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Issue 1, Volume 5,
January 2010
Title of the Paper: Research on the
Stability Problem of Hydroelectric Station Penstock under External Pressure
Based on Neural Network
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Authors: Chenghua Dang,
Tieguo Ji, Xinpei Jiang
Abstract: The stability of steel penstock under external pressure is a main
factor of penstock design in hydroelectric station. Since the assumption
conditions and the boundary conditions are simplified in the currently
existing methods, the obtained computing results have low accuracy level and
every method has its limitation. In this present paper, we apply artificial
neural network model and improved BP algorithm to this problem with more
complicated conditions and factors. By analyzing the influences on losing
stability and breach for reinforcing ring steel penstock caused by
diameter-to-thickness ratio of the steel tube, size and space of reinforce
rings, a new research approach is obtained and test results show this method
is feasible and its validity is verified. This paper provides an efficient
solving path for stability problem of reinforcing ring steel penstock under
external pressure. Furthermore, we use this method to Chinese Yachihe
hydroelectric power station design, the computing results show this method is
reliable, economic and fully satisfies the project requirements.
Keywords: Penstock,
Stability calculation under external pressure, Neural network, Simulated
annealing algorithm
Title of the Paper: Analysis of the
Thermal Damage on Homogenized Multi-Materials under Thermo-Mechanical Behavior
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Authors: Bilal Taher,
Said Abboudi, Rafic Younes
Abstract: In the recent high technologies, the increasing need of structures
having multiple functions orientates designers to combine materials in order
to obtain, according to coupling scales, multi-materials structures. These
structures, while functioning, are subject to variable thermal load, leading
to a damage that can be fatal in some applications. So, the study of the
behavior of these structures, while they are under thermal cycling
solicitations, seems to be very important in order to be able to predict their
lifetime and their response to any applied solicitation. It is obvious that
the variation of the nature of thermal and mechanical solicitation in term of
amplitude and frequency leads to a variation of the resulting damage. But at
the level of our knowledge, this effect is not studied before in the
literature on multi-materials. In this work, we propose a numerical analysis
of the thermo-elasto-plastic behavior of these multi-materials and their
damage under thermal cyclic solicitations, while using the homogenization
technique. This study is done in two dimensions on a cylindrical
multi-material constituted of two layers, subjected to a periodic heat flux
applied in the inner face of this cylinder and an exchange condition on the
opposite face. The other faces are supposed isolated. The sample is supposed
fixed at the isolated faces and free in the radial direction. The damage model
is based on the works of Lemaitre and Chaboche [6]. This damage model is not
done for multimaterials; it is applicable only to one material apart. So the
homogenization of these multi-materials permits us to study the damage of the
multi-layers as it is a unique material. the numerical results are presented
for different forms and frequency of heat flux cycling (triangular, square and
sinusoidal wave excitations) and for different thicknesses of the
multi-material. Finally we do a comparison of the multi-material damage with
respect to different heat flux excitations.
Keywords: Thermal stress,
thermo-mechanical, damage, thermo-elasto-plastic, coupling, multi-material,
cycling, thermal load
Title of the Paper: Real Time Orbit
Determination with Different Force Fields
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Authors: Vivian Martins
Gomes, Antonio F. B. A. Prado, Helio Koiti Kuga
Abstract: The Global Positioning System (GPS) is a satellite navigation system
that allows the users to determine 3D positioning and the time with high
precision. Its main purposes are: aid to radionavigation in three dimensions
with high precision positioning, navigation in real time, time
synchronization, global coverage and quick acquisition of data signal sent by
the GPS satellites. In this work, it is proposed to estimate, in real time, an
orbital state vector composed by position, velocity, bias and drift of the GPS
receiver clock on board satellites by processing the raw navigation solution
obtained by the on-board receiver. In this work the Kalman filter is used to
estimate the state vector based on the stepwise incoming navigation solution
from the receiver. The Kalman filter is used due to its robustness in real
time applications, without unnecessary storage of observations, as they can be
processed while being collected. The filter dynamic model includes
perturbation due to geopotential, solar radiation pressure and perturbations
due to the Sun and the Moon and the observations are the raw navigation
solution composed of position and receiver clock bias. Simulations and tests
are done using actual data from TOPEX/POSEIDON satellite. For performance
assessment, a comparison is done between the estimated state vector and the
precise orbit ephemeris (POE) produced by JPL/NASA.
