Interpretation of Mechanical Testing Measurements for Pastes

2002 ◽  
Author(s):  
Robert A. Basterfield ◽  
Chris J. Lawrence ◽  
Michael J. Adams
Keyword(s):  
Experimental Data ◽  
Numerical Models ◽  
Experimental Methods ◽  
Published Data ◽  
The Finite Element Method ◽  
Material Parameters ◽  
Simulation Techniques ◽  
Manufacturing Sectors ◽  
Product Forms ◽  
Computer Simulation Techniques

Pastes occur as intermediates or final product forms in many industrially important manufacturing sectors. The use of computer simulation techniques, such as the finite element method, is becoming more common in the design of paste processing operations. A major problem in the application of this approach is the development of sufficiently representative materials models. It has been established that pastes may be described as elasto-viscoplastic materials with the plastic flow being governed by the Herschel-Bulkley relationship. This paper describes the development of analytical and numerical models that can be used as a basis for deriving the material parameters from experimental data obtained using extrusion, compression and bending procedures. Measurements have also been carried out on a model paste and the derived material parameters are compared with published data for the same paste. The merits of the three experimental methods are compared on this basis.

The Mechanical Behavior of a Mammalian Lung Alveolar Duct Model

1995 ◽  
Vol 117 (3) ◽  
pp. 254-261 ◽  
Author(s):  
E. Denny ◽  
R. C. Schroter
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Collagen Fiber ◽  
Fiber Bundles ◽  
Published Data ◽  
The Finite Element Method ◽  
Dependent Relationship ◽  
Alveolar Duct ◽  
Mammalian Lung ◽  
Air Liquid Interface

A model for the mechanical properties of an alveolar duct is analyzed using the finite element method. Its geometry comprises an assemblage of truncated octahedral alveoli surrounding a longitudinal air duct. The amounts and distributions of elastin and collagen fiber bundles, modeled by separate stress-strain laws, are based upon published data for dogs. The surface tension of the air-liquid interface is modeled using an area-dependent relationship. Pressure-volume curves are computed that compare well with experimental data for both saline-filled and air-filled lungs. Pressure-volume curves of the separate elastin and collagen fiber contributions are similar in form to the behavior of saline-filled lungs treated with either elastase or collagenase. A comparison with our earlier model, based upon a single alveolus, shows the duct to have a behavior closer to reported experimental data.

scholarly journals The use of the inverse problem methodology in analysis of fluid flow through granular beds with non-uniform grain sizes

2021 ◽  
Author(s):  
Wojciech Sobieski ◽  
Anna Trykozko
Keyword(s):  
Experimental Data ◽  
Inverse Problem ◽  
Numerical Models ◽  
The Finite Element Method ◽  
Optimal Method ◽  
Gravel Beds ◽  
Grain Sizes ◽  
Wide Range ◽  
Large Particles ◽  
Flow Through

The pressure drop during water flow through two gravel beds with 2-8 and 8-16 [mm] grain size was measured across a wide range of filtration velocities, and the optimal method for calculating the coefficients for Darcy’s law and Forchheimer’s law was selected. The laws and the experimental data were used to develop a computational program based on the Finite Element Method (FEM). The results were compared, and errors were analyzed to determine which law better describes flow data. Various methods of measuring porosity and average grain diameter, representative of the sample, were analyzed. The data were used to determine the limits of applicability of both laws. The study was motivated by the observation that computational formulas in the literature produce results that differ by several orders of magnitude, which significantly compromises their applicability. The present study is a continuation of our previous research into artificial granular materials with similarly sized particles. In our previous work, the results produced by analytical and numerical models were highly consistent with the experimental data. The aim of this study was to determine whether the inverse problem methodology can deliver equally reliable results in natural materials composed of large particles. The experimental data were presented in detail to facilitate the replication, reproduction and verification of all analyses and calculations.

