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Mark Hughes - One of the best experts on this subject based on the ideXlab platform.
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analysing density profile characteristics of surface densified solid wood using computational approach
International Wood Products Journal, 2013Co-Authors: Kristiina Laine, Lauri Rautkari, Toni Antikainen, Mark HughesAbstract:In this study, solid Scots pine was surface densified in an open press using different moisture contents (9·6 and 12·4%), temperatures (150 and 200°C), press closing times (0·5 and 5 min), holding times (1 and 10 min) and compression ratios (6·7 and 25%). The characteristics of the formed density profiles were defined and their correlations to the process parameters and Brinell Hardness and elastic recovery were analysed. Compression ratio and closing time had the strongest effect on the formation of the density profile, as well as the Hardness and elastic recovery. The amount of localised deformation (peak area) did not have significant effect on the Brinell Hardness or elastic recovery, whereas, the highest density achieved (peak density) and its location (peak distance) dominated the effect. Brinell Hardness and elastic recovery were found to correlate well with each other.
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Hardness and density profile of surface densified and thermally modified scots pine in relation to degree of densification
Journal of Materials Science, 2013Co-Authors: Kristiina Laine, Sergej Medved, Andreja Kutnar, Lauri Rautkari, Mark HughesAbstract:Solid Scots pine (Pinus sylvestris L.) wood was surface densified to three different degrees of compression and hydrothermal post-treatment after surface densification process was performed. The study determined the significance of degree of compression and hydrothermal post-treatment on the density profile generated and the resulting improved Brinell Hardness. It was found that different degree of compression resulted in only slightly different density profiles, when compared on the absolute thickness scale. Although the hydrothermal post-treatment lead to an average mass loss of 3.8 % in surface densified specimens regardless of the degree of compression, density profile of surface densified specimens was not significantly affected by hydrothermal post-treatment. Furthermore, the surface densification increased the Brinell Hardness more than 90 %. Degree of compression had limited effect, which means that it did not matter if the specimens were compressed from 22 to 15 mm or 18 to 15 mm, the Brinell Hardness was approximately the same. The hydrothermal post-treatment did not reduce the Brinell Hardness of control and surface densified specimens. Furthermore, the surface densification significantly increased the elastic recovery of surface densified wood, which was measured during Hardness measurements and was affected by degree of compression. Additionally, the hydrothermal post-treatment reduced the elastic recovery, in control specimens and surface densified specimens.
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the effect of process parameters on the Hardness of surface densified scots pine solid wood
European Journal of Wood and Wood Products, 2013Co-Authors: Kristiina Laine, Lauri Rautkari, Mark HughesAbstract:This paper addresses the effect of surface densification on the Brinell Hardness of Scots pine sapwood. Densification was performed in an open system under heat and compression using different compression temperatures and closing times. The Hardness was measured using a modified Brinell Hardness method. Furthermore, the density profiles of the samples were measured and their correlation to Hardness analysed. It was found that the process parameters strongly affected the Hardness of surface densified solid wood. This knowledge is relevant when optimising the densification process according to the properties required of the end-product. At 150 °C compression temperature and 0.5 min closing time, the average Brinell Hardness (23.4 N/mm2) was double to that at 200 °C and 5 min closing time (11.6 N/mm2).
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Density profile relation to Hardness of viscoelastic thermal compressed (VTC) wood composite
Wood Science and Technology, 2011Co-Authors: Lauri Rautkari, Frederick A. Kamke, Mark HughesAbstract:Density profile relation to Hardness of VTC wood composites was evaluated using X-ray densitometry and modified Brinell Hardness method using different applied forces. Moreover, surface elasticity was evaluated. Prior to lamination, the low-density hybrid poplar ( Populus deltoides × Populus trichocarpa L.) and Douglas-fir ( Pseudotsuga menziesii L.) thin boards were compressed to 1.22 or 1.14 g/cm^3, respectively. Two different kinds of laminations were made, either single layer of 1.5 mm thickness or two 1.5-mm layers bonded to unmodified wood. The results show that thicker laminate has a great positive influence on Brinell Hardness. This study suggests that results from the existing method for Brinell Hardness are not comparable, and if applied force is chosen without restraint, the effect on the Hardness value is significant for inhomogeneous wood composites.
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Surface modification of wood using friction.
