scholarly journals Theoretical and Computational Analysis on the Melt Flow Behavior of Polylactic Acid in Material Extrusion Additive Manufacturing under Vibration Field

2020 ◽  
Vol 10 (11) ◽  
pp. 3801
Author(s):  
Shijie Jiang ◽  
Pifeng Chen ◽  
Yang Zhan ◽  
Chunyu Zhao
Keyword(s):  
Flow Behavior ◽  
Melt Flow ◽  
Element Analysis ◽  
Forming Quality ◽  
Material Extrusion ◽  
Proposed Model ◽  
Nonlinear Constitutive Equation ◽  
The Time Domain ◽  
Power Law Equation

Material extrusion (ME), an extrusion-based rapid prototyping technique, has been extensively studied to manufacture final functional products, whose forming quality is significantly influenced by the melt flow behavior (MFB) inside the extrusion liquefier. Applied vibration has a great potential to improve the MFB, and thereby promote the forming quality of the built product. To reveal the mechanism, a dynamic model of the melt flow behavior (DMMFB) is established based on fluid dynamics, Tanner nonlinear constitutive equation and Newton’s power law equation. The MFB, i.e., pressure drop, shear stress and apparent viscosity, is investigated without and with different vibration applied. The corresponding finite element analysis (FEA) is then carried out. From the comparison between DMMFB and FEA results, it is concluded that the proposed model is reliable. When vibration is applied onto the extrusion liquefier, the time-domain MFB will change periodically. Its effective value decreases significantly, and further decreases with the increase of vibration frequency or amplitude. This paper provides the theoretical basis to improve the MFB by applied vibration, and thereby to enhance the forming quality of ME products.

Melt Flow Behavior of Polymer Matrix Extrusion for Fused Deposition Modeling (FDM)

2014 ◽  
Vol 660 ◽  
pp. 89-93 ◽  
Author(s):  
Nasuha Sa'ude ◽  
Mustaffa Ibrahim ◽  
Mohd Halim Irwan Ibrahim
Keyword(s):  
Fused Deposition Modeling ◽  
Flow Behavior ◽  
Acrylonitrile Butadiene Styrene ◽  
Extrusion Process ◽  
Melt Flow ◽  
Element Analysis ◽  
Fused Deposition ◽  
Ansys Cfx ◽  
Deposition Modeling ◽  
Higher Temperature

This paper presents the melt flow behavior (MFB) of an acrylonitrile butadiene styrene (ABS), High Density Polyethlene (HDPE), Polyproplene (PP) and a combination of ABS-Iron in the extrusion process. In this study, the effect MFB of variety's polymers and ABS mix with 10% Iron material was investigated based on the viscosity, density, thermal conductivity, melting temperature and specific heat material properties. The MFB of FDM system was investigated using Finite-Element Analysis (FEA) by ANSYS CFX 12. Based on the result obtained, it was found that, the material velocity increase when the nozzle diameter is smaller than the entrance diameter. The higher temperature distribution along the MFB of ABS mix with 10% Iron is 43.15 K compared with original ABS, which is 539.15K.

A Study into Spin-Forming Process of Internal Spline

2011 ◽  
Vol 305 ◽  
pp. 92-95
Author(s):  
Ling Yan Sun ◽  
Qin Xiang Xia ◽  
Xiu Quan Cheng ◽  
Bang Yan Ye
Keyword(s):  
Finite Element Analysis ◽  
Critical Issue ◽  
Product Formation ◽  
Forming Process ◽  
Element Analysis ◽  
Forming Quality ◽  
Forming Defect ◽  
Rotationally Symmetric ◽  
A New Technique

Spin-forming is a new technique for manufacturing the rotationally symmetric component with internal teeth, such as internal spline and gear. In order to optimize the spin-forming process and improve the forming quality of internal spline, the critical issue, the effect of spin-forming process on product formation was investigated by processing experiments and finite element analysis. The result indicates that it is the flow pattern of metal and friction force in the spin-forming that causes forming defect of product; two pass spin-forming helps to improve the homogeneity of deformation for metal with good plasticity; for internal spline forming, a stepped process is a better spin-forming process compared to a non-stepped one.