Image Analysis of Intramembrane Particles in Freeze-Fractured Biomembranes Using Computer Simulation Techniques

1975 ◽  
Vol 33 ◽  
pp. 214-215
Author(s):  
D.J. Benefiel ◽  
R.S. Weinstein
Keyword(s):  
Membrane Proteins ◽  
Freeze Fracture ◽  
Integral Membrane Proteins ◽  
Systematic Evaluation ◽  
Intramembrane Particles ◽  
Modeling Methods ◽  
Simulation Techniques ◽  
Freeze Fracture Electron Microscopy ◽  
Fracture Electron ◽  
Computer Simulation Techniques

Intramembrane particles (IMP or MAP) are components of most biomembranes. They are visualized by freeze-fracture electron microscopy, and they probably represent replicas of integral membrane proteins. The presence of MAP in biomembranes has been extensively investigated but their detailed ultrastructure has been largely ignored. In this study, we have attempted to lay groundwork for a systematic evaluation of MAP ultrastructure. Using mathematical modeling methods, we have simulated the electron optical appearances of idealized globular proteins as they might be expected to appear in replicas under defined conditions. By comparing these images with the apearances of MAPs in replicas, we have attempted to evaluate dimensional and shape distortions that may be introduced by the freeze-fracture technique and further to deduce the actual shapes of integral membrane proteins from their freezefracture images.

Identifying Physico-Chemical Laws from the Robotically Collected Data

2019 ◽  
Author(s):  
Liwei Cao ◽  
Danilo Russo ◽  
Vassilios S. Vassiliadis ◽  
Alexei Lapkin
Keyword(s):  
Experimental Data ◽  
Numerical Models ◽  
Predictor Variable ◽  
Physical Models ◽  
Training Data ◽  
Mixed Integer ◽  
Physico Chemical ◽  
Data Points ◽  
Future Work ◽  
The Relationship

<p>A mixed-integer nonlinear programming (MINLP) formulation for symbolic regression was proposed to identify physical models from noisy experimental data. The formulation was tested using numerical models and was found to be more efficient than the previous literature example with respect to the number of predictor variables and training data points. The globally optimal search was extended to identify physical models and to cope with noise in the experimental data predictor variable. The methodology was coupled with the collection of experimental data in an automated fashion, and was proven to be successful in identifying the correct physical models describing the relationship between the shear stress and shear rate for both Newtonian and non-Newtonian fluids, and simple kinetic laws of reactions. Future work will focus on addressing the limitations of the formulation presented in this work, by extending it to be able to address larger complex physical models.</p><p><br></p>

scholarly journals Simulative investigation of ring creep on a planetary bearing of a wind turbine gearbox

2021 ◽  
Author(s):  
Jonas Gnauert ◽  
Felix Schlüter ◽  
Georg Jacobs ◽  
Dennis Bosse ◽  
Stefan Witter
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Sensitivity Analysis ◽  
Planetary Gear ◽  
The Finite Element Method ◽  
Relative Movement ◽  
Wind Turbine Gearbox ◽  
Interference Fit ◽  
Planetary Gears ◽  
Module Coefficient

AbstractWind turbines (WT) must be further optimized concerning availability and reliability. One of the major reasons of WT downtime is the failure of gearbox bearings. Some of these failures occur, due to the ring creep phenomenon, which is mostly detected in the planetary bearings. The ring creep phenomenon describes a relative movement of the outer ring to the planetary gear. In order to improve the understanding of ring creep, the finite element method (FEM) is used to simulate ring creep in planetary gears. First, a sensitivity analysis is carried out on a small bearing size (NU205), to characterize relevant influence parameters for ring creep—considered parameters are teeth module, coefficient of friction, interference fit and normal tooth forces. Secondly, a full-scale planetary bearing (SL185030) of a 1MW WT is simulated and verified with experimental data.

Boiler Implosion Control in Fossil Fuel Power Plants

1985 ◽  
Vol 107 (4) ◽  
pp. 267-269 ◽  
Author(s):  
S. Z. Wu ◽  
D. N. Wormley ◽  
D. Rowell ◽  
P. Griffith
Keyword(s):  
Power Plants ◽  
Fossil Fuel ◽  
Companion Paper ◽  
Simulation Techniques ◽  
Power Plant Boiler ◽  
Induced Draft Fan ◽  
Fossil Fuel Power Plants ◽  
Computer Simulation Techniques ◽  
Plant Boiler ◽  
Furnace Pressure

An evaluation of systems for control of fossil fuel power plant boiler and stack implosions has been performed using computer simulation techniques described in a companion paper. The simulations have shown that forced and induced draft fan control systems and induced draft fan bypass systems reduce the furnace pressure excursions significantly following a main fuel trip. The limitations of these systems are associated with actuator range and response time and stack pressure excursions during control actions. Preliminary study suggests that an alternative control solution may be achieved by discharging steam into the furnace after a fuel trip.

