bluuebunny/crossref_metadata_2025 huggingface dataset:
CENTRIFUGAL IMPULSE AS COORDINATE IN THE TABARROKIAN FORMULATION
Authors: Rimrott F.P.J. , Szczygielski W.M.
Published: April 2018

While the well-known conventional Lagrange equation, based on kinetic coenergy and potential energy, uses generalized displacements of the inertia (mass) elements of a system as coordinates, the complementary alternative or Tabarrok formulation, is based on kinetic energy and potential coenergy, and uses as coordinates the generalized impulses of the system’s force (spring) elements. A model system specifically selected to be as simple as possible, yet to contain all essential elements for an illustration of the application of the Tabarrokian approach for the case where a centrifugal force is present, has been devised to show that the centrifugal impulse appears as additional coordinate for the complementary Lagrangian, and that the system turns out to be non-Tabarrokian. It is then shown that the centrifugal impulse is related to the other impulse coordinates by a nonholonomic constraint. Eventually the compatibility equations of motion for the model system are obtained.
COMPUTER SIMULATION OF STEADY STATE CURVING PERFORMANCE OF HIGH SPEED ARTICULATED TRAIN SETS
Authors: Ahmed A.K.W. , Liu C. , Haque I.
Published: April 2018

This study focuses on the steady state curving performance of articulated High Speed Rail (HSR) train sets. The models incorporate the essential features of an articulated train system such as shared trucks, and suspension characteristics such as car-to-car and car-to-truck connections. As one of the first studies on the curving performance of articulated HSR train sets, linearized steady state curving models for ten-car, five-car, and three-car consists have been developed. Steady state curving performance of the three models has been evaluated and compared to determine the minimum number of cars required in a consist for effective simulation of curving performance. The models are further used for parametric study to examine the influence of selected parameters on the steady state curving performance. The results are compared with those of a parallel study on lateral stability performance in view of stability-curving trade-off. The results show that a baseline articulated train set corresponding to lateral stability critical speed of 310 km/h is capable of negotiating a standard curved track with 0.43 degree curvature, maximum 4 degree unbalance and 12.5 mm flange clearance without wheel flanging or slip. The parametric study showed that the trade off between stability and curving is less extensive than it is known for a conventional railway vehicle. It is found that there is no conflict for wheel conicity less than 0.035 where both curving and stability performance improves with increase in wheel conicity.
A TURBULENCE INTEGRAL MODEL FOR THE EVALUATION OF THE THERMAL EFFECTIVENESS OF A STATIC DAMPER IN GAS-FIRED WATER HEATERS
Authors: Naterer G.F. , Boros J. , Wang X.
Published: April 2018

A semi-analytic mixed convection model is developed for the solution of forced and free convection heat transfer in the center flue of gas-fired water heaters. The model can be used to examine the feasibility of a new static damper concept in the flue design. The static damper provides a trouble-free and economical alternative to conventional electric vent dampers. An integral model with profile assumptions characterizes the turbulent flow during the main burner operation and a laminar free convection analysis characterizes the standby mode conditions. The numerical and experimental results indicate the damper provides an effective mechanism for a 20% reduction of standby heat losses together with a high relative dynamic pressure drop while introducing only a low pressure difference during the combustion mode of operation. These results indicate an improvement of standby efficiency in comparison to a conventional internal baffle flow obstruction which leads to low dynamic pressure drops during the standby mode of the water heater operation. Applications of the static damper concept to other appliances such as boilers may also be beneficial.
LOW-FREQUENCY APPROXIMATIONS FOR ACOUSTIC POROUS MATERIALS: LINEARISATION OF THE POROELASTIC EIGENVALUE PROBLEM
Authors: Panneton R. , Atalla N.
Published: April 2018

Recently in acoustics, it was shown that a finite element discretisation of Biot’s dynamic equations — for poroelastic media — leads to a non-linear eigenvalue problem. This non-linearity comes from the complex dissipation mechanisms of the elastic and acoustic waves prevailing within the poroelastic material. These complex dissipation mechanisms are related to viscous and thermal effects. The main drawback of the non-linear eigenvalue problem is that it prevents the use of classical modal analysis techniques for efficient solution of the corresponding matrix system. Since the finite element method is mostly used at low-freuqencies, the objective of this paper is to derive low-frequency approximations on the viscous and thermal disssipation mechanisms that will be used to linearise the poroelastic eigenvalue problem. To achieve the linearisation, it will be shown that the first Lamé coefficient of the poroelastic medium can be considered frequency-independent for most acoustic porous materials.
SOOT PARTICULATE FORMATION AND CHARACTERIZATION IN COMBUSTION
Authors: Gülder Ö.L.
Published: April 2018

