Vibrations and waves In continnuous mechanical systems , Vibrations and waves In continnuous mechanical systems , کتابخانه دیجیتالی دانشگاه علوم پزشکی و خدمات درمانی شهید بهشتی

Vibrations and waves In continnuous mechanical systems

Aeroengine is a complex mechanical equipment, and it works at high temperature, pressure, rotational-speed, and severe loads. One of the core problems is that the vibration and mistuning of bladed disk lead to failure and affect the safety and reliability of aeroengine. Previously, one sector taken as the research object is not suitable; the integrally mistuned bladed disk (blisk) is taken as the research object is very necessary; however, the computational efficiency of mistuned blisk is very low. Therefore, a reduced-order model approach, i.e., an improved dynamic substructure finite element model-based state-space technique (IDSFEM-SST), is proposed to investigate the mistuned blisk. Firstly, the reduced-order substructure finite element model is established by this method, and then, the modal frequencies and modal strain energy amplitudes are investigated. Secondly, the maximum displacement responses are analyzed. Finally, the computational efficiency and accuracy of mistuned blisk via IDSFEM-SST is compared with that of the classical dynamic substructure finite element model and the high-fidelity finite element model to verify the effectiveness of this approach. This study has significance to the dynamic research and engineering practices for complex mechanical structures.

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Application of Improved Dynamic Substructure Finite Element Model-Based State-Space Techniques in Mistuned Blisks

Investigation of the vibrating feeding system for sphericity separation of coated fuel particles using DEM

The motion of a part on a curved surface mounted upon a linear vibratory feeder is of great importance in mass production. In this article, the conveying surface or track is modelled by a bilinear ...

Dynamics of part motion on a linear vibratory feeder

To improve the simulation efficiency of mistuned blisk, a method called receptance substructure component modal synthesis method (RSCMSM) is proposed to reduce its degrees of freedom (DOFs). The advantage of this method is that only the interface DOFs need to be solved, which observably enhances the computational efficiency. The modal frequencies, maximum modal shape and frequency response function are calculated via RSCMSM. It is seen that the smooth frequency band is governed by blade vibration and the steep frequency band is governed by disk or bladed-disk coupling vibration. In addition, a peak is observed for the tuned blisk but many peaks appear for the mistuned blisk and many small wave crests are observed near the peak. To verify validity of this method, the computational time of RSCMSM is compared with high fidelity finite element method (HFFEM) and classical substructure component modal synthesis method (CSCMSM), which manifests that the computational efficiency increases by 32.19 %–80.82 % than that of HFFEM when the mistuned level is 0 %~5 %. Moreover, computational efficiency of RSCMSM is increased by 0.85 %–7.56 % than that of CSCMSM. The validity of RSCMSM is verified for calculating the complex mechanical structure.

Vibration characteristics investigation of mistuned blisks with receptance substructure component modal synthesis method

On using a distributed-parameter model for modal analysis of a mistuned bladed disk rotor and extracting the statistical properties of its in-plane natural frequencies

A new three-dimensional dynamic model and experimental validation for motion of a part in a vibratory bowl feeder

Analytical model for coupled torsional-longitudinal vibrations of marine propeller shafting system considering blade characteristics

In this paper, nonlinear vibration of an Euler–Bernoulli beam excited by a harmonic random axial force is studied. The equation of motion contains a term with time-varying coefficient which is solved by modified Lindstedt–Poincare method. Then the effect of the random axial force on the response is investigated using the obtained approximate solution. Two cases are considered in random analysis, namely random amplitude and random phase of the axial force. For both cases, the ensemble average, mean square value and the autocorrelation function are obtained. The results have indicated that for each case the mean and the mean square value are a function of time which means that the lateral displacement of the beam is a nonstationary process. A numerical study is also conducted based on the iteration of numerical solution in order to verify the derived analytical formulae. It is shown that a good agreement is seen between the analytical and numerical solution statistical properties.

Mohammad Shadmani

Papers

On using a distributed-parameter model for modal analysis of a mistuned bladed disk rotor and extracting the statistical properties of its in-plane natural frequencies

A new three-dimensional dynamic model and experimental validation for motion of a part in a vibratory bowl feeder

Analytical model for coupled torsional-longitudinal vibrations of marine propeller shafting system considering blade characteristics

Nonlinear vibration analysis of a beam subjected to a random axial force