Keywords: Astrodynamics,
artificial satellites, orbital dynamics
Title of the Paper: Stability Analysis
for Neo-Hookean Machine-Tools Foundations
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Authors: Nicolae–Doru
Stanescu, Stefan Tabacu
Abstract: It is well known that the vibrations are a major cause for the
instability in the mechanical systems and major source of noises. In this
paper we propose a simple system with two degrees of freedom based on a
non-linear elastic element and the hypothesis for the coefficients of the
elastic force.. For this system, it is proved in the present paper that the
motion is stable, but not asymptotically stable. A comparison between the
non-linear case and the linear case is performed, and for the both cases the
eigenpulsations are also determined. All theoretical results are validated by
numerical simulation. Finally, we considered the general case.
Keywords: Neo-Hookean,
motion, stability, numerical validation
Title of the Paper: Structure Design for
TUUSAT-1A Microsatellite
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Authors: Chin-Feng Lin,
Zuu-Chang Hong, Jeng-Shing Chern, Chien-Ming Lin, Bo-Jyun Chang, Chen-Joe
Fong, Huan-Jung Lin
Abstract: One of the main advantage of microsatellites is their small size.
The reliability, safety, and effectiveness of the satellite structure play an
important role in the normal operation of the satellite. The satellite
structure should be designed that it supports all subsystems, and payloads.
The satellite structure should be stable against vibration and environmental
factors during the rocket launch, in order to ensure normal operation of the
other subsystems and payload. When designing a satellite, we take into account
the features of the attitude control subsystem, thermal control subsystem, and
solar energy subsystem, which are essential for stable operation, as well as
the reliability of the structure. In this article, we discuss a structure
design for the Taiwan Universities United Satellite NO.1A (TUUSAT-1A)
microsatellite. The satellite is a cube with an edge of 28 cm. The surface of
the satellite is covered by six aluminum plates, each of which has a solar
chip attached to it. The satellite mainly comprises four layers-each layer is
an aluminum plates that form a single aluminum alloy block.
Keywords: Structure,
microsatellite, reliability, safety, effectiveness, stable operation
Title of the Paper: Application of
Analytic Functions to the Global Solvabilty of the Cauchy Problem for
Equations of Navier-Stokes
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Authors: Asset
Durmagambetov
Abstract: The interrelation between analytic functions and real-valued
functions is formulated in the work. It is shown such an interrelation
realizes nonlinear representations for real-valued functions that allows to
develop new methods of estimation for them. These methods of estimation are
approved by solving the Cauchy problem for equations of viscous incompressible
liquid.
Keywords: Shroinger,
Cauchy problem, Navier-Stokes', inverse, analytic functions, scattering theory
Title of the Paper: Theory of High Rate
of Fire Automatic Weapon with Together Bound Barrels and Breeches
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Authors: Jiri Balla,
Lubomir Popelinsky, Zbynek Krist
Abstract: The paper decribes the principle of the weapon with together bound
of barrels and breeches at first. Then the kinematics and dynamics of the
weapon mechanism with the crank mechanism inserted between the breech block
and breech block carrier is discussed. Equations enabling the theoretical
solution of the gas operated drive of the weapon mechanism are explained. The
imagination about the utilization of the theory mentioned gives the results of
the solution of the real weapon at the end of the paper.