The subject of soot formation in combustion is being extensively studied to decipher the relevant mechanisms. Despite considerable progress made in understanding some to the features of soot formation, we still do not have sufficient details of the formation mechanisms to be able to calculate soot in the flame of a given hydrocarbon fuel from first principles. This paper first gives and overview of the soot particulate formation in combustion and its contribution to ambient particulate matter. The experimental burner types that are commonly used for soot research are then reviewed and basic features of the most commonly used laminar diffusion burners are summarized. Soot particulate formation and emissions in diesel and gasoline engines, and their relative contributions to ambient particulate matter, are discussed. Methods based on physical sampling and non-intrusive laxer-based soot diagnostic techniques are briefly reviewed and their capabilities and limitations are discussed.
PROPAGATION OF WEAKLY NONLINEAR WAVES IN A FLUID-FILLED THIN ELASTIC TUBE
Authors: Demiray H.
Published: April 2018

In this work, we study the propagation of weakly nonlinear waves in a prestressed thin elastic tube filled with an inviscid fluid. In the analysis, considering the physiological conditions under which the arteries function, the tube is assumed to be subjected to a uniform pressure P0 and a constant axial stretch ratio λz. In the course of blood flow in arteries, it is assumed that a finite time dependent radial displacement is superimposed on this static field but, due to axial tethering, the effect of axial displacement is neglected. The governing nonlinear equation for the radial motion of the tube under the effect of fluid pressure is obtained. Using the exact nonlinear equations of an incompressible inviscid fluid and the reductive perturbation technique, the propagation of weakly nonlinear waves in a fluid-filled thin elastic tube is investigated in the longwave approximation. The governing equation for this special case is obtained as the Korteweg-de-Vries equation. It is shown that, contrary to the result of previous works on the same subject, in the present work, even for Mooney-Rivlin material, it is possible to obtain the nonlinear Korteweg-de-Vries equation.
REYNOLDS STRESSES IN CONFINED VORTEX FLOWS
Authors: Yan L. , Lin S. , Vatistas G.H.
Published: April 2018

Reynolds stresses in confined vortex flows have been studied analytically and experimentally. Equations for the Reynolds shear stresses are derived based on the kinetic energy equations and experimental observations. The Reynolds shear stresses are obtained by solving the equations analytically. The unknown parameters appearing in the analytical solutions are determined from experimental data. The Reynolds normal stresses are obtained directly from the experiments which are performed by means of Laser Doppler Anemometry (LDA). The effects of the contraction ratio and the inlet Reynolds number on the Reynolds stresses in the vortex flow from the main section to the exit section of the vortex chamber are analyzed. It is found that the contraction ratio affects the behaviour of the Reynolds stresses, and that a higher inlet Reynolds number results in a higher level of the Reynolds stresses.
THEORETICAL EVALUATION OF NEW PHASE DELAY METHODS FOR MEASURING LOCAL HEAT TRANSFER COEFFICIENTS
Authors: Turnbull W. , Oosthuizen P.
Published: April 2018

A one-dimensional analytical solution has been derived for unsteady heat conduction within a semi infinite body, of high thermal resistance, that is subject to a surface heat flux that varies periodically with time. The heat flux is assumed to be generated within a thin isothermal coating. The model predicts that a phase delay will develop between the heat flux and the coating thermal response. This phase delay is independent upon the material properties of the substrate and coating, on the heat flux driving frequency, and on the local heat transfer, coefficient. With the exception of this last quantity the other parameters are known a priori, hence if the phase delay can be measured experimentally it can then be used to determine the local heat transfer coefficient. Absolute values of the local coating temperature and local heat flux are not required. Hence calibration of the devices for measuring these quantities should not be required. In contrast to the overall surface temperature, it is predicted that the phase delay angle will attain a steady-state value within a few heat flux cycles, thus reducing the time required obtaining a measurement. Furthermore, the one-dimensional mathematical model that has been developed reduces to those used in previous experimentally validated techniques, when appropriate constants in the boundary condition are used.
KINEMATIC SYNTHESIS OF RRSC MECHANISMS FOR MULTI-PHASE FINITE AND MULTIPLY SEPARATED POSITIONS
Authors: Russel Kevin , Sodhi Raj S.
Published: April 2018

This paper presents a new technique for synthesizing RRSC mechanisms to achieve phases of rigid body positions, velocities and accelerations using the same hardware. This work considers two-phase moving pivot problems with constant R-R and C-S link lengths. By specifying the R-R and C-S link joint axes, the constant length condition becomes the only design constraint for these links. The prescribed finite and multiply separated positions are then incorporated in the link constraint equations with respect to the prescribed coordinate frame for each link and the mechanism joint variables and driving link parameters calculated. The rigid body velocities and accelerations were prescribed using instant screw axis (ISA) parameters.
GEOMETRY DESIGN OF A NOVEL ELEMENTARY PLANETARY GEAR TRAIN WITH HYPERBOLIC TOOTH-PROFILES
Authors: Yan Hong-Sen , Lai Ta-Shi
Published: April 2018

