bluuebunny/crossref_metadata_2025 huggingface dataset:
NUMERICAL STUDY OF NATURAL CONVECTION DOMINATED MELTING OF A PCM WITH CONJUGATE FORCED CONVECTION
Authors: Lacroix M.
Published: April 2018

This paper presents a numerical analysis of natural convection dominated melting inside a rectangular enclosure coupled with forced convection heat transfer in a transport fluid via a finite conductance heat exchanging surface. A computational methodology based on a stream function-vorticity-temperature formulation is adopted and the irregular shape of the moving solid-liquid interface is treated with body-fitted coordinates. The model is then employed to investigate the interaction between natural convection in the PCM filled cavity and forced convection in the HTF. Numerical experiments were carried out for Rayleigh numbers, Ra, between 2.08‧108 and 4.60‧109, modified Reynolds numbers, Re between 4.23 and 423.0, wall-PCM thermal diffusivity ratios, α, between 5.0 and 10.0 and dimensionless wall thickness, w, between 0.005 and 0.05. Results show that the melting process is increasingly delayed by heat conduction across a wall of decreasing thermal conductivity and/or increasing thickness. This effect is accentuated for low HTF flow rates (Re ~ 4.23). On the other hand, for a wail of given thickness and thermal conductivity, the effect of increasing the HTF flow rate on the melting process becomes imperceptible for Re ≥ 4.23.
A NOTE ON HYPERBOLIC HEAT CONDUCTION IN A RIGID SOLID
Authors: Haddow J.B. , Jiang L. , Tait R.J.
Published: April 2018

Two hyperbolic heat conduction theories which predict a finite speed of propagation of thermal effects are considered. Numerical results obtained from these theories are presented for a one spatial dimension boundary-initial value problem, which involves transient heat conduction in a rigid half space. These results are compared with results from the classical theory, which predicts an infinite speed of propagation of thermal effects. It is shown that, for the problem considered, results from the three theories are very similar at times which are large compared to the relaxation time of the hyperbolic theories.
ON THE SIMPLE STATIONARY CONFIGURATIONS OF SINGLE-LOOP SPATIAL N-REVOLUTE OVERCONSTRAINED LINKAGES
Authors: Lee Chung-Ching
Published: April 2018

Based on the derived matrix and its differential equations, a systematic formulation is presented to either identify the simple stationary configurations of movable spatial 4R, 5R and 6R overconstrained linkages or prove none of them occurs at all. Some examples are given to confirm the correctness and validity of the derived mathematical criterion. In addition, the closed-form solutions of linkage joint variables are well-established and with the help of computer graphics, geometrical meanings of linkage configurations are described. This approach can be used to provide a foundation for understanding the range of motion in overconstrained linkage application.
SYSTEMATIC METHOD FOR THE SYNTHESIS OF SOUTH POINTING CHARIOT WITH PLANETARY GEAR TRAINS
Authors: Hsieh Long-Chang , Liu Jen-Yu , Hsu Meng-Hui
Published: April 2018

South pointing chariots have been the fascinating mechanical devices for designers for a long time. Up to date, the gear trains used in the south pointing chariots are the planetary gear trains with two degrees of freedom and with train value -1. The purpose of this work is to present a systematic approach for the kinematic design of south pointing chariots with planetary gear trains. According to train circuit equation, we propose equation of motion of PGTs. Then, based on the equation of motion of PGTs, we derive two constrained equations for the kinematic design of south pointing chariots. Finally, based on these two equations, we synthesize the corresponding south point chariots for arbitrary planetary gear trains with two degrees of freedom. Some design examples are illustrated to demonstrate the design process.
A PSEUDO PROBABILISTIC APPROACH TO TO DETECT DISTINCT INVERSIONS OF KINEMATIC CHAINS
Authors: Shubhashis S. , Choubey M. , Rao A.C.
Published: April 2018

Isomorphism in kinematic chains has been the subject of intensive investigations, but the detection of distinct inversions has received lesser attention. The methods to detect distinct mechanisms reported to-date require extra or separate computational efforts. The method presented saves both computational effort and time. Moreover, it incorporates more information on the type, number and disposition of the links of kinematic chains and is computationaly easier. A pseudo probability scheme (pseudo means it appears to be , but not exactly) is developed to uniquely represent the kinematic chain and the same is used directly to detect distinct inversions of the kinematic chain. The capability of the method has been illustrated by applying it to detect distinct inversions of kinematic chains with simple as well as multiple joints, the latter being a less explored area so far. The method is applied to linkage (kinematic chains with lower pairs) mechanisms with revolute joints only.
AXISYMMETRIC OSCILLATORY FLOW OVER PROLATE SPHEROIDS
Authors: Alassar R.S. , Badr H.M.
Published: April 2018

An analytical solution is obtained for the problem of axisymmetric inviscid incompressible flow over a prolate spheroid placed in an oscillating free stream. The oscillations are harmonic and the free stream is always parallel to the spheroid major axis. The flow is governed by the Strouhal number and the spheroid axis ratio. Analytical expressions are obtained for the potential function, the surface pressure distribution, and the hydrodynamic force coefficient. The solution covers a wide range of spheroidal shapes ranging from a sphere at one end to a thin needle at the other.
EXPLICIT EQUATIONS AND SPECIAL CASES OF THE BURMESTER CURVES FOR THE PPP-P CASE
Authors: Lu Deng-Maw
Published: April 2018

