Abstract: The reliability of the filtered HVBK model is now
investigated via some large eddy simulations (LES) of freely
decaying isotropic superfluid turbulence. For homogeneous
turbulence at very high Reynolds numbers, comparison of the terms
in the spectral kinetic energy budget equation indicates, in the
energy-containing range, that the production and energy transfer
effects become significant except for dissipation. In the inertial range,
where the two fluids are perfectly locked, the mutual friction maybe
neglected with respect to other terms. Also, the LES results for the
other terms of the energy balance are presented.
Abstract: In sheet metal forming process, raw material
mechanical properties are important parameters. This paper is to
compare the wall’s incline angle or formability of SS 400 steel and
SUS 304 stainless steel in single point incremental forming. The two
materials are ferrous base alloyed, which have the different unit cell,
mechanical property and chemical composition. They were forming
into cone shape specimens having 100 mm diameter with different
wall’s incline angle: 90o, 75o and 60o. The investigation was
continued until the specimens formed surface facture. The
experimental result showed that the smaller the wall incline angle
higher the formability with the both materials. The formability limit
of the ferrous base alloy was approx. 60o wall’s incline angle. By
nature, SS 400 has higher formability than SUS 304. This result can
be used as the initial data in designing the single point incremental
forming parts.
Abstract: Quality control helps industries in improvements of its
product quality and productivity. Statistical Process Control (SPC) is
one of the tools to control the quality of products that turning practice
in bringing a department of industrial engineering process under
control. In this research, the process control of a turning
manufactured at workshops machines. The varying measurements
have been recorded for a number of samples of a rice polished
cylinder obtained from a number of trials with the turning practice.
SPC technique has been adopted by the process is finally brought
under control and process capability is improved.
Abstract: Two micromechanical models for 3D smart composite
with embedded periodic or nearly periodic network of generally
orthotropic reinforcements and actuators are developed and applied to
cubic structures with unidirectional orientation of constituents.
Analytical formulas for the effective piezothermoelastic coefficients
are derived using the Asymptotic Homogenization Method (AHM).
Finite Element Analysis (FEA) is subsequently developed and used
to examine the aforementioned periodic 3D network reinforced smart
structures. The deformation responses from the FE simulations are
used to extract effective coefficients. The results from both
techniques are compared. This work considers piezoelectric materials
that respond linearly to changes in electric field, electric
displacement, mechanical stress and strain and thermal effects. This
combination of electric fields and thermo-mechanical response in
smart composite structures is characterized by piezoelectric and
thermal expansion coefficients. The problem is represented by unitcell
and the models are developed using the AHM and the FEA to
determine the effective piezoelectric and thermal expansion
coefficients. Each unit cell contains a number of orthotropic
inclusions in the form of structural reinforcements and actuators.
Using matrix representation of the coupled response of the unit cell,
the effective piezoelectric and thermal expansion coefficients are
calculated and compared with results of the asymptotic
homogenization method. A very good agreement is shown between
these two approaches.
Abstract: This work presents the result of investigations aimed
at determining the hardness of the welded Chromoly (A 4130) steel
plate of 2” thickness. Multi pass welding for the thick sections was
carried out and analyzed for the Chromoly alloy steel plates. The
study of hardness at the weld metal reveals that there is the presence
of different micro structure products which yields diverse properties.
The welding carried out using GMAW with ER70s-2 electrode.
Single V groove design was selected for the butt joint configuration.
The presence of hydrogen has been suppressed by selecting low
hydrogen electrode. Preheating of the plate prior to welding reduces
the cooling rate which also affects the weld metal microstructure. The
shielding gas composition used in this analysis is 80% Ar-20% CO2.
The experimental analysis gives the detailed study of the hardness of
the material.
Abstract: An investigation into the effect of countersunk depth,
plate thickness, countersunk angle and plate width on the stress
concentration around countersunk hole is carried out with the help of
finite element analysis. The variation of stress concentration with
respect to these parameters is studied for three types of loading viz.
uniformly distributed load, uniformly varying load and functionally
distributed load. The results of the finite element analysis are
interpreted and some conclusions are drawn. The distribution of
stress concentration around countersunk hole in isotropic plates
simply supported at all the edges is found similar and is independent
of loading. The maximum stress concentration also occurs at a
particular point irrespective of the loading conditions.