This work presents a novel concept of elementary planetary gear trains such that the tooth-profiles of the pinion are hyperbolic. The pitch radius is kinematically replaced by the distance between the gear center and the tooth center. The triple vector product of differential geometry is used to derive the equation of meshing. A program is developed to solve the conjugate surface equations, and to show the solid modeling of proposed elementary planetary gear trains. This approach can be applied to design the elementary planetary gear trains in which the pinion is with hyperbolic tooth-profiles. The proposed novel elementary planetary gear trains can operate smoothly, can transmit more precision, can endure higher torque, and are more compact than traditional planetary gear trains.
OPTIMAL ASSIGNING MACHINES AND OPERATORS WITH FINITE CAPACITY
Authors: Lan Chun-Hsiung
Published: April 2018

To reach maximal profit, the decision tool for determining the number of machines assigned to an operator and how many operators are required in the production project undergoing the considerations of the related costs, machine reliability, conformity rate of products, variable sales price, finite machines and finite operators are proposed in this study. For an idle or breakdown machine, the fixture cost is charged but no operation cost is considered. With the concept described above, the applicability of this study is extended. In addition, product holding cost and machine repair cost are also considered and addressed into this study for applying closer to the implementation of real industrial cases. The step-by-step algorithm to search the optimal solution is also well developed in this study. This paper surely contributes a newer and more practical technique for decision makers in assigning operators and machines into the production project.
GEOMETRY DESIGN OF A ROLLER-DRIVE SPEED REDUCER
Authors: Lai Ta-Shi , Sheu Kuen-Bao
Published: April 2018

This work presents a mathematical model to design roller drives. It is based on coordinate transformation, triple vector product of differential geometry, and theory of conjugate surfaces and the equation of meshing is derived. Cycloid profiles are obtained and the centre of the cylindrical teeth of the pinion is determined by the equidistant curve principle, then apply the CAD (Pro/ENGINEER software package) to construct the solid modeling of the proposed roller drives. The mathematical model can design easily and the solid modeling is presented to demonstrate this method is feasibility.
GEOMETRIC DESIGN OF ELEMENTARY PLANETARY GEAR TRAINS WITH GENERALIZED MESHING ELEMENTS
Authors: Lai Ta-Shi
Published: April 2018

This work presents a novel concept of elementary planetary gear trains such that the tooth-profiles of the planet gear are generalized meshing elements. The pitch radius is kinematically replaced by the distance between the gear centre and the tooth centre. A program is developed to solve the conjugate surface equations, and to show the solid model of the proposed elementary planetary gear trains. This approach can be applied to design the elementary planetary gear trains in which the planet gear has cylindrical, conical, or hyperbolic tooth-profiles.
THE SELF-DAMPING CHARACTERISTICS OF A MAGNETIC CONSTRAINED FULLY COVERED SANDWICH CANTILEVER BEAM
Authors: Li Ming , He Zeng
Published: April 2018

The Rayleigh-Ritz method is applied for the damping analysis of flexural vibration of a fully covered double sandwich-type cantilever beam with the attraction arrangement magnets on the constraining layers root. The analysis is carried out in terms of resonant frequencies and associated modal system loss factors. Single-term solutions for respective modes are assumed for the longitudinal displacements of the constraining layer and the transverse displacement of the beam. The modeling is validated experimentally. The improvement of damping characteristics using the magnetic constrained layer damping treatment under different physical and geometrical parameters has been reported.
A DEPENDENT-SCREW SUPPRESSION APPROACH TO THE SINGULARITY ANALYSIS OF A 7-DOF REDUNDANT MANIPULATOR: CANADARM2
Authors: Kong Xianwen , Gosselin Clément M.
Published: April 2018

A dependent-screw suppression approach is proposed for the singularity analysis of 7-DOF (degree-of-freedom) redundant manipulators. This approach is applied to the singularity analysis of the Canadarm2. Five families of singular configurations are identified for the Canadarm2. The singular configurations obtained are identical to those obtained using the reciprocity-based method. Unlike the results presented previously, there are no denominators in the equations describing the singular configurations.
STRESS-BASED FINITE ELEMENT METHOD FOR EULER-BERNOULLI BEAMS
Authors: Kuo Y.L. , Cleghorn W.L. , Behdinan K.
Published: April 2018

This paper presents a new technique, which can apply the stress-based finite element method to Euler-Bernoulli beams. An approximated bending stress distribution is selected, and then the approximated transverse displacement is determined by twice integration. Due to the satisfaction of compatibility, the integration constants are determined by the boundary conditions related to transverse displacement and rotation. To compare with the displacement-based finite element method, this technique provides the continuities of not only transverse displacement and rotation but also stress at nodes. Besides, the boundary conditions related to stress are satisfied. Two numerical examples demonstrate the validity of this technique. The results show that the errors are smaller than those generated by the displacement-based finite element method for the same number of degrees of freedom.
THE GAS-ASSISTED FLUID FLOW EXPELLED IN FRONT OF A LONG BUBBLE IN A CIRCULAR TUBE
Authors: Hsu Cheng-Hsing , Kung Kuang-Yuan , Chen Po-Chuang , Huang Sam-Dih
Published: April 2018

