WO2015039200A1 - Apparatus and method for measuring the hardness of lignocellulosic materials - Google Patents
Apparatus and method for measuring the hardness of lignocellulosic materials Download PDFInfo
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- WO2015039200A1 WO2015039200A1 PCT/BR2014/000329 BR2014000329W WO2015039200A1 WO 2015039200 A1 WO2015039200 A1 WO 2015039200A1 BR 2014000329 W BR2014000329 W BR 2014000329W WO 2015039200 A1 WO2015039200 A1 WO 2015039200A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/40—Investigating hardness or rebound hardness
- G01N3/42—Investigating hardness or rebound hardness by performing impressions under a steady load by indentors, e.g. sphere, pyramid
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- the present invention describes an equipment and method for hardness measurement of lignocellulosic materials. More specifically, it comprises a portable electromechanical equipment that measures the hardness of materials, with a working principle similar to the Brinell hardness test, featuring an electronic assembly consisting of an incremental magnetic encoder displacement sensor that allows the hardness reading to be automated by means of integrated digital signal controller.
- the mechanical property called hardness is widely used in material specification, mechanical and metallurgical studies and research and quality control of various materials.
- indentation in the material can be obtained using various instruments such as cylinders, balls, prisms or needles.
- Janka hardness In wood, in particular, Janka hardness is used, which evaluates the resistance offered by the material to the surface penetration of a steel sphere, with a diameter of 1 cm 2 , when the penetration is induced to half its diameter.
- the depth of penetration of the sphere into the wood is fixed and the force to achieve said penetration is evaluated.
- This test is simple, fast and has good correlations with the compressive strength parallel to the wood fibers.
- the Brinell hardness test consists of slowly compressing a diameter steel ball (indentator) "D" on the flat, polished and clean surface of a metal by a force "P" for a time “t". This compression causes a permanent impression on the metal in the shape of a spherical cap having a diameter "d” which is measured by means of an optical micrometer (graduated microscope or magnifying glass) after the load is removed.
- the diameter value "d” shall be taken as the average of two readings taken at 90 degrees from each other.
- the Brinell hardness obtained by the relation between the applied force (P) and the area of the spherical cap printed on the material is given or:
- HB Brinell hardness (kgf / mm 2 );
- d diameter of indented spherical cap (mm).
- the Brinell hardness would make it easier to perform the tests under field conditions, especially due to the smaller magnitude of the efforts involved in crushing the indentator on the material surface.
- the Brinell hardness test may make the assessment of the indented area inaccurate when it comes to sinking in materials on the periphery of the indented surface, such as wood.
- elastic materials it would be preferable to determine the hardness under loading, since, when the force that promoted elastic deformation is removed, the elastic material recovers the deformation suffered (energy conservation).
- some researchers have suggested using Brinell hardness for wood under field conditions, especially considering the smaller magnitude of the forces involved in the Brinell test and the difficulty in controlling under field conditions the depth of penetration of the sphere required in the Janka hardness test.
- the King Type Indentec Portable Durometer is commercially available for Brinell hardness assessment in metals, featuring a pressure gauge with a minimum loading value of 500 kgf (4900N).
- the Durometer called “Laminated Wood Hardness Testing Tool” is presented as an equipment with mobilization of the spring indentation force.
- the Model TH 130 Portable Digital Electronic Readout Durometer combines a number of possibilities for testing various hardnesses with a single electronic processor.
- the principle of operation of the device is the action of a metal sphere, applied directly on the surface of the material to be evaluated.
- the hardness is evaluated by the ball rebound.
- the hardnesse Upon selection in the apparatus one can infer from this reading the hardnesses Brinell, Shore, Vickers and Rockwell.
- equipment for measuring the hardness of lignocellulosic material with an electronic circuit is required. simplified, for automatic evaluation of indentation and calculation and immediate display of hardness, allowing the establishment of regression correlations between the hardness evaluated by the equipment and other properties of interest for these materials.
- It is a feature of the invention a device for measuring the hardness of lignocellulosic materials which is able to calculate, by means of the displacement signal, the force at each moment of the indentation event, allowing the measurement of material strength and stiffness properties.
- Figure 1 presents the exploded view of the hardness measuring equipment of lignocellulosic materials.
- Figure 2 shows the perspective view of the assembled equipment.
- Figure 3 shows the orthogonal equipment positioned at the lignocellulosic material to be evaluated, with the impact mass positioned at the maximum position limit.
- FIG. 4 shows the flowchart of the computational algorithm embedded in the processor.