Wood Science and Technology, 2009Co-Authors: Lauri Rautkari, M. Properzi, Frédéric Pichelin, Mark HughesAbstract:The potential of linear vibration friction as an innovative means of producing increases in both surface density and surface Hardness was explored. The influence of processing pressure and time on the degree of surface densification, surface Hardness and surface elasticity was investigated. It was found that surface Hardness (measured as Brinell Hardness) was positively correlated with densification ratio. Furthermore, surface elasticity, that is the ability of the surface to recover elastically after indentation during the Brinell Hardness test, could be increased by up to 33% depending on the degree of surface densification. The temperature rise due to friction was also studied. During processing, it was found that the temperature rise on both the radial and tangential surfaces was positively correlated with the processing pressure and time.
Lauri Rautkari - One of the best experts on this subject based on the ideXlab platform.
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analysing density profile characteristics of surface densified solid wood using computational approach
International Wood Products Journal, 2013Co-Authors: Kristiina Laine, Lauri Rautkari, Toni Antikainen, Mark HughesAbstract:In this study, solid Scots pine was surface densified in an open press using different moisture contents (9·6 and 12·4%), temperatures (150 and 200°C), press closing times (0·5 and 5 min), holding times (1 and 10 min) and compression ratios (6·7 and 25%). The characteristics of the formed density profiles were defined and their correlations to the process parameters and Brinell Hardness and elastic recovery were analysed. Compression ratio and closing time had the strongest effect on the formation of the density profile, as well as the Hardness and elastic recovery. The amount of localised deformation (peak area) did not have significant effect on the Brinell Hardness or elastic recovery, whereas, the highest density achieved (peak density) and its location (peak distance) dominated the effect. Brinell Hardness and elastic recovery were found to correlate well with each other.
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Hardness and density profile of surface densified and thermally modified scots pine in relation to degree of densification
Journal of Materials Science, 2013Co-Authors: Kristiina Laine, Sergej Medved, Andreja Kutnar, Lauri Rautkari, Mark HughesAbstract:Solid Scots pine (Pinus sylvestris L.) wood was surface densified to three different degrees of compression and hydrothermal post-treatment after surface densification process was performed. The study determined the significance of degree of compression and hydrothermal post-treatment on the density profile generated and the resulting improved Brinell Hardness. It was found that different degree of compression resulted in only slightly different density profiles, when compared on the absolute thickness scale. Although the hydrothermal post-treatment lead to an average mass loss of 3.8 % in surface densified specimens regardless of the degree of compression, density profile of surface densified specimens was not significantly affected by hydrothermal post-treatment. Furthermore, the surface densification increased the Brinell Hardness more than 90 %. Degree of compression had limited effect, which means that it did not matter if the specimens were compressed from 22 to 15 mm or 18 to 15 mm, the Brinell Hardness was approximately the same. The hydrothermal post-treatment did not reduce the Brinell Hardness of control and surface densified specimens. Furthermore, the surface densification significantly increased the elastic recovery of surface densified wood, which was measured during Hardness measurements and was affected by degree of compression. Additionally, the hydrothermal post-treatment reduced the elastic recovery, in control specimens and surface densified specimens.
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the effect of process parameters on the Hardness of surface densified scots pine solid wood
European Journal of Wood and Wood Products, 2013Co-Authors: Kristiina Laine, Lauri Rautkari, Mark HughesAbstract:This paper addresses the effect of surface densification on the Brinell Hardness of Scots pine sapwood. Densification was performed in an open system under heat and compression using different compression temperatures and closing times. The Hardness was measured using a modified Brinell Hardness method. Furthermore, the density profiles of the samples were measured and their correlation to Hardness analysed. It was found that the process parameters strongly affected the Hardness of surface densified solid wood. This knowledge is relevant when optimising the densification process according to the properties required of the end-product. At 150 °C compression temperature and 0.5 min closing time, the average Brinell Hardness (23.4 N/mm2) was double to that at 200 °C and 5 min closing time (11.6 N/mm2).
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Density profile relation to Hardness of viscoelastic thermal compressed (VTC) wood composite
Wood Science and Technology, 2011Co-Authors: Lauri Rautkari, Frederick A. Kamke, Mark HughesAbstract:Density profile relation to Hardness of VTC wood composites was evaluated using X-ray densitometry and modified Brinell Hardness method using different applied forces. Moreover, surface elasticity was evaluated. Prior to lamination, the low-density hybrid poplar ( Populus deltoides × Populus trichocarpa L.) and Douglas-fir ( Pseudotsuga menziesii L.) thin boards were compressed to 1.22 or 1.14 g/cm^3, respectively. Two different kinds of laminations were made, either single layer of 1.5 mm thickness or two 1.5-mm layers bonded to unmodified wood. The results show that thicker laminate has a great positive influence on Brinell Hardness. This study suggests that results from the existing method for Brinell Hardness are not comparable, and if applied force is chosen without restraint, the effect on the Hardness value is significant for inhomogeneous wood composites.
