Analysis of Stress Concentration and Deflectionin Isotropic and Orthotropic Rectangular Plates with Central Circular Hole under Transverse Static Loading
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.
Numerical Analysis of a Centrifugal Fan for Improved Performance using Splitter Vanes
The flow field in a centrifugal fan is highly complex
with flow reversal taking place on the suction side of impeller and
diffuser vanes. Generally performance of the centrifugal fan could be
enhanced by judiciously introducing splitter vanes so as to improve
the diffusion process. An extensive numerical whole field analysis on
the effect of splitter vanes placed in discrete regions of suspected
separation points is possible using CFD. This paper examines the
effect of splitter vanes corresponding to various geometrical
locations on the impeller and diffuser. The analysis shows that the
splitter vanes located near the diffuser exit improves the static
pressure recovery across the diffusing domain to a larger extent. Also
it is found that splitter vanes located at the impeller trailing edge and
diffuser leading edge at the mid-span of the circumferential distance
between the blades show a marginal improvement in the static
pressure recovery across the fan. However, splitters provided near to
the suction side of the impeller trailing edge (25% of the
circumferential gap between the impeller blades towards the suction
side), adversely affect the static pressure recovery of the fan.
Design, Development and Analysis of Automated Storage and Retrieval System with Single and Dual Command Dispatching using MATLAB
Automated material handling is given prime
importance in the semi automated and automated facilities since it
provides solution to the gigantic problems related to inventory and
also support the latest philosophies like just in time production JIT
and lean production. Automated storage and retrieval system is an
antidote (if designed properly) to the facility sufferings like getting
the right material , materials getting perished, long cycle times or
many other similar kind of problems. A working model of automated
storage and retrieval system (AS/RS) is designed and developed
under the design parameters specified by Material Handling Industry
of America (MHIA). Later on analysis was carried out to calculate
the throughput and size of the machine. The possible implementation
of this technology in local scenario is also discussed in this paper.
Accurate Dimensional Measurement of 3D Round Holes Based on Stereo Vision
This paper present an effective method to accurately reconstruct and measure the 3D curve edges of small industrial parts based on stereo vision. To effectively fit the curve of the measured parts using a series of line segments in the images, a strategy from coarse to fine is employed based on multi-scale curve fitting. After reconstructing the 3D curve of a hole through a curved surface, its axis is adjusted so that it is parallel to the Z axis with least squares error and the dimensions of the hole can be calculated on the XY plane easily. Experimental results show that the presented method can accurately measure the dimensions of round holes through a curved surface.
Fuzzy-Genetic Optimal Control for Four Degreeof Freedom Robotic Arm Movement
In this paper, we present optimal control for
movement and trajectory planning for four degrees-of-freedom robot
using Fuzzy Logic (FL) and Genetic Algorithms (GAs). We have
evaluated using Fuzzy Logic (FL) and Genetic Algorithms (GAs)
for four degree-of-freedom (4 DOF) robotics arm, Uncertainties like;
Movement, Friction and Settling Time in robotic arm movement
have been compensated using Fuzzy logic and Genetic Algorithms.
The development of a fuzzy genetic optimization algorithm is
presented and discussed. The result are compared only GA and
Fuzzy GA. This paper describes genetic algorithms, which is
designed to optimize robot movement and trajectory. Though the
model represents is a general model for redundant structures and
could represent any n-link structures. The result is a complete
trajectory planning with Fuzzy logic and Genetic algorithms
demonstrating the flexibility of this technique of artificial
A Supply Chain Perspective of RFID Systems
Radio Frequency Identification (RFID) initially introduced
during WW-II, has revolutionized the world with its numerous
benefits and plethora of implementations in diverse areas ranging
from manufacturing to agriculture to healthcare to hotel management.