This study investigates the steady-state flow field in a circular tube filled with a viscous fluid expelled by a long gas bubble. We use a finite difference method with successive over-relaxation in the computation of the viscous flow field. An empirical bubble profile is employed to simplify the computation of the interface shape between the gas and the viscous fluid. By varying the ratio of the bubble width to the diameter of the circular tube (λ), the numerical simulation shows three fluid flow patterns: the complete bypass flow, the recirculation flow and the transient flow. The transient flow is only observed in a limited λ range of √1/2 < λ < 0.7143 and isn’t clearly discussed in the previous studies. The variation of vorticity also is observed by the various sizes of λ.
VIBRO-ACOUSTIC BEHAVIORS OF FLAT SANDWICH COMPOSITE PANELS
Authors: Ghinet Sebastian , Atalla Noureddine
Published: April 2018

The main objective of this paper is to present a theoretical approach to model the vibro-acoustic behavior of flat sandwich composite panels. Two models are studied: symmetrical laminate composite and sandwich composite panel. The theories are developed in a wave approach context. It is shown that a discrete layers sandwich composite panel modeling type leads to a 12th order relation of dispersion while a laminate composite panel modeling leads to a 6th order relation of dispersion. The two models give similar results at low frequencies but the modeling of a sandwich panel using the laminate panel theory leads to inaccuracies at high frequencies. The dispersion relations are first solved in the context of generalized polynomial complex eigenvalues problems. Next, the dispersion relations are used to derive the analytical expression of the critical frequencies and to calculate the natural frequencies of the panel. Using the dispersion relation’s solutions, the study is then focused on the numerical computation of the group velocity, the modal density and the total transmission loss.
THE USE OF ENRICHED HEXAHEDRAL ELEMENTS WITH BUBBLE FUNCTIONS FOR FINITE ELEMENT ANALYSIS
Authors: Ho Shi-Pin , Yeh Yen-Liang
Published: April 2018

In this paper, the concept that adds the interior nodes of the Lagrange elements to the serendipity elements is described and a family of enriched elements is presented to improve the accuracy of finite element analysis. By the use of the static condensation technique at the element level, the extra computation time in using these elements can be ignored. Three-dimensional elastic problems are used as examples in this paper. The numerical results show that these enriched elements are more accurate than the traditional serendipity elements. The convergence rate of the enriched elements is the same as the traditional serendipity elements. In the numerical example, the error norm of the first order enriched elements can be reduced when compared with the use of the traditional serendipity element, but the computation time is increased a little. The use of enriched second and third order hexahedral elements does not only improve accuracy, but also saves the computation time for solving the system of equations, when the precondition conjugate gradient method is used to solve the system of equations. The saving of computation time is due to the decrease in the number of iteration for the iteration method.
DUAL-AXIS DRIVE FOR A MARS ROVER
Authors: Shoucri Andre , Resch Emmanuel , de Groot Egbert , Drouin-Bouffard Jean-Philippe , Morozov Alexei , Jones Howard
Published: April 2018

Conventional Mars rover designs incorporate complicated drive systems. In order to reduce weight, complexity and power consumption, it may be beneficial to consolidate the orthogonal functions of wheel-walking and steering into a single drive. The simultaneous operation of both steering and wheel-walking is not required. This paper demonstrates the concept of a dual-axis drive through the design and construction of a scaled prototype. The final design is novel in employing a linear actuator which is eccentric to both axes of motion. A switching and locking mechanism provides transfer between the two different functions at multiple angular positions.
DESIGN OF A WIND POWERED MARS ROVER
Authors: Berenbaum Zavie , Brunelle-Yeung Elza , Castonguay Patrice , Chu Boby , Chapman Luke , Hayatian Michael , Manseau Jasmin , Depaoli Michael , Hartman Leo , Morozov Alexei
Published: April 2018

There has been considerable interest in the unmanned exploration of Mars for quite some time [4][7][8] but the current generation of rovers can explore only a small portion of the total planetary surface. One approach to addressing this deficiency is to consider a rover that has greater range and that is cheaper so that it can be deployed in greater numbers. The option explored in this paper uses the wind to propel a rover platform, trading off precise navigation for greater range. The capabilities of such a rover lie between the global perspective of orbiting satellites and the detailed local analysis of current-generation rovers. The design of the Wind-Powered Mars Rover is discussed, and the prototype built at McGill University as part of a student design course is described.
THEORETICAL INVESTIGATION INTO THE PERFORMANCE OF THE ROTARY-SCREW FLUID DISPENSING PROCESS
Authors: Hashemi M. , Chen X.B.
Published: April 2018

This paper represents the development of a dynamic model for the rotary-screw dispensing process, by taking into accounts for both fluid compressibility and non-Newtonian flow behavior. In particular, the flow behavior of the fluid being dispensed is characterized by using the power law equation; and then based on the fundamentals of flow in the screw channel and needle, a model is developed to represent the dynamics of the flow rate in the rotary-screw dispensing process. Simulations are carried out to investigate the process performance, with an emphasis on identifying the influence of the key process parameters.
A COMPARATIVE STUDY OF A SMOOTH VARIABLE STRUCTURE FILTER AND THE EXTENDED KALMAN FILTER
Authors: Wang Shu , Habibi Saeid , Burton Richard
Published: April 2018

