Numerical Simulation of Viscous Jet for Near-Field Electrospinning

2009 ◽  
Vol 60-61 ◽  
pp. 465-469 ◽  
Author(s):  
Yuan Yuan Zhong ◽  
Gao Feng Zheng ◽  
Dao Heng Sun
Keyword(s):  
Numerical Simulation ◽  
Field Strength ◽  
Process Parameters ◽  
Near Field ◽  
Solution Concentration ◽  
Electrospinning Process ◽  
Substrate Distance ◽  
Viscous Jet ◽  
Set Up ◽  
The Impact

Near-Field Electrospinning (NFES) is a newly developed method to fabricate continuous and ordered solid nanofibers, with smaller spinneret-to-collector-distance the behavior of viscous jet would play a more prominent effect on the deposition and morphology of nanofiber. In this paper, a 2-dimentional physical model based on electrohydrodynamics and rheology was set up to discuss the morphology of viscous jet for NFES. The profile of the jet along z direction can be predicted by this model, and the impact of process parameters on the jet radius is analyzed. Radius of jet decreases with spinneret-to-substrate-distance decreasing; jet radius decreases with applied voltage and electric field strength increasing; jet electrospun from PEO solution is thinner than that from PVA solution with the same solution concentration; solution concentration has insignificant influence on the radius of jet from solution of the same polymer (PVA or PEO). This numerical simulation would improve the control of electrospinning process in NFES.

scholarly journals Evaluation of Process Parameters for Fiber Alignment of Electrospun Tubular Nanofibrous Matrices: A DoE Approach

2020 ◽  
Author(s):  
Rossella Dorati ◽  
Enrica Chiesa ◽  
Silvia Pisani ◽  
Ida Genta ◽  
Tiziana Modena ◽  
...  
Keyword(s):  
Process Parameters ◽  
Flow Rate ◽  
Electrospun Fiber ◽  
Environmental Parameters ◽  
Electrospinning Process ◽  
Sem Images ◽  
Fiber Alignment ◽  
Rotating Speed ◽  
Set Up ◽  
The Impact

Electrospinning is known to be an effective and straightforward technique to fabricate polymer non woven matrices made of nano and microfibers. Micro patterned morphology of electrospun matrices results to be outmost advantageous in the biomedical field, since it is able to mimic extracellular matrix (ECM), and favors cell adhesion and proliferation. Controlling electrospun fibers alignment is crucial for the regenerative purposes of certain tissues, such as neuronal and vascular. In this study we investigated the impact of electrospinning process parameters on fiber alignment in tubular nanofibrous matrices made of Poly (L-lactide-co-ε-caprolactone) (PLA-PCL); a Design of Experiments (DoE) approach is here proposed in order to statistically set up the process parameters. The DoE was studied keeping constants the previously set material and environmental parameters; voltage, flow rate and mandrel rotating speed were the process parameters here investigated as variables. Orientation analysis was based on ImageJ and plugin Orientation J analysis of SEM images. The results show that voltage combined with flow rate has significant impact on electrospun fiber orientation, and the greatest orientation is achieved when all the three input parameters (voltage, flow rate and mandrel rotation speed) are at their maximum value.

Numerical Simulation of Process Parameters in Flexible Discrete Clamp Stretch Forming

2012 ◽  
Vol 161 ◽  
pp. 53-57 ◽  
Author(s):  
He Li Peng ◽  
Ming Zhe Li ◽  
Peng Xiao Feng
Keyword(s):  
Numerical Simulation ◽  
Friction Coefficient ◽  
Numerical Simulations ◽  
Process Parameters ◽  
Numerical Results ◽  
Fe Model ◽  
Stretch Forming ◽  
Set Up

Flexible DCSF technology was put forward, and its forming character was described. The flexible DCSF machine was developed and related stretching experiment were carried out. The experimental photos show the DCSF technology is feasible and the DCSF machine is practicable. The FE model of flexible DCSF was set up, and extensive numerical simulations for spherical parts, saddle parts and S-type parts were carried out by Abaqus. The numerical results show that the longer the transitional length is, the more homogeneous the stretching strain and the thickness become. The smaller the friction coefficient is, the more homogeneous the stretching strain and the thickness become. The larger the clamp number is, the better the fit degree becomes. This work may provide useful guidance on the flexible DCSF process.