This paper presents an analytic treatment to investigate the Burmester curves of the PPP-P case. Provided that an instant center associated with an inflection point and rotation angle of a coupler about a pole are specified, the explicit equations of Burmester curves for the PPP-P case are directly derived without any differential process. Because the explicit equations derived are of quadratic form, their geometric properties can be easily investigated. Six degenerated cases and three special cases of the Burmester curves for the PPP-P case are obtained. A design example is presented.
LAMINAR FLOW IN A UNILATERALLY ROUGH CHANNEL
Authors: Hu Jin , Leutheusser H. J
Published: April 2018

This paper deals with an analytical and experimental investigation of laminar sheet flow between a smooth and a rough wall. As such, the material presented may be of special interest within the context of hydrodynamic lubrication. The dynamic and kinematic properties of the flow are described by a newly conceived “reduced Reynolds number”, and the two length parameters of, respectively, “relative roughness” and “steepness of roughness”. The equations of motion are solved by the finite element method for the case of sinusoidal roughness, and corresponding measurements are obtained in a specially designed two-dimensional wind-tunnel. Good agreement is found to exist between numerical and experimental results. The pattern of streamlines and velocity profiles reflect the influence of the three similitude parameters and thereby underline the important role played by surface texture in laminar sheet flow.
CHARACTERISTICS OF A DEVELOPING DROPLET - LADEN JET IMPINGING ON A NORMAL WALL
Authors: Balachandar R. , Tachie M.F.
Published: April 2018

The size-velocity characteristics of a droplet-laden air jet impinging on a normal wall is investigated using a phase-Doppler anemometer. The results of measurements conducted for two jet-exit-to-impingement-wall distances are presented. Experimental data are obtained across the jet at several axial stations covering the first ten jet-exit diameters. The radial variation of droplet mean velocity, rms velocity and skewness coefficient indicates that similarity is not achieved. The rate of spreading of the jet is higher than that noticed in both single-phase flow and previous two-phase flow studies. The presence of the impingement wall does not have a significant effect on the mean velocity distributions for Z/Zi < 0.8. There is an increase in droplet size with increasing distance from the nozzle for Z/D > 4.0. In the early regions of the jet, the water droplet size and velocity are strongly correlated, especially in the core regions. With increasing Z/D, there is no association between size and velocity.
NUMERICAL STUDY OF FLUID FLOW AND HEAT TRANSFER IN TUBE BANKS WITH STREAM-WISE PERIODIC BOUNDARY CONDITIONS
Authors: Beale S.B. , Spalding D.B.
Published: April 2018

A numerical procedure for the calculation of laminar fully-developed cross-flow and heat transfer in tube-banks heat exchangers is presented. Boundary conditions are introduced in a form similar to the treatment at conventional inlets and outlets. Calculations are performed for in-line square, rotated square and equilateral triangle geometries, with pitch-to-diameter ratio 1.25-2, Reynolds number 101-103 and Pradtl number 1-100, under both constant heat flux and constant wall temperature boundary conditions. Overall pressure drop and heat transfer factors are compared to previous numerical work, empirical correlations and experimental data. Overall pressure drop calculations correlate with experimental data, while at low Reynolds number, heat transfer calculations are shown to depend upon the choice of reference bulk temperature in the rate equation. Graphs of local pressure, drag, and heat transfer coefficients are provided and discussed in detail.
PATHOLOGICAL PHENOMENA IN COMPUTATION OF THIN ELASTIC SHELLS
Authors: Sanchez-Palencia E. , Sanchez-Hubert J.
Published: April 2018

We give short account of difficulties appearing when computing thin elastic shells. «Thin» is understood in the sense that the ratio ε between the thickness and any other characteristic length of the shell is small. For small ε the solution uε itself (independently of its numerical approximation [Formula: see text]) exhibits peculiarities which depend highly on the shape and the boundary conditions of the shell. These peculiarities are mainly of three kinds, which do not necessarily appear simultaneously: 1) Boundary layers, 2)Global instability known as “sensitivity”, 3) Constrained solutions in subspaces. The numerical approximation should be reliable in these situations. Finite element schemes involving higher order polynomials appear as more efficient than others. Moreover, an explicit analysis of convergence of the numerical approximation in several typical examples shows that, in order to obtain a good approximation, the mesh step must be taken smaller and smaller as ε decreases. Anisotropic adaptive meshes should probably be suited.
AXISYMMETRIC CHARGE DISTRIBUTIONS ON AN ELASTIC DIELECTRIC HALF SPACE
Authors: Chowdhury K.L.
Published: April 2018

The solution of the axisymmetric boundary value problem of an isotropic elastic dielectric half space subjected to charge distribution on its rigid polarization free surface is constructed by Hankel transforms. For the problem of an electric point dipole applied at origin, exact expressions for the components of displacement and polarization vectors and the potential fields are obtained in terms of Bessel function and fundamental solutions 1/R and e-mR/R, R being the distance from the source point. The electric field is determined both inside and outside the polarized region. In the particular case of a continuous electric charge distribution with density of the form l/(r2+h2)1/2, the mechanical and electric stresses on the surface of the semi-space are derived. The MathematicsTM software is used to present the numerical results on graphs depicting the variation of surface stresses for the particular charge distributions.
OSCILLATING VISCOUS FLOW OVER PROLATE SPHEROIDS
Authors: Alassar R.S. , Badr H.M.
Published: April 2018

