Mechanical properties of some Indian woods

2012

An investigation was carried out to study physical properties, strength and durability of some timber species commercially used in Bangladesh. Seven timber species namely Teak (Tectona grandis), Sal (Shorea robusta), Sil Korai (Albizia procera), Rain Tree (Samanea saman), Jam (Syzygium spp.), Jackfruit (Artocarpus heterophylus), and Mango (Mangifera indica) were tested for density, specific gravity, compressive, tensile and bending strength following ASTM standards. Four different kinds of chemical environments consisting of normal water, sodium chloride (5%), sodium sulphate (10%) and hydrochloric acid (5%) were made and tested for durability in terms of strength loss over a period of 90 days. The test results revealed that Sal, Teak and Jam were the best species of using as compression member while Sal and Teak showed the best performance in tension. In static bending Sal, Sil Korai, Teak and Jam have been found suitable. With respect to durability acidic environment has been show...

Trees, 2012

Obtaining representative values of green wood properties is essential for studies investigating the biomechanical aspects of tree development and ecology. Here we compare the biomechanical properties of wood stored in various conditions between their collection in the field and their measurement. The study was performed on a large sample of wood specimens from different tropical species and different location in the trees, representing a wide diversity in wood structures. Elastic and viscoelastic properties are measured on green wood, and measured again after storage in different conditions: immersion in cold water during various durations, storage in an ethanol solution with or without washing in water, and air-drying with or without re-hydration. The systematic and random errors induced by these storage methods are quantified. Storage in cold water is the best way to preserve wood native properties. Soaking in ethanol is a fair alternative regarding elastic properties, but induces a significant change in viscoelastic properties. Air-drying causes important and partly irreversible changes in mechanical properties. However, regarding elastic properties, this change is a systematic bias so that the airdried elastic modulus provides a good basis for comparative studies of green wood stiffness.

Wood Material Science & Engineering, 2015

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BioResources, 2016

2019

The exploitation of timber in Ghana and many parts of tropical Africa is limited to very few of the over 800 known species whose mechanical properties for structural use are unknown. The global demand for these few species with excellent properties in terms of their strength and quality of finishes has led to their over-exploitation and destruction of other less accepted species during logging operations. The structural use of timber is very limited in tropical Africa in spite of its abundance in the forests and its sustainability by cultivation. Considerable discussion has been held about the fuller utilization of tropical forests with particular reference to lesser-known species (LKS), but the problem has remained intractable and very little has been done. One main problem in promoting the LKS is lack of information on their realistic mechanical properties based on structural size dimensions. This paper reports results of research on the mechanical properties of four lesser-known ...

Materials Science and Nanotechnology, 2017

Wood is a natural polymer and its molecular structure is The present investigation was carried out to determine the different physical properties of various types of timbers used for agricultural implements in India. This study provides information for selection criteria of wood to make a different component of agriculture implement and tools. This article consists of detailed material and methods used in the study. This study was mainly targeted on utilization of different type of wood for their use to make different components of agricultural implements and tools.

Asian Journal of Applied Sciences

Over exploitation of economic tree species in the forest due to their high demand has made wood loggers shift their attention to Lesser Used Species such as Blighia sapida as alternative source of wood in Nigeria. The knowledge on the quality of the wood would to a long extent enhance the utilization of the wood. However, little information is provided on the mechanical properties of the wood species and the general belief among most wood users is that it is not a good timber species and that it cannot be utilized for any wood-based products that require strength. Therefore, investigating the mechanical properties of the timber species for better acceptability in the timber market becomes necessary. Three standing trees of Blighia sapida were purposively felled in the University of Ibadan community, Ibadan, Nigeria. 500 mm billets were gotten from wood dics at the top, middle, and base of the tree and each partitioned into three, the outerrwood, middlewood and the innerwood, in line...

