Mistuning identification and model updating of coating blisk based on modal test

Journal of Low Frequency Noise, Vibration and Active Control

Gao

Sun

et al. 2019

Self Cite

In the damping design of blisks with hard coating, changing coating thickness is one of the frequently used ways for achieving better damping performance. Nevertheless, for the vibration analysis with variable coating thickness by using commercial finite element software, it is necessary to regenerate the finite element mesh, which results in inconvenience in computation. In this paper, a new laminated element is developed to solve this problem, which needs solely the node coordinates corresponding to the maximum coating thickness. The additional virtual layers to simulate the variations of coating thickness are introduced for the presented element to avoid regenerating new node coordinates. By comparing the analysis results obtained by SOLID185 in ANSYS software, experiment and the developed element, this new element is verified that it remains effective for variable coating thickness parameter input. Furthermore, the effects of the coating thickness on the natural frequency and the forced response of an actual blisk are analysed and due to using the same node coordinates, the computational efficiency is improved significantly. The analysis results indicate that with the increase of coating thickness, the resonance response is reduced significantly and even the thinner coating could also achieve better damping performance.

Section: Disadvantages Of Vibration Analysis For Coated Blisk Based O...mentioning

confidence: 99%

A new finite element model for vibration analysis of a coated blisk with variable coating thickness

Journal of Low Frequency Noise, Vibration and Active Control

Gao

Sun

et al. 2019

Self Cite

“…So far, the research on mistuning identification of coated blisk is still in the initial stage. For example, Xu et al 42 studied the mass and stiffness mistuning identification of the coated blisk. Unfortunately, the damping mistuning identification of the coated blisk was not studied.…”

Section: Introductionmentioning

confidence: 99%

Mistuning identification for coated blisks using small amount of experimental data

Proceedings of the Institution of Mechanical Engineers, Part C:

Sun

et al. 2020

Self Cite

Because the coatings are likely to produce new mistuning which aggravates the vibration failure of coated blades, it is particularly important to study the mistuning identification for coated blades. In this study, the degrees of freedom of the whole disk of the coated blisk is completely constrained, and the orders of the dynamic model of the coated blisk based on component mode mistuning (CMM) method is further reduced. Based on this model, a novel mistuning identification method for the coated blade of the coated blisk by small amount of experimental data is proposed, which can identify the mass, stiffness and damping mistuning of the blade substrates and coatings. The input parameters with high amount of data, such as modal shape matrix, are removed from identification formulas, thus, both the amount of data for identification calculation and the workload of vibration testing are reduced. The mistuning identifications of the numerical case and actual case are carried out respectively, and the identification process of the mistuning identification method in this paper is compared with the one based on the classical CMM model. It is shown that the mistuning identification method is effective and feasible, and the identification efficiency is higher than the classical CMM identification method.

“…Therefore, this identification method has strong applicability and has been widely used. [50][51][52][53] Considering the advantages of the CMM mistuning identification method and it focuses on blade mistuning, the identification concept of this method is also used for reference in this study. However, since this method has not been applied to the identification of blade crack mistuning in hard-coated blisk before, the classical identification method based on CMM ROM needs to be improved accordingly in this study.…”

Section: Introductionmentioning

confidence: 99%

Identification and influence factors analysis of blade crack mistuning in hard-coated blisk based on modified component mode mistuning reduced-order model

Journal of Low Frequency Noise, Vibration and Active Control

et al. 2020

Self Cite

Blade crack will cause severe mistuning of hard-coated blisks, which will lead to vibration localization. To identify crack mistuning and analyze influence factors, in this study, a mistuning identification method of blade cracks in hard-coated blisks is presented based on modified component mode mistuning reduced-order model, in which the hard-coated blisk with blade crack is decomposed into a substructure of tuned hard-coated blisk and a substructure of coated blade with cracks. Crack mistuning of each coated blade can be obtained by a single identification calculation. After verifying the rationality of this identification method, the influence factors of blade crack mistuning are analyzed. The influence factors include the crack location on the coated blade (cracks occurring only in coating or only in blade substrate or both in blade substrate and coating), crack length, crack position in the radial direction of the blisk, and modal data type of coated blisk used for mistuning identification calculation. The research results show that, with the increase of crack length, the mistuning of crack occurring only in the coating does not increase continuously but decreases firstly and then increases. For the first bending modes, the closer the blade crack is to the blade root, the larger the mistuning is. For the second bending modes, the blade crack located at the position of maximum modal displacement will produce large mistuning. For hard-coated blisk with blade crack, these crack mistuning variation rules are of great significance to the dynamic analysis and the determination of the crack location.