A new method of filtering strategy, referred to as the Smooth Variable Structure Filter (SVSF) is applied to the problem of state estimation on a class of nonlinear system. The SVSF is revised to reach the better estimation resolution. A comparative study is presented in which the Extended Kalman Filter (EKF) is applied to the same nonlinear system model. The estimation convergence and accuracy of the SVSF and EKF are comparable. The robustness of the SVSF to parameter variations is established through simulation results. This study is important because it allows the new SVSF to be critically compared to a standard technique such as the EKF.
ON MOTION GENERATION OF WATT I MECHANISMS FOR MECHANICAL FINGER DESIGN
Authors: SHEN QIONG , LEE WEN-TZONG , RUSSELL KEVIN , SODHI RAJ S.
Published: April 2018

This work formulates and demonstrates a motion generation method for the synthesis of a particular type of planar six-bar mechanism-the Watt I mechanism. The Watt I mechanism is essentially a “stacked” four-bar mechanism (having two closed loops and a single degree of freedom). Extending the planar motion generation method of Suh and Radcliffe [11] to incorporate relative motion between moving pivots, Watt I mechanisms are synthesized to simultaneously approximate two groups of prescribed rigid-body poses for simultaneous dual motion generation capability. The example included demonstrates the synthesis of a finger mechanism to achieve a prescribed grasping pose sequence.
INFLUENCES OF RAIL SUPPORT CONDITIONS ON MECHANICAL BEHAVIOR OF RAILWAY TRACK SYSTEM
Authors: Sadeghi J. , Hashemi F.
Published: April 2018

All components of the track suffer from a variation in the performance during their lifetime to a different degree. These variations include replacement of timber sleepers with concrete sleepers and changes in the ballast conditions due to tamping or track accumulative loadings. These changes sometimes cause a large discrepancy between results obtained form theoretical evaluations and those obtained from field measurements, making the reliability of the current understanding of the long term behavior of the railway track questionable. There is a need to investigate the impact of the changes in conditions of the track support system on the track design parameters. This research is an attempt to response to this need. In this paper, the influences of the changes in rail support conditions on the magnitude of the rail bending moments (as the main rail design criterion) are investigated. This is achieved through parametric analyses of railway track by developing a theoretical model using dynamic deflection method. The model developed here, considers the main track components and offers the possibility of parametric analyses. The reliability of the model was evaluated by comparing the results obtained from the model with those obtained from measurements in a track field. After calibrating the model, it is used to conduct parametric analyses. The sensitivity of the rail bending moment to the changes in sleeper type and arrangements, and to the ballast mechanical conditions is investigated. The results are discussed aiming at to improve the current understanding of the long term behavior of railways.
DISTRICT HEATING SYSTEM DESIGN FOR RURAL NOVA SCOTIAN COMMUNITIES USING BUILDING SIMULATION AND ENERGY USAGE DATABASES
Authors: Nijjar Jaspreet S. , Fung Alan S. , Hughes Larry , Taherian Hessam
Published: April 2018

There are several benefits to district heating systems. The system design requires knowledge of community peak heating load and annual heating energy requirements. For this purpose, a residential energy model was developed using several energy usage databases. Hourly, peak, and annual heating demands were estimated by simulating 15 archetype houses using an hour-by-hour building simulation program, ENERPASS. Estimated heating profiles from model houses were used to design a district heating system for a hypothetical rural community in Nova Scotia. The findings show that building simulation is a very flexible and valuable tool in identifying the required peak and hourly energy demand of a community for the design of district energy system, and biomass district heating system can reduce community greenhouse gas emissions.
OPTIMIZATION OF HEAT EXCHANGERS FOR GEOTHERMAL DISTRICT HEATING
Authors: Bahadorani P. , Naterer G. F. , Nokleby S. B.
Published: April 2018

This paper analyzes the optimal configuration and operating parameters of a heat exchanger in a geothermal district heating system. An optimization algorithm is presented for the nonlinear constrained problem to maximize the annual net profit for a system of counter-flow heat exchangers. Several parameters that affect the net profit are examined, including the mass flow rates of working fluids and heat transfer area, which both directly affect the outgoing temperatures. The performance of the heat exchanger and fuel savings by reducing fuel consumption to generate heat are modeled within the problem formulation. Also, power input to the pump for fluid circulation is included. By formulating these multiple parameters over a wide range of design conditions, the algorithm presents a useful new design tool for the improvement of heat exchanger networks in geothermal systems.
FINITE ELEMENT ANALYSIS OF A SEMI-ELLIPTICAL EXTERNAL CRACK IN A BURIED PIPE
Authors: Khoramishad Hadi , Ayatollahi Majid Reza
Published: April 2018

