Abstract: This paper deals with the analysis of active constrained layer damping (ACLD) of doubly curved laminated composite shells using active fiber composite (AFC) materials. The constraining layer of the ACLD treatment has been considered to be made of the AFC materials. A three dimensional energy based finite element model of the smart doubly curved laminated composite shell integrated with a patch of such ACLD treatment has been developed to demonstrate the performance of the patch on enhancing the damping characteristics of the doubly curved laminated composite shells. Particular emphasis has been placed on studying the effect of variation of piezoelectric fiber orientation angle in the constraining AFC layer on the control authority of the ACLD patch.
Abstract: Various solar energy technologies exist and they have
different application techniques in the generation of electrical power.
The widespread use of photovoltaic (PV) modules in such
technologies has been limited by relatively high costs and low
efficiencies. The efficiency of PV panels decreases as the operating
temperatures increase. This is due to the affect of solar intensity and
ambient temperature. In this work, Computational Fluid Dynamics
(CFD) was used to model the heat transfer from a standard PV panel
and thus determine the rate of dissipation of heat. To accurately
model the specific climatic conditions of the United Arab Emirates
(UAE), a case study of a new build green building in Dubai was
used. A finned heat pipe arrangement is proposed and analyzed to
determine the improved heat dissipation and thus improved
performance efficiency of the PV panel. A prototype of the
arrangement is built for experimental testing to validate the CFD
modeling and proof of concept.
Abstract: The counter flow solar air heaters, with four
transverse fins and wire mesh layers are constructed and investigated
experimentally for thermal efficiency at a geographic location of
Cyprus in the city of Famagusta. The absorber plate is replaced by
sixteen steel wire mesh layers, 0.18 x 0.18cm in cross section
opening and a 0.02cm in diameter. The wire mesh layers arranged in
three groups, first and second include 6 layers, while the third include
4 layers. All layers fixed in the duct parallel to the glazing and each
group separated from the others by wood frame thickness of 0.5cm to
reduce the pressure drop. The transverse fins arranged in a way to
force the air to flow through the bed like eight letter path with flow
depth 3cm. The proposed design has increased the heat transfer rate,
but on other hand causes a high pressure drop. The obtained results
show that, for air mass flow rate range between 0.011-0.036kg/s, the
thermal efficiency increases with increasing the air mass flow. The
maximum efficiency obtained is 65.6% for the mass flow rate of
0.036kg/s. Moreover, the temperature difference between the outlet
flow and the ambient temperature, ΔT, reduces as the air mass flow
rate increase. The maximum difference between the outlet and
ambient temperature obtained was 43°C for double pass for minimum
mass flow rate of 0.011kg/s. Comparison with a conventional solar
air heater collector shows a significantly development in the thermal
efficiency.
Abstract: In manufacturing industries, development of measurement leads to increase the number of monitoring variables and eventually the importance of multivariate control comes to the fore. Statistical process control (SPC) is one of the most widely used as multivariate control chart. Nevertheless, SPC is restricted to apply in processes because its assumption of data as following specific distribution. Unfortunately, process data are composed by the mixture of several processes and it is hard to estimate as one certain distribution. To alternative conventional SPC, therefore, nonparametric control chart come into the picture because of the strength of nonparametric control chart, the absence of parameter estimation. SVDD based control chart is one of the nonparametric control charts having the advantage of flexible control boundary. However,basic concept of SVDD has been an oversight to the important of data characteristic, density distribution. Therefore, we proposed DW-SVDD (Density Weighted SVDD) to cover up the weakness of conventional SVDD. DW-SVDD makes a new attempt to consider dense of data as introducing the notion of density Weight. We extend as control chart using new proposed SVDD and a simulation study of various distributional data is conducted to demonstrate the improvement of performance.