Keywords: Crank mechanism,
Breech, Gas flow, Equation of motion, Pressure in barrel, Discharge
coefficient
Title of the Paper: Measuring the Creep
and Material Properties of Cement Paste Specimens
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Authors: Pavel Padevet,
Petr Bittnar
Abstract: The paper describes creep tests of the small specimen, and analyses
the material properties of cement pastes. Material properties were tested in
compression tests. Creep of cement pastes was tested on the cylindrical
specimens with diameter 10mm. Tests were focused for the pastes made from
Portland cement CEM I and CEM II and water, whose water-cement ratio was 0.3;
0.4 and 0.5. Tested specimens for measurement of creep were waterlogged and
dried. Shrinkage of cement specimens was measured too. After finalization of
the measuring were specimens used for compression tests and Modulus of
elasticity was measured. History of creep, material properties, history of
specimens are inputs for simulation by finite element method.
Keywords: Cement paste,
shrinkage, creep of cement paste, concrete specimen, compression test, lever
mechanism
Title of the Paper: On the Reduction of
Accelerations Transmitted to Transported Freight for the 4-Axle Platform Car
with Mobile Cover
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Authors: Tanasoiu
Aurelia, Copaci Ion
Abstract: The shock caused by the collision of railway vehicles determines the
transmission of forces and accelerations to the vehicles, which may lead to
unwanted consequences. In order to reduce the effects of the shock, vehicles
are equipped with shock insulators. The paper presents a unique theoretical
approach, completed with an experimental study on the efficiency of
long-displacement dampeners in regards to reducing the response amplitude of
the mechanical system comprising the two colliding vehicles.
Keywords: Shock
insulators, long-displacement dampener, stored and dissipated potential
deformation energy, accelerations and forces transmitted during shock
Title of the Paper: Cooling Demand in
Commercial Buildings - The Influence of Daylight Window Design
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Authors: Hendrik Voll,
Teet-Andrus Koiv, Teet Tark, Monika Sergejeva
Abstract: The objective of the paper is to show how window design could
influence the peak cooling load, daylight availability and direct sun
penetration for a south facing office room in North European circumstances
latitude about 59 ~ 60°. A daylight window is compared with an ordinary window
to find out the design consequence differences. Both size and cost of the HVAC
system needed to avoid unacceptably high room temperatures in office buildings
depend on the peak load. In office rooms with windows this peak load is
usually decided by the solar irradiation. Therewith the architectural design
is decisive for the HVAC solutions needed. The Seattle Daylighting Lab
heliodon table has been used to analyze daylight window potential in North
European circumstances in decreasing the peak cooling load and glare from
direct sun by blocking the direct solar rays from entering the room. Finally,
outgoing from simulations, daylight and solar tests, the possible combination
of window glass share and solar factor for fulfilling the requirements for the
highest accepted dimensioning cooling load and lowest accepted daylight level
for daylight window compared to ordinary window are presented.
Keywords: Commercial
buildings, building design, window share, solar factor, cooling load, daylight
factor, daylight window
Title of the Paper: Towards Automated
Visual Inspection and Classification of Micro-Parts
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Authors: Bernd Scholz-Reiter,
Michael Lutjen, Hendrik Thamer, Tobias Lensing
Abstract: The mechanical manufacturing of micro-parts is a challenging field
of research. Because of high quality requirements and small tolerances,
manufacturing processes have to be very stable and precise. In order to
achieve high precision a suitable quality assurance concept is required. Only
measured features can be used for statistical process control (SPC).
Therefore, this paper presents a concept of an automated visual inspection and
classification methods for micro-parts. Using confocal laser scanning
microscopy, high-resolution 3D-height maps with depth selectivity are
obtained. The identification of surface imperfections is done with a set of
conventional image processing techniques. Afterwards, these kinds of surface
defects are classified by the use of classification methods like decision
trees.
