Abstract: A large variety of pipe flange is required in marine
and construction industry. Pipe flanges are usually welded or screwed
to the pipe end and are connected with bolts. This approach is very
simple and widely used for a long time; however, it results in high
development cost and low productivity, and the productions made by
this approach usually have safety problem at the welding area. In this
research, a new approach of forming pipe flange based on cold
forging and floating die concept is presented. This innovative
approach increases the effectiveness of the material usage and save
the time cost compared with conventional welding method. To ensure the dimensional accuracy of the final product, the finite
element analysis (FEA) was carried out to simulate the process of
cold forging, and the orthogonal experiment methods were used to
investigate the influence of four manufacturing factors (pin die angle,
pipe flange angle, rpm, pin die distance from clamp jig) and predicted
the best combination of them. The manufacturing factors were
obtained by numerical and experimental studies and it shows that the
approach is very useful and effective for the forming of pipe flange,
and can be widely used later.
Abstract: A sliding door system is used in commercial vehicles
and passenger cars to allow a larger unobstructed access to the
interior for loading and unloading. The movement of a sliding door
on vehicle body is ensured by mechanisms and tracks having special
cross-section which is manufactured by roll forming and stretch
bending process. There are three tracks and three mechanisms which
are called upper, central and lower on a sliding door system. There
are static requirements as strength on different directions, rigidity for
mechanisms, door drop off, door sag; dynamic requirements as high
energy slam opening-closing and durability requirement to validate
these products. In addition, there is a kinematic requirement to find
out force values from door handle during manual operating. In this
study, finite element analysis and physical test results which are
realized for sliding door systems will be shared comparatively.
Abstract: In Automotive Industry, sliding door systems that are
also used as body closures are safety members. Extreme product tests
are realized to prevent failures in design process, but these tests
realized experimentally result in high costs. Finite element analysis is
an effective tool used for design process. These analyses are used
before production of prototype for validation of design according to
customer requirement. In result of this, substantial amount of time
and cost is saved. Finite element model is created for geometries that are designed in
3D CAD programs. Different element types as bar, shell and solid,
can be used for creating mesh model. Cheaper model can be created
by selection of element type, but combination of element type that
was used in model, number and geometry of element and degrees of
freedom affects the analysis result. Sliding door system is a good
example which used these methods for this study. Structural analysis
was realized for sliding door mechanism by using FE models. As
well, physical tests that have same boundary conditions with FE
models were realized. Comparison study for these element types,
were done regarding test and analyses results then optimum
combination was achieved.
Abstract: Spacer grid assembly supporting the nuclear fuel rods
is an important concern in the design of structural components of a
Pressurized Water Reactor (PWR). The spacer grid is composed by
springs and dimples which are formed from a strip sheet by means of
blanking and stamping processes. In this paper, the blanking process
and tooling parameters are evaluated by means of a 2D plane-strain
finite element model in order to evaluate the punch load and quality
of the sheared edges of Inconel 718 strips used for nuclear spacer
grids. A 3D finite element model is also proposed to predict the
tooling loads resulting from the stamping process of a preformed
Inconel 718 strip and to analyse the residual stress effects upon the
spring and dimple design geometries of a nuclear spacer grid.
Abstract: Typical load-bearing biological materials like bone,
mineralized tendon and shell, are biocomposites made from both
organic (collagen) and inorganic (biomineral) materials. This
amazing class of materials with intrinsic internally designed
hierarchical structures show superior mechanical properties with
regard to their weak components from which they are formed.
Extensive investigations concentrating on static loading conditions
have been done to study the biological materials failure. However,
most of the damage and failure mechanisms in load-bearing
biological materials will occur whenever their structures are exposed
to dynamic loading conditions. The main question needed to be
answered here is: What is the relation between the layout and
architecture of the load-bearing biological materials and their
dynamic behavior? In this work, a staggered model has been
developed based on the structure of natural materials at nanoscale and
Finite Element Analysis (FEA) has been used to study the dynamic
behavior of the structure of load-bearing biological materials to
answer why the staggered arrangement has been selected by nature to
make the nanocomposite structure of most of the biological materials.
The results showed that the staggered structures will efficiently
attenuate the stress wave rather than the layered structure.
