A Computational Model for High Speed Screening of Polymer Microstructures

2004 ◽  
Vol 25 (1) ◽  
pp. 377-381 ◽  
Author(s):  
Kegang Wang ◽  
Martin E. Glicksman ◽  
Krishna Rajan
Keyword(s):  
Computational Model ◽  
High Speed ◽  
Polymer Microstructures

scholarly journals Numerical and Experimental Investigations on Vocal Fold Approximation in Healthy and Simulated Unilateral Vocal Fold Paralysis

2021 ◽  
Vol 11 (4) ◽  
pp. 1817
Author(s):  
Zheng Li ◽  
Azure Wilson ◽  
Lea Sayce ◽  
Amit Avhad ◽  
Bernard Rousseau ◽  
...  
Keyword(s):  
Computational Model ◽  
Vocal Fold ◽  
High Speed ◽  
Computational Models ◽  
Ex Vivo ◽  
Vocal Fold Paralysis ◽  
Future Application ◽  
Experimental Investigations ◽  
Type I ◽  
Mri Scans

We have developed a novel surgical/computational model for the investigation of unilat-eral vocal fold paralysis (UVFP) which will be used to inform future in silico approaches to improve surgical outcomes in type I thyroplasty. Healthy phonation (HP) was achieved using cricothyroid suture approximation on both sides of the larynx to generate symmetrical vocal fold closure. Following high-speed videoendoscopy (HSV) capture, sutures on the right side of the larynx were removed, partially releasing tension unilaterally and generating asymmetric vocal fold closure characteristic of UVFP (sUVFP condition). HSV revealed symmetric vibration in HP, while in sUVFP the sutured side demonstrated a higher frequency (10–11%). For the computational model, ex vivo magnetic resonance imaging (MRI) scans were captured at three configurations: non-approximated (NA), HP, and sUVFP. A finite-element method (FEM) model was built, in which cartilage displacements from the MRI images were used to prescribe the adduction, and the vocal fold deformation was simulated before the eigenmode calculation. The results showed that the frequency comparison between the two sides was consistent with observations from HSV. This alignment between the surgical and computational models supports the future application of these methods for the investigation of treatment for UVFP.

Computing Cutter Engagement Values in Milling Tessellated Free-Form Surfaces

2010 ◽  
Vol 10 (4) ◽  
Author(s):  
Zhiyang Yao ◽  
Ajay Joneja
Keyword(s):  
Computational Model ◽  
Cutting Force ◽  
High Speed ◽  
Tool Path ◽  
Free Form ◽  
High Speed Milling ◽  
Free Form Surfaces ◽  
Potential Use ◽  
Do So

High speed milling (HSM) has great potential use in die/mold cutting, but traditional machining plans do exploit HSM capabilities effectively. An important consideration in HSM is to limit cutting force variations, and one way to do so is to reduce cutter-workpiece engagement (CWE) variations. CWE is measured as the area of the tool instantaneously engaged with the part. Estimating CWE as a function of the tool path requires repeated, expensive computations. This paper develops algorithms for a discretized computational model to make CWE computations for arbitrary shaped parts.

High Speed Milling Vibration Surveillance with Optimal Spindle Speed Based on Optimal Speeds Map

2013 ◽  
Vol 597 ◽  
pp. 125-130 ◽  
Author(s):  
Krzysztof J. Kalinski ◽  
Marek A. Galewski ◽  
Michał R. Mazur
Keyword(s):  
Experimental Data ◽  
Computational Model ◽  
High Speed ◽  
End Milling ◽  
The Self ◽  
Experimental Results ◽  
Modal Parameters ◽  
Chatter Vibration ◽  
High Speed Milling ◽  
Milling Vibration

The paper presents the method of the surveillance of the self-excited chatter vibration. At first, the workpiece modal parameters are estimated based on experimental data which leads to verification of computational model. Then, for selected surface points optimal spindle speeds are calculated. By considering sufficient amount of points it is possible to build a map of optimal spindle speeds. Experimental results show that this map may be used effectively for eliminating chatter in case of the process of ball end milling of a curved flexible detail.

Assessment of the Dynamic Behavior of a Single Person ATV in Presence of a Passenger: Outcome on the Rider and Passenger Crash Impact Kinematics Using Computational Model

2012 ◽  
Author(s):  
Chandrashekhar K. Thorbole ◽  
Mary Aitken ◽  
James Graham ◽  
Beverly Miller ◽  
Samantha Hope Mullins
Keyword(s):  
Computational Model ◽  
Injury Prevention ◽  
High Speed ◽  
Tilt Table ◽  
Child Injury ◽  
Uneven Terrain ◽  
Handling Characteristics ◽  
Single Person ◽  
Child Injury Prevention ◽  
Multi Body

An ATV (All-terrain vehicle) is a gasoline powered, fast moving off road vehicle often used for farming and industrial activities as well as recreational activities. The popularity of this type of vehicle has increased over the last decade with more than 10 million in use today. Most ATVs are designed for only single rider even though the seat of the ATV may appear big enough to carry a passenger. The presence of an additional person on a single person ATV greatly affects its dynamic handling characteristics. This change increases the risk of a crash and subsequent injuries to both riders. ATV crashes involving climbing and descending on steep hills are common. Lateral rollover crashes are often the result of riding an ATV at a high speed on uneven terrain. The presence of passenger on a single person ATV during these conditions changes the rider impact kinematics and resulting injury outcome, as the ATV behaves differently in the presence of an additional person. The computational model of a single person, adult-sized ATV, as developed previously for the study of child injury prevention, was used for this study. The multi-body computational model of this ATV was developed using biodynamic code MADYMO. This computational model was validated against the laboratory test for its dynamic and suspension characteristics. The tilt table test and the drop test were employed to compare the computational model result. This computer model was used to simulate the crash mechanism involving climbing and descending steep hills with two people on the ATV. This model was also used to simulate the lateral rollover of ATV with two people. The rider and the additional passenger on this single rider ATV were modeled using a 50th percentile male and a 5th percentile female. The two rider simulation was compared with single rider simulation for similar terrain and ATV speed to gain insight about the influence of this additional passenger weight on the crash kinematics of the ATV and the rider. These simulations will also be used in the future to generate more visually dramatic videos for educational intervention for ATV safety programs and other injury prevention activities.

