Modeling and simulation of the dynamic behavior of the macaw palm fruit-rachilla system

SIMULATION ◽  
2021 ◽  
pp. 003754972110437
Author(s):  
Mariana Ribeiro Pereira ◽  
Fábio Lúcio Santos ◽  
Nara Silveira Velloso ◽  
Flora Maria de Melo Villar ◽  
Mateus Resende Rodrigues
Keyword(s):  
Dynamic Behavior ◽  
Elasticity Modulus ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Palm Tree ◽  
Specific Mass ◽  
Palm Fruit ◽  
Modes Of Vibration ◽  
Macaw Palm ◽  
Three Dimensional Models

The macaw palm ( Acrocomia aculeata) is a palm tree native to tropical forests that stand out due to its great potential for oil production. This study was developed with the objective of constructing a high-fidelity model of the macaw palm fruit-rachilla system for the purpose of simulating its dynamic behavior when subjected to mechanical vibrations. The finite element method was used to determine the natural frequencies and modes of vibration of the system. The three-dimensional models of the fruit-rachilla systems were elaborated using CAD3D Fusion 360 software. The modal properties of the fruit-rachilla systems were obtained based on the models developed by varying the elasticity modulus values of the system. The parameters of greatest influence in the estimation of natural frequencies are the elasticity modulus, especially that of the fruit-rachilla joint, and the specific mass. The models that take into account the three-dimensional strains along the rachilla are the least sensitive to variations in the mechanical properties (elasticity modulus and specific mass) and are shown to be more representative of the actual physical system.

scholarly journals Modal properties of fruit-rachilla system of the macaw palm

2020 ◽  
Author(s):  
Flora Maria de Melo Villar ◽  
Francisco de Assis de Carvalho Pinto ◽  
Fabio Lucio Santos ◽  
Daniel Marçal de Queiroz ◽  
Mariana Ribeiro Pereira ◽  
...  
Keyword(s):  
Elasticity Modulus ◽  
Natural Frequencies ◽  
Mechanical Vibration ◽  
Element Model ◽  
Palm Fruit ◽  
Modal Properties ◽  
Frequency Scanning ◽  
Macaw Palm ◽  
The Mean ◽  
Potential Use

AbstractThe macaw palm has been domesticated due to its potential use in the production of biodiesel. One of the current challenges in this area is to determine the proper information and develop the technologies required for using macaw palm, allowing it to contribute to the sustainable production of feedstock for biodiesel industry. The principle of mechanical vibration can be employed for the detachment of fruits from a tree bunch, and it is therefore necessary to study the dynamic behavior of the macaw palm fruit-rachilla system during the vibration. Hence, the modal properties of the system were determined. A study on the dynamic behaviors was carried out using a deterministic finite element model, and the natural frequencies were obtained through a frequency-scanning test to evaluate the model. The mean relative error (MRE) between the measured and simulated natural frequencies was also used to evaluate the model. The natural frequencies, determined experimentally, varied between 26.21 and 33.45 Hz on average, whereas the simulated frequencies varied from 24.81 to 39.27 Hz. The overall MRE was 9.08%. Once the model was validated, a sensibility test showed that the density of fruit and the elasticity modulus are the parameters that most influence the natural frequencies of the fruit-rachilla system.

scholarly journals A Novel Highly Accurate Finite-Element Family

2017 ◽  
Vol 2017 ◽  
pp. 1-20
Author(s):  
Giovanni Bernardini ◽  
Fabio Cetta ◽  
Luigi Morino
Keyword(s):  
Finite Element ◽  
Structural Dynamics ◽  
Hermite Interpolation ◽  
Natural Frequencies ◽  
Finite Thickness ◽  
Three Dimensional ◽  
Numerical Results ◽  
Small Thickness ◽  
Modes Of Vibration ◽  
Patch Technique

A novel Nth order finite element for interior acoustics and structural dynamics is presented, with N arbitrarily large. The element is based upon a three-dimensional extension of the Coons patch technique, which combines high-order Lagrange and Hermite interpolation schemes. Numerical applications are presented, which include the evaluation of the natural frequencies and modes of vibration of (1) air inside a cavity (interior acoustics) and (2) finite-thickness beams and plates (structural dynamics). The numerical results presented are assessed through a comparison with analytical and numerical results. They show that the proposed methodology is highly accurate. The main advantages however are (1) its flexibility in obtaining different level of accuracy (p-convergence) simply by increasing the number of nodes, as one would do for h-convergence, (2) the applicability to arbitrarily complex configurations, and (3) the ability to treat beam- and shell-like structures as three-dimensional small-thickness elements.