Keywords:
Micro-Production, Deep-Drawing, Machine Vision, Quality Control, Height Maps
Issue 2, Volume 5,
April 2010
Title of the Paper: A Research of
Digitizing Ship Design and Stability Analysis
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Authors: Wei-Yuan Dzan,
Hung-Jen Yang, Hsueh-Chih Lin
Abstract: Based upon the digitizing technology, computer applications play
roles in many ways to contribute toward our industries, such as publication,
mobile learning, and specified communication. The ship design and
manufacturiThe Fiberglass Reinforced Plastic (FRP) have characteristics of
qualities to be light, intensity and does not rust or erode easily, often uses
on the yacht, the skiff, the fishery or the special use vessel. The economic
output value and total length of Taiwanese yacht are the top five of the
world, which accounts for above 80% belongs to the FRP vessel. Obviously, the
FRP vessel manufacturing in the shipbuilding aspect are in a pivotal status.
This research applied the digitizing technique of 3D design, the special
customizing of 3D embryonic form the research and development motor skiff
carried on the hull computation, the propulsion system and the still water
performance analysis and so on, the experiment corrects the optimization
vessel design model. Then, by ways of the CAD/CAM system, 3D of the hull chart
the outstanding design, the lofting will draw up the hull cross section, the
longitudinal section and the horizontal section. Compiling various sectional
drawings to form the computer numerical control machine (CNC) programming
language, That produced various types cross section core of wood plate, by the
way of computer numerical control cutting with machine center. Setting up the
above plate, and smooth the shape, the basis, attrition polishing and surface
processing, completes the vessel wooden pattern prototype. Then delivers the
original FRP mold after the wooden pattern prototype, by the vacuum the basic
way completes manufacture of the power speed boat hull. Finally, after the
installation of vessel and the dynamic system disposition finished, accuracy
of the launching test run confirmation computation theory and the 3D design
practice, in order to help entering the step research and development design.
This research is conducted by National Kaohsiung Marine University department
of naval architecture, during one year and six month teaching regulation, we
had completed research and development of practice experience the length 9
meters motor skiff, not only originates the domestic school, researches and
develops precedent of self-reliantly the manufacture motor skiff, also
provides FRP of straggling parameter and the improvement direction the vessel
3D design manufacture.
Keywords: Fiberglass
reinforced plastic, CAD/CAM, 3D design, skiff
Title of the Paper: Optimization of
Induction Brazing for Thin-Walled Aluminum Tubes
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Authors: Mircea Nicoara,
Aurel Radula, Laurenliu Roland Cucuruz, Cosmin Locovei
Abstract: Major environmental concerns have triggered lately some important
developments in applicative research. Innovation programs for manufacturing
industry are intended to achieve both lower emissions of carbon dioxide and
smaller specific energy consumption. Since use of inductive brazing for
aluminum has remained restricted to few applications, a complex research
program has been pursued in order to develop an optimized joining technology
for tubes with thin walls. The new technology should be suitable for large
scale production, to replace torch brazing at better costs and lower carbon
dioxide emissions. An experimental study, which includes complete design of
technology and equipment for inductive brazing, has proved that use of
induction could produce high quality joints and eliminate the considerable
scrap level generated by torch brazing. Induction brazing also lowers energy
consumption and totally eliminates direct emission of carbon dioxide.
Keywords: Emission-free
technology, Induction brazing, Thin-wall aluminum tubes, Reduced energy
consumption
Title of the Paper: On the Dynamics of a
Planetary Transmission for Renewable Energy Systems
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Authors: Jaliu Codruta,
Saulescu Radu, Diaconescu Dorin, Neagoe Mircea, Climescu Oliver
Abstract: The speed increaser placed between a turbine and a generator in a
small hydro plant has to multiply the input speed so that the generator to
function at its best efficiency. The analyzed speed increaser is an innovative
planetary chain transmission that was proposed by the authors. The dynamic
model of the chain speed increaser is presented in the paper based on Lagrange
and Newton-Euler methods. The dynamic modeling allows the establishment of the
working point in stationary regime for the turbine – speed increaser –
generator assembly. The results guarantee the good functioning of the physical
prototype of small hydropower plant in certain conditions.