- Figure 5 presents a scatter plot of the tests performed to compare the measurements of the equipment object of the present invention with the Janka hardness measured in a universal testing machine.
- Figure 6 presents a graph of the association of values between hardness evaluated by the equipment (portable durometer) and the conventional classical method (Janka hardness).
- the hardness measuring equipment of lignocellulosic materials comprises a portable electromechanical structure, operating similar to the Brinell hardness test, ie the equipment has a spherical shaped tip with known diameter which is compressed by a force known about the material to be evaluated.
- the hardness value is obtained by the relation between the applied force and the area of the spherical cap that will be printed on the evaluated material (indentation).
- the hardness measuring equipment of lignocellulosic materials comprises a cylindrical shaped metal support called the main support (10), containing within it an impact mass (20) of metal material and of a weight suitable for its intended purpose, said mass. of impact (20) moving between the ends of the main support (10).
- the impact mass (20) is coupled to a spherically shaped tip (30).
- an incremental magnetic encoder (11) is installed which measures the displacement of the moving impact mass. (20) in relation to the main support (10).
- the base of the main support (10) has a perpendicularly arranged flange (12) which ensures the mechanical stabilization of the equipment on the material to be evaluated (100) as well as serving as the operator's support on the equipment at the time of the test.
- the movable impact mass (20) has a specifically shaped cross section which decreases the contact area with the inner surface of the main support and consequently reduces friction during fall. Additionally, on the surface of the impact mass (20) is attached an alternating pole magnetic strip (not shown) which enables the measurement of the position of the impact mass (20) by the incremental magnetic encoder (11).
- the spherical shaped tip (30) coupled to the impact mass (20) is detachable, and its possible replacement for tests with indentors of different diameters is possible.
- the main support (10) has a side guide (13) projecting externally an operating handle (21) coupled to the impact mass (20) disposed in the inner region of said support (10), allowing the operator to lift of impact mass (20) for mobilization of indentation energy.
- the surface of the operating handle 21 has an appropriate area to ensure greater adhesion at the time of operation.
- the magnetic encoder (11) is connected to an electronic circuit (40) that incorporates a digital signal controller (DSC), a panel (41) and a keyboard (42).
- the electronic circuit (40) receives and interprets the signals transmitted by the encoder (11), calculates and displays the hardness of the evaluated material (100). Through a serial communication port, data stored in the electronic circuit (40) is sent to other electronic devices.
- the method for hardness measurement of lignocellulosic materials using the equipment object of the present invention comprises in a first step positioning the main support (10) perpendicularly over the material under evaluation (100) and then zeroing the encoder position measurement (11). via the keyboard (42) of the electronic circuit (40). The user then moves the impact mass (20) by actuating the handle (21) to the height defined on the main support (10). This lifting height is guaranteed by the mechanical limitation present on the side guide (13) of the main support (10).
- the user releases the handle (21), allowing the downward movement of said impact mass (20) over the material under evaluation (100) for indentation.
- the magnetic encoder (11) measures the position of the impact mass.
- the signal produced by the displacement measurement sensor (11) is in the form of digital pulses in two channels (A and B) 90 degrees apart, as shown in figure 6.
- the combination of channels A and B enables the electronic circuit to detect the direction in which the displacement of the impact mass (20) is taking place - upward or downward.
- the hardness (H) is calculated as a ratio between the energy available in the free fall of the impact mass (20) (instead of the load used in the Brinell hardness) and the area of the indented spherical cap.
- the calculated hardness result for the evaluated material (100) is instantly displayed on the equipment panel (41).
- the measuring sensor (1 1) is supplied with voltages between 8 and 30
- Vcc and has a resolution of up to 0.005mm.
- the panel (41) of the equipment shows the actual position of the impact mass (20) in a measured unit and / or in the form of a horizontal bar graph filled in proportion to the position of the impact mass (20) in relation to to the main support (10), said position of the impact mass (20) obtained by interaction of the displacement sensor (11) with the magnetic tape (not shown).
- the equipment object of the present invention calculates, by integrating the displacement signal obtained by the displacement sensor (1), the force at each moment of the indentation event, proving the potential of the equipment to measure material strength and stiffness properties. .
