scholarly journals Finite Element Analysis of Coffea arabica L. var. Colombia Fruits for Selective Detachment Using Forced Vibrations

Vibration ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 207-219 ◽  
Author(s):  
Hector Tinoco ◽  
Fabio Peña
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Coffea Arabica ◽  
Numerical Procedure ◽  
Final Conclusion ◽  
Frequency Range ◽  
Element Analysis ◽  
Forced Vibration Analysis ◽  
Dynamic Excitations ◽  
Coffea Arabica L

This study provides a forced vibration analysis to evaluate the stresses at the pedicel interfaces of the fruit-peduncle system of Coffea arabica L. var. Colombia by means of finite element analysis. The real topology of the fruit-peduncle system was developed from a proposed numerical procedure to complete a dynamic analysis. The Young’s modulus of the fruit was approximated from firmness indices for all stages of ripening. Numerical computations were performed in the frequency range of 0 to 400 Hz and three vibration modes were identified in this bandwidth. Results show that the second natural frequency (128 Hz) is acceptable for stimulating the detachment of ripe fruits because the fruit-pedicel-peduncle system induces bending in the fruit interface. As a final conclusion, we determine that dynamic excitations between 120 and 150 Hz could permit selective stimulus of ripe fruits, since other ripening stages were not stimulated in this frequency range.

Harmonic stress analysis on Coffea arábica L. var. Colombia fruits in order to stimulate the selective detachment: A finite element analysis

SIMULATION ◽  
2017 ◽  
Vol 94 (2) ◽  
pp. 163-174 ◽  
Author(s):  
Hector A Tinoco ◽  
Fabio M Peña
Keyword(s):  
Finite Element ◽  
Stress Analysis ◽  
Coffea Arabica ◽  
Poisson Ratio ◽  
Numerical Procedure ◽  
Analytical Models ◽  
Element Analysis ◽  
Ripening Stages ◽  
Force Signal ◽  
Coffea Arabica L

This study shows a finite element harmonic stress analysis to evaluate the stress performance at the pedicel interface of a fruit–peduncle system of Coffea arábica L. var. Colombia plants. The aim was to study detachment of fruits subjected to mechanical vibrations. A model of the coffee fruit–peduncle system is designed computationally to reproduce its topology in all ripening stages using a proposed numerical procedure. Young’s modulus, Poisson ratio, and density were adjusted using analytical models for all ripening stages. The glomerulus of three fruits in different ripening stages was proposed and these were combined in four groups. Based on a detachment model, it was verified which fruit was detached first when a chirp force signal was applied on each glomerulus. Results indicated that dynamic excitations applied in between 130 to 150 Hz detached only ripe fruits, since fruits that were in other ripening stages were not stimulated until detachment in that bandwidth.

Bond Thickness Effects upon Dynamic Behaviour in Adhesive Joints

2010 ◽  
Vol 97-101 ◽  
pp. 3920-3923 ◽  
Author(s):  
Xiao Cong He
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dynamic Behaviour ◽  
Adhesive Layer ◽  
Adhesive Joints ◽  
Response Functions ◽  
Frequency Range ◽  
Element Analysis ◽  
Cantilevered Beam ◽  
Different Thickness

The influence of adhesive layer thickness on the dynamic behaviour of the single-lap adhesive joints is investigated in this paper. The ABAQUS finite element analysis (FEA) software was used to predict the frequency response functions (FRFs) of the single-lap adhesive joints of different thickness of the adhesive layer. As a reference, the FRFs of a cantilevered beam without joint were investigated as well. It is clear that the FRFs of the four beams are close to each other within the frequency range 0~1000 Hz. It is also found that the composite damping of the single-lap adhesive joint increases as the thickness of the adhesive layer increases.

Fabrication and finite element analysis of vibrating parallel film actuator made with cellulose acetate for potential haptic application

2016 ◽  
Vol 230 (15) ◽  
pp. 2720-2727 ◽  
Author(s):  
Md Mohiuddin ◽  
Asma Akther ◽  
Eun Byul Jo ◽  
Hyun Chan Kim ◽  
Jaehwan Kim
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cellulose Acetate ◽  
Vibration Characteristics ◽  
Experimental Results ◽  
Vibration Velocity ◽  
Frequency Range ◽  
Actuation Frequency ◽  
Element Analysis ◽  
Wide Range

The present study investigates a film actuator made with dielectric cellulose acetate films separated by narrow spacers as a means of electrostatic actuation for potential haptic application. Fabrication process for the actuator is explained along with experiments conducted over a wide frequency range of actuation frequency. A valid finite element simulation of the actuator is made on the quarter section of the actuator by using full 3D finite elements. Vibration characteristics such as fundamental natural frequency, mode shape and output velocity in the frequency range for haptic feeling generation are obtained from the finite element analysis and compared with the experimental results. Experimental results demonstrate that the finite element model is practical and effective enough in predicting the vibration characteristics of the actuator for haptic application. The film actuator shows many promising properties like high transparency, wide range of actuation frequency and high vibration velocity for instance.