Nanofibrous morphology of electrospun chitosan nanocomposites reinforced with WS2 nanotubes: A design-of-experiments study

2017 ◽  
Vol 48 (1) ◽  
pp. 119-145 ◽  
Author(s):  
Apostolos Baklavaridis ◽  
Ioannis Zuburtikudis ◽  
Costas Panayiotou
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Polymer Solution ◽  
Electric Field Strength ◽  
Response Surface ◽  
Solution Concentration ◽  
Electrospinning Process ◽  
Electron Microscopic ◽  
Inorganic Nanotubes ◽  
The Individual

Chitosan nanofibers reinforced with tungsten disulfide inorganic nanotubes (INT-WS2) were fabricated in this study. The aim was to investigate the effect of the material parameters and the electrospinning process parameters on the obtained nanofibrous morphology of the mats. The INT-WS2 content, the polymer solution concentration, the electric field strength, and the solution's flow rate were the investigated factors within the framework of response surface methodology. Scanning electron microscopic and image analysis were used for the dimensional characterization of the nanofibrous morphology and the estimation of three selected responses. Two responses were related to the quality of the nanofibrous morphology: the number surface density of the beads ( Nbead) and the average bead-to-fiber diameter ( Dbead/ Dfiber). The third response was indicative of the fiber thickness ( Dfiber). The developed models as well as the coupling and the individual effects of the four investigated factors are given. The results indicate that the electrospun nanofibrous morphology is mostly affected by the polymer solution concentration, the electric field strength and the INT-WS2 loading. Furthermore, the response-surface results reveal possible experimental pathways that may be followed in order to obtain specified nanofibrous chitosan/INT-WS2 morphologies.

Design of Experiment, Approximate Model and Optimization of a Muzzle Brake

2011 ◽  
Vol 295-297 ◽  
pp. 2563-2567
Author(s):  
Kun Jiang ◽  
Hao Wang
Keyword(s):  
Numerical Simulation ◽  
Impact Force ◽  
Latin Hypercube Sampling ◽  
Approximate Model ◽  
Shape Parameters ◽  
Analysis Process ◽  
Surface Method ◽  
Brake Performance ◽  
Set Up ◽  
The Impact

The approximate model of the muzzle brake performance was set up and evaluated to simplify the analysis process. LHS(Latin Hypercube Sampling) and numerical simulation of inviscid muzzle flow field were applied to obtain some samples of the muzzle brake performance. The performance was weighted with the impact force on the muzzle brake. Then RSM(Response Surface Method) was adopted to get the approximate model of the muzzle brake performance to establish a mapping of muzzle brake shape parameters and the impact force. In the end GA(Genetic Algorithm) was applied to perform the optimization of the muzzle brake shape parameters with the approximate model.

scholarly journals Evaluation of the Impact of Residual Stresses in Crack Initiation with the Application of the Crack Compliance Method Part I, Numerical Analysis

2010 ◽  
Vol 24-25 ◽  
pp. 253-259 ◽  
Author(s):  
G. Urriolagoitia-Sosa ◽  
B. Romero-Ángeles ◽  
Luis Héctor Hernández-Gómez ◽  
G. Urriolagoitia-Calderón ◽  
Juan Alfonso Beltrán-Fernández ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Numerical Analysis ◽  
Stress Field ◽  
Crack Initiation ◽  
Residual Stresses ◽  
Main Concern ◽  
Residual Stress Field ◽  
Set Up ◽  
The Impact

The understanding of how materials fail is still today a fundamental research problem for scientist and engineers. The main concern is the assessment of the necessary conditions to propagate a crack that will eventually lead to failure. Nevertheless, this kind of analysis tends to be more complicated, when a prior history in the material is taken into consideration and it will be extremely important to recognize all the factors involved in this process. In this work, a numerical simulation of the introduction of residual stresses, which change the crack initiation conditions, in a modified compact tensile specimen to change the condition of crack initiation is presented. Four numerical analyses were carried out; an initial evaluation was performed in a specimen without a crack and it was used for the estimation of a residual stress field produced by an overload; three more cases were simulated and a crack was introduced in each specimen (1 mm, 5 mm and 10 mm, respectively). The overload was then applied to set up a residual stress field into the component; furthermore, in each case the crack compliance method (CCM) was applied to measure the induced residual stress field. By performing this numerical simulation, the accuracy of the crack compliance method can be evaluated. On the other hand, elastic-plastic finite element analysis was utilized for the residual stress estimation. The numerical analysis was based on the mechanical properties of a biocompatible material (AISI 316L). The obtained results provided significant data about diverse factors, like; the manner in which a residual stress field could modify the crack initiation conditions, the convenient set up for induction of a beneficial residual stresses field, as well as useful information that can be applied for the experimental implementation of this research.

OPTIMIZATION OF ELECTROSPINNING PROCESS PARAMETERS FOR TISSUE ENGINEERING SCAFFOLDS

2006 ◽  
Vol 01 (02) ◽  
pp. 153-178 ◽  
Author(s):  
MING CHEN ◽  
PRABIR K. PATRA ◽  
STEVEN B. WARNER ◽  
SANKHA BHOWMICK
Keyword(s):  
Cell Growth ◽  
Process Parameters ◽  
Growth Kinetics ◽  
Fiber Diameter ◽  
Average Diameter ◽  
Solution Concentration ◽  
Electrospinning Process ◽  
Average Fiber Diameter ◽  
High Concentration ◽  
Cell Growth Kinetics

