Document Type : Physics and Mechanical Wood
Authors
1 Phd wood science and technology،department of science&industry and paper،facully of natural resource،university of Tehran،karaj
2 Bachelor's degree, Department of Wood Science and Industries, Technical and Vocational College No. 2, Sari, Technical and Vocational University (TVU), Mazandaran, Iran
3 - Bachelor's degree, Department of Wood Science and Industries, Technical and Vocational College No. 2, Sari, Technical and Vocational University (TVU), Mazandaran, Iran
Abstract
Background and goal: walnut tree (Juglans regia L.) are cultivated in many countries in Asia, Europe and United States. This tree has high resistance with beautiful pattern and are used in furniture industry, building panels, flooring and covering. Iran are ranked third in the world in the production of walnut fruit after China and US. Thus, with considering high production of this tree in Iran and its diverse application in different industries, a comprehensive studding for physical and mechanical properties of this species in different regions of Iran seems necessary.
Materials and methods: Walnut tree (Juglands regia L.) from two different regions, one from northeast (Mashhad) and the other from northwest (Maku) of Iran was selected for this study. Three trees from each region were selected randomly and cut with almost with the same diameter for physical and mechanical experiments. Samples also were cut from 2-4 meter from the ground. ISO 3129 and ASTM (D143-14) were used for doing physical and mechanical experiments respectively and at the humidity of 12%. Statistical analysis of data was performed using Graphpad prism version 8 and t-Test was performed for significant difference of data.
Results: The average dry density of both Mashhad and Mako walnut wood was 0.625 and 0.579 g/cm3 respectively. There were a significant difference for both tangential shrinkage with values of 9.77 and 8.78 and volumetric shrinkage with measurement of 16.26 and 15.42 in Mashhad and Mako respectively. However, there was no significant difference for longitudinal and radial shrinkage in both walnut wood of the two regions. Walnut wood cut from Mashhad region showed higher physical and mechanical properties. The results of the mechanical characteristics of walnuts from two regions showed bending strength 100.54 and 87.61N/mm2 and elasticity modulus 10049.59 and 7504.21 N/ mm2 for Mashhad and Mako regions respectively which were significant. Results also showed not significant difference for compression parallel to the grain with values of 37.91 and 33.88N/mm2, for shear parallel to the grain with values of 9.15 and 8.95N/mm2, for Tensile strength parallel to the grain with 127.97 and 125.83 N/mm2, for Screw withdrawal strength in tangential values of 4031.01 and 3685.97N and Screw withdrawal strength in radial values of 4218.63 and 3915.03N and impact strength with the values of 27.81 and 25.24KJ/m2 for Mashhad and Maku regions respectively. Results also showed that the density of walnut wood in the two regions of Iran was similar to the those in Italy and eastern Europe but the mechanical properties of walnut tree such as bending strength and elasticity modules measured from Mashhad region was similar to the wone in turkey.
Conclusion: The results showed that the physical and mechanical resistance of walnut wood located in Mashhad is higher than Maku wood, which was attributed to the higher dry density and the difference in weather conditions. Considering the appropriate mechanical resistance of walnut wood from both regions of Iran, this wood can be used in coating and furniture industries, building panels and flooring.
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