The axisymmetric viscous oscillating flow over a prolate spheroid is considered. The oscillations are harmonic and the free stream is always parallel to the spheroid major axis. The flow is governed by the Strouhal and the Reynolds numbers as well as the spheroid axis ratio. In the present paper, we only investigate the effect of Reynolds number while keeping the Strouhal number and the axis ratio unchanged. The results are presented in terms of the periodic variation of the drag coefficient, pressure, surface vorticity, separation angle, the wake length, and the streamline and vorticity patterns for Reynolds numbers ranging from 5 to 100. Upon averaging the stream function and vorticity over one complete oscillation, the double boundary-layer structure observed in the case of a sphere is confirmed for the range of parameters considered.
MATHEMATICAL MODELLING OF SIMULTANEOUS HEAT AND MASS TRANSFER IN FLUIDIZED BED DRYING OF LARGE PARTICLES
Authors: Hajidavaloo E. , Hamdullahpur F.
Published: April 2018

A mathematical model for simulation of simultaneous unsteady heat and mass transfer in fluidized-bed drying of large particles is proposed. A set of coupled non-linear partial differential equations is employed to accurately model the process without using adjustable parameters.

A three phase model representing a bubble (dilute) phase, interstitial gas phase and a solid phase is used to describe the thermal and hydrodynamic characteristics of the bed. The bubble and temperature distributions inside the solid phase is applied. The flow field is divided by an orthogonal grid to a finite number of control volumes to simulate the variation of the properties for the three phases in longitudinal direction. The Crank-Nicholson implicit numerical method is applied to solve the set of coupled nonlinear partial differential equations with variable mass and thermal diffusivity for a spherical-shape particle.

A pilot-scaled fluidized bed dryer was built to test the results of proposed model with those obtained by experiments using wheat particles as a bed charge. A good agreement between the numerical and experimental results is observed.
NEW ELECTRONIC CONTROLLED CONTINUOUS FLOW METERING SYSTEMS FOR AUTOMOTIVE APPLICATIONS
Authors: Mohtasebi S.S. , Hong H. , Krepec T.
Published: April 2018

Four different configurations of fuel metering units applicable to automotive gasoline engine throttle body injection systems are introduced, analyzed and compared regarding their deviation from schedule linearity, dynamic response and relative cost. Since the characteristics of the pump which is used to deliver the fuel to injectors through the fuel metering system has a direct impact on the fuel flow linearity and the cost, two different pumps which are a constant displacement fuel pump driven by the engine and a constant displacement fuel pump driven by a DC electric motor, are considered in this investigation.
IMPLEMENTATION OF THE CONDITIONAL MOMENT CLOSURE MODEL TO A TURBULENT NONPREMIXED H2/CO-AIR FLAME STABILIZED ON A BLUFF BODY
Authors: Kim S.- H. , Liu T. , Huh K.Y.
Published: April 2018

A turbulent nonpremixed flame of H2/CO-air stabilized on a bluff-body is simulated by the conditional moment closure (CMC) model. Full spatial variation of the conditional quantities is taken into account for an elliptic recirculating flow field. Comparison has shown reasonable agreement for the conditional and Favre mean temperature and mass fractions of CO and H20 between calculation and experiment. Overprediction of the peak OH mass fraction is attributed to inaccurate modelling of the conditional scalar dissipation rate. The CMC model is capable of predicting major features of a turbulent diffusion flame characterized by finite chemical reaction rates.
CHARACTERISTICS AND MECHANICAL EFFICIENCY OF ROLADRIVES
Authors: Yan Hong-Sen , Lai Ta-Shi
Published: April 2018

This paper analyzes Roladrive reducers and tests their mechanical efficiency. A Roladrive is a planetary gear train that employs rollers instead of cut gears and has multiple teeth (rollers) meshed while operating. The speed ratio is independent of the pitch diameter, but it is dependent on the number of the pin-teeth and rollers. Moreover, Roladrives can be designed for noninteger speed ratios easily. When the speed ratio is greater or equal to 1 and the basic ratio is near to 2, the theoretical mechanical efficiency reaches the optimal values. Mechanical efficiency of a Roladrive is greater than 0.9 as speed ratio is less or equal to 26. The theoretical mechanical efficiency can reach as high as 0.988 when the speed ratio is equal to 2. Experimental results show that the slopes of the theoretical and measured mechanical efficiencies are very close. In conclusion, this paper provides the foundation to use the theoretical mechanical efficiency to predict the real mechanical efficiency of Roladrives.
INVESTIGATION ON THE STIFFNESS OF 3-HSS PARALLEL KINEMATIC MACHINE USING FINITE ELEMENT ANALYSIS
Authors: Zhou Lihua , Huang Tian , Kerle Hanfried
Published: April 2018

A feasible way to estimate the stiffness of a 3-HSS parallel kinematic machine (PKM) by finite element analysis (FEA) is presented. Taking into consideration the base, columns, carriages struts and the mobile platform, a FEA model for the whole machine is established by solving such problems as match between different element types and simulation of moving components. Later on, this approach is applied to a particular 3-HSS PKM, Linapod, and used to steer the conceptual design of the machine. Furthermore, experiments are made on radial and axial stiffness. By comparison, the FE analytical results show good agreement with experimental data.
AUTOMATIC PARALLELIZATION OF ELECTRO-MECHANICAL SYSTEMS GOVERNED BY ODEs
Authors: Rabbath C.A. , Ait El Cadi A. , Abdonne M. , Lechevin N. , Lapierre S. , Crainic T.
Published: April 2018