Melt Flow Behavior of Metal Filled in Polymer Matrix for Fused Deposition Modeling (FDM) Filament

2014 ◽  
Vol 660 ◽  
pp. 84-88 ◽  
Author(s):  
Nasuha Sa'ude ◽  
Mustaffa Ibrahim ◽  
Mohd Halim Irwan Ibrahim
Keyword(s):  
Polymer Matrix ◽  
Fused Deposition Modeling ◽  
Plastic Material ◽  
Flow Behavior ◽  
Acrylonitrile Butadiene Styrene ◽  
Melt Flow ◽  
Element Analysis ◽  
Fused Deposition ◽  
Ansys Cfx ◽  
Exit Nozzle

This paper presents the melt flow behavior (MFB) of an acrylonitrile butadiene styrene (ABS), Polyproplene (PP), Polylactic Acid (PLA), ABS mix 10% Copper and ABS mix 10% Iron in the simulation. In this study, the effect MFB of ABS mix with 10% Iron and 10% Copper material was investigated based on the viscosity, density, thermal conductivity, melting temperature and specific heat of material properties. The MFB of metal filled in polymer matrix composite (PMC) through the FDM nozzle was investigated using Finite-Element Analysis (ANSYS CFX 12). Based on the result obtained, pressure outlet of mix ABS copper and ABS iron in extruder nozzle was higher value compared with others plastic material. The velocity was increased since the nozzle diameter is smaller than the entrance diameter. It can be observed that, the melt flow behavior of metal filled in PMC are affected on pressure drop, velocity and the nozzle size at the exit nozzle.

Towards Predicting Relative Belt Edge Endurance With the Finite Element Method

1990 ◽  
Vol 18 (4) ◽  
pp. 216-235 ◽  
Author(s):  
J. De Eskinazi ◽  
K. Ishihara ◽  
H. Volk ◽  
T. C. Warholic
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Shear Deformations ◽  
Element Analysis ◽  
Vertical Loading ◽  
Predicted Values ◽  
Element Method

Abstract The paper describes the intention of the authors to determine whether it is possible to predict relative belt edge endurance for radial passenger car tires using the finite element method. Three groups of tires with different belt edge configurations were tested on a fleet test in an attempt to validate predictions from the finite element results. A two-dimensional, axisymmetric finite element analysis was first used to determine if the results from such an analysis, with emphasis on the shear deformations between the belts, could be used to predict a relative ranking for belt edge endurance. It is shown that such an analysis can lead to erroneous conclusions. A three-dimensional analysis in which tires are modeled under free rotation and static vertical loading was performed next. This approach resulted in an improvement in the quality of the correlations. The differences in the predicted values of various stress analysis parameters for the three belt edge configurations are studied and their implication on predicting belt edge endurance is discussed.

JOINT INTERPRETATION OF AIRBORNE ELECTROMAGNETIC DATA IN THE TIME DOMAIN AND FREQUENCY DOMAIN

2018 ◽  
Vol 12 (7-8) ◽  
pp. 76-83
Author(s):  
E. V. KARSHAKOV ◽  
J. MOILANEN
Keyword(s):  
Fourier Transform ◽  
Frequency Domain ◽  
Time Domain ◽  
Frequency Interval ◽  
Single Spectrum ◽  
Simultaneous Inversion ◽  
Homogeneous Half Space ◽  
Time Domain Data ◽  
The Time Domain

Тhe advantage of combine processing of frequency domain and time domain data provided by the EQUATOR system is discussed. The heliborne complex has a towed transmitter, and, raised above it on the same cable a towed receiver. The excitation signal contains both pulsed and harmonic components. In fact, there are two independent transmitters operate in the system: one of them is a normal pulsed domain transmitter, with a half-sinusoidal pulse and a small "cut" on the falling edge, and the other one is a classical frequency domain transmitter at several specially selected frequencies. The received signal is first processed to a direct Fourier transform with high Q-factor detection at all significant frequencies. After that, in the spectral region, operations of converting the spectra of two sounding signals to a single spectrum of an ideal transmitter are performed. Than we do an inverse Fourier transform and return to the time domain. The detection of spectral components is done at a frequency band of several Hz, the receiver has the ability to perfectly suppress all sorts of extra-band noise. The detection bandwidth is several dozen times less the frequency interval between the harmonics, it turns out thatto achieve the same measurement quality of ground response without using out-of-band suppression you need several dozen times higher moment of airborne transmitting system. The data obtained from the model of a homogeneous half-space, a two-layered model, and a model of a horizontally layered medium is considered. A time-domain data makes it easier to detect a conductor in a relative insulator at greater depths. The data in the frequency domain gives more detailed information about subsurface. These conclusions are illustrated by the example of processing the survey data of the Republic of Rwanda in 2017. The simultaneous inversion of data in frequency domain and time domain can significantly improve the quality of interpretation.