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Surface modification of wood using friction.
Wood Science and Technology, 2009Co-Authors: Lauri Rautkari, M. Properzi, Frédéric Pichelin, Mark HughesAbstract:The potential of linear vibration friction as an innovative means of producing increases in both surface density and surface Hardness was explored. The influence of processing pressure and time on the degree of surface densification, surface Hardness and surface elasticity was investigated. It was found that surface Hardness (measured as Brinell Hardness) was positively correlated with densification ratio. Furthermore, surface elasticity, that is the ability of the surface to recover elastically after indentation during the Brinell Hardness test, could be increased by up to 33% depending on the degree of surface densification. The temperature rise due to friction was also studied. During processing, it was found that the temperature rise on both the radial and tangential surfaces was positively correlated with the processing pressure and time.
Nadir Ayrilmis - One of the best experts on this subject based on the ideXlab platform.
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Investigation of correlation between Brinell Hardness and tensile strength of wood plastic composites
Composites Part B-engineering, 2014Co-Authors: Alperen Kaymakci, Nadir AyrilmisAbstract:Abstract The relationship between Brinell Hardness and tensile strength of wood plastic composites (WPC) as a function of wood filler content was investigated. The sawdust flour was compounded with polypropylene at 30%, 40% or 50% (by weight) content with and without coupling agent, maleic grafted polypropylene with anhydride, in a twin screw co-rotating extruder. Test specimens were produced by injection moulding process from the pellets dried to moisture content of 1%. The relationship between Brinell Hardness and tensile strength for all the filler loading levels was studied using linear regression method. The strong correlation was found between the Brinell Hardness and tensile Hardness of the WPCs as the filler content was between 30 and 40 wt%. The strong correlation showed that the Brinell Hardness could be a good indicator for tensile strength of the WPCs.
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Determination of the relationships between Brinell Hardness and tensile strength of wood plastic composites.
2013Co-Authors: Alperen Kaymakci, Nadir AyrilmisAbstract:In this study, we evaluated the relationships between Brinell Hardness and tensile strength of polymer composites filled with carpentry wastes (CW) flour. To meet this objective, The CW flour was compounded with polypropylene at 30, 40 and 50% (weight) content with and without coupling agent in a twin screw corotating extruder and then were manufactured by injection moulding process. The relationships between Brinell Hardness and tensile strength for all filler loading were studied using linear regression methods. At the same time flexural strength (MOR) and modulus of elasticity (MOE) were determined. The result showed that, regardless of the filler loading, all the relationships between Brinell Hardness and tensile Hardness of polymer composites filled with CW flour were significant.
Tzu-li Tien - One of the best experts on this subject based on the ideXlab platform.
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the indirect measurement of tensile strength of material by the grey prediction model gmc 1 n
Measurement Science and Technology, 2005Co-Authors: Tzu-li TienAbstract:A new prediction model presented in this paper is called the grey model with convolution integral, abbreviated as GMC(1, n). Additional n − 1 series can be introduced by the new model GMC(1, n) to improve the accuracy of prediction made by the existing grey model GM(1, 1). Improvements on the existing grey prediction model GM(1, n) are made to a large extent and the messages for a system can be inserted sufficiently. The relationship between input series and output series is constructed sufficiently by GMC(1, n) and high accuracy of indirect measurement or prediction for a dynamic system can be broadly anticipated. The relationship between the tensile strength and Brinell Hardness number of a material is very intensive, but a definite explicit or implicit function to describe it does not exist. The property of a material is a grey system. It is more difficult to measure the tensile strength than the Brinell Hardness number of a material especially for a higher temperature. The indirect measurement of the tensile strength of a material for a higher temperature can be made by GMC(1, n) with the Brinell Hardness number of the material acting as a leading indicator. The results show that the accuracy of the indirect measurement of the tensile strength is satisfactory.
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The indirect measurement of fatigue limits of structural steel by the deterministic grey dynamic model DGDM(1,1,1)
Applied Mathematical Modelling, 1997Co-Authors: Tzu-li Tien, Cha'o-kuang ChenAbstract:Abstract This paper studies the dynamic relationship between Hardness and fatigue limits of structural steel, by which we evaluate the fatigue limits of the material for higher carbon concentration from the corresponding experimental data of Brinell Hardness. The fatigue limits of a material based on carbon concentration are important for mechanical engineering design. It is harder and takes more time to obtain experimental data on the fatigue limits than to obtain those of the Brinell Hardness of a material. The prediction model DGDM(1,1,1) is employed in this study. The series of lower bounds and upper bounds of the Brinell Hardness at equispaced intervals of carbon concentration are considered as the leading indicators (the input series), while the series of the corresponding lower bounds and upper bounds of rotational bending, reversed tension and compression, and reversed torsion of fatigue limits of the material at the corresponding carbon concentrations are taken as the output series. The results show that the fatigue limits and the Brinell Hardness of a material are highly correlated and that the accuracy of indirect measurement of the fatigue limits is satisfactory.