Keywords: Planetary speed
increaser, dynamics, numerical simulation, small hydro
Title of the Paper: Development of
Mathematical Models for Analysis of a Vehicle Crash
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Authors: Witold Pawlus,
Jan Eivind Nielsen, Hamid Reza Karimi, Kjell Gunnar Robbersmyr
Abstract: Nowadays, each newly produced car must conform to the appropriate
safety standards and norms. The most direct way to observe how a car behaves
during a collision and to assess its crashworthiness is to perform a crash
test. Because of the fact that vehicle crash tests are complex and complicated
experiments it is advisable to establish their mathematical models. This paper
contains an overview of the kinematic and dynamic relationships of a vehicle
in a collision. There is also presented basic mathematical model representing
a collision together with its analysis. The main part of this paper is devoted
to methods of establishing parameters of the vehicle crash model and to real
crash data investigation i.e. – creation of a Kelvin model for a real
experiment, its analysis and validation. After model’s parameters extraction a
quick assessment of an occupant crash severity is done.
Keywords: Modeling,
vehicle crash, Kelvin model, data processing, ridedown criterion
Title of the Paper: A Rigid-Plastic
Hybrid PCM/FEM for Metal Forming Problems
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Authors: Yong-Ming Guo,
Shunpei Kamitani
Abstract: Point collocation methods (PCM) have some advantages such as no
mesh, no integration. While, the robustness of the point collocation methods
is an issue especially when scattered and random points are used. To improve
the robustness, some studies suggest that the positivity conditions can be
important when using the PCMs. For boundary points, however, the positivity
conditions cannot be satisfied, so that it is possible to get large numerical
errors from the boundary points when using the point collocation methods.
Specifically, the errors could arise in point collocation analyses with
complicated boundary conditions. In this paper, by introducing a boundary
layer of finite element in boundary domain of workpiece, unsatisfactory issue
of the positivity conditions of boundary points can be avoided, and the
complicated boundary conditions of metal forming can be easily imposed with
the boundary layer of finite element. A modified MLS approximation is also
proposed, its shape functions have Kronecker-delta property. Therefore, the
unsatisfactory issue of the essential node condition can be avoided in the
modified MLS approximation. To obtain very simple formulas of the shape
function derivatives, the local coordinates are used in the hybrid PCM/FEM. An
axisymmetric forging problem is analyzed by using the rigid-plastic hybrid
PCM/FEM.
Keywords: Hybrid method,
Meshless method, Point collocation method, FEM, Kronecker-delta property,
Positivity conditions, Local coordinates, Metal forming
Issue 3, Volume 5,
July 2010
Title of the Paper: Using Finite Element
Method in Geotechnical Design. Soil Constitutive Laws and Calibration of the
Parameters. Retaining Wall Case Study
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Authors: Horatiu Popa,
Loretta Batali
Abstract: Using FEM for geotechnical design of constructions with high impact
of the soil – structure interaction is a common practice. However, for
obtaining results close to the real behavior of the analyzed structures it is
required to use complex constitutive models for all materials, especially for
describing the soil behavior. Paper presents the differences in the numerical
modeling when three different constitutive laws are used: one linear elastic –
perfectly plastic and two nonlinear elastic - hardening plastic laws.
Comparisons between numerical modeling and laboratory tests are presented in
order to emphasize the differences between the constitutive laws and to
calibrate their parameters. As well, a numerical calculation using FEM for an
embedded retaining wall is presented, using different soil constitutive
models. The results regarding the displacements of the wall and the bending
moments in the wall are compared with the experimental values.
Keywords: Numerical
modeling, finite element method, soil mechanics, Mohr-Coulomb, Nova, Vermeer,
retaining wall
Title of the Paper: Comparison of FEA
and Experimental Results for a Steel Frame Connection
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Authors: Adrian Ivan,
Marin Ivan, Ioan Both
Abstract: The paper presents the results and the similarity between the
experimental test and FEA of a steel frame connection. The same connection is
analyzed in two situations. The second case analyses the connection having
some of the elements strengthened in order to increase the capacity of the
specimen. The analysis is performed using solid finite element and is compared
to the experimental test performed in the laboratory. Several considerations,
such as identical conditions for force definition, have to be taken into
account in order to obtain good results.
