the reason for a decrease/increase in hardening nonlinear behaviour. The periodic variation of the non-linear steady state stress has also been obtained to throw light into the factors influencing the unequal stress half cycles and multiple cyclic stress reversals, which is detrimental to the fatigue design of laminated composite annular sectorial plates. The frequency spectra of the steady state stress reveals large even and odd higher harmonic contributions for different cases due to changes in the restoring force dynamics. The modal interaction/exchange during a cycle is demonstrated using a deformed configuration of the laminated annular sector plate.

scholarly journals Localization in Multiple Nearly-Identical Tuned Vibration Absorbers

2013 ◽  
Vol 2 (3) ◽  
pp. 157 ◽  
Author(s):  
Abdullah Saleh Alsuwaiyan
Keyword(s):  
Mathematical Model ◽  
Steady State ◽  
Torsional Vibration ◽  
Forced Vibration ◽  
Absolute Magnitude ◽  
Vibration Absorbers ◽  
Steady State Analysis ◽  
Tuned Vibration Absorbers ◽  
Translational Vibration ◽  
The Mathematical Model

The forced vibration of multiple nearly identical translational vibration absorbers is considered. Localization, where the amplitudes of vibration of a group of the absorbers can become relatively large as compared to those of the corresponding perfectly tuned system is investigated. In this work, imperfections amoung the absorbers are allowed and brought into the analysis through the stiffnesses of the absorbers' springs. Steady-state analysis of the mathematical model is used to obtain the results. Results, which focus on translational absorber systems, are found to be consistent with previous results obtained for torsional vibration absorbers. It is found that strengths of the localized responses depend on the levels of imperfections, the relative imperfections among absorbers, and the absorbers' damping. Localization is shown to exist in the undamped multiple nearly-identical vibration absorbers system, or more generally, in the system where the ratio of the level of absorbers' damping to the level of imperfections in the absorbers is small. It is also shown that localized responses can be effectively avoided by introducing some intentional mistuning in the absorbers' stiffnesses. This mistuning should be small in absolute magnitude in order not to reduce the absorbers' performance and should be large when compared to the absorbers' imperfections.

scholarly journals Effects of Damping and Damping Mistuning on the Forced Vibration Response of Bladed Disks

1993 ◽  
Author(s):  
Chung-Chih Lin ◽  
Marc P. Mignolet
Keyword(s):  
Closed Form ◽  
Forced Vibration ◽  
Structural Parameters ◽  
Forced Response ◽  
Vibration Response ◽  
Bladed Disks ◽  
Bladed Disk ◽  
Damping Coefficients ◽  
Simulation Results

The effects of blade-to-blade variations in the damping coefficients on the forced response of a bladed disk are investigated. It is found that this nonuniformity of the disk can lead to variations in the blades’ amplitudes of response which are similar, in magnitude, to those obtained with stiffness mistuning but are potentially more dangerous because of the skewness of the distribution toward large amplitudes. The influence of various structural parameters on the scatter of blade amplitudes is also studied. Finally, the adequacy of the combined Closed Form - Perturbation (CFP) method is demonstrated by comparison with simulation results.

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