Abstract: A stiffened laminated composite panel (1 m length ×
0.5m width) was optimized for minimum weight and deflection under
several constraints using genetic algorithm. Here, a significant study
on the performance of a penalty function with two kinds of static and
dynamic penalty factors was conducted. The results have shown that
linear dynamic penalty factors are more effective than the static ones.
Also, a specially combined linear-exponential function has shown to
perform more effective than the previously mentioned penalty
functions. This was then resulted in the less sensitivity of the GA to
the amount of penalty factor.
Abstract: To date, theoretical studies concerning the Carbon
Fiber Reinforced Polymer (CFRP) strengthening of RC beams with
openings have been rather limited. In addition, various numerical
analyses presented so far have effectively simulated the behaviour of
solid beam strengthened by FRP material. In this paper, a two
dimensional nonlinear finite element analysis is presented to validate
against the laboratory test results of six RC beams. All beams had the
same rectangular cross-section geometry and were loaded under four
point bending. The crack pattern results of the finite element model
show good agreement with the crack pattern of the experimental
beams. The load midspan deflection curves of the finite element
models exhibited a stiffer result compared to the experimental beams.
The possible reason may be due to the perfect bond assumption used
between the concrete and steel reinforcement.
Abstract: The geometric errors in the manufacturing process can
be reduced by optimal positioning of the fixture elements in the
fixture to make the workpiece stiff. We propose a new fixture layout
optimization method N-3-2-1 for large metal sheets in this paper that
combines the genetic algorithm and finite element analysis. The
objective function in this method is to minimize the sum of the nodal
deflection normal to the surface of the workpiece. Two different
kinds of case studies are presented, and optimal position of the
fixturing element is obtained for different cases.
Abstract: Optical burst switching (OBS) has been proposed to
realize the next generation Internet based on the wavelength division
multiplexing (WDM) network technologies. In the OBS, the burst
contention is one of the major problems. The deflection routing has
been designed for resolving the problem. However, the deflection
routing becomes difficult to prevent from the burst contentions as the
network load becomes high. In this paper, we introduce a flow rate
control methods to reduce burst contentions. We propose new flow
rate control methods based on the leaky bucket algorithm and
deflection routing, i.e. separate leaky bucket deflection method, and
dynamic leaky bucket deflection method. In proposed methods, edge
nodes which generate data bursts carry out the flow rate control
protocols. In order to verify the effectiveness of the flow rate control in
OBS networks, we show that the proposed methods improve the
network utilization and reduce the burst loss probability through
computer simulations.
Abstract: A theoretical study of the rigidities of slabs with
circular voids oriented in the longitudinal and in the transverse
direction is discussed. Equations are presented for predicting the
bending and torsional rigidities of the voided slabs. This paper
summarizes the results of an extensive literature search and initial
review of the current methods of analyzing voided slab. The various
methods of calculating the equivalent plate parameters, which are
necessary for two-dimensional analysis, are also reviewed. Static
deflections on voided slabs are shown to be in good agreement with
proposed equation.
Abstract: The main objectives of this study are to inspect and
identify any damage of jaimusi highway prestressed concrete bridge
after repair and strengthening of damaged structural members and to
evaluate the performance of the bridge structural members by
adopting static load test. Inspection program after repair and
strengthening includes identifying and evaluating the structural
members of bridge such as T-shape cantilever structure, hanging
beams, corbels, external tendons, anchor beams, sticking steel plate,
and piers. The results of inspection show that the overall state of the
bridge structural member after repair and strengthening is good. The
results of rebound test of concrete strength show that the average
strength of concrete is 46.31Mpa. Whereas, the average value of
concrete strength of anchor beam is 49.82Mpa. According to the
results of static load test, the experimental values are less than
theoretical values of internal forces, deflection, and strain, indicating
that the stiffness of the experimental structure, overall deformation
and integrity satisfy the designed standard and the working
performance is good, and the undertaking capacity has a certain
surplus. There is not visible change in the length and width of cracks
and there are not new cracks under experimental load.
Abstract: The aim of this paper is to determine the stress levels
at the end of a long slender shaft such as a drilling assembly used in
the oil or gas industry using a mathematical model in real-time. The
torsional deflection experienced by this type of drilling shaft (about 4
KM length and 20 cm diameter hollow shaft with a thickness of 1
cm) can only be determined using a distributed modeling technique.
The main objective of this project is to calculate angular velocity and
torque at the end of the shaft by TLM method and also analyzing of
the behavior of the system by transient response. The obtained result
is compared with lumped modeling technique the importance of these
results will be evident only after the mentioned comparison. Two
systems have different transient responses and in this project because
of the length of the shaft transient response is very important.
Abstract: Reinforced concrete stair slabs with mid landings i.e.