Furthermore, such staggered architecture is effectively in charge of
utilizing the capacity of the biostructure to resist both normal and
shear loads. In this work, the geometrical parameters of the model
like the thickness and aspect ratio of the mineral inclusions selected
from the typical range of the experimentally observed feature sizes
and layout dimensions of the biological materials such as bone and
mineralized tendon. Furthermore, the numerical results validated with
existing theoretical solutions. Findings of the present work emphasize
on the significant effects of dynamic behavior on the natural
evolution of load-bearing biological materials and can help scientists
to design bioinspired materials in the laboratories.
Abstract: Studying stress and strain trends in the femur and
recognizing femur failure mechanism is very important for
preventing hip fracture in the elderly. The aim of this study was to
identify high stress and strain regions in the femur during normal
walking and falling to find the mechanical behavior and failure
mechanism of the femur. We developed a finite element model of the
femur from the subject’s quantitative computed tomography (QCT)
image and used it to identify potentially high stress and strain regions
during the single-leg stance and the sideways fall. It was found that
fracture may initiate from the superior region of femoral neck and
propagate to the inferior region during a high impact force such as
sideways fall. The results of this study showed that the femur bone is
more sensitive to strain than stress which indicates the effect of
strain, in addition to effect of stress, should be considered for failure
analysis.
Abstract: It is a major challenge to build a bridge superstructure
that has long-term durability and low maintenance requirements. A
solution to this challenge may be to use new materials or to
implement new structural systems. Fiber Reinforced Polymer (FRP)
composites have continued to play an important role in solving some
of persistent problems in infrastructure applications because of its
high specific strength, light weight, and durability. In this study, the
concept of the hybrid FRP-concrete structural systems is applied to a
bridge superstructure. The hybrid FRP-concrete bridge superstructure
is intended to have durable, structurally sound, and cost effective
hybrid system that will take full advantage of the inherent properties
of both FRP materials and concrete. In this study, two hybrid FRP-concrete
bridge systems were investigated. The first system consists
of trapezoidal cell units forming a bridge superstructure. The second
one is formed by arch cells. The two systems rely on using cellular
components to form the core of the bridge superstructure, and an
outer shell to warp around those cells to form the integral unit of the
bridge. Both systems were investigated analytically by using finite
element (FE) analysis. From the rigorous FE studies, it was
concluded that first system is more efficient than the second.
Abstract: Encapsulated O-rings are specifically designed to address the problem of sealing the most hostile chemicals and extreme temperature applications. Ultrasonic vibration hot embossing and ultrasonic welding techniques provide a fast and reliable method to fabricate encapsulated O-ring. This paper performs the design and analysis method of the acoustic horns with double extrusion to process tube double side flange simultaneously. The paper deals with study through Finite Element Method (FEM) of ultrasonic stepped horn used to process a capsulated O-ring, the theoretical dimensions of horns, and their natural frequencies and amplitudes are obtained through the simulations of COMOSOL software. Furthermore, real horns were fabricated, tested and verified to proof the practical utility of these horns.
Abstract: Transportation of long turbine blades from one place
to another is a difficult process. Hence a feasibility study of
modularization of wind turbine blade was taken from structural
standpoint through finite element analysis. Initially, a non-segmented
blade is modeled and its structural behavior is evaluated to serve as
reference. The resonant, static bending and fatigue tests are simulated
in accordance with IEC61400-23 standard for comparison purpose.
The non-segmented test blade is separated at suitable location based
on trade off studies and the segments are joined with an innovative
double strap bonded joint configuration. The adhesive joint is
modeled by adopting cohesive zone modeling approach in ANSYS.
The developed blade model is analyzed for its structural response
through simulation. Performances of both the blades are found to be
similar, which indicates that, efficient segmentation of the long blade
is possible which facilitates easy transportation of the blades and on
site reassembling. The location selected for segmentation and
adopted joint configuration has resulted in an efficient segmented
blade model which proves the methodology adopted for segmentation
was quite effective. The developed segmented blade appears to be the
viable alternative considering its structural response specifically in
fatigue within considered assumptions.
Abstract: The model tests were conducted in the laboratory
without and with Plastic recycled polymer in fly ash steep slopes
overlaying soft foundation soils like fly ash and powai soil in order to
check the stability of steep slope. In this experiment, fly ash is used
as a filling material and Plastic Recycled Polymers of diameter =
3mm and length = 4mm were made from waste plastic product (lower
grade plastic product). The properties of fly ash and Plastic recycled
polymers are determined. From the experiments, load and settlement
have measured. From these data, load –settlement curves have
reported. It has been observed from test results that load carrying
capacity of mixture fly ash with Plastic Recycled Polymers slope is
more than that of fly ash slope. The deformation of Plastic Recycled
Polymers slope is slightly more than that of fly ash slope. A Finite
Element Method (F.E.M.) was also evaluated using PLAXIS 3D
version. The failure pattern, deformations and factor of safety are
reported based on analytical programme. The results from
experimental data and analytical programme are compared and
reported.