Abstract: The changing economic climate has made global
manufacturing a growing reality over the last decade, forcing
companies from east and west and all over the world to
collaborate beyond geographic boundaries in the design,
manufacture and assemble of products. The ISO10303 and
ISO14649 Standards (STEP and STEP-NC) have been
developed to introduce interoperability into manufacturing
enterprises so as to meet the challenge of responding to
production on demand. This paper describes and illustrates a
STEP compliant CAD/CAPP/CAM System for the manufacture
of rotational parts on CNC turning centers. The information
models to support the proposed system together with the data
models defined in the ISO14649 standard used to create the NC
programs are also described. A structured view of a STEP
compliant CAD/CAPP/CAM system framework supporting the
next generation of intelligent CNC controllers for turn/mill
component manufacture is provided. Finally a proposed
computational environment for a STEP-NC compliant system
for turning operations (SCSTO) is described. SCSTO is the
experimental part of the research supported by the specification
of information models and constructed using a structured
methodology and object-oriented methods. SCSTO was
developed to generate a Part 21 file based on machining
features to support the interactive generation of process plans
utilizing feature extraction. A case study component has been
developed to prove the concept for using the milling and turning
parts of ISO14649 to provide a turn-mill CAD/CAPP/CAM
environment.
Abstract: This paper presents an iterative algorithm to find a
inverse kinematic solution of 5-DOF robot. The algorithm is to
minimize the iteration number. Since the 5-DOF robot cannot give full
orientation of tool. Only z-direction of tool is satisfied while rotation
of tool is determined by kinematic constraint. This work therefore
described how to specify the tool direction and let the tool rotation free.
The simulation results show that this algorithm effectively worked.
Using the proposed iteration algorithm, error due to inverse kinematics
converged to zero rapidly in 5 iterations. This algorithm was applied in
real welding robot and verified through various practical works.
Abstract: This paper presents the development of a hybrid
thermal model for the EVO Electric AFM 140 Axial Flux Permanent
Magnet (AFPM) machine as used in hybrid and electric vehicles. The
adopted approach is based on a hybrid lumped parameter and finite
difference method. The proposed method divides each motor
component into regular elements which are connected together in a
thermal resistance network representing all the physical connections
in all three dimensions. The element shape and size are chosen
according to the component geometry to ensure consistency. The
fluid domain is lumped into one region with averaged heat transfer
parameters connecting it to the solid domain. Some model parameters
are obtained from Computation Fluid Dynamic (CFD) simulation and
empirical data. The hybrid thermal model is described by a set of
coupled linear first order differential equations which is discretised
and solved iteratively to obtain the temperature profile. The
computation involved is low and thus the model is suitable for
transient temperature predictions. The maximum error in temperature
prediction is 3.4% and the mean error is consistently lower than the
mean error due to uncertainty in measurements. The details of the
model development, temperature predictions and suggestions for
design improvements are presented in this paper.
Abstract: Microwave energy can be used for drying purpose. It is unique process. It is distinctly different from conventional drying process. It is advantageous over conventional drying / heating processes. When microwave energy is used for drying purpose, the process can be accelerated with a better control to achieve uniform heating, more conversion efficiency, selective drying and ultimately improved product quality of the output. Also, less floor space and compact system are the added advantages. Existing low power microwave drying system is to be modified with suitable applicator. Appropriate sensors are to be used to measure parameters like moisture, temperature, weight of sample. Suitable high tech controller is to be used to control microwave power continuously from minimum to maximum. Phase - controller, cycle - controller and PWM - controller are some of the advanced power control techniques. It has been proposed to work on turmeric using high-tech phase controller to control the microwave power conveniently. The drying of turmeric with microwave energy employing phase controller gives better results as formulated in this paper and hence new approach of processing turmeric will open future doors of profit making to allied industries and the farmers.
Abstract: an intelligent BRT system is necessary when
communities looking for new ways to use high capacity rapid transit
at a reduced cost.This paper will describe the intelligent control
system that works with Datacenter. With the help of GPS system, the
data center can monitor the situation of each bus and bus station.
Through RFID technology, bus station and traffic light can transfer
data with bus and by Wimax communication technology all of parts
can talk together; data center learns all information about the location
of bus, the arrival of bus in each station and the number of passengers
in station and bus.Finally, the paper presents the case study of those
theories in Tehran BRT.