Modal analysis of the diaphragm of the semicircular canal

2001 ◽  
Vol 11 (1) ◽  
pp. 43-54
Author(s):  
E. Njeugna ◽  
C.M. Kopp ◽  
J.-L. Eichhorn
Keyword(s):  
Modal Analysis ◽  
Semicircular Canal ◽  
Static Pressure ◽  
Three Dimensional ◽  
Vibration Modes ◽  
Modes Of Vibration ◽  
Crista Ampullaris ◽  
Static Pressure Difference ◽  
Three Dimensional Models ◽  
Internal Viscosity

The aim of this paper is to determine the domain of validity of calculated quasi-static deformations of the cupula and of ciliar deflections on the crista ampullaris. Several three-dimensional models of the isolated ampullar diaphragm of the human semicircular canal and of that of the frog are studied theoretically by modal analysis. The four first modes of vibration are determined for each structure. Numerical simulations prove that for the first mode of vibration, the cupular deformation has the same shape as that obtained by applying a static pressure difference across the ampullar diaphragm. We studied also the effect of the mechanical properties (Young's modulus and Poisson's coefficient) of the components of the ampullar diaphragm on the vibration modes and their frequencies. The condition, which must be satisfied by the cupular internal viscosity, to have resonance near the natural frequency of the ampullar diaphragm is determined.

scholarly journals Modal properties of fruit-rachilla system of the macaw palm

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0237291
Author(s):  
Flora Maria de Melo Villar ◽  
Francisco de Assis de Carvalho Pinto ◽  
Fabio Lucio Santos ◽  
Daniel Marçal de Queiroz ◽  
Mariana Ribeiro Pereira ◽  
...  
Keyword(s):  
Elasticity Modulus ◽  
Natural Frequencies ◽  
Mechanical Vibration ◽  
Element Model ◽  
Raw Material ◽  
Modal Properties ◽  
Frequency Scanning ◽  
Macaw Palm ◽  
The Mean ◽  
Potential Use

The macaw palm has been domesticated due to its potential use in the production of biofuel, in addition to several co-products that can be generated from its oil and pulp. One of the current challenges in this area is the harvesting, as there are no specific machines for this operation. Therefore, it is necessary to determine the appropriate information regarding the physical properties of the plant, so that it is feasible to develop the technologies necessary for the commercial scale application of macaw palm, allowing it to contribute to the sustainable production of raw material for the biofuel industry and other co-products. The principle of mechanical vibration can be used to shed fruit from trees when ripe, and it can be a method used for harvesting. Thus, as proposed in this study, it was necessary to study the dynamic behavior of the fruit-rachilla system during vibration. Hence, the modal properties of the system were determined. A study on the dynamic behaviors was carried out using a deterministic finite element model, and the natural frequencies were obtained through a frequency-scanning test to evaluate the model. The mean relative error (MRE) between the measured and simulated natural frequencies was also used to evaluate the model. The natural frequencies, determined experimentally, varied from 26.21 to 33.45 Hz on average, whereas the simulated frequencies varied from 24.81 to 39.27 Hz. The overall MRE was 9.08%. Once the model was validated, a sensibility test was carried out, which showed that the density of fruit and the elasticity modulus are the parameters that most influence the natural frequencies of the fruit-rachilla system.

scholarly journals Experimental Verification and Comparative Analysis of Equivalent Methods on Metal’s Fixed Joint Interface

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2381 ◽  
Author(s):  
Renxiu Han ◽  
Guoxi Li ◽  
Jingzhong Gong ◽  
Meng Zhang ◽  
Kai Zhang
Keyword(s):  
Natural Frequencies ◽  
Three Dimensional ◽  
Equivalent Model ◽  
Joint Interface ◽  
Ansys Software ◽  
Theoretical Methods ◽  
Mechanics Model ◽  
Metal Joint ◽  
Three Dimensional Models ◽  
Equivalent Method