Abstract: This paper is part of a study to develop robots for
farming. As such power requirement to operate equipment attach to
such robots become an important factor. Soil-tool interaction plays
major role in power consumption, thus predicting accurately the
forces which act on the blade during the farming is very important for
optimal designing of farm equipment. In this paper, a finite element
investigation for tillage tools and soil interaction is described by
using an inelastic constitutive material law for agriculture
application. A 3-dimensional (3D) nonlinear finite element analysis
(FEA) is developed to examine behavior of a blade with different
rake angles moving in a block of soil, and to estimate the blade force.
The soil model considered is an elastic-plastic with non-associated
Drucker-Prager material model. Special use of contact elements are
employed to consider connection between soil-blade and soil-soil
surfaces. The FEA results are compared with experimental ones,
which show good agreement in accurately predicting draft forces
developed on the blade when it moves through the soil. Also a very
good correlation was obtained between FEA results and analytical
results from classical soil mechanics theories for straight blades.
These comparisons verified the FEA model developed. For analyzing
complicated soil-tool interactions and for optimum design of blades,
this method will be useful.
Abstract: This paper presents experimental investigation and
finite element analysis on buckling behavior of irregular section coldformed
steel columns under axially concentric loading. For the
experimental study, four different sections of columns were tested to
investigate effect of stiffening and width-to-thickness ratio on
buckling behavior. For each of the section, three lengths of 230, 950
and 1900 mm. were studied representing short, intermediate long and
long columns, respectively. Then, nonlinear finite element analyses
of the tested columns were performed. The comparisons in terms of
load-deformation response and buckling mode show good agreement
and hence the FEM models were validated. Parametric study of
stiffening element and thickness of 1.0, 1.15, 1.2, 1.5, 1.6 and 2.0
mm. was analyzed. The test results showed that stiffening effect pays
a large contribution to prevent distortional mode. The increase in wall
thickness enhanced buckling stress beyond the yielding strength in
short and intermediate columns, but not for the long columns.
Abstract: Fixed-geometry hydrodynamic journal bearings are
one of the best supporting systems for several applications of rotating
machinery. Cylindrical journal bearings present excellent loadcarrying
capacity and low manufacturing costs, but they are subjected
to the oil-film instability at high speeds. An attempt of overcoming
this instability problem has been the development of non-circular
journal bearings. This work deals with an analysis of oil-lubricated
elliptical journal bearings using the finite element method. Steadystate
and dynamic performance characteristics of elliptical bearings
are rendered by zeroth- and first-order lubrication equations obtained
through a linearized perturbation method applied on the classical
Reynolds equation. Four-node isoparametric rectangular finite
elements are employed to model the bearing thin film flow. Curves of
elliptical bearing load capacity and dynamic force coefficients are
rendered at several operating conditions. The results presented in this
work demonstrate the influence of the bearing ellipticity on its
performance at different loading conditions.
Abstract: Total hip replacement had been one of the most
successful operations in hip arthritis surgery. The purpose of this
research had been to develop a dynamic hip contact of Thai femoral
bone to analyze the stress distribution on the implant and the strain
distribution on the bone model under daily activities and compared
with the static load simulation. The results showed the different of
maximum von Mises stress 0.14 percent under walking and 0.03
percent under climbing stair condition and the different of equivalent
total strain 0.52 percent under walking and 0.05 percent under
climbing stair condition. The muscular forces should be evaluated
with dynamic condition to reduce the maximum von Mises stress and
equivalent total strain.
Abstract: The pullout strength had an effect on the stability of
plate screw fixation when inserted in the cervical spine. Nine
different titanium alloy bone screws were used to test the pullout
strength through finite element analysis. The result showed that the
Moss Miami I can bear the highest pullout force at 1,075 N, which
causes the maximum von Mises stress at 858.87 MPa, a value over
the yield strength of titanium. The bone screw should have large
outer diameter, core diameter and proximal root radius to increase the
pullout strength.