Keywords: Deformed shape,
strengthen, strain gauge, boundary conditions, stresses
Title of the Paper: On the Influence of
Residual Stresses on Fatigue Fracture of Railway Axles
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Authors: Aurel Raduta,
Cosmin Locovei, Mircea Nicoara, Laurentiu Roland Cucuruz
Abstract: Influence of residual stresses on the fatigue propagation of cracks
represents a major concern for important components subject to complex
loading. The purpose of present research is to numerically predict the
lifetime of axles used for railway tank wagons in various theoretical
conditions. The developed procedure is based on both calculating residual
thermal stresses by mean of finite element method, and the number of cycles to
fracture, using the closed form solution of NASGRO equation for fatigue.
Calculations of fatigue resistance are based on fatigue crack development
starting from an initial crack detectable by means of non-destructive testing.
The numerical prediction of number of cycles (or kilometers) to fracture for
axles belonging to railway tank wagons has proved the deep negative impact of
residual thermal stresses introduced by poorly controlled heat treatments or
other processing procedures.
Keywords: Fatigue
fracture, NASGRO equation (Forman–Newman–de Koning equation), Von Misses
stresses, Finite element analysis (FEA), Residual thermal stresses, Lifetime
prediction.
Title of the Paper: Optimal Design of
Heating Elements Sheathed with INCOLOY Superalloy 800
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Authors: Aurel Raduta,
Mircea Nicoara, Laurentiu Roland Cucuruz, Cosmin Locovei
Abstract: Electric heating has become in recent years the first choice for
both industrial and household applications, since reduction of carbon dioxide
emissions represents a major concern, and has caused replacement of solutions
based on burning of gas or oil. Considering the importance of low energy
consumption and increased functional safety, significant efforts have been
made for design optimization. Microstructural analysis has determined that
most of failures reported during exploitation and maintenance of electric
heaters for production of hot water are caused by overheating of metallic
components, although existing components are usually fabricated from heat
resistant steels or super-alloys such as INCOLOY 800. Therefore constructive
optimization has been based of an analysis of temperature distribution in
heated water and on surface of heating element, using the finite elements, for
both classical solutions, which are mostly based on empirical experience, and
some new technical solutions that have been proposed to improve the existing
design experience. The newly optimized solutions are based on new forms of
heating elements, as well as different positions for water inlet or outlet.
Simulations of temperature distributions indicate that optimized shapes of
heating element are likely to improve both heating efficiency and reduce
occurrence of failures.
Keywords: INCOLOY 800,
Heat transfer, Pitting corrosion, Fluid flow, Electric heating, Finite
elements
Issue 4, Volume 5,
October 2010
Title of the Paper: Applicability
Analysis of 2D-Models for Masonry Arch Bridge Assessment: Ring, Archie-M and
the Elasto-Plastic Model
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Authors: Amaryllis
Audenaert, Johan Beke
Abstract: A lot of different tools are available for the assessment of masonry
arch bridges:experimental formulae,2D-models and finite-element models and
discrete-element models (2D as well as 3D) . Due to the complex behaviour of
the arches and the disability of determine the material properties of the arch
and the infill of these ancient constructions, many different suppositions
have been made for the different models. Until now there is not yet a
generally accepted method for assessment. This study covers a comparison of
some 2D assessment tools. Three models are compared based on a case study:
Ring, Archie-M and an elasto-plastic model. It is concluded that every model
has advantages and disadvantages. Thus it cannot be stated which model should
be preferred.