The paper proposes an effective approach for the automatic parallelization of models of electro-mechanical systems governed by ordinary differential equations. The novel method takes a nominal mathematical model, expressed in block diagram language, and portions in parallel the code to be executed on a set of standard microprocessors. The integrity of the simulations is preserved, the computing resources available are efficiently used, and the simulations are compliant with real-time constraints; that is, the time integration of the ordinary differential equations is performed within restricted time limits at each iteration step. The proposed method is applied to a two-degree-of-freedom revolute joint robotic system that includes an induction motor and two inner-outer loop control laws. Numerical simulations validate the proposed approach.
OPTIMAL GEOMETRICAL DESIGN OF AIRCRAFT USING GENETIC ALGORITHMS
Authors: Ali Nicholas , Behdinan Kamran
Published: April 2018

With the advent of computers and search and optimization tools such as the genetic algorithm, the ability to manipulate numerous aircraft design parameters in a reasonable amount of time is feasible. From this angle, the lengthy time and effort spent creating and integrating aerodynamics codes, sizing routines, and performance modules, can be mitigated by the use of a genetic algorithm. Consequently, a genetic algorithm has been created and employed as a cost effective tool to explore possible aircraft geometries in the conceptual design process of the aircraft. A program has been developed to address most aspects of aircraft design such as aircraft sizing and configuration, performance, and propulsion, to name a few. These codes have been integrated into a genetic algorithm, which performs the task of searching and optimizing. The adaptive penalty method has been employed to handle all constraints imposed on the design. In addition, adjustments for varying degrees of selection and crossover intensities and types have been studied. A design study has also been carried out to compare an existing aircraft shape with the genetic algorithm optimized aircraft shape and configuration. Results indicate that the genetic algorithm is a powerful multi-disciplinary optimization and search tool, capable of simultaneously managing and varying numerous aircraft design parameters. Moreover, the genetic algorithm is capable of finding aircraft geometries and configurations that are both efficient and cost effective.
A MEASUREMENT OF ULTRASONIC ATTENUATION COEFFICIENT BY FREQUENCY RESPONSE IN STEELS WITH DIFFERENT GRAIN SIZES
Authors: Kim Kyung-Cho
Published: April 2018

A new evaluation method of ultrasonic attenuation in materials is proposed based on the frequency response property of the material evaluated by employing the sound impulse of a wide frequency band. Borrowing from ordinary system theory, the material to be tested is considered to have a characteristic impulse response, representing its micro-structural non-uniformities and thus resulting in the sound attenuation of the material. The concept is resumed as an attenuation system that simulates the material’s micro-structural behavior. Experimental results on a series of specimens, having different grain sizes but all made of a single austenitic stainless steel, showed that the attenuation could properly be evaluated from a single bottom echo in a plate specimen. The attenuation coefficient α, was corrlated in this case to the grain size, D, by the equation, αD=H(πD/λ)n, where λ is wave length and H and n are constants. It was also shown that the micro structural change of materials could be evaluated by the energy loss of sound waves passing through the attenuation systems.
NON-UNDERCUTTING CONDITIONS OF ROLLER GEAR CAMS
Authors: Lo Jie-Shing , Tseng Ching-Haun , Tsay Chung-Biau
Published: April 2018

The undercutting conditions in a planar cam can be predicted by comparing the radius of the curvatures of the pitch curves with the radius of the cutter. For the complexity of the spatial cam generation, the principle radius of the curvatures and the directions of the generated cam surface are different from point to point along the pitch curve so that predicting the undercutting condition becomes very difficult. The undercutting conditions on the roller gear cams use the concept of limiting conjugate motion generation. In this study, the feasible design region without undercutting is presented. The investigation results are very useful to the designer and the manufacturing engineer for understanding the undercutting characteristics of the roller gear cam.
VIBRATION ANALYSIS OF CANTILEVER TYPE CRACKED ROTOR IN VISCOUS FLUID
Authors: Parhi Dayal R. , Behera A.K.
Published: April 2018

The increasing utilisation of rotors in industries and other fields require interpretation of their vibration characteristics and failure conditions. Therefore, computer programmes that have been used will have to be constantly updated. This paper deals with the cantilever type rotor containing a transverse crack subjected to viscous medium. Damping effect and virtual mass effect are taken into account through Navier Stokes equation. The stiff-ness of the cracked shaft is evaluated from the theory of fracture mechanics. For analysis rotor with different crack depth, subjected different viscous medium is considered. The numerical result obtained from theoretical analysis is compared with the experimental results, which agree well.
FINITE ELEMENT MODELING AND STABILITY ANALYSIS OF CHATTER IN END MILLING MACHINING
Authors: Qu Tong , Khajepour Amir , Lin Der Chyan , Behdinan Kamran
Published: April 2018

In this paper, chatter in end milling machine tools is investigated using a Timoshenko beam model and finite element analysis. The model is developed for the cases where the slender machining cutters are flexible along the axial direction. A closed form solution for obtaining the stability lobes is derived assuming cutting forces as point loads applied to the end of the tool. It is shown that the stability lobes converge as the number of elements increase. The results indicate that using a single mass model used in the literature predict a more conservative chatter stability compared to the more accurate model using finite element and Timoshenko beam model.
THERMAL ANALYSIS OF JOINING NYLON 66 COMPOSITES USING MICROWAVE IRRADIATIONS
Authors: Ku H.S. , Widjaya B. , Lee K.F. , Li C.W.
Published: April 2018

