Effects of Free Damping Layers on Harmonic Response of Rotating Blades

1989 ◽  
Author(s):  
T. H. Young ◽  
T. N. Shiau ◽  
S. H. Chiu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Modulus ◽  
Loss Factor ◽  
Harmonic Excitation ◽  
The Finite Element Method ◽  
Harmonic Response ◽  
Rotating Blades ◽  
Rotating Blade ◽  
Triangular Elements

This paper studies the forced vibration of a rotating blade with free damping layers to harmonic excitation by means of the finite element method. The damping layers are made of viscoelastic material with complex elastic modulus, and the excitation may be either distributed or concentrated. Triangular elements with totally 15 d.o.f. are used to allow for a great variety of shapes and boundary conditions. The effects of various parameters, such as loss factor, storage modulus and thickness of damping layers, are investigated. The results show that the vibration amplitudes near resonances can be significantly reduced by the free damping layers.

scholarly journals Integrating the Finite Element Method with a Data-Driven Approach for Dam Displacement Prediction

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Chenfei Shao ◽  
Chongshi Gu ◽  
Zhenzhu Meng ◽  
Yating Hu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Modulus ◽  
Random Coefficient ◽  
Arch Dam ◽  
Data Driven ◽  
The Finite Element Method ◽  
Random Coefficient Model ◽  
Proposed Model ◽  
Element Method

Both numerical simulations and data-driven methods have been applied in dam’s displacement modeling. For monitored displacement data-driven methods, the physical mechanism and structural correlations were rarely discussed. In order to take the spatial and temporal correlations among all monitoring points into account, we took the first step toward integrating the finite element method into a data-driven model. As the data-driven method, we selected the random coefficient model, which can make each explanatory variable coefficient of all monitoring points following one or several normal distributions. In this way, explanatory variables are constrained. Another contribution of the proposed model is that the actual elastic modulus at each monitoring point can be back-calculated. Moreover, with a Lagrange polynomial interpolation, we can obtain the distribution field of elastic modulus, rather than gaining one value for the whole dam in previous studies. The proposed model was validated by a case study of the concrete arch dam in Jinping-I hydropower station. It has a better prediction precision than the random coefficient model without the finite element method.

Numeric Loading Simulation of Titanium Implant Manufactured Using 3D Printing

2018 ◽  
Vol 284 ◽  
pp. 380-385 ◽  
Author(s):  
Anton I. Golodnov ◽  
Yu.N. Loginov ◽  
Stepan I. Stepanov
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Titanium Alloy ◽  
Elastic Modulus ◽  
Titanium Implant ◽  
Finite Element Method Simulation ◽  
Medical Implants ◽  
The Finite Element Method ◽  
Simulation Data

The problem of medical implants honeycomb structures loading has been stated. The problem was solved using simulation by the finite element method. Simulation revealed that it is possible to change the elastic modulus of the material more than three times with respect to the bulk titanium alloy. The quality of the simulation was estimated based on the convergence of the simulation data.

Finite Element Research on Damping of Viscoelastic Free Layer Damping Sheet

2014 ◽  
Vol 472 ◽  
pp. 56-61
Author(s):  
Yuan Chao He ◽  
Wen Lin Chen ◽  
Shi Wei Sun ◽  
Li Na Hao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Loss Factor ◽  
Element Model ◽  
The Finite Element Method ◽  
Free Layer ◽  
Modal Strain Energy ◽  
Modal Strain Energy Method ◽  
The Finite Element Model ◽  
Element Method

Based on modal strain energy method, the paper discusses viscoelastic free layer damping sheet, establishes the finite element model of it and obtains the natural frequencies and loss factor. Then the paper calculates the loss factor of viscoelastic free layer damping structure with engineering empirical formula, and compares the result with that obtained by finite element method. By comparing the two results, it indicates that the finite element method is effective in analyzing this kind of problems.

Dynamic Response of Packets of Blades by The Finite Element Method

1978 ◽  
Vol 100 (4) ◽  
pp. 660-666 ◽  
Author(s):  
A. L. Salama ◽  
M. Petyt
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Response ◽  
Harmonic Excitation ◽  
Mass Ratio ◽  
The Finite Element Method ◽  
Periodic Loading ◽  
Engine Order ◽  
Partial Admission ◽  
Element Method

The finite element method is used to study the free vibration of packets of blades. A packet of six shrouded blades is analyzed, only the tangential vibrations being considered. Results are obtained to establish the effect of certain parameters such as stiffness ratio, mass ratio, the number of blades in the packet, the effect of rotation and the position of the lacing wires. The dynamic response of a packet to periodic loading is also studied. The cases of engine order harmonic excitation and partial admission of gas are considered with reference to a packet of six shrouded blades.