Abstract: In the present work, the finite element formulation for
the investigation of the effects of a localized interfacial degeneration
on the dynamic behavior of the [90°/0°] laminated composite plate
employing the state-space technique is performed. The stiffness of
the laminate is determined by assembling the stiffnesses of subelements.
This includes an introduction of an interface layer adopting
the virtually zero-thickness formulation to model the interfacial
degeneration. Also, the kinematically consistent mass matrix and
proportional damping have been formulated to complete the free
vibration governing expression. To simulate the interfacial
degeneration of the laminate, the degenerated areas are defined from
the center propagating outwards in a localized manner. It is found
that the natural frequency, damped frequency and damping ratio of
the plate decreases as the degenerated area of the interface increases.
On the contrary, the loss factor increases correspondingly.
Abstract: In today’s world, the LED display has been used for
presenting visual information under various circumstances. Such
information is an important intermediary in the human information
processing. Researchers have been investigated diverse factors that
influence this process effectiveness. The letter size is undoubtedly
one major factor that has been tested and recommended by many
standards and guidelines. However, viewing information on the
display from direct perpendicular position is a typical assumption
whereas many actual events are required viewing from the angles.
This current research aims to study the effect of oblique viewing
angle and viewing distance on ability to recognize alphabet, number,
and English word. The total of ten participants was volunteered to our
3 x 4 x 4 within subject study. Independent variables include three
distance levels (2, 6, and 12 m), four oblique angles (0, 45, 60, 75
degree), and four target types (alphabet, number, short word, and
long word). Following the method of constant stimuli our study
suggests that the larger oblique angle, ranging from 0 to 75 degree
from the line of sight, results in significant higher legibility threshold
or larger font size required (p-value < 0.05). Viewing distance factor
also shows to have significant effect on the threshold (p-value
Abstract: The substantial similarity of fatigue mechanism in a
new test rig for rolling contact fatigue (RCF) has been investigated. A
new reduced-scale test rig is designed to perform controlled RCF
tests in wheel-rail materials. The fatigue mechanism of the rig is
evaluated in this study using a combined finite element-fatigue
prediction approach. The influences of loading conditions on fatigue
crack initiation have been studied. Furthermore, the effects of some
artificial defects (squat-shape) on fatigue lives are examined. To
simulate the vehicle-track interaction by means of the test rig, a threedimensional
finite element (FE) model is built up. The nonlinear
material behaviour of the rail steel is modelled in the contact
interface. The results of FE simulations are combined with the critical
plane concept to determine the material points with the greatest
possibility of fatigue failure. Based on the stress-strain responses, by
employing of previously postulated criteria for fatigue crack initiation
(plastic shakedown and ratchetting), fatigue life analysis is carried
out. The results are reported for various loading conditions and
different defect sizes. Afterward, the cyclic mechanism of the test rig
is evaluated from the operational viewpoint. The results of fatigue
life predictions are compared with the expected number of cycles of
the test rig by its cyclic nature. Finally, the estimative duration of the
experiments until fatigue crack initiation is roughly determined.
Abstract: A new small–scale test rig developed for rolling
contact fatigue (RCF) investigations in wheel–rail material. This
paper presents the scaling strategy of the rig based on dimensional
analysis and mechanical modelling. The new experimental rig is
indeed a spinning frame structure with multiple wheel components
over a fixed rail-track ring, capable of simulating continuous wheelrail
contact in a laboratory scale. This paper describes the
dimensional design of the rig, to derive its overall scaling strategy
and to determine the key elements’ specifications. Finite element
(FE) modelling is used to simulate the mechanical behavior of the rig
with two sample scale factors of 1/5 and 1/7. The results of FE
models are compared with the actual railway system to observe the
effectiveness of the chosen scales. The mechanical properties of the
components and variables of the system are finally determined
through the design process.
