Pub Date : 2023-08-03DOI: 10.22320/s0718221x/2024.01
María del Rocío Ramos, Pamela Yohana Fank, Eduardo Antonio Torrán, María Alexandra Sosa-Zitto, Juan Carlos Piter
En este artículo se presentan y discuten los resultados de un proyecto orientado a investigar el comportamiento mecánico de muros de corte típicos de construcciones de entramado ligero y construidos con bastidor de Eucalyptus grandis de la Mesopotamia Argentina. La investigación se llevó a cabo sobre 17 paneles, 15 de los cuales integraron 5 series con distintas configuraciones que cumplieron los requerimientos constructivos del Método A del Eurocódigo 5 (AENOR 2016a), y 2 con anomalías. Los ensayos se realizaron según la norma UNE-EN 594 (AENOR 2011). La resistencia al descuadre determinada experimentalmente superó a la obtenida según el Método A en todos los paneles que cumplieron los requerimientos constructivos, ubicando del lado de la seguridad al valor calculado según las reglas europeas. Los resultados experimentales probaron una mayor variabilidad de la rigidez que de la resistencia y mostraron que los paneles que fallaron bajo cargas elevadas no siempre desarrollaron la resistencia esperada para deformaciones admisibles bajo cargas de servicio, indicando la conveniencia de focalizar sobre este aspecto en futuras investigaciones sobre estos sistemas estructurales.
{"title":"Comportamiento mecánico de muros de corte de Eucalyptus grandis: Resultados experimentales versus el criterio de las normas europeas","authors":"María del Rocío Ramos, Pamela Yohana Fank, Eduardo Antonio Torrán, María Alexandra Sosa-Zitto, Juan Carlos Piter","doi":"10.22320/s0718221x/2024.01","DOIUrl":"https://doi.org/10.22320/s0718221x/2024.01","url":null,"abstract":"En este artículo se presentan y discuten los resultados de un proyecto orientado a investigar el comportamiento mecánico de muros de corte típicos de construcciones de entramado ligero y construidos con bastidor de Eucalyptus grandis de la Mesopotamia Argentina. La investigación se llevó a cabo sobre 17 paneles, 15 de los cuales integraron 5 series con distintas configuraciones que cumplieron los requerimientos constructivos del Método A del Eurocódigo 5 (AENOR 2016a), y 2 con anomalías. Los ensayos se realizaron según la norma UNE-EN 594 (AENOR 2011). La resistencia al descuadre determinada experimentalmente superó a la obtenida según el Método A en todos los paneles que cumplieron los requerimientos constructivos, ubicando del lado de la seguridad al valor calculado según las reglas europeas. Los resultados experimentales probaron una mayor variabilidad de la rigidez que de la resistencia y mostraron que los paneles que fallaron bajo cargas elevadas no siempre desarrollaron la resistencia esperada para deformaciones admisibles bajo cargas de servicio, indicando la conveniencia de focalizar sobre este aspecto en futuras investigaciones sobre estos sistemas estructurales.","PeriodicalId":49055,"journal":{"name":"Maderas-Ciencia Y Tecnologia","volume":"293 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136383992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-03DOI: 10.22320/s0718221x/2024.02
João Vítor Felippe Silva, Karina Aparecida De Oliveira, Carolina Aparecida Barros Oliveira, Maria Fernanda Felippe Silva, Julio Cesar Molina
The proper choice of raw materials and manufacturing parameters for Cross Laminated Timber is essential to promote the proper bonding of the lamellas, aiming at their application in construction. However, few Brazilian species are currently used in the production of Cross Laminated Timber. The aim of this work was to characterize the bonding quality of four Brazilian reforestation species (Pinus elliottii, Eucalyptus grandis, Toona ciliata and Acrocarpus fraxinifolius) in the manufacture of Cross Laminated Timber with two-component polyurethane adhesive and five different pressure levels (from 0,1 MPa to 1,3 MPa). Bonding quality was evaluated through delamination and glue line shear tests based on the standard EN 14080 (2013). Delamination was affected by the wood species, and the best adhesion occurred for the Cross Laminated Timber manufactured with Pinus elliottii and Acrocarpus fraxinifolius at the bonding pressure of 0,7 MPa. Cross Laminated Timber bonding pressure did not affect the percentage of wood in the shear test fractured surface, whereas higher density Cross Laminated Timber showed higher percentages.