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Abstract
Description
EQUIPAMENTO E MÉTODO PARA MEDIÇÃO DE DUREZA DE EQUIPMENT AND METHOD FOR MEASURING HARDNESS
MATERIAIS LIGNOCELULÓSICOS CAMPO DA INVENÇÃO LIGNOCELLULOSTIC MATERIALS FIELD OF INVENTION
A presente invenção descreve um equipamento e método para medição de dureza de materiais lignocelulósicos. Mais especificamente compreende um equipamento portátil eletromecânico que mede a dureza de materiais, com princípio de funcionamento semelhante ao ensaio de dureza Brinell, apresentando um conjunto eletrônico composto por um sensor de deslocamento do tipo encoder magnético incremental que permite a automatização da leitura da dureza por meio de controlador digital de sinais integrado. The present invention describes an equipment and method for hardness measurement of lignocellulosic materials. More specifically, it comprises a portable electromechanical equipment that measures the hardness of materials, with a working principle similar to the Brinell hardness test, featuring an electronic assembly consisting of an incremental magnetic encoder displacement sensor that allows the hardness reading to be automated by means of integrated digital signal controller.
ANTECEDENTES DA INVENÇÃO BACKGROUND OF THE INVENTION
A propriedade mecânica denominada dureza é largamente utilizada na especificação de materiais, nos estudos e pesquisas mecânicas e metalúrgicas e no controle de qualidade de diversos materiais. The mechanical property called hardness is widely used in material specification, mechanical and metallurgical studies and research and quality control of various materials.
Nos ensaios de dureza, a endentação no material pode ser obtida com o uso de vários instrumentos, como cilindros, esferas, prismas ou agulhas. In hardness testing, indentation in the material can be obtained using various instruments such as cylinders, balls, prisms or needles.
Na madeira, em particular, é utilizada a dureza Janka, que avalia a resistência oferecida pelo material à penetração superficial de uma esfera de aço, com seção diametral de 1 cm2, quando a penetração é induzida até a metade do seu diâmetro. Assim, neste caso, é fixada a profundidade de penetração da esfera na madeira e avaliada a força para conseguir dita penetração. Este ensaio é simples, rápido e apresenta boas correlações com a resistência à compressão paralela às fibras da madeira. In wood, in particular, Janka hardness is used, which evaluates the resistance offered by the material to the surface penetration of a steel sphere, with a diameter of 1 cm 2 , when the penetration is induced to half its diameter. Thus, in this case, the depth of penetration of the sphere into the wood is fixed and the force to achieve said penetration is evaluated. This test is simple, fast and has good correlations with the compressive strength parallel to the wood fibers.
Mais recentemente, trabalhos internacionais reportam o uso da dureza Brinell para avaliação de madeiras. More recently, international studies report the use of Brinell hardness for wood evaluation.
O ensaio de dureza Brinell consiste em comprimir lentamente uma
esfera de aço de diâmetro (endentador) "D" sobre a superfície plana, polida e limpa de um metal através de uma força "P" durante um tempo "t". Essa compressão provoca uma impressão permanente no metal, com o formato de uma calota esférica, tendo um diâmetro "d", o qual é medido por intermédio de um micrômetro óptico (microscópio ou lupa graduados) depois de removida a carga. O valor do diâmetro "d" deve ser tomado como a média de duas leituras feitas a 90 graus uma da outra. A dureza Brinell obtida pela relação entre a força aplicada (P) e a área da calota esférica impressa no material é dada or:
onde: Where:
HB = dureza Brinell (kgf/mm2); HB = Brinell hardness (kgf / mm 2 );
P = carga aplicada (kgf); P = applied load (kgf);
D = diâmetro da esfera de aço - endentador (mm); D = diameter of steel ball - indentator (mm);
d = diâmetro da calota esférica endentada (mm). d = diameter of indented spherical cap (mm).
Além das vantagens já reportadas para a dureza Janka, a dureza Brinell traria a facilidade de realização dos ensaios em condições de campo, sobretudo pela menor magnitude dos esforços envolvidos na cravação do endentador na superfície do material. In addition to the advantages already reported for Janka hardness, the Brinell hardness would make it easier to perform the tests under field conditions, especially due to the smaller magnitude of the efforts involved in crushing the indentator on the material surface.
O ensaio de dureza Brinell, no entanto, pode tomar imprecisa a avaliação da área endentada quando se tratar de materiais que apresentam o fenómeno de afundamento ("sinking in") na periferia da superfície endentada, como é o caso da madeira. Além disso, para materiais elásticos seria preferível a determinação da dureza sob carregamento, visto que, ao ser retirada a força que promoveu a deformação elástica, o material elástico recupera a deformação sofrida (conservação da energia). Mesmo com essas limitações, alguns pesquisadores têm sugerido a utilização da dureza Brinell para madeiras em condições de campo considerando-se, sobretudo, a menor magnitude das forças envolvidas no ensaio Brinell e a dificuldade de se controlar, em condições de campo, a profundidade de penetração da esfera, exigida no ensaio de dureza Janka. The Brinell hardness test, however, may make the assessment of the indented area inaccurate when it comes to sinking in materials on the periphery of the indented surface, such as wood. In addition, for elastic materials it would be preferable to determine the hardness under loading, since, when the force that promoted elastic deformation is removed, the elastic material recovers the deformation suffered (energy conservation). Even with these limitations, some researchers have suggested using Brinell hardness for wood under field conditions, especially considering the smaller magnitude of the forces involved in the Brinell test and the difficulty in controlling under field conditions the depth of penetration of the sphere required in the Janka hardness test.