Annals of Forest Science, 2003

The influence of temperature on transverse mechanical properties of 10 tropical species in green condition was studied in radial compression (0 to 99°C), transverse shear with longitudinal-radial shearing plane and rupture of the longitudinal-tangential plane (20 to 80°C). Basic density ranged from 0.21 to 0.91 g cm-3. Load-displacement curves were characterised by initial rigidity, yield stress, yield strain and strain energy at 20% strain level. The relation between each criterion and basic density was expressed by a power law. The dependency on temperature evidenced a sharp glassy transition, except for the fracture energy only slightly influenced by temperature. An empirical model allowed evaluating a transition temperature between 51 and 69°C, depending on the species and the criterion, which was attributed to lignin. Detailed analysis of the apparent modulus in radial compression suggested that complex relaxation phenomena occur around 10°C and that the rubbery state is not fully reached at 80°C. green wood / tropical wood / transverse mechanical properties / basic density / softening temperature Résumé-Influence de l'infradensité et de la température sur les propriétés mécaniques transverses de dix bois tropicaux. L'influence de la température sur les propriétés mécaniques transverses du bois vert de 10 essences tropicales a été étudiée. Trois types d'essais ont été réalisés : compression radiale (entre 0 et 99°C), cisaillement transverse suivant le plan longitudinal-radial et rupture dans le plan longitudinaltangentiel (entre 20 et 80°C). L'infradensité des essences est comprise entre 0,21 et 0,91 g cm-3. Les courbes force-déplacement ont été caractérisées par la rigidité initiale, la contrainte de flambement, la déformation de flambement et l'énergie de déformation pour 20 % de déformation. La relation entre chaque critère et l'infradensité est exprimée par une loi puissance. La dépendance des critères avec la température met en évidence une transition vitreuse très prononcée, excepté pour l'énergie de rupture peu influencée par la température. Un modèle empirique permet d'évaluer une température de transition entre 51 et 69°C, selon les essences et les critères. Ce phénomène est expliqué par la transition vitreuse des lignines. Une analyse détaillée du module radial apparent en compression suggère qu'un phénomène de relaxation complexe a lieu autour de 10°C et que l'état caoutchoutique n'est pas complètement atteint à 80°C. bois vert / essences tropicales / propriétés mécaniques transverses / infradensité / température de transition vitreuse

The aim of this work was to determine the main physical and mechanical properties of athel wood (Tamarix aphylla), one of the least studied non-commercial wood species. Wood samples of Tamarix aphylla were harvested from a small tree stand in Molyvos coastal area (Lesvos, Greece) and standard test methods were followed on small green specimens. Athel wood’s air- and oven dry densities were determined at 0.73 and 0.66 g/cm3, while maximum tangential shrinkage and swelling were approximately 10.8 and 12.1%, respectively. The volumetric shrinkage and swelling were estimated at 14.0 and 15.5%, respectively. Modulus of rupture, modulus of elasticity, compression strength parallel to grain and Janka hardness (perpendicular to grain) values were found to be 88.5 N/mm2, 7,533 N/mm2, 40.9 N/mm2 and 33.7 N/mm2, respectively. Keywords: Wood; Tamarix aphylla; Mechanical properties; Density; Shrinkage; Swelling

The aim of this work was to determine the main physical and mechanical properties of athel wood (Tamarix aphylla), one of the least studied non-commercial wood species. Wood samples of Tamarix aphylla were collected from a small tree stand in Molyvos coastal area (Lesvos, Greece) and standard test methods were followed on small green specimens. Athel wood's air-and oven dry densities were determined at 0.73 and 0.66 g/cm 3 , while maximum tangential shrinkage and swelling were approximately 10.8 and 12.1%, respectively. The volumetric shrinkage and swelling were estimated at 14.0 and 15.5%, respectively. Modulus of rupture, modulus of elasticity, compression strength parallel to grain and Janka hardness (perpendicular to grain) values were found to be 88.5 N/mm 2 , 7,533 N/mm 2 , 40.9 N/mm 2 and 33.7 N/mm 2 , respectively.