Abstract: To improve the dynamics response of the vehicle
passive suspension, a two-terminal mass is suggested to connect in
parallel with the suspension strut. Three performance criteria, tire grip,
ride comfort and suspension deflection, are taken into consideration to
optimize the suspension parameters. However, the three criteria are
conflicting and non-commensurable. For this reason, the Chebyshev
goal programming method is applied to find the best tradeoff among
the three objectives. A simulation case is presented to describe the
multi-objective optimization procedure. For comparison, the
Chebyshev method is also employed to optimize the design of a
conventional passive suspension. The effectiveness of the proposed
design method has been clearly demonstrated by the result. It is also
shown that the suspension with a two-terminal mass in parallel has
better performance in terms of the three objectives.
Abstract: Launch and recovery helicopter wind envelope for a
ship type was determined as the first step to the helicopter
qualification program. Flight deck velocities data were obtained by
means of a two components laser Doppler anemometer testing a
1/50th model in the wind tunnel stream. Full-scale flight deck
measurements were obtained on board the ship using a sonic
anemometer. Wind tunnel and full-scale measurements were
compared, showing good agreement and finally, a preliminary launch
and recovery helicopter wind envelope for this specific ship was
built.
Abstract: This paper provides a replacement policy for warranty products with different failure rate from the consumer-s viewpoint. Assume that the product is replaced once within a finite planning horizon, and the failure rate of the second product is lower than the failure rate of the first product. Within warranty period (WP), the failed product is corrected by minimal repair without any cost to the consumers. After WP, the failed product is repaired with a fixed repair cost to the consumers. However, each failure incurs a fixed downtime cost to the consumers over a finite planning horizon. In this paper, we derive the model of the expected total disbursement cost within a finite planning horizon and some properties of the optimal replacement policy under some reasonable conditions are obtained. Finally, numerical examples are given to illustrate the features of the optimal replacement policy under various maintenance costs.
Abstract: Accurate evaluation of damping ratios involving soilstructure interaction (SSI) effects is the prerequisite for seismic design of in-situ buildings. This study proposes a combined approach to identify damping ratios of SSI systems based on ambient excitation technique. The proposed approach is illustrated with main test process, sampling principle and algorithm steps through an engineering example, as along with its feasibility and validity. The proposed approach is employed for damping ratio identification of 82 buildings in Xi-an, China. Based on the experimental data, the variation range and tendency of damping ratios of these SSI systems, along with the preliminary influence factor, are shown and discussed. In addition, a fitting curve indicates the relation between the damping ratio and fundamental natural period of SSI system.
Abstract: This paper deals with the experimental investigations
of the in-cylinder tumble flows in an unfired internal combustion
engine with a flat piston at the engine speeds ranging from 400 to
1000 rev/min., and also with the dome and dome-cavity pistons at an
engine speed of 1000 rev/min., using particle image velocimetry.
From the two-dimensional in-cylinder flow measurements, tumble
flow analysis is carried out in the combustion space on a vertical
plane passing through cylinder axis. To analyze the tumble flows,
ensemble average velocity vectors are used and to characterize it,
tumble ratio is estimated. From the results, generally, we have found
that tumble ratio varies mainly with crank angle position. Also, at the
end of compression stroke, average turbulent kinetic energy is more
at higher engine speeds. We have also found that, at 330 crank angle
position, flat piston shows an improvement of about 85 and 23% in
tumble ratio, and about 24 and 2.5% in average turbulent kinetic
energy compared to dome and dome-cavity pistons respectively
Abstract: Object-oriented simulation is considered one of the most sophisticated techniques that has been widely used in planning, designing, executing and maintaining construction projects. This technique enables the modeler to focus on objects which is extremely important for thorough understanding of a system. Thus, identifying an object is an essential point of building a successful simulation model. In a maintenance process an object is a maintenance work order (MWO). This study demonstrates a maintenance simulation model for the building maintenance division of Saudi Consolidated Electric Company (SCECO) in Dammam, Saudi Arabia. The model focused on both types of maintenance processes namely: (1) preventive maintenance (PM) and (2) corrective maintenance (CM). It is apparent from the findings that object-oriented simulation is a good diagnostic and experimental tool. This is because problems, limitations, bottlenecks and so forth are easily identified. These features are very difficult to obtain when using other tools.