Bektas ef a/. (BEKTAS, I., ALMA, M.E., AS, N. Determination of the relationships between Brinell and Janka hardness of eastern beech (Fagus orientalis LIPSKY). Forest Products Journal, v. 51 , n° 11/12 p. 84- 87, 2001 ), por meio de ensaios de dureza utilizando os dois métodos— Brinell e Janka— estudou a existência de uma relação linear entre esses dois métodos. Foram realizados ensaios de dureza nas três direções de orientação das fibras da madeira: tangencial, radial e longitudinal, onde chegou-se aos valores máximos dos coeficientes de correlação (R = 0,91 ) e determinação (R2 = 0,83), quando consideradas as três direções em conjunto. Os valores médios das durezas variaram de um mínimo de 41 ,8 MPa e 28 kgf/mm2 e um máximo de 69,03 MPa e 58 kgf/mm2 para os métodos Janka e Brinell, respectivamente. Bektas ef a /. (BEKTAS, I., ALMA, ME, AS, N. Determination of relationships between Brinell and Janka hardness of eastern beech (Fagus orientalis LIPSKY). Forest Products Journal, v. 51, no. 11/12, pp. 84-87. , 2001), through hardness tests using the two methods - Brinell and Janka - studied the existence of a linear relationship between these two methods. Hardness tests were performed in the three wood fiber orientation directions: tangential, radial and longitudinal, where the maximum values of the correlation coefficients (R = 0.91) and determination (R 2 = 0.83) were reached. when considered the three directions together. The average hardness values ranged from a minimum of 41.8 MPa and 28 kgf / mm 2 and a maximum of 69.03 MPa and 58 kgf / mm 2 for the Janka and Brinell methods, respectively.
O estado da técnica descreve alguns equipamentos portáteis específicos para a medição de dureza em madeiras. The state of the art describes some specific portable hardness measurement equipment in wood.
O Durômetro Portátil tipo King, marca Indentec, é disponibilizado comercialmente para avaliação da dureza Brinell em metais, apresentando um manómetro com indicação de valor mínimo de carga de 500 kgf (4900N). The King Type Indentec Portable Durometer is commercially available for Brinell hardness assessment in metals, featuring a pressure gauge with a minimum loading value of 500 kgf (4900N).
O Durômetro denominado "Laminated Wood Hardness Testing Tool" apresenta-se como um equipamento com mobilização da força de endentação por meio de mola. The Durometer called "Laminated Wood Hardness Testing Tool" is presented as an equipment with mobilization of the spring indentation force.
O Durômetro portátil com leitura eletrônica digital - Modelo TH 130 combina uma série de possibilidades de se testarem várias durezas com um único processador eletrônico. O princípio de funcionamento do aparelho se dá pela ação de uma esfera metálica, aplicada diretamente na superfície do material a ser avaliado. Quando a esfera é projetada contra a superfície do material, pela ação de uma mola acionada a partir de um gatilho, avalia-se a dureza pelo ricochete da esfera. Mediante seleção no aparelho pode-se inferir, a partir dessa leitura, as durezas Brinell, Shore, Vickers e Rockwell. Testes com o equipamento, realizados por Colenci (Testes efetuados pelo autor na loja Salvi Casagrande, de São Paulo - SP em 2004, não reportados em relatório) mostraram sua inadequação na avaliação da dureza em madeiras, caracterizada pela grande oscilação de leituras em pontos adjacentes do material. The Model TH 130 Portable Digital Electronic Readout Durometer combines a number of possibilities for testing various hardnesses with a single electronic processor. The principle of operation of the device is the action of a metal sphere, applied directly on the surface of the material to be evaluated. When the ball is projected against the material surface by the action of a spring triggered by a trigger, the hardness is evaluated by the ball rebound. Upon selection in the apparatus one can infer from this reading the hardnesses Brinell, Shore, Vickers and Rockwell. Tests on the equipment by Colenci (Tests carried out by the author at the Salvi Casagrande store, in São Paulo - SP in 2004, not reported in a report) showed its inadequacy in hardness evaluation in wood, characterized by the large oscillation of readings in adjacent points. of material.