This work reviews the current research in this area with emphasis
on applications for supply chain management and to develop a
taxonomic framework to classify literature which will enable swift
and easy content analysis and also help identify areas for future
Modified Data Mining Approach for Defective Diagnosis in Hard Disk Drive Industry
Currently, slider process of Hard Disk Drive Industry
become more complex, defective diagnosis for yield improvement
becomes more complicated and time-consumed. Manufacturing data
analysis with data mining approach is widely used for solving that
problem. The existing mining approach from combining of the KMean
clustering, the machine oriented Kruskal-Wallis test and the
multivariate chart were applied for defective diagnosis but it is still
be a semiautomatic diagnosis system. This article aims to modify an
algorithm to support an automatic decision for the existing approach.
Based on the research framework, the new approach can do an
automatic diagnosis and help engineer to find out the defective
factors faster than the existing approach about 50%.
Design of Angular Estimator of Inertial Sensor Using the Least Square Method
Since MEMS gyro sensors measure not angle of rotation but angular rate, an estimator is designed to estimate the angles in many applications. Gyro and accelerometer are used to improve estimating accuracy of the angle. This paper presents a method of finding filter coefficients of the well-known estimator which is to get rotation angles from gyro and accelerometer data. In order to verify the performance of our method, the estimated angle is compared with the encoder output in a rotary pendulum system.
A Combined Fuzzy Decision Making Approach to Supply Chain Risk Assessment
Many firms implemented various initiatives such as outsourced manufacturing which could make a supply chain (SC) more vulnerable to various types of disruptions. So managing risk has become a critical component of SC management. Different types of SC vulnerability management methodologies have been proposed for managing SC risk, most offer only point-based solutions that deal with a limited set of risks. This research aims to reinforce SC risk management by proposing an integrated approach. SC risks are identified and a risk index classification structure is created. Then we develop a SC risk assessment approach based on the analytic network process (ANP) and the VIKOR methods under the fuzzy environment where the vagueness and subjectivity are handled with linguistic terms parameterized by triangular fuzzy numbers. By using FANP, risks weights are calculated and then inserted to the FVIKOR to rank the SC members and find the most risky partner.
Motion Protection System Design for a Parallel Motion Platform
A motion protection system is designed for a parallel
motion platform with subsided cabin. Due to its complex structure,
parallel mechanism is easy to encounter interference problems
including link length limits, joints limits and self-collision. Thus a
virtual spring algorithm in operational space is developed for the
motion protection system to avoid potential damages caused by
interference. Simulation results show that the proposed motion
protection system can effectively eliminate interference problems and
ensure safety of the whole motion platform.
Study of Integrated Vehicle Image System Including LDW, FCW, and AFS
The objective of this research is to develop an advanced driver assistance system characterized with the functions of lane departure warning (LDW), forward collision warning (FCW) and adaptive front-lighting system (AFS). The system is mainly configured a CCD/CMOS camera to acquire the images of roadway ahead in association with the analysis made by an image-processing unit concerning the lane ahead and the preceding vehicles. The input image captured by a camera is used to recognize the lane and the preceding vehicle positions by image detection and DROI (Dynamic Range of Interesting) algorithms. Therefore, the system is able to issue real-time auditory and visual outputs of warning when a driver is departing the lane or driving too close to approach the preceding vehicle unwittingly so that the danger could be prevented from occurring. During the nighttime, in addition to the foregoing warning functions, the system is able to control the bending light of headlamp to provide an immediate light illumination when making a turn at a curved lane and adjust the level automatically to reduce the lighting interference against the oncoming vehicles driving in the opposite direction by the curvature of lane and the vanishing point estimations. The experimental results show that the integrated vehicle image system is robust to most environments such as the lane detection and preceding vehicle detection average accuracy performances are both above 90 %.
CFD Analysis on Aerodynamic Design Optimization of Wind Turbine Rotor Blades
Wind energy has been shown to be one of the most
viable sources of renewable energy. With current technology, the low
cost of wind energy is competitive with more conventional sources of
energy such as coal. Most blades available for commercial grade
wind turbines incorporate a straight span-wise profile and airfoil
shaped cross sections. These blades are found to be very efficient at
lower wind speeds in comparison to the potential energy that can be
extracted. However as the oncoming wind speed increases the
efficiency of the blades decreases as they approach a stall point. This
paper explores the possibility of increasing the efficiency of the
blades at higher wind speeds while maintaining efficiency at the
lower wind speeds. The design intends to maintain efficiency at
lower wind speeds by selecting the appropriate orientation and size
of the airfoil cross sections based on a low oncoming wind speed and
given constant rotation rate. The blades will be made more efficient
at higher wind speeds by implementing a swept blade profile.
