Determination of Elastic Constants for Black Pine Wood Using Ultrasound under Different Humidity Regimes

Öz

In this study, elastic constants of Anatolian black pine wood were investigated using ultrasonic method under different humidity conditions. Three modulus of elasticity (EL, ER, ET), three shear modulus (GLR, GLT, GRT), and six Poisson's ratios (ʋLR, ʋLT, ʋRL, ʋRT, ʋTL, ʋTR) were calculated using cubic samples with a length of 2 cm. Longitudinal and transverse ultrasonic sound wave velocities in fiber (L), radial (R) and tangential (T) directions were measured using 2.25 MHz and 1 MHz sensors, respectively. In order to determine the Poisson ratios, transverse sound wave velocities at an angle of 45° to the L, R and T directions were also measured with a 1 MHz sensor. Sound velocities measured in black pine samples are inversely proportional to the increase in humidity. Overall, the results show the well-known order between sound velocities (V11> V22> V66> V55> V33> V44). Compared to the values found in the literature; elastic modulus values estimated by ultrasonic method in L, R and T directions are similar, shear modulus values are slightly higher except for GRT. Although there are higher differences in Poisson's ratios, they are acceptable values. Results of the study indicate that ultrasonic method can be used as an alternative to determine the elastic constants for black pine wood under different humidity conditions.

Anahtar Kelimeler

• Black pine
• elastic constants
• ultrasound methods

Karaçam Odununun Elastik Sabitlerinin Farklı Rutubet Şartlarında Ultrasonik Yöntem ile Belirlenmesi

Öz

Bu çalışmada Anadolu karaçamı odununun elastik sabitleri, farklı rutubet şartları altında ultrasonik yöntem ve basma testleri kullanılarak incelenmiştir. Üç elastikiyet modülü (EL, ER, ET), üç kayma modülü (GLR, GLT, GRT) ve altı Poisson oranı (ʋLR, ʋLT, ʋRL, ʋRT, ʋTL, ʋTR) hesaplanmıştır. Ultrasonik yöntemde kenar uzunluğu 2 cm olan kübik örnekler kullanılırken basma testleri 2 x 2 x 6 cm boyutlarındaki örneklere uygulanmıştır. Lif yönü (L), radyal (R) ve teğet (T) yönlerde boyuna ve enine ultrasonik ses dalgası hızları sırasıyla 2.25 MHz ve 1 MHz sensörler kullanılarak ölçülmüştür. Poisson oranlarının belirlenmesi için L, R ve T yönlerine 45° açıyla enine ses dalgası hızları da 1 MHz sensörle ölçülmüştür. Ultrasonik yöntemi doğrulamak için basma testleri yapılmıştır. Basma testlerinden hesaplanan değerlerle karşılaştırıldığında, L, R ve T yönlerinde ultrasonik yöntemle tahmin edilen elastikiyet modülü değerleri benzerdir. Ultrasonik yöntemle hesaplanan kayma modülü değerleri, basma testlerinden hesaplanan değerlerden GRT hariç biraz yüksektir. Poisson oranlarında daha yüksek farklar olmasına rağmen kabul edilebilir görünmektedir. Çalışma sonuçlarına göre, farklı rutubet koşullarında karaçam için elastik sabitlerin belirlenmesinde alternatif olarak ultrasonik yöntemin kullanılabileceği sonucuna varılabilir.

Anahtar Kelimeler

• Karaçam
• elastik sabitler
• ultrasonik yöntem
• basma testi

Kaynakça

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