In this research, a buried pipe containing an external semi-elliptical crack has been modeled and investigated using finite element analysis. The interaction between the soil and pipe has been considered according to the Burns and Richard model. A few major parameters, namely, the soil height over pipe, the geometries of pipe and crack and the circumferential position of crack on pipe have been changed and their effects on elastic stress intensity factors have been studied at different positions along the crack front. The results showed that the crack experienced mixed mode loading condition and the circumferential crack position on pipe had a significant influence on the stress intensity factors.
SINGULARITY ANALYSIS OF A KINEMATICALLY SIMPLE CLASS OF 7-JOINTED REVOLUTE MANIPULATORS
Authors: Boudreau Roger , Podhorodeski Ron P.
Published: April 2018

The singularities for a class of kinematically simple 7-jointed revolute manipulators are found. Within the class, unnecessary lengths and 4-jointed spherical groups of joints are avoided, and successive joints are perpendicular or parallel. Four different joint layouts are required to complete this class. The concept of screw reciprocity is used to find the singular (velocity-degenerate) configurations. Reciprocal screw quantities characterizing the lost instantaneous motions are derived.
QUATERNION REPRESENTATION OF THE POWER MANIPULABILITY
Authors: Mansouri Imed , Ouali Mohammed
Published: April 2018

In this paper, a quaternion formulation of the power manipulability is developed. Quantifying the mechanical transmissibility of a mechanism, this parameter was previously introduced as a new homogeneous performance index of robot manipulators; however, its evaluation requires complex manipulations, particularly those of quadri-vectors. Furthermore, the quadri-vector form fits exactly with the structure of quaternions. Hence, a quaternion based method may be useful for power performance indices evaluation. It will be shown that this method leads to a recursive algorithm that manipulates kinematics’ parameters as matrices defined over the real quaternion space. Therefore, a new mostly simplified procedure is elaborated, which is suitable to robots performance analysis related issues. The resultant algorithm is largely simpler and more efficient to evaluate the power based performance indices.
MIXED CONVECTIVE SLIP FLOWS IN A VERTICAL PARALLEL PLATE MICROCHANNEL WITH SYMMETRIC AND ASYMMETRIC WALL HEAT FLUXES
Authors: Niazmand Hamid , Rahimi Behnam
Published: April 2018

Mixed convective gaseous slip flows in an open-ended vertical parallel-plate channel with symmetric and asymmetric wall heat fluxes are numerically investigated. Buoyancy effects on developing and fully developed solutions are studied using the SIMPLE algorithm. The velocity and temperature fields are examined for different values of Knudsen number, mixed convection parameter and heat flux ratio. It is found that increasing Gr/Re leads to an increase in the heat transfer rate and friction coefficient. Also, rarefaction effects decrease the heat transfer rate and friction coefficient. The friction coefficient decreases with an increase in heat flux ratio.
DESIGN FOR OPTIMAL PERFORMANCE OF 3-RPS PARALLEL MANIPULATOR USING EVOLUTIONARY ALGORITHMS
Authors: Babu Sabbavarapu Ramana , Raju Vegesina Ramachandra , Ramji Koona
Published: April 2018

This paper presents an optimal kinematic design for a general type of 3-RPS spatial parallel manipulator based on multi-objective optimization. The objective functions considered are Global Conditioning Index (GCI), Global stiffness Index (GSI) and Workspace volume. The objective functions are optimized simultaneously to improve the dexterity as well as the workspace volume which represents the working capacity of a parallel manipulator. A multi-objective Evolutionary Algorithm based on the control elitist non-dominated sorting genetic algorithm is adopted to find the true optimal Pareto front. A constraint Jacobian matrix is derived analytically and the manipulator workspace is generated by numerical search method. The static analysis of the manipulator is also carried out to determine the compliance of the end-effecter.
DESIGN OF A SONIC DRILL BASED ON VIRTUAL PROTOTYPE TECHNOLOGY
Authors: Wang Yu , Liu Baolin , Zhou Qin , Hu Yuanbiao , Li Guomin
Published: April 2018

Sonic drilling is a novel sampling technology applied in many fields. Based on SolidWorks software, a dynamics virtual prototyping is utilized to develop a physical sonic driller by demonstrating collision detection and optimizing overall layout and key component structures. Key hydraulic and structural parameters are optimized using a mathematical model. Search for the optimized parameters and operating conditions for this multi-body mechanical system is conducted experimentally. The practical results show that the virtual prototype technology not only shortens the design cycle but also improves the quality of the conventional design. The new sonic driller designed by this method is both environmentally friendly and smarter.
AN ADAPTIVE-NETWORK-BASED FUZZY INFERENCE SYSTEM FOR PREDICTING SPRINGBACK OF U-BENDING
Authors: Lin Bor-Tsuen , Huang Kun-Min
Published: April 2018