scholarly journals Mid Frequency Shock Response Determination by Using Energy Flow Method and Time Domain Correction

2013 ◽  
Vol 20 (5) ◽  
pp. 847-861 ◽  
Author(s):  
Sung-Hyun Woo ◽  
Jae-Hung Han
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Time Domain ◽  
Energy Flow ◽  
Practical Method ◽  
Frequency Range ◽  
Element Analysis ◽  
Flow Method ◽  
Force Signal ◽  
Structural Parts

Shock induced vibration can be more crucial in the mid frequency range where the dynamic couplings with structural parts and components play important roles. To estimate the behavior of structures in this frequency range where conventional analytical schemes, such as statistical energy analysis (SEA) and finite element analysis (FEA) methods may become inaccurate, many alternative methodologies have been tried up to date. This study presents an effective and practical method to accurately predict transient responses in the mid frequency range without having to resort to the large computational efforts. Specifically, the present study employs the more realistic frequency response functions (FRFs) from the energy flow method (EFM) which is a hybrid method combining the pseudo SEA equation (or SEA-Like equation) and modal information obtained by the finite element analysis (FEA). Furthermore, to obtain the time responses synthesized with modal characteristics, a time domain correction is practiced with the input force signal and the reference FRF on a position of the response subsystem. A numerical simulation is performed for a simple five plate model to show its suitability and effectiveness over the standard analytical schemes.

A Numerical Procedure for Obtaining the Static and Pull-In Deflection and Voltage of Capacitive Microcantilever Beams

2006 ◽  
Author(s):  
Seyed Babak Ghaemi Oskouei ◽  
Aria Alasty
Keyword(s):  
Differential Equation ◽  
Ordinary Differential Equation ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Procedure ◽  
Nonlinear Ordinary Differential Equation ◽  
Static Deflection ◽  
Element Analysis ◽  
Fringing Field ◽  
Good Agreement

A numerical procedure is proposed for obtaining the static deflection, pull-in (PI) deflection and PI voltage of electrostatically excited capacitive microcantilever beams. The method is not time and memory consuming as Finite Element Analysis (FEA). Nonlinear ordinary differential equation of the static deflection of the beam is derived, w/wo considering the fringing field effects. The nondimensional parameters upon which PI voltage is dependent are then found. Thereafter, using the parameters and the numerical method, three closed form equations for pull-in voltage are developed. The results are in good agreement with others in literature.

A Hybrid Finite Element Method for Calculating the Vibration of Co-Linear Beams in the Mid-Frequency Range

1999 ◽  
Author(s):  
Xi Zhao ◽  
Nickolas Vlahopoulos
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Theoretical Development ◽  
Frequency Range ◽  
Element Analysis ◽  
Hybrid Finite Element Method ◽  
Hybrid Finite Element ◽  
New Formulation ◽  
Element Method

Abstract The theoretical development of a hybrid finite element method is presented. It combines conventional Finite Element Analysis (FEA) with Energy Finite Element Analysis (EFEA) in order to achieve a numerical solution to mid-frequency vibrations. In the mid-frequency range a system is comprised by some members that contain several wavelengths and some members that contain a small number of wavelengths. The former are considered long members and they are modeled by the EFEA. The latter are considered short and they are modeled by the FEA. The new formulation is based on deriving appropriate interface conditions at the joints between sections modeled by the EFEA and the FEA methods. Since the work presented in this paper constitutes a fundamental step in the development of a hybrid method for mid-frequency analysis, the formulation for one flexural degree of freedom in co-linear beams is presented. The excitation is considered to be applied on a long member and the response of the entire system is computed. Uncertainty effects are imposed only on the long members of the system. Validation cases for several configurations are presented.

Optimization Study of Pipeline Rock Armour Protection Design Based on Finite Element Analysis

2010 ◽  
Author(s):  
LeQin Wang ◽  
HongKiat Chia
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Physical Model ◽  
Numerical Procedure ◽  
Extensive Study ◽  
Design Guidelines ◽  
Physical Model Test ◽  
Element Analysis ◽  
Protection Mechanism ◽  
Set Up

The design of pipeline protection with rock armour berms has been traditionally based on model testing because there has been no closed-form analytical solution available to resolve the complex interaction between the anchor, anchor chain, seabed soil and rock armour. Compared to the costly physical model test, a numerical procedure properly set up allows effective and extensive study on various rock berm configurations. It is expected that better optimized pipeline rock armour protection berm can be designed to offer appreciable savings on project cost. The authors have developed a Finite Element Analysis (FEA) based procedure which can predict the clearance between the anchor fluke tip and pipeline as well as the pushing force on the pipeline during anchor dragging. Both the clearance and pushing force can be used to assess the potential anchor damage to a pipeline with rock backfill protection. The FEA results have been successfully validated against results obtained from physical model tests. A series of numerical tests are performed considering the variations in the trench profile, the armour rock shape, rock particle size and grading properties etc. The protection mechanism of the rock armour berm, with regard to the above factors, is discussed to provide a better understanding for the significance of each parameter in the protection design. Guidelines in achieving an optimized rock berm protection design are also given.

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