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The indirect measurement of tensile strength by the deterministic grey dynamic model DGDM(1, 1, 1)
International Journal of Systems Science, 1997Co-Authors: Cha'o-kuang Chen, Tzu-li TienAbstract:Abstract This paper studies the dynamic relationship between Hardness and tensile strength of a material, through which we evaluate the tensile strength of the material for a higher temperature from the corresponding experimental data of Brinell Hardness. The tensile strength of a material based on temperature is important for mechanical engineering design. It is harder and takes more time to obtain experimental data of the tensile strength than to obtain those data of the Brinell Hardness of a material. The prediction model DGDM( 1, 1, I) is employed in this study. The series of Brinell Hardness at equispaced intervals of temperature is considered as the leading indicator ( the input series) while the series of tensile strength of the material at the corresponding temperature is taken as the output series. The result shows that the tensile strength and the Brinell Hardness of a material are highly correlated and the accuracy of indirect measurement of the tensile strength is satisfactory.
Kristiina Laine - One of the best experts on this subject based on the ideXlab platform.
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analysing density profile characteristics of surface densified solid wood using computational approach
International Wood Products Journal, 2013Co-Authors: Kristiina Laine, Lauri Rautkari, Toni Antikainen, Mark HughesAbstract:In this study, solid Scots pine was surface densified in an open press using different moisture contents (9·6 and 12·4%), temperatures (150 and 200°C), press closing times (0·5 and 5 min), holding times (1 and 10 min) and compression ratios (6·7 and 25%). The characteristics of the formed density profiles were defined and their correlations to the process parameters and Brinell Hardness and elastic recovery were analysed. Compression ratio and closing time had the strongest effect on the formation of the density profile, as well as the Hardness and elastic recovery. The amount of localised deformation (peak area) did not have significant effect on the Brinell Hardness or elastic recovery, whereas, the highest density achieved (peak density) and its location (peak distance) dominated the effect. Brinell Hardness and elastic recovery were found to correlate well with each other.
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Hardness and density profile of surface densified and thermally modified scots pine in relation to degree of densification
Journal of Materials Science, 2013Co-Authors: Kristiina Laine, Sergej Medved, Andreja Kutnar, Lauri Rautkari, Mark HughesAbstract:Solid Scots pine (Pinus sylvestris L.) wood was surface densified to three different degrees of compression and hydrothermal post-treatment after surface densification process was performed. The study determined the significance of degree of compression and hydrothermal post-treatment on the density profile generated and the resulting improved Brinell Hardness. It was found that different degree of compression resulted in only slightly different density profiles, when compared on the absolute thickness scale. Although the hydrothermal post-treatment lead to an average mass loss of 3.8 % in surface densified specimens regardless of the degree of compression, density profile of surface densified specimens was not significantly affected by hydrothermal post-treatment. Furthermore, the surface densification increased the Brinell Hardness more than 90 %. Degree of compression had limited effect, which means that it did not matter if the specimens were compressed from 22 to 15 mm or 18 to 15 mm, the Brinell Hardness was approximately the same. The hydrothermal post-treatment did not reduce the Brinell Hardness of control and surface densified specimens. Furthermore, the surface densification significantly increased the elastic recovery of surface densified wood, which was measured during Hardness measurements and was affected by degree of compression. Additionally, the hydrothermal post-treatment reduced the elastic recovery, in control specimens and surface densified specimens.
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the effect of process parameters on the Hardness of surface densified scots pine solid wood
European Journal of Wood and Wood Products, 2013Co-Authors: Kristiina Laine, Lauri Rautkari, Mark HughesAbstract:This paper addresses the effect of surface densification on the Brinell Hardness of Scots pine sapwood. Densification was performed in an open system under heat and compression using different compression temperatures and closing times. The Hardness was measured using a modified Brinell Hardness method. Furthermore, the density profiles of the samples were measured and their correlation to Hardness analysed. It was found that the process parameters strongly affected the Hardness of surface densified solid wood. This knowledge is relevant when optimising the densification process according to the properties required of the end-product. At 150 °C compression temperature and 0.5 min closing time, the average Brinell Hardness (23.4 N/mm2) was double to that at 200 °C and 5 min closing time (11.6 N/mm2).