Identification of structural loss factor from spatially distributed measurements on beams with viscoelastic layer

Rak, Michal; Ichchou, Mohamed; Holnicki‐Szulc, Jan

doi:10.1016/j.jsv.2007.11.026

Cited by 29 publications

(21 citation statements)

References 6 publications

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“…Separating the 2n a modes into kept (k) and eliminated (e) categories with numbers n k and n e , respectively, the equations of motion (12) can be rewritten as:…”

Section: Modified Modal Based Adaptive Direct Methodsmentioning

confidence: 99%

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Identification of Damping Characteristic of a Structural Adhesive by Extended Modal Based Direct Model Updating Method

Nobari

Jahani

2008

Exp Mech

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In order to identify damping characteristics (loss factors in bending and shear modes versus frequency) of an adhesive material, modal based direct model updating method used in previous paper (Jahani and Nobari, Exp Mech, 48:2008) is modified here. Two approaches adopted in the identification process. In the first one, the pre identified moduli from undamped model were used in identification of loss factors and in the second approach loss factors and moduli are identified simultaneously. The loss factors of a typical adhesive were identified using both approaches leading to acceptable results in both cases. The results show that loss factors and Young's and shear moduli of adhesive are frequency dependent. All experiments and subsequent identifications are conducted both in bending and shear modes. The repeatability and consistency of method is proved by repeating the identification process for several times.

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“…Separating the 2n a modes into kept (k) and eliminated (e) categories with numbers n k and n e , respectively, the equations of motion (12) can be rewritten as:…”

Section: Modified Modal Based Adaptive Direct Methodsmentioning

confidence: 99%

“…(a) Studies in which the adhesive is tested as a bonding medium between two adherends [11,12]. (b) Studies that consider adhesive as a bulk material and try to directly measure the loss factor of the bulk specimen of the adhesive material [13].…”

Section: Introductionmentioning

confidence: 99%

Identification of Damping Characteristic of a Structural Adhesive by Extended Modal Based Direct Model Updating Method

Nobari

Jahani

2008

Exp Mech

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“…From Eq. (14) and (15) it can be derived that the loss factor η is related to the complex wavenumber k f as follows [15]:…”

Section: Green's Functions Of a Point Excited Platementioning

confidence: 99%

Estimation of plate material properties by means of a complex wavenumber fit using Hankel's functions and the image source method

Roozen

Leclère

Ege

et al. 2017

Journal of Sound and Vibration

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This paper presents a new wave fitting approach to estimate the frequency dependent material properties of thin isotropic plate structures from an experimentally obtained vibrational field, exciting the plate at a single point. The method projects the measurement data on to an analytical image source model, in which Hankel's functions are used for a description of the wave fields emanating from the point of excitation, including the reflected wave fields from the edges of the finite plate. By minimizing the error between the projected field and the measured field, varying the complex wave number and the source strengths of the image sources, an optimum fit is searched for. Thus the source strengths of the image sources do not need to be determined theoretically, but are estimated from the fit on to the experimental data instead (thus avoiding difficulties in theoretically assessing the reflection coefficient of the edges of the plate). The approach uses a complex wavenumber fit, enabling the determination of the dynamic stiffness of the plate structure and its damping properties as function of frequency. The method is especially suited for plates with a sufficient amount of damping, excited at high frequencies.

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“…The complex wavenumber method was developed by Mcdaniel and Dupont [16] to estimate frequency-dependent loss factor of a beam with arbitrary transient loading. Subsequently, Rak et al [17] employed this method to determine structural damping property over discrete but regularly spaced frequency with the experimental validation based on cantilever beam test. The wavenumber method was also implemented by Ichchou et al [18] to obtain effective sandwich structural properties and identify the equivalent models.…”

Section: Introductionmentioning

confidence: 99%

Study on the Dynamic Mechanical Properties of Viscoelastic Materials Based on Asymmetrical Sandwich Beams

Qing-qing¹,

Wang²

2018

Applied Sciences

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A modified estimation method for the dynamic mechanical properties of viscoelastic materials via asymmetrical sandwich specimens is presented. In contrast to the traditional vibrating cantilever beam test method (VCBTM), the proposed method allows asymmetrical base beams in sandwich specimens. Based on the complex stiffness method, complex parameters are introduced for general sandwich configurations. Calculation formulas for loss factor and shear modulus of the core material are presented. The effectiveness of this approach is validated numerically and experimentally by analysis of one symmetrical sandwich beam specimen and two specimens with asymmetrical thicknesses and materials. It is shown that dynamic mechanical parameters of the core material can be obtained regardless of sandwiches' symmetry. The proposed method breaks the symmetrical criteria for sandwich specimens and may provide a wider application to measure viscoelastic materials' dynamic properties.

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Identification of structural loss factor from spatially distributed measurements on beams with viscoelastic layer

Cited by 29 publications

References 6 publications

Identification of Damping Characteristic of a Structural Adhesive by Extended Modal Based Direct Model Updating Method

Identification of Damping Characteristic of a Structural Adhesive by Extended Modal Based Direct Model Updating Method

Estimation of plate material properties by means of a complex wavenumber fit using Hankel's functions and the image source method

Study on the Dynamic Mechanical Properties of Viscoelastic Materials Based on Asymmetrical Sandwich Beams

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