Abstract: The work presented in this study is related to an
energy system analysis based on passive cooling system for
dwellings. It consists to solar chimney energy performances
determination versus geometrical and environmental considerations
as the size and inlet width conditions of the chimney. Adrar site
located in the southern region of Algeria is chosen for this study
according to ambient temperature and solar irradiance technical data
availability. Obtained results are related to the glazing temperature
distributions, the chimney air flow and internal wall temperatures.
The air room change per hour (ACH) parameter, the outlet air
velocity and mass air flow rate are also determined. It is shown that
the chimney width has a significant effect on energy performances
compared to its entry size. A good agreement is observed between
these results and those obtained by others from the literature.
Abstract: We developed a new method based on quasimolecular
modeling to simulate the cavity flow in three cavity
shapes: rectangular, half-circular and bucket beer in cgs units. Each
quasi-molecule was a group of particles that interacted in a fashion
entirely analogous to classical Newtonian molecular interactions.
When a cavity flow was simulated, the instantaneous velocity vector
fields were obtained by using an inverse distance weighted
interpolation method. In all three cavity shapes, fluid motion was
rotated counter-clockwise. The velocity vector fields of the three
cavity shapes showed a primary vortex located near the upstream
corners at time t ~ 0.500 s, t ~ 0.450 s and t ~ 0.350 s, respectively.
The configurational kinetic energy of the cavities increased as time
increased until the kinetic energy reached a maximum at time t ~
0.02 s and, then, the kinetic energy decreased as time increased. The
rectangular cavity system showed the lowest kinetic energy, while
the half-circular cavity system showed the highest kinetic energy.
The kinetic energy of rectangular, beer bucket and half-circular
cavities fluctuated about stable average values 35.62 x 103, 38.04 x
103 and 40.80 x 103 ergs/particle, respectively. This indicated that the
half-circular shapes were the most suitable shape for a shrimp pond
because the water in shrimp pond flows best when we compared with
rectangular and beer bucket shape.
Abstract: The Canadian aerospace industry faces many
challenges. One of them is the difficulty in estimating costs. In
particular, the design effort required in a project impacts resource
requirements and lead-time, and consequently the final cost. This
paper presents the findings of a case study conducted for recognized
global leader in the design and manufacturing of aircraft engines. The
study models parametric cost estimation relationships to estimate the
design effort of integrated blade-rotor low-pressure compressor fans.
Several effort drivers are selected to model the relationship.
Comparative analyses of three types of models are conducted. The
model with the best accuracy and significance in design estimation is
retained.
Abstract: Traditionally, wind tunnel models are made of metal
and are very expensive. In these years, everyone is looking for ways
to do more with less. Under the right test conditions, a rapid
prototype part could be tested in a wind tunnel. Using rapid prototype
manufacturing techniques and materials in this way significantly
reduces time and cost of production of wind tunnel models. This
study was done of fused deposition modeling (FDM) and their ability
to make components for wind tunnel models in a timely and cost
effective manner. This paper discusses the application of wind tunnel
model configuration constructed using FDM for transonic wind
tunnel testing. A study was undertaken comparing a rapid
prototyping model constructed of FDM Technologies using
polycarbonate to that of a standard machined steel model. Testing
covered the Mach range of Mach 0.3 to Mach 0.75 at an angle-ofattack
range of - 2° to +12°. Results from this study show relatively
good agreement between the two models and rapid prototyping
Method reduces time and cost of production of wind tunnel models.
It can be concluded from this study that wind tunnel models
constructed using rapid prototyping method and materials can be
used in wind tunnel testing for initial baseline aerodynamic database
development.
Abstract: The present study focuses on methods allowing a convenient and quick calculation of the SIFs in order to predict the static adhesive strength of bonded joints. A new SIF calculation method is proposed, based on the stresses obtained from a FE model at a reference point located in the adhesive layer at equal distance of the free-edge and of the two interfaces. It is shown that, even limiting ourselves to the two main modes, i.e. the opening and the shearing modes, and using the values of the stresses resulting from a low detailed FE model, an efficient calculation of the peeling stress at adhesive-substrate corners can be obtained by this way. The proposed method is interesting in that it can be the basis of a prediction tool that will allow the designer to quickly evaluate the SIFs characterizing a particular application without developing a detailed analysis.