Structural Analysis of Agricultural Truck Frame Based on the Finite Element Method

2010 ◽  
Vol 37-38 ◽  
pp. 1236-1239
Author(s):  
Yun Wang ◽  
Bin Lin
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Modification ◽  
Response Analysis ◽  
The Finite Element Method ◽  
Transient Dynamic Analysis ◽  
Frame Design ◽  
Harmonic Response ◽  
Harmonic Response Analysis ◽  
External Incentives

Frame is an important truck part to connect and support engine, transmission, carriage and cab etc. It is important to analyze strength, stiffness and dynamic characteristics for frame design. This paper developed static analysis of a specific agricultural truck frame under two conditions of full load bending and reverse. The corresponding suggestions of structural modification were proposed. Then the dynamic response of truck frame caused by the external incentives was studied, namely harmonic response analysis and transient dynamic analysis. The paper not only analyzed whether the truck frame met the strength requirements, but also proposed the corresponding solutions for the possible cases of fatigue fracture and stress overloaded of the frame.

Effect of Matching Performance on J-Integral of Inhomogeneous Welded Joints

2012 ◽  
Vol 503-504 ◽  
pp. 568-571
Author(s):  
Bo He ◽  
Hong Cai Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Engineering Design ◽  
Welded Joints ◽  
Welded Joint ◽  
J Integral ◽  
The Finite Element Method ◽  
Matching Performance

In this paper, J-integral of 3-zone inhomogeneous welded joint is calculated by use of the finite element method, and the impacts of yield strength matching factor and elastic modulus matching factor on J-integral are studied as well. The analysis results show that the yield strength matching factor affects J-integral value greatly, that is, low matching of inhomogeneous welded joint of same steel can help to improve the ductility of the welded joint and the influence of yield strength matching factor on J-integral is much greater than that of elastic modulus matching factor, so it plays a very important role in the engineering design.

scholarly journals Elastic modulus of defected graphene sheets

2021 ◽  
Vol 1199 (1) ◽  
pp. 012021
Author(s):  
J Bocko ◽  
P Lengvarský
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Modulus ◽  
Graphene Sheets ◽  
The Finite Element Method ◽  
Beam Elements ◽  
Element Method ◽  
Defected Graphene

Abstract In this paper, the elastic modulus of single-layered graphene sheets (SLGSs) with and without defects is investigated using the finite element method. The SLGSs with two chiralities (armchair and zigzag) are modeled by beam elements. At first, the SLGSs without defects are investigated then the carbon atoms and corresponding beam elements are removed and the elastic modulus of SLGSs is determined. The increasing number of defects apparently decreased the elastic modulus of graphene sheets.

Determination of Elastic Modulus and Poisson Ratio for Nanoporous Materials

2012 ◽  
Vol 466-467 ◽  
pp. 366-370
Author(s):  
Fue Han ◽  
Chang Qing Chen ◽  
Ya Peng Shen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Modulus ◽  
Poisson Ratio ◽  
Nanoporous Materials ◽  
The Finite Element Method ◽  
Out Of Plane ◽  
Element Method

Through the finite element method, the elastic modulus and Poisson ratio out of plane of the honeycomb nanoporous materials are obtained. In the end, the values are contrasted with the scale values. Results show that the values are same to the scale values.

Numerical Modeling of Elastic Modulus and Bucking Load of Honeycombs

2012 ◽  
Vol 271-272 ◽  
pp. 1044-1048
Author(s):  
Ji Ne Li ◽  
Bao Lin Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Modeling ◽  
Elastic Modulus ◽  
The Finite Element Method ◽  
Buckling Modes ◽  
Square Cells ◽  
Equivalent Modulus ◽  
Orthotropic Properties ◽  
Theoretical Results

In this paper, both equivalent Young’s modulus and bucking load of the honeycombs are calculated using the finite element method. Honeycombs consisting of either regular hexagonal, equilateral triangular or square cells are considered. Numerical results are systematically compared with theoretical results from other literature. It is found that honeycombs display orthotropic properties. Such a fact is different from that reported in open literature. Moreover, the buckling modes are discussed, and the modified expressions of the equivalent modulus and bucking load are given.

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