Relationship between density and ultrasonic velocity in Brazilian tropical woods

Oliveira, Fabiana Goia Rosa de; Sales, Almir

doi:10.1016/j.biortech.2005.04.050

Cited by 60 publications

(41 citation statements)

References 7 publications

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“…Segundo Oliveira & Sales (2006) e Shimoyama (2005, a menor velocidade da onda encontrada para a madeira de pinus em relação à madeira de eucalipto pode ser explicada pela menor massa específica do pinus, ou seja, é mais porosa, o que favorece a menor velocidade de propagação da onda. Já as madeiras mais densas, no caso do eucalipto, são as que apresentam maior teor de substância madeira, portanto, menores espaços vazios, propiciando maior velocidade de propagação das ondas.…”

Section: Influência Da Espécieunclassified

Monitoramento do teor de umidade de madeiras de Pinus elliottii Engelm. e Eucalyptus grandis W. Hill ex Maiden, sob diferentes temperaturas de secagem, através do ultra-som.

Calegari

Stangerlin²,

Santini³

et al. 2007

Ciênc. Florest.

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Com o objetivo de avaliar a viabilidade de uso da técnica ultra-sônica para estimar o teor de umidade da madeira durante o processo de secagem, amostras de Pinus elliottii Engelm. e Eucalyptus grandis W. Hill ex Maiden, com dimensões nominais 3,5 x 10 x 25 cm de espessura, largura e comprimento, respectivamente, foram submetidas às temperaturas de 20, 40 e 70ºC. Um equipamento ultra-sônico PUNDIT com transdutores de faces planas de 50 kHz foi utilizado para medir a velocidade de propagação do som na direção longitudinal da madeira. Os resultados indicaram aumento da velocidade ultra-sônica estimada em função da redução do teor de umidade. Essa relação mostrou-se válida no intervalo desde verde até o final da secagem, sendo que os melhores coeficientes de determinação ocorreram na madeira de eucalipto (R² = 81%). Embora não tenha sido observada uma influência da espécie na velocidade ultra-sônica, esta foi influenciada pela massa específica da madeira e pela temperatura de secagem. O efeito da massa específica foi diretamente proporcional para a madeira de pinus e inversamente proporcional para a madeira de eucalipto. A velocidade ultra-sônica apresentou tendência de redução com o aumento da temperatura de secagem para ambas as espécies, e os resultados obtidos sugerem que o método ultra-sônico apresenta bom potencial para o controle do processo de secagem.

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Section: Influência Da Espécieunclassified

Monitoramento do teor de umidade de madeiras de Pinus elliottii Engelm. e Eucalyptus grandis W. Hill ex Maiden, sob diferentes temperaturas de secagem, através do ultra-som.

Calegari

Stangerlin²,

Santini³

et al. 2007

Ciênc. Florest.

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“…There is a contradiction in the literature on whether SV is correlated with wood density or not. Some authors (Oliveira et al 2002;Ilic 2003;Teles et al 2011) determined that there is no relationship between density and velocity, while others (Oliveira and Sales 2006;Baradit and Niemz 2012) reported a positive relationship between density and velocity. Some authors (Ilic 2003;Krauss and Kúdela 2011) claim that velocity is related to the micro-fibrillar angle, while Gerhards (1982b) and Beall (2002) pointed out that grain angle has a major impact on the SV.…”

Section: Resultsmentioning

confidence: 99%

“…The ultrasonic technique has been utilized in many applications including tree quality evaluations in forests (Wang et al 2004) and condition assessments of wood structures in service (Ross and Pellerin 1994). Determination of the ultrasonic modulus of elasticity in a solid depends on its elastic properties and its density (Oliveira and Sales 2006). The velocity of sound in wood is influenced by factors such as MC, grain orientation, density, decay, temperature, and geometry (Beall 2002;Oliveira et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Prediction of Compression Properties in Three Orthotropic Directions for Some Important Turkish Wood Species Using Ultrasound

Güntekin¹,

Aydın²,

Niemz³

2015

BioResources

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Compression properties in three orthotropic directions for some important Turkish wood species, including Calabrian pine (Pinus brutia Ten.), Taurus cedar (Cedrus libani), Oriental beech (Fagus orientalis), and sessile oak (Quercus petraea), were studied using non-destructive and destructive techniques. The materials used in the study consisted of 720 small clear specimens of nominal dimensions of 20 x 20 x 60 mm. The influence of equilibrium moisture content (EMC) was studied over four batches of 15 specimens each, conditioned for six to eight weeks before testing at a temperature of 20 ± 2 °C and at four different relative humidity conditions (50%, 65%, 85%, and 95%). Time of flight values were measured with a commercial ultrasonic tester. Using the time results from the ultrasound device, the wave velocities (length/time) and Edyn values were calculated. Samples were also tested in uniaxial compression to determine the Young's modulus and compression strength values in three orthotropic directions. The Edyn correlated well with the Young's modulus and compression strength of the specimens; coefficients of determination ranged between 0.75 and 0.96. Moisture content seems to have more influence than density on sound velocities. Results showed that there is a weak and mostly negative correlation between the density of the specimens and the sound velocity values.

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“…Materials with high densities correspond to high propagation velocities. In the case of wood and wood products, several researchers have examined the effect of wood density on the wave velocity (Bucur and Chivers 1991;Mishiro 1996;Oliveira and Sales 2006;Hasegawa et al 2011). In this context, Mishiro (1996) reported that the velocities along the radial and tangential directions increased with increases in density; however, the wave velocities were found to be independent of the density upon eliminating the lightest (balsa (Ochroma pyramidale)) and heaviest (Lignum vitae (Guaiacum sanctum)) woods.…”

Section: Relationship Between Chemical Retention and Ultrasonic Wave mentioning

confidence: 99%

Relationship between Chemical Retention and Velocity of Air-Coupled Ultrasonic Waves in Fire-Retardant-Treated Wood

et al. 2017

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The ultrasonic wave velocities in wood impregnated with a fire-retardant chemical were measured via a non-contact method. An air-coupled ultrasonic wave was made to propagate along the radial direction of the wood. The wave velocities in the wood samples after chemical impregnation were larger than those before impregnation. With increased chemical concentration, the relative changes in the velocities increased to a maximum of 16.3%, and these velocity changes exhibited a strong correlation with the chemical retention. These findings suggest that it is possible to evaluate the uniformity distributions of chemicals in fireretardant-treated wood via a non-contact and nondestructive method based on air-coupled ultrasonics.

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Relationship between density and ultrasonic velocity in Brazilian tropical woods

Cited by 60 publications

References 7 publications

Monitoramento do teor de umidade de madeiras de <i>Pinus elliottii</i> Engelm. e <i>Eucalyptus grandis</i> W. Hill ex Maiden, sob diferentes temperaturas de secagem, através do ultra-som.

Monitoramento do teor de umidade de madeiras de <i>Pinus elliottii</i> Engelm. e <i>Eucalyptus grandis</i> W. Hill ex Maiden, sob diferentes temperaturas de secagem, através do ultra-som.

Prediction of Compression Properties in Three Orthotropic Directions for Some Important Turkish Wood Species Using Ultrasound

Relationship between Chemical Retention and Velocity of Air-Coupled Ultrasonic Waves in Fire-Retardant-Treated Wood

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