Performance was investigated using the computational fluid
Robust Control Synthesis for an Unmanned Underwater Vehicle
The control design for unmanned underwater vehicles (UUVs) is challenging due to the uncertainties in the complex dynamic modeling of the vehicle as well as its unstructured operational environment. To cope with these difficulties, a practical robust control is therefore desirable. The paper deals with the application of coefficient diagram method (CDM) for a robust control design of an autonomous underwater vehicle. The CDM is an algebraic approach in which the characteristic polynomial and the controller are synthesized simultaneously. Particularly, a coefficient diagram (comparable to Bode diagram) is used effectively to convey pertinent design information and as a measure of trade-off between stability, response speed and robustness. In the polynomial ring, Kharitonov polynomials are employed to analyze the robustness of the controller due to parametric uncertainties.
CFD Analysis of a Centrifugal Fan for Performance Enhancement using Converging Boundary Layer Suction Slots
Generally flow behavior in centrifugal fan is observed
to be in a state of instability with flow separation zones on suction
surface as well as near the front shroud. Overall performance of the
diffusion process in a centrifugal fan could be enhanced by
judiciously introducing the boundary layer suction slots. With easy
accessibility of CFD as an analytical tool, an extensive numerical
whole field analysis of the effect of boundary layer suction slots in
discrete regions of suspected separation points is possible. This paper
attempts to explore the effect of boundary layer suction slots
corresponding to various geometrical locations on the impeller with
converging configurations for the slots. The analysis shows that the
converging suction slots located on the impeller blade about 25%
from the trailing edge, significantly improves the static pressure
recovery across the fan. Also it is found that Slots provided at a
radial distance of about 12% from the leading and trailing edges
marginally improve the static pressure recovery across the fan.
Application of Ant Colony Optimization for Multi-objective Production Problems
This paper proposes a meta-heuristic called Ant Colony Optimization to solve multi-objective production problems. The multi-objective function is to minimize lead time and work in process. The problem is related to the decision variables, i.e.; distance and process time. According to decision criteria, the mathematical model is formulated. In order to solve the model an ant colony optimization approach has been developed. The proposed algorithm is parameterized by the number of ant colonies and the number of pheromone trails. One example is given to illustrate the effectiveness of the proposed model. The proposed formulations; Max-Min Ant system are then used to solve the problem and the results evaluate the performance and efficiency of the proposed algorithm using simulation.
Maintenance Management System for Upstream Operations in Oil and Gas Industry: Case Study
This paper explores the plant maintenance management system that has been used by giant oil and gas company in Malaysia. The system also called as PMMS used to manage the upstream operations for more than 100 plants of the case study company. Moreover, from the observations, focus group discussion with PMMS personnel and application through simulation (SAP R/3), the paper reviews the step-by-step approach and the elements that required for the PMMS. The findings show that the PMMS integrates the overall business strategy in upstream operations that consist of asset management, work management and performance management. In addition, PMMS roles are to help operations personnel organize and plan their daily activities, to improve productivity and reduce equipment downtime and to help operations management analyze the facilities and create performance, and to provide and maintain the operational effectiveness of the facilities.
The Use of Minor Setups in an EPQ Model with Constrained Production Period Length
Extensive research has been devoted to economic
production quantity (EPQ) problem. However, no attention has been
paid to problems where production period length is constrained. In
this paper, we address the problem of deciding the optimal
production quantity and the number of minor setups within each
cycle, in which, production period length is constrained but a minor
setup is possible for pass the constraint. A mathematical model is
developed and Iterated Local Search (ILS) is proposed to solve this
problem. Finally, solution procedure illustrated with a numerical
example and results are analyzed.