Industrial microwave technology for processing polymers and polymer-based composites is currently in a state of considerable flux. Ku et al. used the equipment used in his previous study to join random glass or carbon fibres reinforced thermoplastic composites (Ku et al., 1997a; 1997b; 1999, 2002b)). The material used for the research is 33% by weight random glass fibre reinforced Nylon 66 [Nylon 66/GF (33%)] using Araldite as primer. The heat absorbed and heat flow in the sample materials are studied. The temperatures at different points of the samples are also measured using infrared thermometer. The effect of power input and cycle time on the temperature distribution in the test piece are detailed together with the underlying principles of sample material interactions with electromagnetic field.
AN OPTIMAL REAL-TIME TRAJECTORY TRACKING CONTROL DESIGN FOR PENDUBOT VIA TAKAGI-SUGENO FUZZY MODEL
Authors: Cai Zhen , Su Chun-Yi
Published: April 2018

In this paper, an optimal fuzzy control scheme is presented to achieve trajectory tracking for the Pendubot, an underactuated robot by combining linear optimal control theory and linear regulator theory with the Takagi-Sugeno fuzzy methodology. The stability of the entire closed-loop fuzzy system is analyzed by the designed optimal fuzzy controller. The real-time application of the proposed algorithm on the Pendubot is also addressed.
PERFORMANCE MEASURES OF THE VARIABLE STRUCTURE FILTER
Authors: Habibi Saeid
Published: April 2018

A new method for state estimation, referred to as the Variable Structure Filter (VSF), has recently been proposed. The VSF is a model based predictor-corrector method. It uses an internal model to provide an initial estimate of the states and subsequently refines this initial estimate by a corrective term that is a function of the system output and the upper bound of uncertainties. As such, the VSF can explicitly cater for uncertainties in its internal model. In this paper, a conceptual discussion of the VSF strategy and its performance in terms of stability, accuracy, and convergence is provided. The impact of modeling uncertainties on the performance of the VSF is discussed and quantified. The analysis is augmented by comparative simulation studies to further illustrate the concept.
CHASSIS DESIGN & PERFORMANCE ANALYSIS FOR THE EUROPEAN EXOMARS ROVER
Authors: Ellery Alex , Richter Lutz , Bertrand Reinhold
Published: April 2018

The European Space Agency’s (ESA) ExoMars rover has recently been subject to a Phase A study led by EADS Astrium, UK. This rover mission represents a highly ambitious venture in that the rover is of considerable size ~200+kg with high mobility carrying a highly complex scientific instrument suite (Pasteur) of up to 40 kg in mass devoted to exobiological investigation of the Martian surface and sub-surface. The chassis design has been a particular challenge given the inhospitable terrain on Mars and the need to traverse such terrain robustly in order to deliver the scientific instruments to science targets of exobiological interest, We present some of the results and design issues encountered during the Phase A study related to the chassis. In particular, we have focussed on the overall tractive performance of a number of candidate chassis designs and selected the RCL (Science & Technology Rover Company Ltd in Russian) concept C design as the baseline option in terms of high performance with minimal mechanical complexity overhead. This design is a six-wheeled double-rocker bogie design to provide springless suspension and maintain approximately equal weight distribution across each wheel.
SEVERAL DESIGN ISSUES ON THE TUNABLE ELECTROMAGNETIC VIBRATION ABSORBER
Authors: Liu Jie , Liu Kefu
Published: April 2018

This paper addresses several design issues related to a newly developed electromagnetic vibration absorber (EMVA). The EMVA consists of a clamped-clamped aluminum beam and a permanent magnet that is embedded in the centre of the beam and placed between two poles of a C-shaped electromagnet. By varying the current of the electromagnet, stiffness of the EMVA can be adjusted instantaneously. The EMVA is capable of suppressing vibration of the primary system excited by a harmonic force with a variable frequency. First a simplified equation is proposed to compute the flux density distribution in the gap of the electromagnet. The approximation error caused by the simplification is investigated. Second, the effect of cross-sectional shapes of the permanent magnet on the variable magnetic stiffness and the constant magnetic stiffness is examined. Finally, the effect of the gap spaces of the electromagnet on the variable magnetic stiffness is studied.
KINEMATIC INVERSION OF FUNCTIONALLY-REDUNDANT SERIAL MANIPULATORS: APPLICATION TO ARC-WELDING
Authors: Huo Liguo , Baron Luc
Published: April 2018

This paper introduces the concept of functional redundancy of serial manipulators, and presents a new resolution scheme to solve such redundant robotic tasks requiring less than six degrees-of-freedom. Instead of projecting the secondary task onto the null space of the Jacobian matrix in order to take advantage of the redundancy, the twist of end-effector is directly decomposes into two orthogonal subspaces where the main and secondary tasks lie, respectively. The algorithm has shown to be computationally efficient and well suited to solve functionally-redundant robotic tasks, such as arc-welding.
KINEMATIC OPTIMIZATION OF MECHANICAL PRESSES BY OPTIMAL SYNTHESIS OF CAM-INTEGRATED LINKAGES
Authors: Mundo D. , Danieli G.A. , Yan H.S.
Published: April 2018