Dog-legged shaped are conventionally designed as per specifications
of standard codes of practices which guide about the effective span
according to the varying support conditions. Presently, the behavior
of such slabs has been investigated using Finite Element method. A
single flight stair slab with landings on both sides and supported at
ends on wall, and a multi flight stair slab with landings and six
different support arrangements have been analyzed. The results
obtained for stresses, strains and deflections are used to describe the
behavior of such stair slabs, including locations of critical moments
and deflections. Values of critical moments obtained by F.E. analysis
have also have been compared with that obtained from conventional
analysis. Analytical results show that the moments are also critical
near the kinks i.e. junction of mid-landing and inclined waist slab.
This change in the behavior of dog-legged stair slab may be due to
continuity of the material in transverse direction in two landings
adjoining the waist slab, hence additional stiffness achieved. This
change in the behavior is generally not taken care of in conventional
method of design.
Abstract: The objective of positioning the fixture elements in
the fixture is to make the workpiece stiff, so that geometric errors in
the manufacturing process can be reduced. Most of the work for
optimal fixture layout used the minimization of the sum of the nodal
deflection normal to the surface as objective function. All deflections
in other direction have been neglected. We propose a new method for
fixture layout optimization in this paper, which uses the element
strain energy. The deformations in all the directions have been
considered in this way. The objective function in this method is to
minimize the sum of square of element strain energy. Strain energy
and stiffness are inversely proportional to each other. The
optimization problem is solved by the sequential quadratic
programming method. Three different kinds of case studies are
presented, and results are compared with the method using nodal
deflections as objective function to verify the propose method.
Abstract: A Vehicle-s door wireing harness arrangement structure is provided. In vehicle-s door wiring harness(W/H) system is more toward to arrange a passenger compartment than a hinge and a weatherstrip. This article gives some insight into the dimensioning process, with special focus on large deflection analysis of wiring harness(W/H) in vehicle-s door structures for durability problem. An Finite elements analysis for door wiring harness(W/H) are used for residual stresses and dimensional stability with bending flexible. Durability test data for slim test specimens were compared with the numerical predicted fatigue life for verification. The final lifing of the component combines the effects of these microstructural features with the complex stress state arising from the combined service loading and residual stresses.
Abstract: State-dependent Riccati equation based controllers are
becoming increasingly popular because of having attractive
properties like optimality, stability and robustness. This paper focuses
on the design of a roll autopilot for a fin stabilized and canard
controlled 122mm artillery rocket using state-dependent Riccati
equation technique. Initial spin is imparted to rocket during launch
and it quickly decays due to straight tail fins. After the spin phase, the
roll orientation of rocket is brought to zero with the canard deflection
commands generated by the roll autopilot. Roll autopilot has been
developed by considering uncoupled roll, pitch and yaw channels.
The canard actuator is modeled as a second-order nonlinear system.
Elements of the state weighing matrix for Riccati equation have been
chosen to be state dependent to exploit the design flexibility offered
by the Riccati equation technique. Simulation results under varying
conditions of flight demonstrate the wide operating range of the
proposed autopilot.
Abstract: In recent years, scanning probe atomic force
microscopy SPM AFM has gained acceptance over a wide spectrum
of research and science applications. Most fields focuses on physical,
chemical, biological while less attention is devoted to manufacturing
and machining aspects. The purpose of the current study is to assess
the possible implementation of the SPM AFM features and its
NanoScope software in general machining applications with special
attention to the tribological aspects of cutting tool. The surface
morphology of coated and uncoated as-received carbide inserts is
examined, analyzed, and characterized through the determination of
the appropriate scanning setting, the suitable data type imaging
techniques and the most representative data analysis parameters
using the MultiMode SPM AFM in contact mode. The NanoScope
operating software is used to capture realtime three data types
images: “Height", “Deflection" and “Friction". Three scan sizes are
independently performed: 2, 6, and 12 μm with a 2.5 μm vertical
range (Z). Offline mode analysis includes the determination of three
functional topographical parameters: surface “Roughness", power
spectral density “PSD" and “Section". The 12 μm scan size in
association with “Height" imaging is found efficient to capture every
tiny features and tribological aspects of the examined surface. Also,
“Friction" analysis is found to produce a comprehensive explanation
about the lateral characteristics of the scanned surface. Configuration
of many surface defects and drawbacks has been precisely detected
and analyzed.
Abstract: High strength concrete (HSC) provides high strength
but lower ductility than normal strength concrete. This low ductility
limits the benefit of using HSC in building safe structures. On the
other hand, when designing reinforced concrete beams, designers
have to limit the amount of tensile reinforcement to prevent the
brittle failure of concrete. Therefore the full potential of the use of
steel reinforcement can not be achieved. This paper presents the idea
of confining concrete in the compression zone so that the HSC will
be in a state of triaxial compression, which leads to improvements in
strength and ductility. Five beams made of HSC were cast and tested.
