Assessment of timber element mechanical properties using experimental modal analysis

Kouroussis, Georges; Fekih, Lassaad Ben; Descamps, Thierry

doi:10.1016/j.conbuildmat.2016.12.081

Cited by 29 publications

(13 citation statements)

References 10 publications

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“…The updating is based on a minimum of unconstrained multivariable functions using a derivative-free method. The objective function was selected from the three aforementioned criteria using a large number of n modes, so that the dynamic behaviour and the stiffness of the clamping or of the rubber bands could be estimated using an optimization algorithm [13].…”

Section: Implemented Finite Element Updating Proceduresmentioning

confidence: 99%

Using experimental modal analysis to assess the behaviour of timber elements

Kouroussis

Fekih

Descamps

2017

Mechanics & Industry

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Timber frameworks are one of the most important and widespread types of structures. Their configurations and joints are usually complex and require a high level of craftsmanship to assemble. In the field of restoration, a good understanding of the structural behaviour is necessary and is often based on assessment techniques dedicated to wood characterisation. This paper presents the use of experimental modal analysis for finite element updating. To do this, several timber beams in a free supported condition were analysed in order to extract their bending natural characteristics (frequency, damping and mode shapes). Corresponding ABAQUS finite element models were derived which included the effects of local defects (holes, cracks and wood nodes), moisture and structural decay. To achieve the modal updating, additional simulations were performed in order to study the sensitivity of the mechanical parameters. With the intent to estimate their mechanical properties, a procedure of modal updating was carried out in MatLab with a Python script. This was created to extract the modal information from the ABAQUS modal analysis results to be compared with the experimental results. The updating was based on a minimum of unconstrained multivariable function using a derivative-free method. The objective function was selected from the conventional comparison tools (absolute or relative frequency difference, and/or modal assurance criterion). This testing technique was used to determine the dynamic mechanical properties of timber beams, such as the anisotropic Young's Moduli and damping ratio. To verify the modulus, a series of static 4-point bending tests and STS04 classifications were conducted. The results also revealed that local defects have a negligible influence on natural frequencies. The results demonstrate that this assessment tool offers an effective method to obtain the mechanical properties of timber elements, especially when on-site and non-destructive techniques are needed, for example when retrofitting an existing structure.

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Section: Implemented Finite Element Updating Proceduresmentioning

confidence: 99%

Using experimental modal analysis to assess the behaviour of timber elements

Kouroussis

Fekih

Descamps

2017

Mechanics & Industry

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“…The traditional way to calculate E x of a timber board is through a four-point pseudo-static bending test, performed in certified laboratories [ 20 ]. However, in recent years, several researchers have looked for faster, non-destructive techniques based on short-duration dynamic excitations [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. The so-called dynamic modulus of elasticity ( E xd ) determined by this vibration technics is, then, correlated to the E x obtained by applying the pseudo static bending test.…”

Section: Introductionmentioning

confidence: 99%

Non-Destructive Assessment of the Dynamic Elasticity Modulus of Eucalyptus nitens Timber Boards

2021

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Eucalyptus nitens is a fast-growing wood species with a relevant presence in countries like Australia and Chile. The sustainable construction goals have driven the search of structural applications for Eucalyptus nitens; however, this process has been complicated due to the defects usually presented in these timber boards. This study aims to evaluate the dynamic elasticity modulus (Exd) of Eucalyptus nitens timber boards through non-destructive vibration-based tests. Thirty-six timber boards with different levels of knots and cracks were instrumented and tested in a simply supported condition by measuring longitudinal and transverse vibrations. In the first stage, the Exd was calculated globally through simplified normative formulas. Then, in a second stage, the local variability of the Exd was estimated using operational modal analysis (OMA), finite element numerical simulations (FEM), and regional sensitivity analysis (RSA). The positive correlation found between the global static modulus of elasticity and Exd suggests that non-destructive techniques could be used as a reliable and fast alternative for the assessment of bending stiffness. Finally, the proposed method to estimate the local variability of Exdt based on the combination of OMA, FEM, and RSA techniques was useful to improve the structural selection process of timber boards for lightweight social housing floors.

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“…Otra forma de determinar experimentalmente el módulo de elasticidad es bajo condiciones dinámicas empleando métodos no destructivos (Pellerin y Ross, 2002;Bucur, 2006). Esta tecnología aporta parámetros según los tipos de pruebas: el ultrasonido (Gonçalves et al, 2014;Dackermann et al, 2016), las ondas de esfuerzo (Neto et al, 2016;Freitas et al, 2016), las vibraciones transversales (Spycher et al, 2008;Kouroussis et al, 2017) y las vibraciones longitudinales (Chauhan y Sethy, 2016;Sotelo et al, 2017).…”

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Densidad y módulo dinámico longitudinal de tres maderas angiospermas impregnadas con boro.

Castellanos

Calderón

2020

BIOTECNIA

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El objetivo de la investigación fue determinar las densidades y los módulos dinámicos con vibraciones longitudinales, antes y después de impregnar con sales de boro las maderas de Spathodea campanulata, Fraxinus americana y Albizia plurijuga. Para cada especie se prepararon 40 probetas, se impregnaron con el método de baño caliente-frío y se determinaron las retenciones correspondientes a concentraciones de 1 %, 2 % y 3 %. Las densidades de las maderas no se modifican después del tratamiento. Los módulos dinámicos de F. americana y A. plurijuga no variaron por el tratamiento. Caso diferente es S. campanulata cuyos módulos dinámicos sí variaron.

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Assessment of timber element mechanical properties using experimental modal analysis

Cited by 29 publications

References 10 publications

Using experimental modal analysis to assess the behaviour of timber elements

Using experimental modal analysis to assess the behaviour of timber elements

Non-Destructive Assessment of the Dynamic Elasticity Modulus of Eucalyptus nitens Timber Boards

Densidad y módulo dinámico longitudinal de tres maderas angiospermas impregnadas con boro.

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