Three-dimensional predator–prey interactions: a computer simulation of bird flocks and aircraft

1986 ◽  
Vol 64 (11) ◽  
pp. 2624-2633 ◽  
Author(s):  
Peter F. Major ◽  
Lawrence M. Dill ◽  
David M. Eaves
Keyword(s):  
Computer Simulation ◽  
Prey Species ◽  
Three Dimensional ◽  
Aircraft Engine ◽  
Aquatic Environments ◽  
Aircraft Engines ◽  
Predator Prey ◽  
Simulation Techniques ◽  
Computer Simulation Techniques ◽  
Individual Prey

Three-dimensional interactions between grouped aerial predators (frontal discs of aircraft engines), either linearly arrayed or clustered, and flocks of small birds were studied using interactive computer simulation techniques. Each predator modelled was orders of magnitude larger than an individual prey, but the prey flock was larger than each predator. Expected numbers of individual prey captured from flocks were determined for various predator speeds and trajectories, flock–predator initial distances and angles, and flock sizes, shapes, densities, trajectories, and speeds. Generally, larger predators and clustered predators caught more prey. The simulation techniques employed in this study may also prove useful in studies of predator–prey interactions between schools or swarms of small aquatic prey species and their much larger vertebrate predators, such as mysticete cetaceans.The study also provides a method to study problems associated with turbine aircraft engine damage caused by the ingestion of small flocking birds, as well as net sampling of organisms in open aquatic environments.

Leakage Flow Investigations on a Through-Wall Crack Related to Thermal Fatigue of Nuclear Power Plant Piping

2017 ◽  
Author(s):  
Stefan Schmid ◽  
Rudi Kulenovic ◽  
Eckart Laurien
Keyword(s):  
Experimental Data ◽  
Nuclear Power ◽  
Numerical Models ◽  
Measurement Techniques ◽  
Experimental Investigations ◽  
Leakage Flow ◽  
Test Rig ◽  
Reduced Pressure ◽  
Flow Rates ◽  
Set Up

For the validation of empirical models to calculate leakage flow rates in through-wall cracks of piping, reliable experimental data are essential. In this context, the Leakage Flow (LF) test rig was built up at the IKE for measurements of leakage flow rates with reduced pressure (maximum 1 MPA) and temperature (maximum 170 °C) compared to real plant conditions. The design of the test rig enables experimental investigations of through-wall cracks with different geometries and orientations by means of circular blank sheets with integrated cracks which are installed in the tubular test section of the test rig. In the paper, the experimental LF set-up and used measurement techniques are explained in detail. Furthermore, first leakage flow measurement results for one through-wall crack geometry and different imposed fluid pressures at ambient temperature conditions are presented and discussed. As an additional aspect the experimental data are used for the determination of the flow resistance of the investigated leak channel. Finally, the experimental results are compared with numerical results of WinLeck calculations to prove specifically in WinLeck implemented numerical models.

DIFFUSION MECHANISMS AT fcc METAL SURFACES — EMBEDDED ATOM METHOD CALCULATIONS

1995 ◽  
Vol 09 (01) ◽  
pp. 1-44 ◽  
Author(s):  
CHUN-LI LIU
Keyword(s):  
Metal Surfaces ◽  
Diffusion Processes ◽  
Embedded Atom Method ◽  
Embedded Atom ◽  
Simulation Techniques ◽  
Theoretical Investigations ◽  
Diffusion Mechanisms ◽  
Fcc Metal ◽  
Dynamic Diffusion ◽  
Computer Simulation Techniques

Recent development in theoretical investigations using computer simulation techniques and the embedded atom method (EAM) on diffusion processes critical to nucleation and growth of thin films at fcc metal surfaces is reviewed. Through these investigations, interactions between adatoms and substrate, adatoms and steps, and clusters and substrate and the effect of these interactions on dynamic diffusion processes are further understood. The results from these theoretical investigations are generally consistent with available experimental data and have provided explanations for some experimental observations. Some predictions made a few years ago from these studies have been confirmed by the latest experiments.

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