Line Balancing in the Hard Disk Drive Process Using Simulation Techniques
Simulation model is an easy way to build up models
to represent real life scenarios, to identify bottlenecks and to enhance
system performance. Using a valid simulation model may give
several advantages in creating better manufacturing design in order to
improve the system performances. This paper presents result of
implementing a simulation model to design hard disk drive
manufacturing process by applying line balancing to improve both
productivity and quality of hard disk drive process. The line balance
efficiency showed 86% decrease in work in process, output was
increased by an average of 80%, average time in the system was
decreased 86% and waiting time was decreased 90%.
Modular Hybrid Robots for Safe Human-Robot Interaction
The paper considers a novel modular and intrinsically safe redundant robotic system with biologically inspired actuators (pneumatic artificial muscles and rubber bellows actuators). Similarly to the biological systems, the stiffness of the internal parallel modules, representing 2 DOF joints in the serial robotic chains, is controlled by co-activation of opposing redundant actuator groups in the null-space of the module Jacobian, without influencing the actual robot position. The decoupled position/stiffness control allows the realization of variable joint stiffness according to different force-displacement relationships. The variable joint stiffness, as well as limited pneumatic muscle/bellows force ability, ensures internal system safety that is crucial for development of human-friendly robots intended for human-robot collaboration. The initial experiments with the system prototype demonstrate the capabilities of independently, simultaneously controlling both joint (Cartesian) motion and joint stiffness. The paper also presents the possible industrial applications of snake-like robots built using the new modules.
A New Fuzzy DSS/ES for Stock Portfolio Selection using Technical and Fundamental Approaches in Parallel
A Decision Support System/Expert System for stock
portfolio selection presented where at first step, both technical and
fundamental data used to estimate technical and fundamental return
and risk (1st phase); Then, the estimated values are aggregated with
the investor preferences (2nd phase) to produce convenient stock
In the 1st phase, there are two expert systems, each of which is
responsible for technical or fundamental estimation. In the technical
expert system, for each stock, twenty seven candidates are identified
and with using rough sets-based clustering method (RC) the effective
variables have been selected. Next, for each stock two fuzzy rulebases
are developed with fuzzy C-Mean method and Takai-Sugeno-
Kang (TSK) approach; one for return estimation and the other for
risk. Thereafter, the parameters of the rule-bases are tuned with backpropagation
method. In parallel, for fundamental expert systems,
fuzzy rule-bases have been identified in the form of “IF-THEN" rules
through brainstorming with the stock market experts and the input
data have been derived from financial statements; as a result two
fuzzy rule-bases have been generated for all the stocks, one for return
and the other for risk.
In the 2nd phase, user preferences represented by four criteria and
are obtained by questionnaire. Using an expert system, four estimated
values of return and risk have been aggregated with the respective
values of user preference. At last, a fuzzy rule base having four rules,
treats these values and produce a ranking score for each stock which
will lead to a satisfactory portfolio for the user.
The stocks of six manufacturing companies and the period of
2003-2006 selected for data gathering.
Mobile Medical Operation Route Planning
Medical services are usually provided in hospitals; however, in developing country, some rural residences have fewer opportunities to access in healthcare services due to the limitation of transportation communication. Therefore, in Thailand, there are charitable organizations operating to provide medical treatments to these people by shifting the medical services to operation sites; this is commonly known as mobile medical service. Operation routing is important for the organization to reduce its transportation cost in order to focus more on other important activities; for instance, the development of medical apparatus. VRP is applied to solve the problem of high transportation cost of the studied organization with the searching techniques of saving algorithm to find the minimum total distance of operation route and satisfy available time constraints of voluntary medical staffs.
Development of a Novel Low-Cost Flight Simulator for Pilot Training
A novel low-cost flight simulator with the development
goals cost effectiveness and high performance has been realized for
meeting the huge pilot training needs of airlines. The simulator
consists of an aircraft dynamics model, a sophisticated designed
low-profile electrical driven motion system with a subsided cabin, a
mixed reality based semi-virtual cockpit system, a control loading
system and some other subsystems. It shows its advantages over
traditional flight simulator by its features achieved with open
architecture, software solutions and low-cost hardware.