Abstract: The crude oil in an oil well exists in various phases
such as gas, seawater, and sand, as well as oil. Therefore, a phase
separator is needed at the front of a single-phase pump for
pressurization and transfer. On the other hand, the application of a
multiphase pump can provide such advantages as simplification of the
equipment structure and cost savings, because there is no need for a
phase separation process. Therefore, the crude oil transfer method
using a multiphase pump is being applied to recently developed oil
wells. Due to this increase in demand, technical demands for the
development of multiphase pumps are sharply increasing, but the
progress of research into related technologies is insufficient, due to the
nature of multiphase pumps that require high levels of skills. This
study was conducted to verify the reliability of pump performance
evaluation using numerical analysis, which is the basis of the
development of a multiphase pump. For this study, a model was
designed by selecting the specifications of this study. The performance
of the designed model was evaluated through numerical analysis and
experiment. The results of the performance evaluation were compared
to verify the reliability of the result using numerical analysis.
Abstract: In structures, stress concentration is a factor of fatigue
fracture. Basically, the stress concentration is a phenomenon that
should be avoided. However, it is difficult to avoid the stress
concentration. Therefore, relaxation of the stress concentration is
important. The stress concentration arises from notches and circular
holes. There is a relaxation method that a composite patch covers a
notch and a circular hole. This relaxation method is used to repair
aerial wings, but it is not systematized. Composites are more
expensive than single materials. Accordingly, we propose the
relaxation method that a single material patch covers a notch and a
circular hole, and aim to systematize this relaxation method.
We performed FEA (Finite Element Analysis) about an object by
using a three-dimensional FEA model. The object was that a patch
adheres to a plate with a circular hole. And, a uniaxial tensile load acts
on the patched plate with a circular hole. In the three-dimensional FEA
model, it is not easy to model the adhesion layer. Basically, the yield
stress of the adhesive is smaller than that of adherents. Accordingly,
the adhesion layer gets to plastic deformation earlier than the adherents
under the yield load of adherents. Therefore, we propose the
three-dimensional FEA model which is applied a nonlinear elastic
region to the adhesion layer. The nonlinear elastic region was
calculated by a bilinear approximation. We compared the analysis
results with the tensile test results to confirm whether the analysis
model has usefulness. As a result, the analysis results agreed with the
tensile test results. And, we confirmed that the analysis model has
usefulness.
As a result that the three-dimensional FEA model was used to the
analysis, it was confirmed that an out-of-plane deformation occurred
to the patched plate with a circular hole. The out-of-plane deformation
causes stress increase of the patched plate with a circular hole.
Therefore, we investigated that the out-of-plane deformation affects
relaxation of the stress concentration in the plate with a circular hole
on this relaxation method. As a result, it was confirmed that the
out-of-plane deformation inhibits relaxation of the stress concentration
on the plate with a circular hole.
Abstract: Recently, there have been a lot of earthquakes in Japan.
It is necessary to promote seismic isolation devices for buildings. The
devices have been hardly diffused in attached houses, because the
devices are very expensive. We should develop a low-cost seismic
isolation device for detached houses. We suggested a new seismic
isolation device which uses a two-layer circular tube as a unit. If
hysteresis is produced in the two-layer circular tube under lateral
compression load, we think that the two-layer circular tube can have
energy absorbing capacity. It is necessary to contact the outer layer
and the inner layer to produce hysteresis. We have previously reported
how the inner layer comes in contact with the outer layer from a
perspective of analysis used mechanics of materials. We have clarified
that the inner layer comes in contact with the outer layer under a lateral
compression load. In this paper, we explored contact area between the
outer layer and the inner layer under a lateral compression load by
using FEA. We think that changing the inner layer’s thickness is
effective in increase the contact area. In order to change the inner
layer’s thickness, we changed the shape of the inner layer. As a result,
the contact area changes depending on the inner layer’s thickness.
Additionally, we experimented to check whether hysteresis occurs in
fact. As a consequence, we can reveal hysteresis in the two-layer
circular tube under the condition.