The paper proposes a method for the synthesis of planar mechanisms, where a combination of cams and linkages is used in order to improve the kinematic behaviour of mechanical presses. The purpose is to synthesize a function generating mechanism, with a constant input-velocity, able to move the press ram according to an optimal law of motion. The proposed synthesis methodology consists of two phases. As a first step, a linkage type-synthesis is performed, based on the mobility the generation task requires. An initial multi degree-of-freedom (d.o.f.) mechanism is thus selected. One or more disc cams are then synthesized in order to reduce the system’s mobility and to obtain a single-input combined mechanism. The final system is able to generate a specific input/output relationship, as defined by any number of precision configurations. In order to optimize the synthesis process, according to dimensional and kinematical criteria, a genetic algorithm is employed. A goal function is defined on the basis of both performance criteria and design rules, and minimized by means of evolutionary theory.

The proposed methodology is applied to the kinematic optimization of mechanical presses for deep drawing and precision cutting processes.
GENERALIZED RECONFIGURABLE 6 - JOINT ROBOT MODELING
Authors: Djuric A. M. , ElMaraghy W. H.
Published: April 2018

Automated model generation and solution for motion planning and re-planning of robotic systems will play an important role in the future reconfigurable manufacturing systems. Solving the inverse kinematic problem has always been the key issue for computer-controlled robots. Considering the large amount of similarities that exist among the industrial 6R robotic systems, this work classifies them into two main types (Puma-type and Fanuc-type) and then provides a unified geometric solution based on a unified kinematic structure called Generic Puma-Fanuc (GPF) model. A widespread study of different kinematic groups originating from eleven robot manufacturers made it possible to develop the GPF model that can be reconfigured according to the D-H rules (Denavit, and Hartenberg1). A graphical interface by which the robot kinematic model is represented and the D-H parameters are auto-generated for use in solving the inverse kinematic problem. A generic solution module called Unified Kinematic Modeler and Solver (UKMS) implements the geometric approach for solving the inverse kinematic problem. The outcomes are then employed for robot control. Numerical examples are presented for exploring the solution capabilities of our unified approach.
ON UNIQUENESS OF FILIPPOV’S SOLUTIONS FOR NON-SMOOTH SYSTEMS HAVING MULTIPLE DISCONTINUITY SURFACES WITH APPLICATIONS TO ROBOTIC CONTROL SYSTEMS
Authors: Wu Q. , Zeng H.
Published: April 2018

Analysis of the uniqueness of Filippov's solutions to non-smooth robotic control systems is important before the solutions can be sought. Such an analysis is extremely challenging when the discontinuity surface is the intersection of multiple discontinuity surfaces. The key step is to study the intersections of the convex sets from Filippov's inclusions and their associated sets containing vectors tangent to the discontinuity surfaces. For practical non-smooth robotic systems, due to their complexities, the determination of the intersections of these sets symbolically is extremely difficult if not impossible. In this paper, we propose a method such that the determinations of the intersections become feasible. Two examples of practical non-smooth robotic control systems are presented to demonstrate the efficacy of the method. The work contributes significantly to the analysis of non-smooth systems where the proof of the uniqueness of Filippov’s solution is crucial to keep the mathematical model relevant to physical systems and to ensure the numerical solutions can be sought.
MODELLING AND FABRICATION OF A MECHANICAL CELL STIMULATOR
Authors: Lai Yongjun , Bordatchev Evgueni
Published: April 2018

In the field of tissue engineering, mechanical cell stimulators are widely used to simulate forces in natural body environments, or to accelerate the growth of tissue. Simulation of the natural body environment, in vitro, enables researchers to understand the effect of different disturbance on cells, independently. For tissue such as the cartilage, which grows relatively slow in a mature natural body environment, a cell stimulator can be used to speed up the growth of tissue. This paper presents a novel design of planar mechanical cell stimulator which is able to provide mobility of four. The stimulator was fabricated from polymethyl-methacrylate (PMMA) thin plates using advanced micromilling material-removal process with an accuracy of ±3 μm and a surface roughness of 120 nm. The kinematic model of the stimulator is developed and corresponding performance is simulated.
A PLANETARY GEAR TRAIN WITH RING-INVOLUTE TOOTH
Authors: Yang Shyue-Cheng , Liang Tsang-Lang
Published: April 2018

This paper proposes a planetary gear train with ring-involute tooth profile. Inherent in a planetary gear train is the conjugate problem among the sun, the planet gears and the ring gear. The sun gear and the planet gear can be obtained by applying the envelope method to a one-parameter family of a conical tooth surface. The conical tooth rack cutter was presented in a previous paper [5]. The obtained planet gear then becomes the generating surface. The double envelope method can be used to obtain the envelope to the family of generating surfaces. Subsequently the profile of a ring gear of the planetary gear trains can be easily obtained, and using the generated planet gear and applying the gear theory, the ring gear is generated. To illustrate, the planetary gear train with a gear ratio of 24:10:7 is presented. Using rapid prototyping and manufacturing technology, a sun gear, four planet gears, and a ring gear are designed. The RP primitives provide an actual full-size physical model that can be analyzed and used for further development. Results from these mathematical models are applicable to the design of a planetary gear train.
STUDY OF A SINGLE SCREW COMPRESSOR WITH A CONICAL TEETH GATE ROTOR
Authors: Shyue-Cheng Yang , Liang Tsang-Lang
Published: April 2018