Model and Method for Contributor’s Quality Assessment in Community Image Tagging Systems

2018 ◽  
pp. 45-51
Author(s):  
A. V. Ponomarev
Keyword(s):  
Large Scale ◽  
Wide Spectrum ◽  
Preference Relation ◽  
Pairwise Comparison ◽  
Ground Truth ◽  
Comparison Method ◽  
Characteristic Matrix ◽  
Image Tagging ◽  
Proposed Model

Introduction: Large-scale human-computer systems involving people of various skills and motivation into the information processing process are currently used in a wide spectrum of applications. An acute problem in such systems is assessing the expected quality of each contributor; for example, in order to penalize incompetent or inaccurate ones and to promote diligent ones.Purpose: To develop a method of assessing the expected contributor’s quality in community tagging systems. This method should only use generally unreliable and incomplete information provided by contributors (with ground truth tags unknown).Results:A mathematical model is proposed for community image tagging (including the model of a contributor), along with a method of assessing the expected contributor’s quality. The method is based on comparing tag sets provided by different contributors for the same images, being a modification of pairwise comparison method with preference relation replaced by a special domination characteristic. Expected contributors’ quality is evaluated as a positive eigenvector of a pairwise domination characteristic matrix. Community tagging simulation has confirmed that the proposed method allows you to adequately estimate the expected quality of community tagging system contributors (provided that the contributors' behavior fits the proposed model).Practical relevance: The obtained results can be used in the development of systems based on coordinated efforts of community (primarily, community tagging systems). 

scholarly journals Nodule Detection with Convolutional Neural Network Using Apache Spark and GPU Frameworks

2021 ◽  
Vol 11 (6) ◽  
pp. 2838
Author(s):  
Nikitha Johnsirani Venkatesan ◽  
Dong Ryeol Shin ◽  
Choon Sung Nam
Keyword(s):  
Neural Network ◽  
Radiation Dose ◽  
Convolutional Neural Network ◽  
Model Performance ◽  
Performance Comparison ◽  
Apache Spark ◽  
Training Time ◽  
Learning Framework ◽  
Proposed Model

In the pharmaceutical field, early detection of lung nodules is indispensable for increasing patient survival. We can enhance the quality of the medical images by intensifying the radiation dose. High radiation dose provokes cancer, which forces experts to use limited radiation. Using abrupt radiation generates noise in CT scans. We propose an optimal Convolutional Neural Network model in which Gaussian noise is removed for better classification and increased training accuracy. Experimental demonstration on the LUNA16 dataset of size 160 GB shows that our proposed method exhibit superior results. Classification accuracy, specificity, sensitivity, Precision, Recall, F1 measurement, and area under the ROC curve (AUC) of the model performance are taken as evaluation metrics. We conducted a performance comparison of our proposed model on numerous platforms, like Apache Spark, GPU, and CPU, to depreciate the training time without compromising the accuracy percentage. Our results show that Apache Spark, integrated with a deep learning framework, is suitable for parallel training computation with high accuracy.

scholarly journals Key Determinants of Airline Loyalty Modeling in Thailand

2020 ◽  
Vol 12 (10) ◽  
pp. 4165 ◽  
Author(s):  
Dissakoon Chonsalasin ◽  
Sajjakaj Jomnonkwao ◽  
Vatanavongs Ratanavaraha
Keyword(s):  
Airline Industry ◽  
Structural Equation ◽  
Statistical Significance ◽  
Perceived Quality ◽  
Equation Modeling ◽  
Structural Factors ◽  
Proposed Model ◽  
Airline Passengers ◽  
Domestic Airline

The airline industry in Thailand has grown enormously over the past decade. Competition among airline companies to reach market share and profit has been intense, requiring strong strategic abilities. To increase the service quality of such companies, identifying factors related to the context of airlines is important for policymakers. Thus, this study aims to present empirical data on structural factors related to the loyalty of domestic airline passengers. Structural equation modeling was used to confirm the proposed model. The questionnaire was used to survey and collect data from 1600 airline passengers. The results indicate that satisfaction, trust, perceived quality, relationship, and image of airlines positively influenced loyalty with a statistical significance of α = 0.05. Moreover, the study found that expectation and perceived quality indirectly influenced loyalty. The findings provide a reference for airline operators to clearly understand the factors that motivate passenger loyalty, which can be used to develop the sustainability of marketing strategies and support competitiveness.

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