{"title":"Cross laminated timber bonding quality for different brazilian species and pressing levels","authors":"João Vítor Felippe Silva, Karina Aparecida De Oliveira, Carolina Aparecida Barros Oliveira, Maria Fernanda Felippe Silva, Julio Cesar Molina","doi":"10.22320/s0718221x/2024.02","DOIUrl":"https://doi.org/10.22320/s0718221x/2024.02","url":null,"abstract":"The proper choice of raw materials and manufacturing parameters for Cross Laminated Timber is essential to promote the proper bonding of the lamellas, aiming at their application in construction. However, few Brazilian species are currently used in the production of Cross Laminated Timber. The aim of this work was to characterize the bonding quality of four Brazilian reforestation species (Pinus elliottii, Eucalyptus grandis, Toona ciliata and Acrocarpus fraxinifolius) in the manufacture of Cross Laminated Timber with two-component polyurethane adhesive and five different pressure levels (from 0,1 MPa to 1,3 MPa). Bonding quality was evaluated through delamination and glue line shear tests based on the standard EN 14080 (2013). Delamination was affected by the wood species, and the best adhesion occurred for the Cross Laminated Timber manufactured with Pinus elliottii and Acrocarpus fraxinifolius at the bonding pressure of 0,7 MPa. Cross Laminated Timber bonding pressure did not affect the percentage of wood in the shear test fractured surface, whereas higher density Cross Laminated Timber showed higher percentages.","PeriodicalId":49055,"journal":{"name":"Maderas-Ciencia Y Tecnologia","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136383993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-01DOI: 10.4067/s0718-221x2023000100439
Wengang Hu, Runzhong Yu
The mechanical and acoustic properties of four commonly used wood species, including Populus tomentosa (Poplar), Swietenia mahagoni (Mahogany), Fagus orientalis (Beech), and Fraxinus excelsior (Ash) wood were investigated through using three-point bending and notched bending tests synchronizing with power spectrum analysis method and fractal dimension theory. The results showed that the bending modulus of elasticity and modulus of rapture changed in the same trend with the order ranging from high to low was ash, beech, poplar, and mahogany, successively. The brittle fracture occurred in mahogany samples and ductile fracture raised in the other three wood species. Positive proportional correlation was observed between maximum acoustic pressure and fractal dimension of power spectrum regardless of seeing four wood species as independent or population samples. The failure modes can be identified by amplitude-frequency curve and fractal dimension of power spectrum with following laws: the peak value in amplitude-frequency curve and fractal dimension of power spectrum were relatively higher when a single crack developed at latewood; for crack developed at earlywood, only one peak was observed in power amplitude-frequency curves, and the corresponding fractal dimension of power spectrum was smaller than the that of latewood; in case of failure modes with two cracks developed at earlywood, there are two peaks in amplitude-frequency curve and the fractal dimension of power spectrum was between those of single crack developed at earlywood and latewood. The vibrational properties of the four wood species can be characterized through using power spectrum analysis method and notched bending test method can be used to distinguish the failure modes of samples.
{"title":"Mechanical and acoustic characteristics of four wood species subjected to bending load","authors":"Wengang Hu, Runzhong Yu","doi":"10.4067/s0718-221x2023000100439","DOIUrl":"https://doi.org/10.4067/s0718-221x2023000100439","url":null,"abstract":"The mechanical and acoustic properties of four commonly used wood species, including Populus tomentosa (Poplar), Swietenia mahagoni (Mahogany), Fagus orientalis (Beech), and Fraxinus excelsior (Ash) wood were investigated through using three-point bending and notched bending tests synchronizing with power spectrum analysis method and fractal dimension theory. The results showed that the bending modulus of elasticity and modulus of rapture changed in the same trend with the order ranging from high to low was ash, beech, poplar, and mahogany, successively. The brittle fracture occurred in mahogany samples and ductile fracture raised in the other three wood species. Positive proportional correlation was observed between maximum acoustic pressure and fractal dimension of power spectrum regardless of seeing four wood species as independent or population samples. The failure modes can be identified by amplitude-frequency curve and fractal dimension of power spectrum with following laws: the peak value in amplitude-frequency curve and fractal dimension of power spectrum were relatively higher when a single crack developed at latewood; for crack developed at earlywood, only one peak was observed in power amplitude-frequency curves, and the corresponding fractal dimension of power spectrum was smaller than the that of latewood; in case of failure modes with two cracks developed at earlywood, there are two peaks in amplitude-frequency curve and the fractal dimension of power spectrum was between those of single crack developed at earlywood and latewood. The vibrational properties of the four wood species can be characterized through using power spectrum analysis method and notched bending test method can be used to distinguish the failure modes of samples.","PeriodicalId":49055,"journal":{"name":"Maderas-Ciencia Y Tecnologia","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135807313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-01DOI: 10.4067/s0718-221x2023000100438
Nanci Vanesa Ehman, Yanina Susel Aguerre, María Evangelina Vallejos, Fernando Esteban Felissia, María Cristina Area
This study assesses the incorporation of nanocellulose in a paperboard feedstock emulating two scenarios of industrial processes. It included the production of 170 g/m2 paperboard, using mixtures of short-fiber and long-fiber fractions from recycled pulps with typical mill additives. In all cases, 3 wt. % of nanocellulose was added to the pulp suspensions. The first scenario involved three types of nanocellulose addition in a mixture of 78 % long-fiber/22 % short-fiber pulps. The second scenario included the addition of two types of nanocellulose to an unrefined long fiber pulp to produce a multilayer paperboard. Drainage time and physical-mechanical properties of the handsheets were evaluated. Nanocellulose improved the mechanical properties in all cases. The tensile and burst indexes increased 19 % and 28 % in Scenario 1 and up to 60 % and 43 % in Scenario 2, respectively. The lower values in mechanical properties for Scenario 1 were attributed to the effect of the retention system. A new retention system using a cationic polymer with a high charge density produced decreases up to 79 % in the drainage time.