From a geometric viewpoint, a mathematical model of a single screw compressor with a conjugate pair of meshing conical teeth gate rotor is a conjugate problem. Coordinate transformation and envelope theory are applied to determine the sets of spatial points of the contacting surfaces that define the main rotor of a single screw compressor. Envelope theory and analytical procedure are used to derive mathematical models of a gate rotor and a main rotor. Stress analysis for the single screw compressor mechanism is performed. PowerMILL software package is used to simulate the manufacture of a main rotor. A numerical example with a compressor ratio of 11:6 is presented to demonstrate the application of the mathematical models developed in this paper.
MECHANICALLY INDUCED TRABECULAR BONE REMODELING INCLUDING CELLULAR ACCOMMODATION EFFECT: A COMPUTER SIMULATION
Authors: Vahdati Ali , Rouhi Gholamreza , Ghalichi Farzan , Tahani Masoud
Published: April 2018

Trabecular bone’s capability to adapt its architecture to the surrounding environment has been a subject of research for more than a century. The purpose of the present work is to simulate and improve a semi-mechanistic bone remodeling theory. In doing so, a computer code was developed using finite element method, also a cellular accommodation effect was incorporated in the model. Using this novel approach, trabecular-like structures for different loading conditions and directionalities similar to actual human bone have resulted for a square plate. Furthermore, it was shown that the model is sensitive loading time history. In summary, results of our research showed that a semi-mechanistic model including cellular accommodation effect is scientifically valid, and is able to predict more realistic morphologies in time-dependent simulations.
AN ADJUSTABLE SIX-BAR MECHANISM WITH VARIABLE INPUT SPEED FOR MECHANICAL FORMING PRESSES
Authors: Soong Ren-Chung
Published: April 2018

An adjustable six-bar mechanism mechanical press, in which one of its link length can be adjusted and its driving crank also can be varied according to different forming processes, is proved to be feasible in this paper. By properly designing the speed trajectory of the driving crank and the adjusting magnitudes of the adjustable link in length, the desired kinamatic characteristics of the ram can be obtained. The examples are given to verify its feasibility and effectiveness in practical applications.
EFFICIENCY ASSESSMENT OF GLYCOL COLD THERMAL ENERGY STORAGE AND EFFECT OF VARYING ENVIRONMENT TEMPERATURE
Authors: Rosen Marc A. , Dincer Ibrahim
Published: April 2018

The effect of varying environment temperature on the efficiency of glycol cold thermal energy storage (CTES) is investigated. Several thermodynamic system parameters are analyzed, such as change in storage temperature, storage heat load, energy and exergy efficiencies and exergy destruction. Glycol CTES is treated as a potential application of sensible heat storage systems. A storage tank with a capacity of 150,000 kg is considered with an ethylene glycol- based water solution storage medium. Exergy analysis is used, which provides more useful information than energy analysis about energy quality, efficiency, losses and irreversibilities. Modelling results indicate that the system exergy efficiency is 46% less than energy efficiency. The system exergy efficiencies are 40% and 20% at 50°C and 10°C ambient temperatures, respectively. The results imply that cold energy is more efficient at higher ambient temperatures, storage heat loss depends weakly on ambient temperature, and the reference-environment temperature affects significantly exergy destruction and efficiency.
AN EXTENSION OF AN ALGORITHM FOR PLANAR FOUR-BAR PATH GENERATION WITH OPTIMIZATION
Authors: Al-Smadi Yahia M. , Russell Kevin , Lee Wen-Tzong , Sodhi Raj S.
Published: April 2018

This work is an extension of the authors’ published work on a planar four-bar motion generation search algorithm with Grashof, transmission angle and linkage perimeter conditions [1], This latest work considers planar four-bar path generation with a coupler point load, crank static torque, crank transverse deflection and follower buckling in a modified search algorithm. As demonstrated in the example, a conventional methodology used in kinematic path generation has been expanded to consider static loading, elastic deflection and buckling in path generation. These factors must be considered in mechanical design, but are not the focus in traditional kinematic synthesis.
PATH PLACEMENT OPTIMIZATION OF MANIPULATORS BASED ON ENERGY CONSUMPTION: APPLICATION TO THE ORTHOGLIDE 3-AXIS
Authors: Ur-Rehman Raza , Caro Stéphane , Chablat Damien , Wenger Philippe
Published: April 2018

This paper deals with the optimal path placement for a manipulator based on energy consumption. It proposes a methodology to determine the optimal location of a given test path within the workspace of a manipulator with minimal electric energy used by the actuators while taking into account the geometric, kinematic and dynamic constraints. The proposed methodology is applied to the Orthoglide 3-axis, a three-degree-of-freedom translational parallel kinematic machine (PKM), as an illustrative example.
PERFORMANCE AND ENERGY BALANCE OF A LOW HEAT REJECTION DIESEL ENGINE OPERATED WITH DIESEL FUEL AND ETHANOL BLEND
Authors: Ciniviz Murat
Published: April 2018