Abstract: This work presents a Computational Fluid Dynamics
(CFD) simulation of a butterfly valve used to control the flow of
combustible gas mixture in an industrial process setting.The work
uses CFD simulation to analyze the flow characteristics in the
vicinity of the valve, including the pressure distributions and
Frequency spectrum of the pressure pulsations downstream the valves
and the vortex shedding allow predicting the torque fluctuations
acting on the valve shaft and the possibility of generating mechanical
vibration and resonance.These fluctuations are due to aerodynamic
torque resulting from fluid turbulence and vortex shedding in the
valve vicinity.
The valve analyzed is located in a pipeline between two opposing
90o elbows, which exposes the valve and the surrounding structure to
the turbulence generated upstream and downstream the elbows at
either end of the pipe.CFD simulations show that the best location for
the valve from a vibration point of view is in the middle of the pipe
joining the elbows.
Abstract: This paper presents the design analysis of saddle
support of a horizontal pressure vessel. Since saddle have the vital
role to support the pressure vessel and to maintain its stability, it
should be designed in such a way that it can afford the vessel load
and internal pressure of the vessel due to liquid contained in the
vessel. A model of horizontal pressure vessel and saddle support is
created in ANSYS. Stresses are calculated using mathematical
approach and ANSYS software. The analysis reveals the zone of high
localized stress at the junction part of the pressure vessel and saddle
support due to operating conditions. The results obtained by both the
methods are compared with allowable stress value for safe designing.
Abstract: The cooling channels of injection mould play a crucial
role in determining the productivity of moulding process and the
product quality. It’s not a simple task to design high quality cooling
channels. In this paper, an intelligent cooling channels design system
including automatic layout of cooling channels, interference checking
and assembly of accessories is studied. Automatic layout of cooling
channels using genetic algorithm is analyzed. Through integrating
experience criteria of designing cooling channels, considering the
factors such as the mould temperature and interference checking, the
automatic layout of cooling channels is implemented. The method of
checking interference based on distance constraint algorithm and the
function of automatic and continuous assembly of accessories are
developed and integrated into the system. Case studies demonstrate the
feasibility and practicality of the intelligent design system.
Abstract: Bone properties and response behavior after static or
dynamic activation (loading) are still interesting topics in many fields
of the science especially in the biomechanical problems such as bone
loss of astronauts in space, osteoporosis, bone remodeling after
fracture or remodeling after surgery (endoprosthesis and implants)
and in osteointegration. This contribution deals with the relation
between physiological, demineralized and deproteinized state of the
turkey long bone – tibia. Three methods for comparison were used: 1)
densitometry, 2) three point bending and 3) frequency analysis. The
main goal of this work was to describe the decrease of the protein
(collagen) or mineral of the bone with relation to the fracture in three
point bending. The comparison is linked to the problem of different
bone mechanical behavior in physiological and osteoporotic state.
Abstract: The global solved problem is the calculation of the
parameters of ceramic material from a set of destruction tests of
ceramic heads of total hip joint endoprosthesis. The standard way of
calculation of the material parameters consists in carrying out a set of
3 or 4 point bending tests of specimens cut out from parts of the
ceramic material to be analysed. In case of ceramic heads, it is not
possible to cut out specimens of required dimensions because the
heads are too small (if the cut out specimens were smaller than the
normalised ones, the material parameters derived from them would
exhibit higher strength values than those which the given ceramic
material really has). A special destruction device for heads
destruction was designed and the solved local problem is the
modification of this destructive device based on the analysis of
tensile stress in the head for two different values of the depth of the
conical hole in the head. The goal of device modification is a shift of
the location with extreme value of σ1max from the region of head’s
hole bottom to its opening. This modification will increase the
credibility of the obtained material properties of bioceramics, which
will be determined from a set of head destructions using the Weibull
weakest link theory.
Abstract: 3D part library is an ideal approach to reuse the
existing design and thus facilitates the modeling process, which will
enhance the efficiency. In this paper, we implemented the thought on
the SolidWorks platform. The system supports the functions of type
and parameter selection, 3D template driving and part assembly.
Finally, BOM is exported in Excel format. Experiment shows that our
method can satisfy the requirement of die and mold designers.