ﺑﺮرﺳﯽ ﺧﺼﻮﺻﯿﺎت ﻓﯿﺰﯾﮑﯽ و ﻣﮑﺎﻧﯿﮑﯽ ﭼﻮب راش اﯾﺮان و اﻟﻮارﻫﺎي وارداﺗﯽ راش ﮔﺮﺟﺴﺘﺎن

Investigation of Physical and Mechanical Properties of Iranian and Imported Georgian Beech Wood

ﭼﻮب و ﻣﺤﺼﻮﻻت ﭼﻮﺑﯽ ﺑﻪ دﻟﯿﻞ ﻣﻘﺎوﻣﺖﻫﺎي ﺑﺴﯿﺎر ﺑﺎﻻ، ﯾﮑﯽ از ﻣﻬﻢ ﺗﺮﯾﻦ ﻣﺤﺼﻮﻻت ﻣﻮرد اﺳﺘﻔﺎده در ﺳﺎﺧﺘﻤﺎن ﺳﺎزي در ﺳﺮاﺳﺮ ﺟﻬﺎن اﺳﺖ. در اﯾﻦ ﭘﮋوﻫﺶ از ﭼﻮب راش ﺳﻨﮕﺪه ﻣﺎزﻧﺪران و اﻟﻮارﻫﺎي وارداﺗﯽ راش ﮔﺮﺟﺴﺘﺎن اﺳﺘﻔﺎده ﺷﺪ. ﺧﻮاص ﻓﯿﺰﯾﮑﯽ ﺷﺎﻣﻞ داﻧﺴﯿﺘﻪ ﺧﺸﮏ و ﺑﺤﺮاﻧﯽ، ﻫﻢﮐﺸﯿﺪﮔﯽ و واﮐﺸﯿﺪﮔﯽ( و ﺧﻮاص ﻣﮑﺎﻧﯿﮑﯽ ﺷﺎﻣﻞ ﻣﻘﺎوﻣﺖ ﺧﻤﺸﯽ، ﻣﺪول اﻻﺳﺘﯿﺴﯿﺘﻪ، ﻓﺸﺎر ﻣﻮازي ﺑﻪ اﻟﯿﺎف، ﺑﺮش ﻣﻮازي ﺑﻪ اﻟﯿﺎف، ﮐﺸﺶ ﻣﻮازي و ﻋﻤﻮد ﺑﻪ اﻟﯿﺎف، ﻣﻘﺎوﻣﺖ ﺑﻪ ﻧﮕﻪ داري ﭘﯿﭻ در دو ﺟﻬﺖ ﻣﻤﺎﺳﯽ و ﺷﻌﺎﻋﯽ و ﺳﺨﺘﯽ( ﺑﺮرﺳﯽ ﺷﺪﻧﺪ. در اﯾﻦ آزﻣﺎﯾﺶ از اﺳﺘﺎﻧﺪاردﻫﺎي 3129 ISO و ASTM )D143( ﺑﻪ ﺗﺮﺗﯿﺐ ﺑﺮاي اﻧﺠﺎم آزﻣﺎﯾﺶﻫﺎي ﻓﯿﺰﯾﮑﯽ و ﻣﮑﺎﻧﯿﮑﯽ اﺳﺘﻔﺎده ﺷﺪ. رﻃﻮﺑﺖ ﮐﻠﯿﻪ ﻧﻤﻮﻧﻪ ﻫﺎ در ﻫﻨﮕﺎم اﻧﺠﺎم آزﻣﺎﯾﺶ ﻫﺎي ﻣﮑﺎﻧﯿﮑﯽ 12 درﺻﺪ ﺑﻮد. ﻣﺘﻮﺳﻂ داﻧﺴﯿﺘﻪ ﺧﺸﮏ ﺑﻪ دﺳﺖآﻣﺪه از ﭼﻮب راش ﺳﻨﮕﺪه و ﮔﺮﺟﺴﺘﺎن ﺑﻪ ﺗﺮﺗﯿﺐ ﺑﺮاﺑﺮ ﺑﺎ 0.616 و 0.65 ﮔﺮمﺑﺮ ﺳﺎﻧﺘﯽﻣﺘﺮ ﻣﮑﻌﺐ ﺑﻮد. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﺗﻔﺎوت ﻣﻌﻨﯽداري ﺑﯿﻦ ﺧﺼﻮﺻﯿﺎت ﻓﯿﺰﯾﮑﯽ و ﻣﮑﺎﻧﯿﮑﯽ اﯾﻦ دو راش ﻣﻮرد اﺳﺘﻔﺎده، ﺑﻌﺪ از آزﻣﻮن )T-test( ﺑﻪ ﺟﺰ داﻧﺴﯿﺘﻪ ﺑﺤﺮاﻧﯽ، ﻫﻢ ﮐﺸﯿﺪﮔﯽ ﺷﻌﺎﻋﯽ و واﮐﺸﯿﺪﮔﯽ ﺷﻌﺎﻋﯽ ﻣﺸﺎﻫﺪه ﺷﺪ. ﻫﻤﭽﻨﯿﻦ ﻣﻘﺎوﻣﺖ ﻫﺎي ﻣﮑﺎﻧﯿﮑﯽ اﻧﺪازهﮔﯿﺮي ﺷﺪه اﻟﻮارﻫﺎي راش ﮔﺮﺟﺴﺘﺎن ﺑﺴﯿﺎر ﺑﺎﻻﺗﺮ از ﭼﻮب راش ﺳﻨﮕﺪهﺑﻮد ﮐﻪ ﺑﻪ داﻧﺴﯿﺘﻪ ﺑﺎﻻﺗﺮ اﻟﻮار راش ﮔﺮﺟﺴﺘﺎن ﻧﺴﺒﺖ داده ﺷﺪ.

Wood and wooden products are one of the most important materials that have been traditionally used for building constructions. In this study, Mazandaran Sangdeh Beech and imported Georgian Beech wood were used. Physical properties (including dry and critical densities, shrinkage and swelling) and mechanical properties (including bending strength, modulus of elasticity, compression parallel to grain, shear parallel strength to grain, tensile strength parallel and perpendicular to grain, screw withdrawal strength and hardness) were investigated. Physical and mechanical tests were performed according to international standard methods such as ISO 3129 (2012) and ASTM (D143-14). The moisture content of all samples was 12% during mechanical tests. The mean dry densities of Sangdeh and Georgian beech were 0.61(g/cm3) and 0.65(g/cm3), respectively. The result showed that significant differences were observed among the properties of the mentioned species after T-test, except in critical density, radial shrinkage and radial swelling. Moreover, the obtained strengths of Georgian timber were significantly higher than the Iranian beech, which was attributed to the higher density of Georgian timber.