O Instituto de Pesquisas Tecnológicas de São Paulo desenvolveu um equipamento para medição de dureza em madeiras utilizando o princípio de bomba hidráulica manual. The Institute of Technological Research of São Paulo has developed equipment for hardness measurement in wood using the principle of manual hydraulic pump.
Ainda, alguns equipamentos do estado da técnica são dotados de acelerômetros. Esta solução técnica, no entanto, apresenta uma característica indesejada: o impacto metal-metal entre a massa de impacto e a ponteira que ocorre no instante inicial da endentação, além de dissipar parte da energia mobilizada na queda livre, ainda proporciona um pico elevado no sinal de aceleração captado. No instante inicial do impacto, a ponteira que se encontrava em repouso assume a velocidade da massa de impacto. Este choque minimamente elástico proporciona uma elevada aceleração na ponteira, alcançando valores maiores que 500 g (4900 m/s2), sendo gerado excesso de ruídos nos valores de aceleração de baixa magnitude. Convencionalmente são utilizados filtros eletrônicos e computacionais para minimizar o efeito dos ruídos. Porém, os filtros que se mostram eficientes na remoção dos ruídos, também amortecem o sinal principal, comprometendo o resultado final de leitura da endentação. Still, some state of the art equipment is equipped with accelerometers. This technical solution, however, has an undesirable feature: the metal-to-metal impact between the impact mass and the tip that occurs at the initial moment of indentation, in addition to dissipating some of the energy mobilized in the free fall, still provides a high peak in acceleration signal picked up. At the initial moment of impact, the resting tip assumes the velocity of the impact mass. This minimally elastic shock provides high tip acceleration, reaching values greater than 500 g (4900 m / s 2 ), and excess noise is generated at low magnitude acceleration values. Conventional electronic and computational filters are used to minimize the effect of noise. However, filters that are efficient in noise removal also dampen the main signal, compromising the final indentation reading result.
Portanto, se faz necessário um equipamento para medição da dureza de material lignocelulósico com um circuito eletrônico simplificado, para avaliação automática da endentação e cálculo e exibição imediata da dureza, permitindo o estabelecimento de correlações de regressão entre a dureza avaliada pelo equipamento e outras propriedades de interesse para esses materiais. Therefore, equipment for measuring the hardness of lignocellulosic material with an electronic circuit is required. simplified, for automatic evaluation of indentation and calculation and immediate display of hardness, allowing the establishment of regression correlations between the hardness evaluated by the equipment and other properties of interest for these materials.
SUMÁRIO SUMMARY
É característica da invenção um equipamento para medição de dureza de materiais lignocelulósicos que possibilita a automatização das leituras de endentação na madeira e a validação das equações de regressão inicialmente estabelecidas, com uso de novas amostras de madeira. It is a feature of the invention that equipment for hardness measurement of lignocellulosic materials enables the automation of indentation readings in wood and the validation of regression equations initially established using new wood samples.
É característica da invenção um equipamento para medição de dureza de materiais lignocelulósicos que possibilita o acoplamento direto entre massa de impacto e ponteira endentadora, eliminando o impacto metal-metal que ocorre no instante inicial da endentação nos equipamentos do estado da técnica, o que causa excesso de ruídos que influencia no resultado final de leitura da endentação. It is a feature of the invention to provide a hardness measuring device for lignocellulosic materials that enables direct coupling between impact mass and indentation tip, eliminating the metal-to-metal impact that occurs at the initial moment of indentation in state of the art equipment, which causes excess of noise that influences the final reading result of the indentation.
É característica da invenção um equipamento para medição de dureza de materiais lignocelulósicos que é capaz de calcular, por meio da integração do sinal de deslocamento, a força em cada instante do evento de endentação, permitindo a medição de propriedades de resistência e rigidez do material. It is a feature of the invention a device for measuring the hardness of lignocellulosic materials which is able to calculate, by means of the displacement signal, the force at each moment of the indentation event, allowing the measurement of material strength and stiffness properties.
É característica da invenção um equipamento que utiliza carga de endentação fixa mobilizada por queda livre de massa. It is a feature of the invention that equipment utilizes fixed mass indentation load mobilized by free fall.
BREVE DESCRIÇÃO DAS FIGURAS BRIEF DESCRIPTION OF THE FIGURES
A figura 1 apresenta a vista explodida do equipamento para medição de dureza de materiais lignocelulósicos. Figure 1 presents the exploded view of the hardness measuring equipment of lignocellulosic materials.