Springback will occur when the external force is removed after bending process in sheet metal forming. This paper proposed an adaptive-network-based fuzzy inference system (ANFIS) model for prediction the springback angle of the SPCC material after U-bending. Three parameters were selected as the main factors of affecting the springback after bending, including the die clearance, the punch radius, and the die radius. The training data were obtained from results of U-bending experiment. The training data with four different membership functions – triangular, trapezoidal, bell, and Gaussian functions – were employed in the ANFIS to construct a predictive model for the springback of the U-bending. After the comparison of the predicted value with the checking data, the results show that the triangular membership function has the best accuracy, which make it the best function to predict the springback angle of sheet metals after U-bending.
PERFORMANCE ANALYSIS OF AN AKF BASED TIGHTLY-COUPLED INS/GNSS INTEGRATED SCHEME WITH NHC FOR LAND VEHICULAR APPLICATIONS
Authors: Peng Kun-Yao , Lin Cheng-An , Chiang Kai-Wei
Published: April 2018

INS/GNSS integrated scheme can overcome the shortcoming of INS or GNSS alone to provide superior performance. AKF is based on the maximum likelihood criterion for choosing appropriate weight and thus to adjust factors online. The primary advantage of AKF is that the filter has less relationship with priori statistical information. There are two NHC available for land navigation which the velocity of vehicle in the plane perpendicular to the forward direction is zero. To validate the performance of proposed scheme, the preliminary results illustrated AKF based tightly-coupled INS/GNSS integrated scheme can provide more stable solutions combined with NHC during GNSS outages. Generally speaking, the improvement ratio of 3D positioning reach 40% compared to EKF.
A STUDY ON THE ENGINE COMPARTMENT AIRFLOW OF A LIGHT AIRCRAFT USING COMPUTATIONAL FLUID DYNAMICS
Authors: Liu Hsu-jeng , Su Chih-chun , Huang Sheng-liang
Published: April 2018

This study applies FLUENT to simulate and analyze the flow characteristics in the engine compartment of a light aircraft. The air inlet, air duct, guide vane, and air outlet are designed to improve the flow conditions according to the drawbacks of the prototype model. The results show that the air duct and guide vane lead the airflow to the certain position of cylinders, and the air outlet reduces the pressure in the engine compartment. Moreover, combining these designs significantly increases the overall airflow velocity in the engine compartment.
EXPERIMENTAL ANALYSIS OF MIXED CONVECTION HEAT TRANSFER ON HEAT SINK OF LED LAMP
Authors: Tzeng Sheng-Chung , Jeng Tzer-Ming
Published: April 2018

The device made of fan and pin-fin heat sink should be a powerful heat sink for LED lamp. This study used transient liquid crystal experimentation to measure the end-wall heat transfer coefficient of linearly arrayed square pin array in the rectangular channel, and discussed the influence of longitudinal spacing on heat transfer. The relative transverse spacing (XT = ST/d) was set as 3, and the relative longitudinal spacing (XL = SL/d = 1.88−5) and the Reynolds number (Re = 11047−17937) were changed. Considering the endwall area, the average Nusselt number with square pin was 1.46−2.58 times of that without square pin, and the square pin array of XL = 3.75 had the maximum end-wall heat transfer gain.
THE INFLUENCE ON THE THERMAL RESISTANCE OF LED PACKAGING WITH DIFFERENT SUBMOUNT AND SURROUNDING CONDITIONS
Authors: Hwu Farn-Shiun , Cheng Ho-Chih , Hu Ya-Hui , Sheu Gwo-Jiun
Published: April 2018

A three-dimensional numerical model using the finite element method is proposed in the present study to accurately simulate the influences of the thermal resistance on the submount of an LED. In a system with adiabatic lateral boundaries, the internal thermal resistance of the submount is principally analyzed from the series connection effect of the spreading thermal resistance and one-dimensional material resistance. However, the total thermal resistance is used for analysis under various heat dissipating conditions due to the complex coupling relations among the material resistance, the spreading thermal resistance, and the external thermal resistance. A higher contact ratio between heat source and submount, a larger external convective effect, and dissipation of heat from the symmetrical axis of the submount will decrease the spreading thermal resistance.
THERMAL PERFORMANCE OF VERTICAL HEAT SINKS WITH DIFFERENT PIEZOFAN ARRANGEMENTS
Authors: Shyu Jin-Cherng , Syu Jhih-Zong
Published: April 2018

This study examines various effects on the heat transfer enhancement of several vertical heat sinks with a running piezofan. Both plate-fin heat sink and pin-fin heat sink having a 10-mm-high or 30-mm-high fin array were tested with either a vertical or a horizontal piezofan. Results show that the piezofan tip located at x/L = 0.5 usually yielded the highest heat transfer enhancement. Besides, heat transfer enhancement factors ranged from 1.2 to 2.4 for the present 10-mm-high plate-fin heat sink, and from 1.1 to 2.6 for the 10-mm-high pin-fin heat sink.
PREDICTION OF FLUID FLOW AND HEAT TRANSFER THROUGH SQUARE DUCT WITH TWISTED TAPE INSERT AND INTERRUPTED RIB
Authors: Kang Ho Keun , Ahn Soo Whan , Lee Myung Sung , Lee Dae Hee
Published: April 2018

