Layout Optimization of Unconstrained Viscoelastic Layer on Beams Using Fractional Derivative Model

Lee, Doo-Ho; Hwang, Woo-Seok

doi:10.2514/6.2004-4419

Cited by 2 publications

(3 citation statements)

References 14 publications

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“…E Ã , E, and are the complex modulus, the storage modulus, and the loss factor, respectively. The fractional derivative model of order one represents the stress-strain relationship in the time domain as follows 21,22 ðtÞ þc 1 D ðtÞ ¼ a 0 "ðtÞ þã 1 D "ðtÞ ð 2Þ where 0 5 5 1, and a 0 , a˜1, c˜1, and are material coefficients. D indicates the fractional derivative such that…”

Section: Characterization Of Uncertaintiesmentioning

confidence: 99%

“…The elastomers consist of viscoelastic rubber. In order to quantify the uncertainties of the material properties, the fractional derivative model [19][20][21][22] was used. Then, the experimental data for the rubber and the maximum likelihood approach can be used to estimate the uncertainties of the material properties and of the modelling error in terms of the material model parameters.…”

Section: Characterization Of Uncertaintiesmentioning

confidence: 99%

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Variability analysis of vibrational responses in a passenger car considering the uncertainties of elastomers

Kwon

Lee

2015

Proceedings of the Institution of Mechanical Engineers, Part C:

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Passenger cars have many elastomeric joints that are used to reduce the vibration transmission from the source to the cabin structure. In the design stage, the dynamic characteristics of the elastomeric joints are optimally determined in order to satisfy the design goals for interior noise and vibration. However, the material properties of the elastomeric joints have large variations due to production variability. In addition, operational conditions, e.g. environmental temperature, vary according to the locations of the car. As a result, the vibrational comfort of a passenger car exhibits large variations. In this paper, the amount of vibration fluctuation due to uncertain elastomeric joint parameters is estimated using a statistical approach. First, the dynamic characteristics of the elastomers are described using the fractional derivative model. The uncertainties of the fractional derivative model parameters of the elastomers are characterized using a statistical calibration approach based on specimen test data. Then, a finite element model for the elastomers and the passenger car structure are constructed in order to calculate the vibrational response. In order to estimate the variability of the vibrational response due to the uncertainties of the elastomers, uncertainty propagation analyses are conducted using the eigenvector dimension reduction (EDR) method. The operational conditions such as temperature are also included in the variability analysis. The performance of the EDR method is assessed through comparing the estimated response distribution with that of the Monte Carlo simulation (MCS) method in a simplified structure. The variability analysis results demonstrate that the vibrational response variation due to the uncertainties of the elastomers can be efficiently predicted using the proposed method. The proposed variability analysis procedure could be an effective tool in the design stage for quality control of passenger car comfort.

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Section: Characterization Of Uncertaintiesmentioning

confidence: 99%

Section: Characterization Of Uncertaintiesmentioning

confidence: 99%

Variability analysis of vibrational responses in a passenger car considering the uncertainties of elastomers

Kwon

Lee

2015

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…Many researchers have suggested various kinds of optimal design formulations on damping layout structures [2][3][4][5][6][7][8][9]. In these investigations, damping performances were maximized by controlling structural dimensions and/or damping properties.…”

Section: Introductionmentioning

confidence: 99%

A statistical characterization method for damping material properties and its application to structural-acoustic system design

et al. 2011

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The performance of surface damping treatments may vary once the surface is exposed to a wide range of temperatures, because the performance of viscoelastic damping material is highly dependent on operational temperature. In addition, experimental data for dynamic responses of viscoelastic material are inherently random, which makes it difficult to design a robust damping layout. In this paper a statistical modeling procedure with a statistical calibration method is suggested for the variability characterization of viscoelastic damping material in constrained-layer damping structures. First, the viscoelastic material property is decomposed into two sources: (i) a random complex modulus due to operational temperature variability, and (ii) experimental/model errors in the complex modulus. Next, the variability in the damping material property is obtained using the statistical calibration method by solving an unconstrained optimization problem with a likelihood function metric. Two case studies are considered to show the influence of the material variability on the acoustic performances in the structural-acoustic systems. It is shown that the variability of the damping material is propagated to that of the acoustic performances in the systems. Finally, robust and reliable damping layout designs of the two case studies are obtained through the reliability-based design optimization (RBDO) amidst severe variability in operational temperature and the damping material.

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Layout Optimization of Unconstrained Viscoelastic Layer on Beams Using Fractional Derivative Model

Cited by 2 publications

References 14 publications

Variability analysis of vibrational responses in a passenger car considering the uncertainties of elastomers

Variability analysis of vibrational responses in a passenger car considering the uncertainties of elastomers

A statistical characterization method for damping material properties and its application to structural-acoustic system design

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