|
|
|
|
|
| Christoforo,André L.; Arroyo,Felipe N.; Silva,Diogo A. Lopes; Panzera,Tulio H.; Lahr,Francisco A. R.. |
| ABSTRACT: Wood is a material that for years has been used by man for a variety of purposes, particularly in rural and civil constructions and furniture industry. The possibility of shortages of some wood species, the characterization of other unfamiliar species is an alternative source for use in civil and rural construction. This study aimed to determine, with the aid of Brazilian standard NBR 7190, physical and mechanical properties of Castelo (Calycophyllum multiflorum) wood specie. Twelve determinations were obtained by property, totaling 204 experimental values. In the characterization of wood, regression models were used to estimate the values of timber strength and stiffness as a function of apparent density, being density the physical property more... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Calycophyllum multiflorum; Physical-mechanical properties; Hardwood; Regression model. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162017000400637 |
| |
|
|
| Christoforo,André L.; Aftimus,Bruno H. C.; Panzera,Tulio H.; Machado,Gilmara de O.; Lahr,Francisco A. R.. |
| ABSTRACT In Brazil, the characterization of wood is carried out in accordance with the premises established by ABNT NBR 7190standard; however, the determination of wood properties requires the use of equipment, which hinders the wood characterization for the construction professional. To circumvent this problem, the properties of wood strength and stiffness can be estimated through regression models using the apparent density as estimator, being the density a physical property of easy determination. This study aimed to determine 4 physical and 13 mechanical properties of “Angico Branco” wood (Anadenanthera colubrina), and with the aid of regression models based on analysis of variance, estimate the strength and stiffness properties as a function of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Anadenanthera colubrina; Physico-mechanical characterization; Apparent density; Regression models; Analysis of variance (ANOVA). |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162017000200376 |
| |
|
|
| Christoforo,André L.; Panzera,Tulio H.; Neto Junior,Carlito Calil; Demarzo,Mauro A.; Ribeiro Filho,Sérgio L. M.; Toniolo,Luiz E.; Amstalden,Rogério A. S.; Lahr,Francisco A. R.. |
| This study aims to present an alternative calculation methodology based on the Least Squares Method for determining the modulus of elasticity in bending wooden beams of structural dimensions. The equations developed require knowledge of three or five points measured in displacements along the piece, allowing greater reliability on the response variable, using the statistical bending test at three points and non-destructively, resulting from imposition of measures from small displacements L/300 and L/200, the largest being stipulated by the Brazilian norm NBR 7190:1997. The woods tested were Angico, Cumaru, Garapa and Jatoba. Besides obtaining the modulus of elasticity through the alternative methodology proposed, these were also obtained employing the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Wood; Beam theory; Modulus of elasticity; Least Squares Method. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162014000100016 |
| |
|
|
| Christoforo,André L.; Nascimento,Maria F. do; Panzera,Tulio H.; Ribeiro Filho,Sérgio L. M; Lahr,Francisco A. R.. |
| ABSTRACT This study aimed to evaluate the mechanical performance of laminated composite materials (fiberglass, carbon, sisal, palm fiber) in epoxy matrix as reinforcement in wood particleboards of Pinus sp. with bicomponent polyurethane resin from castor oil. Modulus of elasticity (MOE) and modulus of rupture (MOR) were investigated using a three-point bending test. Single-layered laminated plates were used to reinforce traction of specimens obtained from boards. MOE and MOR of materials developed without reinforcements exceeded limits in ABNT standards both NBR 12810-2:2002 and A208.1:199, proving therefore their feasibility. In all investigated cases, inclusion of reinforcements led to higher values for both MOE and MOR. Composites in fiberglass... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Particleboard; Laminated composites; Structural reinforcement. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000300558 |
| |
|
| |
|
|
| Christoforo,André L.; Panzera,Tulio H.; Lahr,Francisco A. R.. |
| ABSTRACT According to the ABNT NBR 7190: 1997 standard, tensile strength of wood samples shall be defined as the ratio between the ultimate strength from a stress test and the specimen cross-sectional area (350 mm2). However, due to the complex wood anatomy and experimental difficulties, the fractured surface in tested samples are not perpendicular to the loading direction; therefore, such fractured surface becomes larger than the sample cross section, overestimating tensile strength by this method. Using an alternative approach, we aimed to determine the approximate fracture surface of wood specimens subjected to tensile test. For this purpose, we used the least square method to estimate tensile strength of four hardwood species, which were equally... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Tensile Strength; Wood; Hardwood; Least Square Method. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000400533 |
| |
|
|
| Christoforo,André L.; Almeida,Diego H. de; Varanda,Luciano D.; Panzera,Tulio H.; Lahr,Francisco A. R.. |
| ABSTRACT Wood has been used for several purposes such as in civil and rural construction. Knowing wood mechanical behavior under short-term loading is essential for safer structural designs. However, wood toughness is a mechanical property little investigated for this purpose. Thus, this study aimed to evaluate, using exponential and polynomial regression models (linear, quadratic, and cubic), the possibility of estimating toughness as a function of apparent density, compression parallel to grain strength, and modulus of rupture in static bending. Thirty-six Brazilian tropical wood species from south of Roraima, Mato Grosso do Sul, and north and northeast of Mato Grosso were tested. Our results showed the significance and representativeness of all... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Apparent density; Tropical wood species; Modulus of elasticity; Compression parallel to grain strength; Toughness. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000200232 |
| |
|
|
| Christoforo,André L.; Barbosa,Thaina Q.; Almeida,Diego H. de; Panzera,Tulio H.; Lahr,Francisco A. R.. |
| ABSTRACT This research aimed to evaluate the effect of the number of fatigue cycles (NC, 0 – reference, 450, 4500, 45000, and 90000) for frequencies (Fr) of oscillation equal to 0.5 and 1.0 Hz on the modulus of elasticity (Em) and operating stress (σm) in the static bending of Pinus caribaea wood. Em and σm were determined taking into account three specimens (SPEC) manufactured for reference condition and another three for each of the four NC levels and each Fr level, resulting in 27 SPEC. Sixty experimental determinations were obtained, being the approximate total time of sample exposure to fatigue of 350 hours. The same specimens used to determine Em and σm for the reference condition were also used (via non-destructive tests) to obtain these properties... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fatigue; Pinus caribaea; Static bending; Analysis of variance; Regression models. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000200238 |
| |
|
|
|
