Abstract: In this work, the effect of material type, diameter, orientation and closeness of fibers on the general performance of reinforced vulcanized rubbers are investigated using finite element method with experimental verification. Various fiber materials such as hemp, nylon, polyester are used for different fiber diameters, orientations and closeness. 3D finite element models are developed by considering bonded contact elements between fiber and rubber sheet interfaces. The fibers are assumed as linear elastic, while vulcanized rubber is considered as hyper-elastic. After an experimental verification of finite element results, the developed models are analyzed under prescribed displacement that causes tension. The normal stresses in fibers and shear stresses between fibers and rubber sheet are investigated in all models. Large deformation of reinforced rubber sheet also represented with various fiber conditions under incremental loading. A general assessment is achieved about best fiber properties of reinforced rubber sheets for tension-load conditions.
Abstract: Electric discharge machining (EDM) is one of the most widely used non-conventional manufacturing process to shape difficult-to-cut materials. The process yield, in terms of material removal rate, surface roughness and tool wear rate, of EDM may considerably be improved by selecting the optimal combination(s) of process parameters. This paper employs Multi-response signal-to-noise (MRSN) ratio technique to find the optimal combination(s) of the process parameters during EDM of Inconel 718. Three cases v.i.z. high cutting efficiency, high surface finish, and normal machining have been taken and the optimal combinations of input parameters have been obtained for each case. Analysis of variance (ANOVA) has been employed to find the dominant parameter(s) in all three cases. The experimental verification of the obtained results has also been made. MRSN ratio technique found to be a simple and effective multi-objective optimization technique.
Abstract: An experiment to verify the relationships between
physiological indexes of an e-learner and the presence or absence of an
operation during e-learning is described. Electroencephalogram
(EEG), hemoencephalography (HEG), skin conductance (SC), and
blood volume pulse (BVP) values were measured while participants
performed experimental learning tasks. The results show that there are
significant differences between the SC values when reading with
clicking on learning materials and the SC values when reading without
clicking, and between the HEG ratio when reading (with and without
clicking) and the HEG ratio when resting for four of five participants.
We conclude that the SC signals can be used to estimate whether or not
a learner is performing an active task and that the HEG ratios can be
used to estimate whether a learner is learning.
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: The article deals with modelling of the fire
pragmatism in the area of military management and its experimental
verification. Potential approaches are based on the synergy of
mathematical and theoretical ideas, operational and tactical
requirements and the military decision-making process. This issue
has taken on importance in recent times, particularly with the
increasing trend of digitized battlefield, the development of C4ISR
systems and intention to streamline the command and control process
at the lowest levels of command. From fundamental and
philosophical point of view, these new approaches seek to
significantly upgrade and enhance the decision-making process of the
tactical commanders.
Abstract: Conical sections and shells made from metal plates are widely used in various industrial applications. 3-roller conical bending process is preferably used to produce such conical sections and shells. Bending mechanics involved in the process is complex and little work is done in this area. In the present paper an analytical model is developed to predict bending force which will be acting during 3-roller conical bending process. To verify the developed model, conical bending experiments are performed. Analytical results and experimental results were compared. Force predicted by analytical model is in close proximity of the experimental results. The error in the prediction is ±10%. Hence the model gives quite satisfactory results. Present model is also compared with the previously published bending force prediction model and it is found that the present model gives better results. The developed model can be used to estimate the bending force during 3-roller bending process and can be useful to the designers for designing the 3-roller conical bending machine.
Abstract: This work presents a methodology for the selection
and design of propeller oriented to the experimental verification of
theoretical results. The problem of propeller selection and design
usually present itself in the following manner: a certain air volume
and static pressure are required for a certain system. Once the
necessity of fan design on a theoretical basis has been recognized, it
is possible to determinate the dimensions for a fan unit so that it will
perform in accordance with a certain set of specifications. The same
procedures in this work then can be applied in other propeller
selection.
