Determinação das propriedades geométricas, físicas e mecânicas do sistema fruto-pedúnculo-ramo do cafeeiro

Coelho, André Luiz de Freitas; Santos, Fábio Lúcio; Pinto, Francisco; Queiroz, Daniel Marçal de

doi:10.1590/1807-1929/agriambi.v19n3p286-292

Cited by 20 publications

(32 citation statements)

References 15 publications

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“…Damping ratios obtained confirm that the fruit-rachilla system is under-damped given that the average values were always below one (Table 3), as determined by COELHO et al (2015) for coffee plant branch stems.…”

Section: Villar Et Alsupporting

confidence: 63%

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Elasticity modulus and damping ratio of macaw palm rachillas

et al. 2017

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The macaw palm has been identified as a prime feed stock for biodiesel industries in the near future coming decades. However, there are no machines for harvesting and detaching fruits in the biofuel industry; hence, the study of the dynamic behavior of the fruit-rachilla system would aid in the development of such machines. Thus, this study seeks to determine the modulus of elasticity and the damping ratio of four different plant accessions obtained from the Active Germplasm Bank of the Universidade Federal de Viçosa (UFV). Tensile testing was conducted to determine the modulus of elasticity. From the graphical results of tension versus specific strain, it was possible to determine the modulus of elasticity by using the tangent method. To determine the damping ratio, the logarithmic decrement method was performed using vibration testing. Vibration test consisted of a generated impulse of 100% of the amplitude of acceleration that was used to excite the system. The acquisition of the generated information was performed by a piezoelectric accelerometer. The average modulus of elasticity ranged from 2.22 to 3.17MPa, and the average damping ratios ranged from 0.04 to 0.08. Thus, the macaw fruit-rachilla was an under-damped system.

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Section: Villar Et Alsupporting

confidence: 63%

“…For soya, RIBEIRO et al (2007) reported values for the modulus of elasticity, analyzing different axes, to be between 10.2 and 23.1MPa for moist grains. In a study on coffee stalks, using green fruit, COELHO et al (2015) reported a modulus of elasticity of 3.91MPa.…”

Section: Villar Et Almentioning

confidence: 99%

Elasticity modulus and damping ratio of macaw palm rachillas

et al. 2017

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“…Several factors influence vibration harvest, such as the shape, size, structure and maturity stage of fruits, as well as frequency and amplitude of vibration (Ferraz et al 2012, Coelho et al 2015, Santos et al 2015, Ferreira Junior et al 2016.…”

Section: Abstract Resumomentioning

confidence: 99%

“…These properties are specific for each species and product and can be influenced by the environment, during its formation and development (Costa et al 2014, Coelho et al 2015, Villar et al 2017.…”

Section: Abstract Resumomentioning

confidence: 99%

Mechanical properties of the macaw palm fruit-rachilla system1

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Santos

Pinto

et al. 2017

Pesqui. Agropecu. Trop.

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The fruit of the native macaw palm [Acrocomia aculeata (lacq) Lood. ex Mart] is an alternative for biodiesel production because of the plant characteristics, as well as its adaptability, hardiness and high vegetable oil yield. However, its exploitation remains extractive and there are significant difficulties in its harvest. This study aimed to determine the mechanical properties of the macaw palm fruit-rachilla system that will support the design of harvest machines based on mechanical vibration. Ten samples of four accessions in the immature and mature stages of maturity were used. Traction and vibration tests were conducted to determine the mechanical properties of the macaw palm fruit-rachilla system. The elastic modulus of the rachilla was 188.39-385.09 MPa for the immature stage and 109.02-320.54 MPa for the mature stage. The Poisson's ratio for the rachilla varied between 0.20 and 0.52 for the immature stage and between 0.16 and 0.52 for the mature stage. The damping ratio varied between 0.02 and 0.12 for the immature stage and between 0.06 and 0.12 for the mature stage. The fruit-rachilla system was characterized as underdamped.

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“…Models of the fruit-stem and branch geometries ( Figure 3) were generated using the Solid Works 2011 CAD software and were based on dimensions determined experimentally by Coelho, Santos, Pinto, and Queiroz (2015) ( Table 3, 4 and 5). Figure 3.…”

Section: Experimental Determination Of Natural Frequenciesmentioning

confidence: 99%

<b>Dynamic test for determining the elastic modulus of coffee fruit-stem-branch system

et al. 2017

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ABSTRACT. The finite element method, which has been used to determine natural frequencies and mode shapes, is used to generate and solve differential equations that describe the investigated physical phenomenon. However, this method requires the use of geometric and mechanical properties as input parameters, which may be difficult to obtain experimentally. The objective of this study was to develop a method for determining the elastic moduli of coffee stems and branches by comparing the experimentally obtained natural frequency with the frequency obtained using the finite element method. The natural frequency was experimentally obtained using a dynamic sweep test of frequencies, in which the fruit-stembranch system was excited over a range from 10 to 30 Hz. The natural frequency of the fruit-stem system was higher at the green stage than at the cherry stage, and the elastic modulus of the stem at the cherry stage was higher than for the green stage. The mean elastic modulus values were 15.74, 23.90 and 4645.90 MPa for the stem at the green and cherry stages and for the branch, respectively.Keywords: algorithm, finite element method, natural frequency.Ensaio dinâmico para determinação do módulo de elasticidade do sistema frutopedúnculo-ramo RESUMO. Entre as ferramentas para determinação das frequências naturais e modos de vibração tem-se a modelagem pelo método dos elementos finitos, que consiste na geração e solução de equações diferenciais que descrevem o fenômeno físico em estudo. No entanto, essa ferramenta exige como parâmetros de entrada as propriedades geométricas e mecânicas do sistema, difíceis de serem obtidas experimentalmente. Assim, objetivou-se desenvolver uma metodologia para a determinação do módulo de elasticidade do pedúnculo e do ramo do cafeeiro por meio da comparação da frequência natural experimental com a frequência obtida pelo método de elementos finitos. A frequência natural experimental foi obtida a partir de um ensaio de varredura de frequências, em que o sistema fruto-pedúnculo e o ramo foram excitados em uma faixa de 10 a 30 Hz. A partir dos resultados, verificou-se que a frequência natural do sistema frutopedúnculo no estádio de maturação verde foi superior ao cereja e que o módulo de elasticidade do pedúnculo no estádio de cereja foi superior ao valor para verde. Os valores médios para os módulos de elasticidade foram de 15,74; 23,90 e 4645,90 MPa para o pedúnculo nos estágios de maturação verde, cereja e para o ramo, respectivamente.Palavras-chave: algoritmo, método de elementos finitos, frequência natural.

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Determinação das propriedades geométricas, físicas e mecânicas do sistema fruto-pedúnculo-ramo do cafeeiro

Cited by 20 publications

References 15 publications

Elasticity modulus and damping ratio of macaw palm rachillas

Elasticity modulus and damping ratio of macaw palm rachillas

Mechanical properties of the macaw palm fruit-rachilla system1

<b>Dynamic test for determining the elastic modulus of coffee fruit-stem-branch system

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