The cross section of the beams was 200×300 mm, with a length of 4
m and a clear span of 3.6 m subjected to four-point loading, with
emphasis placed on the midspan deflection. The first beam served as
a reference beam. The remaining beams had different tensile
reinforcement and the confinement shapes were changed to gauge
their effectiveness in improving the strength and ductility of the
beams. The compressive strength of the concrete was 85 MPa and the
tensile strength of the steel was 500 MPa and for the stirrups and
helixes was 250 MPa. Results of testing the five beams proved that
placing helixes with different diameters as a variable parameter in the
compression zone of reinforced concrete beams improve their
strength and ductility.
Abstract: Experimental study on the influence of fibre content
on crack behaviour and propagation in synthetic-fibre reinforced
beams has been reported in this paper. The tensile behaviour of
metallic fibre concrete is evaluated in terms of residual flexural
tensile strength values determined from the load-crack mouth
opening displacement curve or load-deflection curve obtained by
applying a centre-point load on a simply supported notched prism.
The results achieved demonstrate that an increase in fibre content has
an almost negligible effect on compressive and tensile splitting
properties, causes a marginal increment in flexural tensile strength
and increasesthe Re3 value.
Abstract: Helical milling operations are used to generate or
enlarge boreholes by means of a milling tool. The bore diameter can be
adjusted through the diameter of the helical path. The kinematics of
helical milling on a three axis machine tool is analysed firstly. The
relationships between processing parameters, cutting tool geometry
characters with machined hole feature are formulated. The feed motion
of the cutting tool has been decomposed to plane circular feed and
axial linear motion. In this paper, the time varying cutting forces acted
on the side cutting edges and end cutting edges of the flat end cylinder
miller is analysed using a discrete method separately. These two
components then are combined to produce the cutting force model
considering the complicated interaction between the cutters and
workpiece. The time varying cutting force model describes the
instantaneous cutting force during processing. This model could be
used to predict cutting force, calculate statics deflection of cutter and
workpiece, and also could be the foundation of dynamics model and
predicting chatter limitation of the helical milling operations.
Abstract: In this paper, 3X3 routing nodes are proposed to
provide speedup and parallel processing capability in Data Vortex
network architectures. The new design not only significantly
improves network throughput and latency, but also eliminates the
need for distributive traffic control mechanism originally embedded
among nodes and the need for nodal buffering. The cost effectiveness
is studied by a comparison study with the previously proposed 2-
input buffered networks, and considerable performance enhancement
can be achieved with similar or lower cost of hardware. Unlike
previous implementation, the network leaves small probability of
contention, therefore, the packet drop rate must be kept low for such
implementation to be feasible and attractive, and it can be achieved
with proper choice of operation conditions.
Abstract: In this paper by measuring the cutting forces the effect
of the tool shape and qualifications (sharp and worn cutting tools of
both vee and knife edge profile) and cutting conditions (depth of cut
and cutting speed) in the turning operation on the tool deflection and
cutting force is investigated. The workpiece material was mild steel
and the cutting tool was made of high speed steel. Cutting forces
were measured by a dynamometer (type P.E.I. serial No 154). The
dynamometer essentially consisted of a cantilever structure which
held the cutting tool. Deflection of the cantilever was measured by an
L.V.D.T (Mercer 122) deflection indicator. No cutting fluid was used
during the turning operations. A modern CNC lathe machine (Okuma
LH35-N) was used for the tests. It was noted that worn vee profile
tools tended to produce a greater increase in the vertical force
component than the axial component, whereas knife tools tended to
show a more pronounced increase in the axial component.
Abstract: This paper deals with a numerical analysis of the
transient response of composite beams with strain rate dependent
mechanical properties by use of a finite difference method. The
equations of motion based on Timoshenko beam theory are derived.
The geometric nonlinearity effects are taken into account with von
Kármán large deflection theory. The finite difference method in
conjunction with Newmark average acceleration method is applied to
solve the differential equations. A modified progressive damage
model which accounts for strain rate effects is developed based on
the material property degradation rules and modified Hashin-type
failure criteria and added to the finite difference model. The
components of the model are implemented into a computer code in
Mathematica 6. Glass/epoxy laminated composite beams with
constant and strain rate dependent mechanical properties under
dynamic load are analyzed. Effects of strain rate on dynamic
response of the beam for various stacking sequences, load and
boundary conditions are investigated.
Abstract: The distributions of stresses and deflection in
rectangular isotropic and orthotropic plates with central
circular hole under transverse static loading have been studied
using finite element method. The aim of author is to analyze
the effect of D/A ratio (where D is hole diameter and A is plate
width) upon stress concentration factor (SCF) and deflection
in isotropic and orthotropic plates under transverse static
loading. The D/A ratio is varied from 0.01 to 0.9. The analysis
is done for plates of isotropic and two different orthotropic
materials. The results are obtained for three different boundary
conditions. The variations of SCF and deflection with respect
to D/A ratio are presented in graphical form and discussed.
The finite element formulation is carried out in the analysis
section of the ANSYS package.