A figura 2 apresenta a vista em perspectiva do equipamento montado. Figure 2 shows the perspective view of the assembled equipment.
A figura 3 apresenta o equipamento posicionado ortogonal ao material lignocelulósico a ser avaliado, com a massa de impacto posicionada no limite máximo de posição. Figure 3 shows the orthogonal equipment positioned at the lignocellulosic material to be evaluated, with the impact mass positioned at the maximum position limit.
A figura 4 apresenta o fluxograma do algoritmo computacional embarcado no processador. Figure 4 shows the flowchart of the computational algorithm embedded in the processor.
A figura 5 apresenta gráfico de dispersão dos ensaios realizados para comparação das medições do equipamento objeto da presente invenção com a dureza Janka medida em máquina universal de ensaios. Figure 5 presents a scatter plot of the tests performed to compare the measurements of the equipment object of the present invention with the Janka hardness measured in a universal testing machine.
A figura 6 apresenta gráfico da associação de valores entre dureza avaliada pelo equipamento (durômetro portátil) e pelo método clássico convencional (dureza Janka) Figure 6 presents a graph of the association of values between hardness evaluated by the equipment (portable durometer) and the conventional classical method (Janka hardness).
DESCRIÇÃO DETALHADA DA INVENÇÃO DETAILED DESCRIPTION OF THE INVENTION
O equipamento para medição de dureza de materiais lignocelulósicos, objeto da presente invenção, compreende uma estrutura portátil eletromecânica, com funcionamento semelhante ao ensaio de dureza Brinell, ou seja, o equipamento apresenta uma ponteira em formato esférico com diâmetro conhecido que é comprimida por uma força conhecida sobre o material a ser avaliado. O valor de dureza é obtido pela relação entre a força aplicada e a área da calota esférica que será impressa no material avaliado (endentação). The hardness measuring equipment of lignocellulosic materials, object of the present invention, comprises a portable electromechanical structure, operating similar to the Brinell hardness test, ie the equipment has a spherical shaped tip with known diameter which is compressed by a force known about the material to be evaluated. The hardness value is obtained by the relation between the applied force and the area of the spherical cap that will be printed on the evaluated material (indentation).
O equipamento para medição de dureza de materiais lignocelulósicos compreende um suporte metálico em formato cilíndrico denominado suporte principal (10), contendo em seu interior uma massa de impacto (20) de material metálico e com peso adequado ao fim a que se destina, dita massa de impacto (20) que se desloca entre os extremos do suporte principal (10). The hardness measuring equipment of lignocellulosic materials comprises a cylindrical shaped metal support called the main support (10), containing within it an impact mass (20) of metal material and of a weight suitable for its intended purpose, said mass. of impact (20) moving between the ends of the main support (10).
A massa de impacto (20) é acoplada a uma ponteira de formato esférico (30). The impact mass (20) is coupled to a spherically shaped tip (30).
No suporte principal (10) é instalado um encoder magnético incremental (11 ) que mede o deslocamento da massa de impacto móvel (20) em relação ao suporte principal (10). In the main support (10) an incremental magnetic encoder (11) is installed which measures the displacement of the moving impact mass. (20) in relation to the main support (10).
A base do suporte principal (10) possui um flange (12) disposto perpendicular que garante a estabilização mecânica do equipamento sobre o material a ser avaliado (100) bem como servindo de apoio do operador sobre o equipamento no momento da realização do ensaio. The base of the main support (10) has a perpendicularly arranged flange (12) which ensures the mechanical stabilization of the equipment on the material to be evaluated (100) as well as serving as the operator's support on the equipment at the time of the test.
A massa de impacto móvel (20) apresenta seção transversal de formato específico que diminui a área de contato com a superfície interna do suporte principal e, consequentemente, reduz o atrito durante a queda. Adicionalmente, na superfície da massa de impacto (20) é fixada uma fita magnética de pólos alternados (não representado) que possibilita a medição da posição da massa de impacto (20) pelo encoder magnético incremental (11 ). The movable impact mass (20) has a specifically shaped cross section which decreases the contact area with the inner surface of the main support and consequently reduces friction during fall. Additionally, on the surface of the impact mass (20) is attached an alternating pole magnetic strip (not shown) which enables the measurement of the position of the impact mass (20) by the incremental magnetic encoder (11).
A ponteira de formato esférico (30) acoplada na massa de impacto (20) é destacável, sendo possível sua eventual substituição para a realização de ensaios com endentadores de diâmetros distintos. The spherical shaped tip (30) coupled to the impact mass (20) is detachable, and its possible replacement for tests with indentors of different diameters is possible.