Keywords: Masonry arch
bridge, assessment methods, collapse load, comparison study, Ring, Archie-M,
elastoplastic model
Title of the Paper: Quantitative and
Qualitative Study on the State of Stresses and Strains of the Strength
Structure of a Crane Bridge
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Authors: Camelia
Bretotean Pinca, Gelu Ovidiu Tirian, Ana Josan, Gladiola Chete
Abstract: In heavy-duty material handling equipment, major concern is optimum
utilization of material for equipment construction without sacrificing the
design parameters. To understand this aspect and also to validate the design,
as this kind of equipment are vital part of any manufacturing industry, finite
element analysis is one of the best method that can be used extensively. This
paper work provides a modeling of the structural strength of a crane bridge,
in operation for 15 years in the continuous casting department of a steel
plant. Due to the importance of the cranes bridge within the technological
processes in which they are involved, either from the point of view of steel
consumption or functionality, their resistance calculation, during the design
phase and after a certain operation period, constitutes a permanent field of
investigation which aims a faithful schematization to be used in further
modeling, appropriate for our target. Modeling will be done with the aid of a
COSMOS/M software in two numerical variants using beam3 and shell 3 type
finite element. This paper work is meant for checking out the limit state of
the structure subject to normal operation, which involved the evaluation of
its reaction while under working in terms of quantity and quality. In
quantitative terms, we have revealed that the structure had reserves of
strength; qualitatively speaking it had confirmed the validity of modeling.
Keywords: Crane bridge,
modeling, strength, structure, finite elements, shell
Title of the Paper: Resistance of
Thin-Walled Plate Girders under Combined Bending and Shear
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Authors: Zdenek Kala,
Jiri Kala
Abstract: The objective of the paper is to analyze the influence of initial
imperfections on the behavior of thin-walled girders welded of slender plate
elements. A number of full-scale plate girders are modeled and analyzed to
determine their bending and shear failure mechanism characteristics. The
design of a thin-walled system is always rather complicated as also the
influence of initial imperfections is to be taken into account to a greater
extent. The theoretical analysis was based on a nonlinear variant of the
finite element method. All input imperfections were considered to be random
quantities. The statistical distributions were introduced according to both
experimentally obtained results and data given in literature. Random
realizations of input random quantities were simulated by the LHS (Latin
Hypercube Sampling) method. By means of sensitivity analysis, it was studied
to what extend the variability of initial imperfections was reflected in the
variability of stresses in the crack-prone areas of the girder.
Keywords: Resistance,
steel, imperfections, shell elements, girder, stability, sensitivity analysis,
reliability
Title of the Paper: Comparative Study of
Contact Stresses and Strains at Horizontal and Vertical Continuous Casting
Using Conventional and Innovative Methods of Withdrawing Profiles
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Authors: Marius Tufoi,
Ion Vela, Constantin Marta, Lenuta Suciu, Ionel Adelin Tuta, Cornel Mituletu
Abstract: This paper presents comparative study of contact stresses and
strains at horizontal continuous casting and an innovative method of the
half-finished products to horizontal continuous casting of metals. Withdrawal
of half-finished products to continuous casting of metals is generally
realized by using one or more pairs of metal rollers made of steel. The pairs
of rollers are electromechanical and hydraulic driven. This method of
half-finished products, although most prevalent, also presents drawbacks. The
method proposed by the authors, using jaws firing concentrically oriented,
with the half-finished product which is subject of the withdrawal
operation.The proposed method is an innovative, and eliminates the hydraulic
system of roller shrinkage on the profile, the necessary system in withdrawals
roller case. In this way is ensure energy saving and improves facility
efficiency and product quality. In terms of curvilinear wire vertical
continuous casting, the authors propose the optimization of withdrawal
cylinders. In vertical continuous casting withdrawal cylinders are generally
used to withdraw several sizes and types of profiles. This is because vertical
continuous casting applies only to the large semi-manufactured and change
withdrawal cylinders for every size and shape of the semi-manufacturing is not
economical. Thus, because the same cylinders are used to withdraw for several
types and sizes of semi-manufactured products, slip and deformation may occur,
which may affect product quality and reliability of vertical continuous
casting. To overcome this problem, the authors propose optimization withdrawal
cylinders. This optimization is done by machining the cylinder with more rays
that adapts to different kinds of round shapes, but also may withdraw and
blooms or billets.
Keywords: Continuous
casting, withdrawal, rollers, jaws, cylinder, advantages, FEM
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