In order to effectively improve the dynamic characteristics of the fixed metal joint interface, it is important to establish a correct equivalent model of the metal joint interface. In this paper, three equivalent methods for simulating the metal joint interface are analyzed, including the virtual material method, spring damping method, finite element method, and verification by modal experiment. First, according to the contact mechanics model of the constructed metal joint interface, the physical properties of the three-dimensional models of the fixed joint interface are assigned in the ANSYS software. Then, three methods are used for the modal analysis and compared with a modal experiment. The results show that the modal shapes of the three theoretical methods are consistent with those of the experimental modes. The first five natural frequencies obtained by the virtual material method are closest to the experimental natural frequencies, and the errors are within 10%. The errors of the other two methods are between 9% and 39%. Therefore, the virtual material method is a better equivalent method of the metal joint interface.

Bending, Buckling and Vibration of Orthotropic Plate-Beam Structures

1968 ◽  
Vol 12 (04) ◽  
pp. 249-268 ◽  
Author(s):  
C. S. Smith
Keyword(s):  
Orthotropic Plate ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Elastic Buckling ◽  
Lateral Loads ◽  
Orthotropic Plates ◽  
Approximate Methods ◽  
Buckling Loads ◽  
Natural Frequencies And Modes ◽  
Modes Of Vibration

A method is described of estimating elastic deflections and stresses in systems of interconnected rectangular orthotropic plates and single-direction beams, under distributed or concentrated lateral loads combined with compressive or tensile stresses applied either normal to or in the direction of the beams. The effects of initial deformation of beams and plates are included. Elastic buckling loads and modes and natural frequencies and modes of vibration may be computed. The methods described have been incorporated in a family of FORTRAN IV computer programs which are used to obtain a number of illustrative solutions, including:(/) deflections and stresses in an orthogonally stiffened, three-dimensional ship compartment; these are compared with results computed by an alternative finite element method; (//) buckling loads and modes and natural frequencies and modes of vibration for a typical deck structure; these are compared with results calculated by more approximate methods commonly used in design.

Plastic replicas as three-dimensional models of pulps

1975 ◽  
Vol 39 (8) ◽  
pp. 544-546
Author(s):  
HL Wakkerman ◽  
GS The ◽  
AJ Spanauf
Keyword(s):  
Three Dimensional ◽  
Dimensional Models ◽  
Three Dimensional Models

Validation of a Belt Model for Prediction of Hub Forces from a Rolling Tire4

2009 ◽  
Vol 37 (2) ◽  
pp. 62-102 ◽  
Author(s):  
C. Lecomte ◽  
W. R. Graham ◽  
D. J. O’Boy
Keyword(s):  
Internal Pressure ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Prediction Method ◽  
Analytical Models ◽  
Beam Model ◽  
Impedance Boundary ◽  
Bending Waves ◽  
Tire Rotation ◽  
Three Dimensional Models

Abstract An integrated model is under development which will be able to predict the interior noise due to the vibrations of a rolling tire structurally transmitted to the hub of a vehicle. Here, the tire belt model used as part of this prediction method is first briefly presented and discussed, and it is then compared to other models available in the literature. This component will be linked to the tread blocks through normal and tangential forces and to the sidewalls through impedance boundary conditions. The tire belt is modeled as an orthotropic cylindrical ring of negligible thickness with rotational effects, internal pressure, and prestresses included. The associated equations of motion are derived by a variational approach and are investigated for both unforced and forced motions. The model supports extensional and bending waves, which are believed to be the important features to correctly predict the hub forces in the midfrequency (50–500 Hz) range of interest. The predicted waves and forced responses of a benchmark structure are compared to the predictions of several alternative analytical models: two three dimensional models that can support multiple isotropic layers, one of these models include curvature and the other one is flat; a one-dimensional beam model which does not consider axial variations; and several shell models. Finally, the effects of internal pressure, prestress, curvature, and tire rotation on free waves are discussed.

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