Modelling of Rolling Contact Fatigue of Rails

2006 ◽  
Vol 324-325 ◽  
pp. 987-990 ◽  
Author(s):  
Gorazd Fajdiga ◽  
Matjaž Šraml ◽  
Janez Kramar
Keyword(s):  
Fatigue Crack ◽  
Computational Model ◽  
Fatigue Failure ◽  
High Speed ◽  
Rolling Contact Fatigue ◽  
Fatigue Crack Initiation ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Dark Spot ◽  
Probable Number

Rail dark spot defect, also termed as squat failure or shelling, is a rolling contact fatigue failure which occurs frequently on the high speed traffic railway rails. The main goal of this study is to develop a computational model for simulation of the squat phenomena on rails in rail-wheel contact. The proposed computational model consists of two parts: (i) Contact Fatigue Crack Initiation (CFCI) and (ii) Contact Fatigue Crack Propagation (CFCP). The results of proposed unified model enable a computational prediction of a probable number of loading cycles that a wheel-rail system can sustain before development of the initial crack in the rail, as well as the number of loading cycles required for a crack to propagate from initial to critical length, when the final fatigue failure (squat) can be expected to occur.

Computational Model for Predicting the Location of Glass Solidification in Optic Fiber Drawing

Volume 3 ◽  
2004 ◽  
Author(s):  
Zhiyong Wei ◽  
Kok-Meng Lee ◽  
Zhi Zhou ◽  
Siu-Ping Hong
Keyword(s):  
Free Surface ◽  
Computational Model ◽  
High Speed ◽  
Production Efficiency ◽  
Small Diameter ◽  
Optical Loss ◽  
Surface Flow ◽  
Optic Fiber ◽  
Drawing Process ◽  
Fiber Drawing

This paper presents a computational model for predicting the location at which the glass fiber solidifies during a high-speed drawing process. Although modeling of the optic fiber drawing process has been of interest for the past two decades, traditional fiber drawing process uses small diameter preforms and low draw speeds, where the glass usually solidifies and turns into fiber inside the furnace. Much larger preforms drawn at higher speeds have been used in the state-of-the-art fiber drawing systems to improve production efficiency and reduce cost. Insulated post-chambers are often added below the furnace to reduce the glass cooling rate so that the optical loss in the fiber is low. To provide a basis for design optimization of the post-chamber, we have solved the conjugate problem of the glass free surface flow and the air convection to determine the location where the glass solidifies. As radiation is the dominant mode of heat transfer in the glass, the radiative transfer equation (RTE) is solved directly by discrete ordinate method (DOM). The heat flux due to the mixed convection of the air is also numerically calculated along the glass free surface, which involves the boundary layer flow around a continuously moving fiber and the buoyancy driven flow through the open-ended channel. The calculated free shapes are compared against the experimentally measured data to verify the computational model.

Multibody Based Tool for Simulation of the Turbocharger Rotor Dynamics

2016 ◽  
Vol 821 ◽  
pp. 229-234 ◽  
Author(s):  
Jiří Knotek ◽  
Pavel Novotný ◽  
Ondřej Maršálek
Keyword(s):  
High Temperature ◽  
Computational Model ◽  
High Speed ◽  
Rotor Dynamics ◽  
Rotating Machinery ◽  
Operating Conditions ◽  
Simulation Tool ◽  
The Real ◽  
Compact Design ◽  
Very High

The turbocharger is a unique example of the rotating machinery. Not only for its very high speed, but also because of its compact design and difficult operating conditions (i.e. high temperature, harsh vibrations, etc.). Moreover, measuring of most parameters characterizing the rotor dynamics is a very difficult task. Thus, it is advantageous to replace the real turbocharger by computational model and determine the turbocharger rotor dynamics using simulation tool. The development of such tool will be presented in this paper.

scholarly journals Characterisation of Mach number 1.5 and 2 Nozzle Jets using Computational Techniques

2019 ◽  
Vol 9 (2) ◽  
pp. 2967-2971
Keyword(s):  
Mach Number ◽  
Computational Model ◽  
High Speed ◽  
Supersonic Nozzle ◽  
Computational Techniques ◽  
Noise Sources ◽  
Flow Solver ◽  
Nozzle Contour ◽  
Field Noise ◽  
Jet Characteristics

In this paper a supersonic nozzle was designed using the MOC method and the nozzle contour has been created. The computational model was developed to model the characteristics of the jet of Mach number 1.5 & Mach number 2 nozzles. The computational model was created with compressible flow field properties in order to get the most accurate result. The pressure inlet and outlet boundary conditions have been applied with viscous flow solver. In order to get the shock flow visualization and high-speed jet characteristics the exit has been extended to 5D vertical and 15D horizontal and the virtual atmosphere has been created. For both models, the CAA (computation acoustical analysis) carried out using flows, Williams and Hawkings acoustic solver to get far-field noise radiation. The experimental technique and future works were discussed. The Jet characteristics of two nozzles were examined and noise sources have been compared.

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