O suporte principal (10) apresenta um guia lateral (13) onde se projeta externamente um manipulo (21 ) de operação acoplado à massa de impacto (20) disposta na região interna do dito suporte (10), permitindo que o operador realize a elevação da massa de impacto (20) para mobilização da energia de endentação. The main support (10) has a side guide (13) projecting externally an operating handle (21) coupled to the impact mass (20) disposed in the inner region of said support (10), allowing the operator to lift of impact mass (20) for mobilization of indentation energy.
Preferentemente, a superfície do manipulo de operação (21 ) apresenta uma área apropriada para garantir maior aderência no momento da operação. Preferably, the surface of the operating handle 21 has an appropriate area to ensure greater adhesion at the time of operation.
O encoder magnético (11 ) é conectado a um circuito eletrônico (40) que agrega um controlador digital de sinais (DSC), um painel (41 ) e um teclado (42). O circuito eletrônico (40) recebe e interpreta os sinais transmitidos pelo encoder (11), calcula e exibe a dureza do material avaliado (100). Através de uma porta de comunicação serial, os dados armazenados no circuito eletrônico (40) são enviados para outros dispositivos eletrônicos. The magnetic encoder (11) is connected to an electronic circuit (40) that incorporates a digital signal controller (DSC), a panel (41) and a keyboard (42). The electronic circuit (40) receives and interprets the signals transmitted by the encoder (11), calculates and displays the hardness of the evaluated material (100). Through a serial communication port, data stored in the electronic circuit (40) is sent to other electronic devices.
O método para medição de dureza de materiais lignocelulósicos utilizando o equipamento objeto da presente invenção compreende em uma primeira etapa posicionar o suporte principal (10) perpendicularmente sobre o material em avaliação (100) e em seguida zerar a medição de posição do encoder (11) por meio do teclado (42) do circuito eletrônico (40). Em seguida, o usuário desloca a massa de impacto (20) por meio do acionamento do manipulo (21 ) até a altura definida no suporte principal (10). Esta altura de elevação é garantida pela limitação mecânica presente no guia lateral (13) do suporte principal (10). The method for hardness measurement of lignocellulosic materials using the equipment object of the present invention comprises in a first step positioning the main support (10) perpendicularly over the material under evaluation (100) and then zeroing the encoder position measurement (11). via the keyboard (42) of the electronic circuit (40). The user then moves the impact mass (20) by actuating the handle (21) to the height defined on the main support (10). This lifting height is guaranteed by the mechanical limitation present on the side guide (13) of the main support (10).
Uma vez posicionada a massa de impacto (20), o usuário solta o manipulo (21 ), permitindo o deslocamento descendente da dita massa de impacto (20) sobre o material em avaliação (100) para a endentação. Once the impact mass (20) is positioned, the user releases the handle (21), allowing the downward movement of said impact mass (20) over the material under evaluation (100) for indentation.
O encoder magnético (11) mede a posição da massa de impacto The magnetic encoder (11) measures the position of the impact mass.
(20) através da verificação da fita magnética (não representada) e envia os dados ao circuito eletrônico (40) para cálculo da dureza do material avaliado (100). O sinal produzido pelo sensor de medição de deslocamento (11) se apresenta na forma de pulsos digitais em dois canais (A e B) defasados em 90 graus, conforme apresentado na figura 6. A combinação dos canais A e B possibilita ao circuito eletrônico detectar o sentido em que está ocorrendo o deslocamento da massa de impacto (20) - ascendente ou descendente. (20) by checking the magnetic tape (not shown) and sending the data to the electronic circuit (40) to calculate the hardness of the evaluated material (100). The signal produced by the displacement measurement sensor (11) is in the form of digital pulses in two channels (A and B) 90 degrees apart, as shown in figure 6. The combination of channels A and B enables the electronic circuit to detect the direction in which the displacement of the impact mass (20) is taking place - upward or downward.
No circuito eletrônico (40), a dureza (H) é calculada como uma relação entre a energia disponibilizada na queda livre da massa de impacto (20) (ao invés da carga utilizada na dureza Brinell) e a área da calota esférica endentada. In the electronic circuit (40), the hardness (H) is calculated as a ratio between the energy available in the free fall of the impact mass (20) (instead of the load used in the Brinell hardness) and the area of the indented spherical cap.