Effect of Groove Location on the Dynamic Characteristics of Multiple Axial Groove Water Lubricated Journal Bearing
The stability characteristics of water lubricated journal bearings having three axial grooves are obtained theoretically. In this lubricant (water) is fed under pressure from one end of the bearing, through the 3-axial grooves (groove angles may vary). These bearings can use the process fluid as the lubricant, as in the case of feed water pumps. The Reynolds equation is solved numerically by the finite difference method satisfying the boundary conditions. The stiffness and damping coefficient for various bearing number and eccentricity ratios, assuming linear pressure drop along the groove, shows that smaller groove angles better results.
Investigation and Congestion Management to Solvethe Over-Load Problem of Shiraz Substation in FREC
In this paper, the transformers over-load problem of Shiraz substation in Fars Regional Electric Company (FREC) is investigated for a period of three years plan. So the suggestions for using phase shifting transformer (PST) and unified power flow controller (UPFC) in order to solve this problem are examined in details and finally, some economical and practical designs will be given in order to solve the related problems. Practical consideration and using the basic and fundamental concept of powers in transmission lines in order to find the economical design are the main advantages of this research. The simulation results of the integrated overall system with different designs compare them base on economical and practical aspects to solve the over-load and loss-reduction.
Research on the Correlation of the Fluctuating Density Gradient of the Compressible Flows
This work is to study a roll of the fluctuating density
gradient in the compressible flows for the computational fluid dynamics
(CFD). A new anisotropy tensor with the fluctuating density
gradient is introduced, and is used for an invariant modeling technique
to model the turbulent density gradient correlation equation derived
from the continuity equation. The modeling equation is decomposed
into three groups: group proportional to the mean velocity, and that
proportional to the mean strain rate, and that proportional to the mean
density. The characteristics of the correlation in a wake are extracted
from the results by the two dimensional direct simulation, and shows
the strong correlation with the vorticity in the wake near the body.
Thus, it can be concluded that the correlation of the density gradient
is a significant parameter to describe the quick generation of the
turbulent property in the compressible flows.
Independent Design of Multi-loop PI/PID Controllers for Multi-delay Processes
The interactions between input/output variables are a very common phenomenon encountered in the design of multi-loop controllers for interacting multivariable processes, which can be a serious obstacle for achieving a good overall performance of multiloop control system. To overcome this impediment, the decomposed dynamic interaction analysis is proposed by decomposing the multiloop control system into a set of n independent SISO systems with the corresponding effective open-loop transfer function (EOTF) within the dynamic interactions embedded explicitly. For each EOTF, the reduced model is independently formulated by using the proposed reduction design strategy, and then the paired multi-loop proportional-integral-derivative (PID) controller is derived quite simply and straightforwardly by using internal model control (IMC) theory. This design method can easily be implemented for various industrial processes because of its effectiveness. Several case studies are considered to demonstrate the superior of the proposed method.
Capsule-substrate Adhesion in the Presence of Osmosis by the Immersed Interface Method
A two-dimensional thin-walled capsule of a flexible
semi-permeable membrane is adhered onto a rigid planar substrate
under adhesive forces (derived from a potential function) in the
presence of osmosis across the membrane. The capsule is immersed
in a hypotonic and diluted binary solution of a non-electrolyte
solute. The Stokes flow problem is solved by the immersed interface
method (IIM) with equal viscosities for the enclosed and
surrounding fluid of the capsule. The numerical results obtained are
verified against two simplified theoretical solutions and the
agreements are good. The osmotic inflation of the adhered capsule is
studied as a function of the solute concentration field, hydraulic
conductivity, and the initial capsule shape. Our findings indicate that
the contact length shrinks in dimension as capsule inflates in the
hypotonic medium, and the equilibrium contact length does not
depend on the hydraulic conductivity of the membrane and the
initial shape of the capsule.