Abstract: These days, the field of tissue engineering is getting
serious attention due to its usefulness. Bone tissue engineering helps
to address and sort-out the critical sized and non-healing orthopedic
problems by the creation of manmade bone tissue. We will design
and validate an efficient numerical model, which will simulate the
effective diffusivity in bone tissue engineering. Our numerical model
will be based on the finite element analysis of the diffusion-reaction
equations. It will have the ability to optimize the diffusivity, even
at multi-scale, with the variation of time. It will also have a special
feature “parametric sweep”, with which we will be able to predict
the oxygen, glucose and cell density dynamics, more accurately. We
will fix these problems by modifying the governing equations, by
selecting appropriate spatio-temporal finite element schemes and by
transient analysis.
Abstract: The use OF adhesive anchors for wooden constructions is an efficient technology to connect and design timber members in new timber structures and to rehabilitate the damaged structural members of historical buildings. Due to the lack of standard regulation in this specific area of structural design, designers’ choices are still supported by test analysis that enables knowledge, and the prediction, of the structural behaviour of glued in rod joints. The paper outlines an experimental research activity aimed at identifying the tensile resistance capacity of several new adhesive joint prototypes made of epoxy resin, steel bar and timber, Oak and Douglas Fir species. The development of new adhesive connectors has been carried out by using epoxy to glue stainless steel bars into pre-drilled holes, characterised by smooth and rough internal surfaces, in timber samples. The realization of a threaded contact surface using a specific drill bit has led to an improved bond between wood and epoxy. The applied changes have also reduced the cost of the joints’ production. The paper presents the results of this parametric analysis and a Finite Element analysis that enables identification and study of the internal stress distribution in the proposed adhesive anchors.
Abstract: The aim of this study is to develop an anterior lumbar
interbody fusion (ALIF) PEEK cage suitable for Korean people. In this
study, CT images were obtained from Korean male (173cm, 71kg) and
3D Korean lumbar models were reconstructed based on the CT images
to investigate anatomical characteristics. Major design parameters of
anterior lumbar interbody fusion (ALIF) PEEK Cage were selected
using the morphological measurement information of the Korean
Lumbar models. Through finite element analysis and mechanical tests,
the developed ALIFPEEK Cage prototype was compared with the
Fidji Cage (Zimmer. Inc, USA) and it was found that the ALIF
prototype showed similar and/or superior mechanical performance
compared to the FidJi Cage. Also, clinical validation for the ALIF
PEEK Cage prototype was carried out to check predictable troubles in
surgical operations. Finally, it is considered that the convenience and
stability of the prototype was clinically verified.
Abstract: In this paper, a nonlinear Finite Element Analysis
(FEA) was carried out using ANSYS software to build a model able
of predicting the behavior of Reinforced Concrete (RC) beams with
unbonded reinforcement. The FEA model was compared to existing
experimental data by other researchers. The existing experimental
data consisted of 16 beams that varied from structurally sound beams
to beams with unbonded reinforcement with different unbonded
lengths and reinforcement ratios. The model was able to predict the
ultimate flexural strength, load-deflection curve, and crack pattern of
concrete beams with unbonded reinforcement. It was concluded that
when the when the unbonded length is less than 45% of the span,
there will be no decrease in the ultimate flexural strength due to the
loss of bond between the steel reinforcement and the surrounding
concrete regardless of the reinforcement ratio. Moreover, when the
reinforcement ratio is relatively low, there will be no decrease in
ultimate flexural strength regardless of the length of unbond.
Abstract: Regardless of the manufacturing process used,
subtractive or additive, material, purpose and application, produced
components are conventionally solid mass with more or less complex
shape depending on the production technology selected. Aspects
such as reducing the weight of components, associated with the low
volume of material required and the almost non-existent material
waste, speed and flexibility of production and, primarily, a high
mechanical strength combined with high structural performance, are
competitive advantages in any industrial sector, from automotive,
molds, aviation, aerospace, construction, pharmaceuticals, medicine
and more recently in human tissue engineering. Such features,
properties and functionalities are attained in metal components
produced using the additive technique of Rapid Prototyping from
metal powders commonly known as Selective Laser Melting (SLM),
with optimized internal topologies and varying densities. In order to
produce components with high strength and high structural and
functional performance, regardless of the type of application, three
different internal topologies were developed and analyzed using
numerical computational tools. The developed topologies were
numerically submitted to mechanical compression and four point
bending testing. Finite Element Analysis results demonstrate how
different internal topologies can contribute to improve mechanical
properties, even with a high degree of porosity relatively to fully
dense components. Results are very promising not only from the
point of view of mechanical resistance, but especially through the
achievement of considerable variation in density without loss of
structural and functional high performance.