FÓRMULA 1 : cálculo da dureza (H) para madeiras H =——, h> 0 sendo: FORMULA 1: Hardness Calculation (H) for Woods H = ——, h> 0 where:
E - energia disponibilizada na queda livre da massa de impacto E - energy available in free fall of impact mass
(20); (20);
D - diâmetro do endentador metálico (ponteira (30)); D - diameter of the metallic indentator (nozzle (30));
h - profundidade da calota endentada no material lignocelulósico em avaliação (100). h - depth of the indented cap on the lignocellulosic material under evaluation (100).
O resultado da dureza calculada para o material avaliado (100) é exibido instantaneamente no painel (41 ) do equipamento. The calculated hardness result for the evaluated material (100) is instantly displayed on the equipment panel (41).
O sensor de medição (1 1 ) é alimentado com tensões entre 8 e 30 The measuring sensor (1 1) is supplied with voltages between 8 and 30
Vcc e tem resolução de até 0,005 milímetros. Vcc and has a resolution of up to 0.005mm.
O painel (41 ) do equipamento apresenta a posição real da massa de impacto (20), em uma unidade medida e/ou sob a forma de um gráfico do tipo barra horizontal com preenchimento proporcional à posição da massa de impacto (20) em relação ao suporte principal (10), dita posição da massa de impacto (20) obtida mediante interação do sensor de deslocamento (1 1 ) com a fita magnética (não representada). The panel (41) of the equipment shows the actual position of the impact mass (20) in a measured unit and / or in the form of a horizontal bar graph filled in proportion to the position of the impact mass (20) in relation to to the main support (10), said position of the impact mass (20) obtained by interaction of the displacement sensor (11) with the magnetic tape (not shown).
Conforme apresentado na figura 5, o coeficiente de determinação (R2) da regressão entre o resultado de dureza calculado pelo equipamento e a dureza Janka medida em máquina universal de ensaios foi de 0,86. As shown in Figure 5, the regression coefficient of determination (R 2 ) between the hardness result calculated by the equipment and the Janka hardness measured on a universal testing machine was 0.86.
O equipamento objeto da presente invenção calcula, por meio da integração do sinal de deslocamento obtido pelo sensor de deslocamento ( 1 ), a força em cada instante do evento de endentação, comprovando o potencial do equipamento para medição de propriedades de resistência e rigidez do material. The equipment object of the present invention calculates, by integrating the displacement signal obtained by the displacement sensor (1), the force at each moment of the indentation event, proving the potential of the equipment to measure material strength and stiffness properties. .
Claims
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| BRBR1020130241393 | 2013-09-20 | ||
| BR102013024139-3A BR102013024139B1 (en) | 2013-09-20 | 2013-09-20 | EQUIPMENT AND METHOD FOR MEASURING HARDNESS OF LIGNOCELLULOSIC MATERIALS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2015039200A1 true WO2015039200A1 (en) | 2015-03-26 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/BR2014/000329 Ceased WO2015039200A1 (en) | 2013-09-20 | 2014-09-12 | Apparatus and method for measuring the hardness of lignocellulosic materials |
Country Status (2)
| Country | Link |
|---|---|
| BR (1) | BR102013024139B1 (en) |
| WO (1) | WO2015039200A1 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2323428C1 (en) * | 2006-08-09 | 2008-04-27 | Государственное образовательное учреждение высшего профессионального образования "Брянская государственная инженерно-технологическая академия" | Method for determining the wood static hardness |
| US8590367B2 (en) * | 2011-08-31 | 2013-11-26 | King Tester Corporation | Portable Brinell hardness tester |
| US20140224003A1 (en) * | 2012-03-13 | 2014-08-14 | Shenyang Tianxing Testing Instruments Co., LTD | Portable digital display hardness tester |
-
2013
- 2013-09-20 BR BR102013024139-3A patent/BR102013024139B1/en active IP Right Grant
-
2014
- 2014-09-12 WO PCT/BR2014/000329 patent/WO2015039200A1/en not_active Ceased
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2323428C1 (en) * | 2006-08-09 | 2008-04-27 | Государственное образовательное учреждение высшего профессионального образования "Брянская государственная инженерно-технологическая академия" | Method for determining the wood static hardness |
| US8590367B2 (en) * | 2011-08-31 | 2013-11-26 | King Tester Corporation | Portable Brinell hardness tester |
| US20140224003A1 (en) * | 2012-03-13 | 2014-08-14 | Shenyang Tianxing Testing Instruments Co., LTD | Portable digital display hardness tester |
Also Published As
| Publication number | Publication date |
|---|---|
| BR102013024139A2 (en) | 2015-11-17 |
| BR102013024139B1 (en) | 2020-09-15 |
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