{"title":"Nanocellulose addition to recycled pulps in two scenarios emulating industrial processes for the production of paperboard","authors":"Nanci Vanesa Ehman, Yanina Susel Aguerre, María Evangelina Vallejos, Fernando Esteban Felissia, María Cristina Area","doi":"10.4067/s0718-221x2023000100438","DOIUrl":"https://doi.org/10.4067/s0718-221x2023000100438","url":null,"abstract":"This study assesses the incorporation of nanocellulose in a paperboard feedstock emulating two scenarios of industrial processes. It included the production of 170 g/m2 paperboard, using mixtures of short-fiber and long-fiber fractions from recycled pulps with typical mill additives. In all cases, 3 wt. % of nanocellulose was added to the pulp suspensions. The first scenario involved three types of nanocellulose addition in a mixture of 78 % long-fiber/22 % short-fiber pulps. The second scenario included the addition of two types of nanocellulose to an unrefined long fiber pulp to produce a multilayer paperboard. Drainage time and physical-mechanical properties of the handsheets were evaluated. Nanocellulose improved the mechanical properties in all cases. The tensile and burst indexes increased 19 % and 28 % in Scenario 1 and up to 60 % and 43 % in Scenario 2, respectively. The lower values in mechanical properties for Scenario 1 were attributed to the effect of the retention system. A new retention system using a cationic polymer with a high charge density produced decreases up to 79 % in the drainage time.","PeriodicalId":49055,"journal":{"name":"Maderas-Ciencia Y Tecnologia","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135807316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wood veneer based composites have a great demand in present market as the material can utilize small diameter plantation timbers grown at short rotation cycle. This paper presents preparation and characterization of hybrid composites made of wood veneer and wood polymer composite. The study explored utilization of wood polymer composite as an adhesive for bonding veneers replacing formaldehyde-based adhesives. Wood polymer composite containing 40 % bamboo particles embedded in the matrix of polypropylene was used in sheet form to bind the veneers of Melia dubia (Malabar neem) wood. The composites were prepared in both laminated veneer lumber and plywood configurations. The assessment of physical and mechanical properties indicated that the properties of wood polymer composite contribute significantly to the properties of the hybrid composites. The density of the resultant composites was significantly higher (690 kg/m3 - 750 kg/m3) than conventional plywood or laminated veneer lumber. Among mechanical properties, there was no statistical difference in tensile and flexural strength of plywood and laminated veneer lumber configuration. Modulus of elasticity and compressive strength of laminated veneer lumber configuration were significantly higher than plywood. Glue shear strength and internal bond strength of the composites indicated acceptable bonding properties of wood polymer composite which suggests the potential application of these composites as a binding agent for wood veneers. These composites could be a special class of laminated composites with no formaldehyde emission hazards.
{"title":"Wood polymer composite bonded veneer based hybrid composites","authors":"Siddhartha Arya, Shakti Chauhan, Ritesh Kumar, Bhushan Kelkar","doi":"10.4067/s0718-221x2023000100440","DOIUrl":"https://doi.org/10.4067/s0718-221x2023000100440","url":null,"abstract":"Wood veneer based composites have a great demand in present market as the material can utilize small diameter plantation timbers grown at short rotation cycle. This paper presents preparation and characterization of hybrid composites made of wood veneer and wood polymer composite. The study explored utilization of wood polymer composite as an adhesive for bonding veneers replacing formaldehyde-based adhesives. Wood polymer composite containing 40 % bamboo particles embedded in the matrix of polypropylene was used in sheet form to bind the veneers of Melia dubia (Malabar neem) wood. The composites were prepared in both laminated veneer lumber and plywood configurations. The assessment of physical and mechanical properties indicated that the properties of wood polymer composite contribute significantly to the properties of the hybrid composites. The density of the resultant composites was significantly higher (690 kg/m3 - 750 kg/m3) than conventional plywood or laminated veneer lumber. Among mechanical properties, there was no statistical difference in tensile and flexural strength of plywood and laminated veneer lumber configuration. Modulus of elasticity and compressive strength of laminated veneer lumber configuration were significantly higher than plywood. Glue shear strength and internal bond strength of the composites indicated acceptable bonding properties of wood polymer composite which suggests the potential application of these composites as a binding agent for wood veneers. These composites could be a special class of laminated composites with no formaldehyde emission hazards.","PeriodicalId":49055,"journal":{"name":"Maderas-Ciencia Y Tecnologia","volume":"131 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135807311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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