A Study of the Change of Damping Coefficient Regarding Minimum Displacement
This research proposes the change of damping coefficient regarding minimum displacement. From the mass with external forced and damper problem, when is the constant external forced transmitted to the understructure in the difference angle between 30 and 60 degrees. This force generates the vibration as general known; however, the objective of this problem is to have minimum displacement. As the angle is changed and the goal is the same; therefore, the damper of the system must be varied while keeping constant spring stiffness. The problem is solved by using nonlinear programming and the suitable changing of the damping coefficient is provided.
Minimum Energy of a Prismatic Joint with out: Actuator: Application on RRP Robot
This research proposes the state of art on how to control or find the trajectory paths of the RRP robot when the prismatic joint is malfunction. According to this situation, the minimum energy of the dynamic optimization is applied. The RRP robot or similar systems have been used in many areas such as fire fighter truck, laboratory equipment and military truck for example a rocket launcher. In order to keep on task that assigned, the trajectory paths must be computed. Here, the open loop control is applied and the result of an example show the reasonable solution which can be applied to the controllable system.
Fuzzy Sliding Mode Control of an MR Mount for Vibration Attenuation
In this paper, an magnetorheological (MR) mount with
fuzzy sliding mode controller (FSMC) is studied for vibration
suppression when the system is subject to base excitations. In recent
years, magnetorheological fluids are becoming a popular material in
the field of the semi-active control. However, the dynamic equation of
an MR mount is highly nonlinear and it is difficult to identify. FSMC
provides a simple method to achieve vibration attenuation of the
nonlinear system with uncertain disturbances. This method is capable
of handling the chattering problem of sliding mode control effectively
and the fuzzy control rules are obtained by using the Lyapunov
stability theory. The numerical simulations using one-dimension and
two-dimension FSMC show effectiveness of the proposed controller
for vibration suppression. Further, the well-known skyhook control
scheme and an adaptive sliding mode controller are also included in
the simulation for comparison with the proposed FSMC.
Improvement in Mechanical Behavior of Expulsion with Heat treated Thermite Welded Rail Steel
Thermite welding is mainly used in world. The
reasons why the thermite welding method is widely used are
that the equipment has good mobility and total working time
of that is shorter than that of the enclosed arc welding method
on site. Moreover, the operating skill, which required for
thermite welding, is less than that of for enclosed arc welding.
In the present research work, heat treatment and combined
'expulsion and heat treatment' techniques were used improve
the mechanical properties and weldment structure. The
specimens were cut in the transverse direction from expulsion
with Heat treated and heat treated Thermite Welded rails.
Specimens were prepared according to AWS standard and
subjected to tensile test, Impact test and hardness and their
results were tabulated. Microstructural analysis was carried
out with the help of SEM. Then analyze to effect of heat
treated and 'expulsion with heat treated' with the properties of
their thermite welded rails. Compare the mechanical and
microstructural properties of thermite welded rails between
heat expulsion with heat treated and heat treated. Mechanical
and microstructural response expulsion with heat treated
thermite welded rail is higher value as compared to heat
New Regression Model and I-Kaz Method for Online Cutting Tool Wear Monitoring
This study presents a new method for detecting the
cutting tool wear based on the measured cutting force signals using
the regression model and I-kaz method. The detection of tool wear
was done automatically using the in-house developed regression
model and 3D graphic presentation of I-kaz 3D coefficient during
machining process. The machining tests were carried out on a CNC
turning machine Colchester Master Tornado T4 in dry cutting
condition, and Kistler 9255B dynamometer was used to measure the
cutting force signals, which then stored and displayed in the DasyLab
software. The progression of the cutting tool flank wear land (VB)
was indicated by the amount of the cutting force generated. Later, the
I-kaz was used to analyze all the cutting force signals from beginning
of the cut until the rejection stage of the cutting tool. Results of the IKaz
analysis were represented by various characteristic of I-kaz 3D
coefficient and 3D graphic presentation. The I-kaz 3D coefficient
number decreases when the tool wear increases. This method can be
used for real time tool wear monitoring.