The goal of the current study was to optimize important process parameters for electrospinning polycaprolactone (PCL) for growing 3T3 fibroblasts. We hypothesized that the smallest obtainable fiber diameter would provide the best cell growth kinetics and we tested this hypothesis for three different process parameters: solution concentration, voltage and collector screen distance. Beaded structures were formed when using low concentration electrospinning solutions (8 wt% to 13 wt%), in which the viscosity ranged from 16.0 c P to 340.0 c P . In this concentration range, cell growth kinetics was impeded when using a high concentration of cells (8–10 × 105). Higher PCL concentration led to an increase in the average fiber diameter from 400 nm to 1600 nm when PCL solution concentration changed from 15 wt% to 20 wt%. Although, the mean values indicated that cell growth kinetics were higher at the lower end of the concentration (15% as opposed to 20%) and this correlated with lower average fiber diameter, the results in this range were not statistically significant (p > 0.05). The average fiber diameter of scaffolds first decreased and then increased when electrospinning voltage was increased. The cell growth kinetics demonstrated that smaller average diameter PCL fiber scaffolds had higher growth kinetics than larger average diameter scaffolds with the best conditions obtained at 15 KV. By increasing the screen distance, the average fiber diameter decreased but had no significant impact on cell growth kinetics. In summary, the optimal parametric space for 3T3 fibroblast growth for our studies was electrospinning a 15 wt% PCL solution using 15 kV voltage and a 25 cm collector distance.

Residual Charges during Electrospinning Assist in Formation of Piezoelectricity in Poly(Vinylidene Fluoride-co-Trifluoroethylene) Nanofibers

2015 ◽  
Vol 37 ◽  
pp. 13-19 ◽  
Author(s):  
A Young Choi ◽  
Hyeon Jun Sim ◽  
Min Kyoon Shin ◽  
Seon Jeong Kim ◽  
Youn Tae Kim
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Vinylidene Fluoride ◽  
Near Field ◽  
Electrospun Nanofibers ◽  
Electrospinning Process ◽  
Local Electric Field ◽  
Output Measurement ◽  
Poly Vinylidene Fluoride

We confirm piezoelectric performance of bottom electrospun PVDF-TrFE mat is higher than that of top mat and report the mechanism of additional poling process of electrospun nanofibers by local electric field which is originating from residual charges in far-field electrospinning process. Piezoelectric output measurement of poly (vinylidene fluoride-co-trifluoroethylene) electrospun nanofibers was performed by push test and output signals of bottom and top were compared. The local electric field strength calculated by simulation was higher than reported electric field strength of near-field electrospinning (10 MV/m). It can be concluded that the piezoelectric outputs of electrospun nanofibers tend to be improved by residual charge density and electrospinning condition.

scholarly journals Application of ANN modeling techniques in the prediction of the diameter of PCL/gelatin nanofibers in environmental and medical studies

RSC Advances ◽  
2019 ◽  
Vol 9 (43) ◽  
pp. 24858-24874 ◽  
Author(s):  
Saba Kalantary ◽  
Ali Jahani ◽  
Reza Pourbabaki ◽  
Zahra Beigzadeh
Keyword(s):  
Process Parameters ◽  
Fiber Diameter ◽  
Electrospinning Process ◽  
Medical Studies ◽  
Adaptive Modeling ◽  
Ann Modeling ◽  
Modeling Techniques ◽  
The Impact

A new tool for prediction the diameter of nanofibers is presented: the use of adaptive modeling techniques to predict fiber diameter and study the impact of electrospinning process parameters on electrospinning fiber diameter.

Using Orthogonal Design in Optimizing Parameters for Bubble Electrospinning of Polyvinyl Alcohol (PVA) Nanofibers

2010 ◽  
Vol 29-32 ◽  
pp. 1943-1947 ◽  
Author(s):  
Liang Dong ◽  
Wan Shou ◽  
Yong Liu ◽  
Rui Wang ◽  
Ru Dong Chen
Keyword(s):  
Polyvinyl Alcohol ◽  
Process Parameters ◽  
Applied Voltage ◽  
Orthogonal Design ◽  
Solution Concentration ◽  
Electrospinning Process ◽  
Electrospinning Technique ◽  
Array Design ◽  
Nanofiber Diameter ◽  
Lower Medium

The present work was aimed at studying the effects of process parameters on morphologies of Polyvinyl alcohol (PVA) nanofibers in a novel electrospinning technique, bubble electrospinning. The process was optimized by constructing L 9(34) orthogonal experimental array design. Three factors were investigated and nine tests were run under lower, medium and higher levels of these factors. The results showed that PVA solution concentration plays an important role in affecting the morphologies of PVA nanofibers in bubble electrospinning process. With the increase of the concentration of PVA solution, the morphologies of fibers were changed from beaded fibers to uniform cylinder fibers and the average nanofiber diameter also increased. The optimization process was 12w% for PVA solution, 30kV for applied voltage and 10cm for spinning distance.

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