In this study, it was aimed to investigate the effect of ceramic coating on a turbocharged diesel engine performance and energy balance. For this purpose, cylinder head, valves and pistons of the engine were coated with yttria stabilized zirconia layer with a thickness of 0.35 mm nickel-chromium- aluminium bond coat, as well as the atmospheric plasma spray coating method with a thickness of 0.15 mm. Then, the engines were tested for full load. The heating values of the diesel fuel and ethanol were 46.2 and 25.182 MJ/kg, respectively. Because of the lower heating values of the ethanol, compared with the diesel fuel, it appears to have lower following to engine power, torque and SFC. Compare to engine power of SDE, LHRe has increased about 2%, LHReth has decreased about 22% at all engine speed. Compare to engine torque of SDE, LHRe has increased about 2.5%, LHReth has decreased about 23 % at all engine speeds. Compare to SFC of SDE, LHRe has decreased about 1.1 %, LHReth has increased about 54 % at all engine speeds. Compare to exhaust turbine inlet temperature of SDE, LHRe has increased about 15 %, LHReth has decreased about 17 % at all engine speeds.
OPTIMAL DESIGN OF DAMPED DYNAMIC VIBRATION ABSORBER FOR DAMPED PRIMARY SYSTEMS
Authors: Liu Kefu , Coppola Gianmarc
Published: April 2018

This study focuses on the optimum design of the damped dynamic vibration absorber (DVA) for damped primary systems. Different from the conventional way, the DVA damper is connected between the absorber mass and the ground. Two numerical approaches are employed. The first approach solves a set of nonlinear equations established by the Chebyshev’s equioscillation theorem. The second approach minimizes a compound objective subject to a set of the constraints. First the two methods are applied to classical systems and the results are compared with those from the analytical solutions. Then the modified Chebyshev’s equioscillation theorem method is applied to find the optimum damped DVAs for the damped primary system. Various results are obtained and analyzed.
RAY-TRACING ANALYSIS OF A TWO-STAGE SOLAR CONCENTRATOR
Authors: Groulx Dominic , Sponagle Benjamin
Published: April 2018

A ray-tracing analysis was conducted on a 2-stage solar concentrator made of two parabolic mirrors created by Lunenburg Industrial Foundry & Engineering (LIFE). The effects of the secondary mirror’s focal length, the distance between the secondary mirror and the target, and the misalignment with the sun were studied. The focal length of the secondary mirror determines the maximum local solar energy flux Φ that can be achieve on the target. For the optimal focal length of 157.9ʺ, a maximum Φ = 1.2 x 104 MW/m2 was achieve compare to Φ = 1680 MW/m2 for the initial LIFE’s focal length of 158.8125ʺ. The concentrator concentrates all the incident energy from the sun on the target, and that independently of the secondary mirror’s focal length (within the range studied), as long as the target position is within an 11 cm zone. Small misalignments in the order of ±0.2° would bring the concentration efficiency to zero.
THERMOCAPILLARY EFFECTS IN LIQUID SYSTEMS OF VARIABLE MASS CONFINED IN A NON-ISOTHERMAL CONTAINER
Authors: El-Gammal Mohamed M. , Floryan Jerzy M.
Published: April 2018

Interface deformation and thermocapillary rupture in a non-isothermal cavity with free upper surface is investigated. Temperature variations along the interface are induced by differentially heated walls. The dynamics of the process is modulated by changing mass of the liquid. The results determined for the large Biot and zero Marangoni numbers show the existence of limit points beyond processes leading to the interface rupture set in. Evolution of the limit point as a function of the liquid mass is investigated. The topology of the flow field is very similar regardless of whether the cavity is over-filled or only partially filled. It is shown that the cavity over-filling may, in general, extend the range of admissible capillary numbers and thus it can be used as a tool for prevention of rupture.
DESIGN OF A LOAD CELL WITH LARGE OVERLOAD CAPACITY
Authors: Aghili Farhad
Published: April 2018

To increase the signal-to-noise (S/N) ratio and sensitivity of a load cell, it is desirable to design a structure that generates large strain close to maximum allowable strain of the sensor material for a given rating load force. However, accommodating the margin of safety with respect to overloading, compromises the sensitivity. This paper presents the design, analysis, and prototype testing of a load cell which can provide large overload protection capacity without compromising the sensitivity of the sensor. This is achieved by a special design of sensor structure that becomes virtually rigid after its flexures reach their maximum deflection, thereby the sensor can be protected against a large over load. The sensor dimensions, which maximizes the sensor’s sensitivity, for given values of rating load and overload are obtained through mechanical strength analysis. A load cell prototype is fabricated and then tested to measure its linearity and overload characteristics. The experimental results show an accuracy of 0.2% of full scale and overload protection of the sensor flexures.
INVESTIGATION ON STATOR AND ROTOR VIBRATION CHARACTERISTICS OF TURBO-GENERATOR UNDER AIR GAP ECCENTRICITY FAULT
Authors: Wan Shuting , He Yuling
Published: April 2018

This paper investigates the stator and the rotor vibration characteristics of turbo-generator under the air gap eccentricity fault. Firstly the air gap magnetic flux density of the fault is deduced, and the formula of the magnetic pull per unit area acting on the stator and the unbalanced magnetic pulls of x-axis and y-axis acting on the rotor are respectively gotten. Then the static eccentricity, the dynamic eccentricity and the mixed eccentricity are respectively studied to analyze the stator and the rotor vibration characteristics. Finally experiments are done on a SDF-9 non-salient fault simulating generator to verify the theoretical results. The investigation results of this paper will be beneficial to the air gap eccentricity fault diagnosis of turbo-generator.