Abstract: Chatter vibration has been a troublesome problem
for a machine tool toward the high precision and high speed machining.
Essentially, the machining performance is determined by the dynamic
characteristics of the machine tool structure and dynamics of cutting
process, which can further be identified in terms of the stability lobe
diagram. Therefore, realization on the machine tool dynamic behavior
can help to enhance the cutting stability. To assess the dynamic
characteristics and machining stability of a vertical milling system
under the influence of a linear guide, this study developed a finite
element model integrated the modeling of linear components with the
implementation of contact stiffness at the rolling interface. Both the
finite element simulations and experimental measurements reveal that
the linear guide with different preload greatly affects the vibration
behavior and milling stability of the vertical column spindle head
system, which also clearly indicate that the predictions of the
machining stability agree well with the cutting tests. It is believed that
the proposed model can be successfully applied to evaluate the
dynamics performance of machine tool systems of various
configurations.
Abstract: It is believed that continuously variable transmission (CVT) will dominate the automotive transmissions in the future. The most popular design is Van Doorne-s CVT with single metal pushing V-belt. However, it is only applicable to low power passenger cars because its major limitation is low torque capacity. Therefore, this research studies a novel dual-belt CVT system to overcome the limitation of traditional single-belt CVT, such that it can be applicable to the heavy-duty vehicles. This paper presents the mathematical model of the design and its experimental verification. Experimental and simulated results show that the model developed is valid and the proposed dual-belt CVT can really overcome the traditional limitation of single-belt Van Doorne-s CVT.
Abstract: Two approaches for model development of a smart acoustic box are suggested in this paper: the finite element (FE) approach and the subspace identification. Both approaches result in a state-space model, which can be used for obtaining the frequency responses and for the controller design. In order to validate the developed FE model and to perform the subspace identification, an experimental set-up with the acoustic box and dSPACE system was used. Experimentally obtained frequency responses show good agreement with the frequency responses obtained from the FE model and from the identified model.
Abstract: This work presents a methodology for the design and
manufacture of propellers oriented to the experimental verification of
theoretical results based on the combined model. The design process
begins by using algorithms in Matlab which output data contain the
coordinates of the points that define the blade airfoils, in this case the
NACA 6512 airfoil was used. The modeling for the propeller blade
was made in NX7, through the imported files in Matlab and with the
help of surfaces. Later, the hub and the clamps were also modeled.
Finally, NX 7 also made possible to create post-processed files to the
required machine. It is possible to find the block of numbers with G
& M codes about the type of driver on the machine. The file
extension is .ptp. These files made possible to manufacture the blade,
and the hub of the propeller.
Abstract: Clearance in the joints of multibody mechanical
systems such as linkage mechanisms and robots is a main source of
vibration, and noise of the whole system, and wear of the joints
themselves. This clearance is an inevitable matter and cannot be
eliminated, since it allows the relative motion between joint
components and make them assemblage. This paper presents an
experimental verification of the obtained simulation results of a slider
– crank mechanism of one clearance revolute joint. The simulation
results are obtained with the aid of CAD and dynamic simulation
softwares, which is an effective method of simulation multibody
systems with clearance joints and have many advantages. The
comparison between both simulation and experimental results shows
that the simulation results are so close to the experimental ones which
proves the accuracy and efficiency of this method of modeling and
simulation of mechanical systems with clearance joints.
Abstract: This paper presents a novel method for prediction of
the mechanical behavior of proximal femur using the general
framework of the quantitative computed tomography (QCT)-based
finite element Analysis (FEA). A systematic imaging and modeling
procedure was developed for reliable correspondence between the
QCT-based FEA and the in-vitro mechanical testing. A speciallydesigned
holding frame was used to define and maintain a unique
geometrical reference system during the analysis and testing. The
QCT images were directly converted into voxel-based 3D finite
element models for linear and nonlinear analyses. The equivalent
plastic strain and the strain energy density measures were used to
identify the critical elements and predict the failure patterns. The
samples were destructively tested using a specially-designed gripping
fixture (with five degrees of freedom) mounted within a universal
mechanical testing machine. Very good agreements were found
between the experimental and the predicted failure patterns and the
associated load levels.
