Modal properties of macaw palm fruit-rachilla system: An approach by the stochastic finite element method (SFEM)

Santos, Fábio Lúcio; Scinocca, Francisco; Marques, Deisenara de Siqueira; Velloso, Nara Silveira; Villar, Flora Maria de Melo

doi:10.1016/j.compag.2021.106099

Cited by 9 publications

(4 citation statements)

References 29 publications

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“…In this way, the obtained results in the present research could serve as reference to use different approach to quantify uncertainties from the inherent variability of the Coffee plant. Uncertainty analysis using stochastic modeling with low computational cost could use the range parameters obtained here [29,33,34].…”

Section: Resultsmentioning

confidence: 99%

Dynamic Behavior of Coffee Branches: an Analysis Using the Finite Element Method

Melo Junior,

Santos,

Scinocca

et al. 2024

Braz. arch. biol. technol.

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The use of computational simulation techniques is an important tool for the coffee harvesting issues, particularly the finite element method. The method is widely used in the structural analysis of agricultural machinery, as well as in the analysis of the stresses and vibrations of coffee branches and peduncles during the harvesting process. The present study aimed to develop three-dimensional finite element models of the plagiotropic branches of the Catuaí Vermelho variety of Arabica coffee in different positions along the orthotropic branches of the plant; considering high-fidelity models. Additionally, by considering the branches' experimental properties (physical-mechanical), the natural frequencies and vibration modes of the branches were determined by means of computer simulations. First, the geometric properties of the coffee branches were obtained by means of two images taken using a professional camera to obtain the input data of the virtual simulation. For the mechanical properties, it was used a semi-analytical digital scale, to obtain the mass of the specimens. The modulus of elasticity was determined using a universal testing machine. The variability in the simulated natural frequencies could be identified, which was on the order of 30% for the first frequency, regardless of the position of the branch in the plant. These values were lower for the other frequencies. Linear regression fits showed a coefficient of determination, and correlation tests were used to verify the relationship between the values obtained numerically and experimentally, which were validated by using experimental data using the modal analysis techniques.

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Section: Resultsmentioning

confidence: 99%

Dynamic Behavior of Coffee Branches: an Analysis Using the Finite Element Method

Melo Junior,

Santos,

Scinocca

et al. 2024

Braz. arch. biol. technol.

Self Cite

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“…In order to select the optimal natural frequencies for fruit trees, the frequency at which the acceleration exceeds 120 ms -2 in different branches of the tree is chosen as the first evaluation criterion [4,13,16,17,28]. Typically, the acceleration of fruit detachment falls within the range of 0 to 120 ms -2 .…”

Section: Discussionmentioning

confidence: 99%

“…When a fruit tree is subjected to a vibration stimulus, both the branches and fruits will vibrate. The fruit undergoes pendulum motion relative to the branches, and when the fruit experiences an inertial force due to the magnitude of acceleration and its own mass, the fruit stem will break when the inertial force exceeds the adhesion force of the stem, resulting in fruit detachment and successful harvest [13,[15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Finite Element Simulation of Branch Vibration Model Based on Discrete Elements

Jiao,

Luo,

Tang

et al. 2023

Preprint

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To investigate the variation patterns of spectral characteristics of main branches in fruit trees due to uneven distribution of growth, pruning, and fruit quality, as well as to determine the optimal fruit vi-bration harvesting, a vibration differential model of tree branches was constructed using the concen-trated mass method. A three-dimensional model of the fruit tree was built using finite element software. The spectral characteristics of each branch were obtained using the linear sweep frequency method. The method of changing the mass of each branch was employed to simulate the variation in branch mass. The frequency of occurrence, mean acceleration, and coefficient of variation of the inherent frequencies were used as evaluation indicators. The results revealed that when the vibration frequency of the fruit tree was at the peak frequency in the tree trunk spectrum, the frequency of occurrence and mean accel-eration were optimal. And the coefficient of variation of branch acceleration was less than 1, indicating a moderate dispersion. Additionally, reducing the branch mass resulted in an increase in the peak fre-quency of the tree trunk spectrum. Therefore, the growth, pruning, and uneven distribution of the branches in fruit trees can alter the spectral characteristics. When harvesting fruit by vibration, selecting the peak frequency in the trunk vibration spectrum as the excitation force frequency yields the best fruit detachment.

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“…However, for the basic subsystems of the same tree species, the topology of the stem-fruit system varies less. This suggests that they may share similar modal parameters [15,16], indicating that certain vibrational frequencies might induce a significant resonant response in the fruit with only minimal vibration of the tree body, thus facilitating fruit drop. Such an approach could optimize harvesting efficiency while minimizing damage to fruit trees.…”

Section: Introductionmentioning

confidence: 99%

Modal Variability of Ginkgo Seed–Stem System Based on Model Updating

Zhou,

Xu,

Zhou

et al. 2024

Forests

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An accurate simulation model is crucial for the analysis of the correct modal information of the ginkgo seed–stem system (ginkgo subsystem). This underpins the provision of technical rationale for efficient and low-damage precision vibrational harvesting operations in ginkgo cultivation. In this study, based on the modal parameters of the ginkgo subsystem, a finite element model updating method is proposed to correct the elastic modulus of the stem with the natural frequency of the first bending mode. The large difference in the modal results calculated before and after model updating reveals that model updating is a critical step in the finite element analysis of crop subsystems. Then, an uncertainty parameter modeling method is proposed to investigate the modal variability of the ginkgo subsystem by finite element analysis. The results show that the stem length is a key parameter affecting the variability of natural frequencies, and the seed weight is a minor parameter. The variability of the ginkgo seed’s gravity center offset has a negligible effect on the natural frequencies of the system. The first natural frequency of the ginkgo subsystem can be utilized for vibrational harvesting. In addition, since the difference between the upper and lower limits of the first natural frequency of the ginkgo subsystem does not exceed 1 Hz, a specific excitation frequency can cause most ginkgo subsystems to resonate. This result facilitates the determination of precise excitation frequencies for efficient and low-damage ginkgo vibrational harvesting, ensuring both economic and ecological benefits in the management of ginkgo plantations.

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Modal properties of macaw palm fruit-rachilla system: An approach by the stochastic finite element method (SFEM)

Cited by 9 publications

References 29 publications

Dynamic Behavior of Coffee Branches: an Analysis Using the Finite Element Method

Dynamic Behavior of Coffee Branches: an Analysis Using the Finite Element Method

Finite Element Simulation of Branch Vibration Model Based on Discrete Elements

Modal Variability of Ginkgo Seed–Stem System Based on Model Updating

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