Abstract: Small-scale RC models of both piles and tunnel ducts
were produced as mockups of reality and loaded under soil
confinement conditionsto investigate the damage evolution of
structural RC interacting with soil. Experimental verifications usinga
3D nonlinear FE analysis program called COM3D, which was
developed at the University of Tokyo, are introduced. This analysis
has been used in practice for seismic performance assessment of
underground ducts and in-ground LNG storage tanks in consideration
of soil-structure interactionunder static and dynamic loading. Varying
modes of failure of RCpilessubjected to different magnitudes of soil
confinement were successfully reproduced in the proposed small-scale
experiments and numerically simulated as well. Analytical simulation
was applied to RC tunnel mockups under a wide variety of depth and
soil confinement conditions, and reasonable matching was confirmed.
Abstract: In built-up structures, one of the effective ways of
dissipating unwanted vibration is to exploit the occurrence of slip at
the interfaces of structural laminates. The present work focuses on
the dynamic analysis of welded structures. A mathematical
formulation has been developed for the mechanism of slip damping
in layered and welded mild steel beams with unequal thickness
subjected to both periodic and non-periodic forces. It is observed that
a number of vital parameters such as; thickness ratio, pressure
distribution characteristics, relative slip and kinematic co-efficient of
friction at the interfaces, nature of exciting forces, length and
thickness of the beam specimen govern the damping characteristics of
these structures. Experimental verification has been carried out to
validate the analysis and study the effect of these parameters. The
developed damping model for the structure is found to be in fairly
good agreement with the measured data. Finally, the results of the
analysis are discussed and rationalized.
Abstract: This paper presents preliminary results regarding system-level power awareness for FPGA implementations in wireless sensor networks. Re-configurability of field programmable gate arrays (FPGA) allows for significant flexibility in its applications to embedded systems. However, high power consumption in FPGA becomes a significant factor in design considerations. We present several ideas and their experimental verifications on how to optimize power consumption at high level of designing process while maintaining the same energy per operation (low-level methods can be used additionally). This paper demonstrates that it is possible to estimate feasible power consumption savings even at the high level of designing process. It is envisaged that our results can be also applied to other embedded systems applications, not limited to FPGA-based.
Abstract: The paper presents the brief information on particular results of experimental study focused to the problems of behavior of structural plated components made of fiber-cement-based materials and used in building constructions, exposed to atmospheric physical effects given by the weather changes in the summer period. Weather changes represented namely by temperature and rain cause also the changes of the temperature and moisture of the investigated structural components. This can affect their static behavior that means stresses and deformations, which have been monitored as the main outputs of tests performed. Experimental verification is based on the simulation of the influence of temperature and rain using the defined procedure of warming and water sprinkling with respect to the corresponding weather conditions during summer period in the South Moravian region at the Czech Republic, for which the application of these structural components is mainly planned. Two types of components have been tested: (i) glass-fiber-concrete panels used for building façades and (ii) fiber-cement slabs used mainly for claddings, but also as a part of floor structures or lost shuttering, and so on.
Abstract: The purpose of this research is to reduce the amount of incomplete coating of stainless steel washers in the electrodeposition painting process by using an experimental design technique. The surface preparation was found to be a major cause of painted surface quality. The influence of pretreating and painting process parameters, which are cleaning time, chemical concentration and shape of hanger were studied. A 23 factorial design with two replications was performed. The analysis of variance for the designed experiment showed the great influence of cleaning time and shape of hanger. From this study, optimized cleaning time was determined and a newly designed electrical conductive hanger was proved to be superior to the original one. The experimental verification results showed that the amount of incomplete coating defects decreased from 4% to 1.02% and operation cost decreased by 10.5%.