Numerical predictions of characteristics of turbulent flows through a square duct (30 × 30 mm) with twisted tape inserts and with twisted tape inserts plus interrupted ribs are conducted to investigate regionally averaged heat transfer and friction factors. The twisted tape is a 0.1 mm thick carbon steel sheet with a diameter of 28 mm, length of 900 mm and 2.5 turns. The present study demonstrates that the twisted tape with interrupted ribs provides a greater overall heat transfer performance over the twisted tape with no ribs in the square duct.
GA BASED HYBRID FUZZY RULE OPTIMIZATION APPROACH FOR ELEVATOR GROUP CONTROL SYSTEM
Authors: Chen Ta-Cheng , Hsu Yuan-Yong , Lee An-Chen , Wang Shiang-Yu
Published: April 2018

Elevators are the essential transportation tools in high buildings so that elevator group control system (EGCS) is developed to dynamically layout the schedule of elevators in a group. In this study, a fuzzy rule based intelligent EGCS optimized by genetic algorithm has been proposed where the rules with the corresponding parameters are generated optimally so as to maximize service quality. The experimental results show that the performance of our approach is superior to these of traditional approaches in the literature.
ON THE SYMBOLIZED REPRESENTATION OF INNOVATIVE BICYCLE WITH FUNCTIONAL ELEMENTS CHARACTERISTICS FOR CREATIVE DESIGN
Authors: Liu Nien-Te , Wu Chang-Tzuoh
Published: April 2018

This paper proposes representations for bicycles. Innovative bicycles are analyzed and arranged one by one to find functional elements of creative characteristics. The elements of bicycles can be classified into three kinds: functional elements, form elements, and material elements. For the functional elements, they are classified into 14 kinds, where controlling, moving, and input elements are necessary for bicycles. By using symbols, bicycles can be represented simply and quickly for innovation design.
APPLICATION OF A POLYGENERATION OPTIMIZATION TECHNIQUE FOR A HOSPITAL IN NORTHERN ONTARIO
Authors: Romero Alberto , Carvalho Monica , Millar Dean L.
Published: April 2018

An optimization technique based on Mixed Integer Linear Programming (MILP) was applied to a hospital located in Sudbury, Ontario, Canada. The energy services included electricity, heat, steam, and coolth. Different options for the system’s operation were also considered in the optimization procedure. The optimization model determines the optimal configuration of the polygeneration system and the best operational strategy. The primary objective for optimization is to minimize the hospital’s annual energy costs. This objective can be achieved by consuming low-priced natural gas, operating the gas engines at full load to generate electricity, and selling all of this electricity into the provincial grid, which ensures the hospital’s eligibility to receive government payments for cogeneration.
AERODYNAMIC EFFECT OF 3D PATTERN ON AIRFOIL
Authors: Wang Xiao Yu , Lee Sooyoung , Kim Pilkee , Seok Jongwon
Published: April 2018

It is known from recent observations that the textured surface plays a role in reducing the drag force and increasing the lift force of a moving body. Comparing the numerical simulation between smooth surface and textured surface in this study, we also observe that the textured surface reduces the drag coefficient and increases the lift coefficient of the surface. As for the two simulation models performed in this study, we use the modified NACA0018 model for the basic airfoil configurations. After the simulation using Fluent, the results about the two models are mutually compared, and we found that the textured airfoils can decrease the drag coefficient and increase the lift coefficient dramatically. We also found that there exists an optimal angle, at which both the drag coefficient decrement and the lift coefficient become maximum. The final goal of this study is to design the airfoil with the reduced drag coefficient and the improved aerodynamic efficiency
HEALTH ASSESSMENT FOR HYDRAULIC SERVO SYSTEM USING MANIFOLD LEARNING BASED ON EMD
Authors: Cheng Yujie , Lu Chen , Ma Jian
Published: April 2018

This study proposes a health assessment method for the hydraulic servo system using manifold learning based on empirical mode decomposition (EMD). An RBF neural network is adopted as a fault observer for the hydraulic servo system to generate a residual error signal. Then, the residual error signal is decomposed by EMD to form the initial feature matrix. To extract more sensitive features and reduce time consumption, isometric mapping algorithm is introduced to reduce the dimensionality of the initial feature matrix. Furthermore, the singular values of the reduced feature matrix are extracted for the subsequent health assessment. Considering the traditional Euclidean distance metric can only reflect local consistency, this study utilizes manifold distance (ManiD) to measure the health condition of the hydraulic servo system. Finally, the ManiD is converted into a confidence value, which directly represents the health status. Experiment results demonstrate the effectiveness of the proposed method.
A NEW GEARBOX FAULT DIAGNOSIS METHOD BASED ON LUCY–RICHARDSON DECONVOLUTION
Authors: Zhang Xinghui , Kang Jianshe , Teng Hongzhi , Zhao Jianmin
Published: April 2018

Gear and bearing faults are the main causes of gearbox failure. Till now, incipient fault diagnosis of these two components has been a problem and needs further research. In this context, it is found that Lucy–Richardson deconvolution (LRD) proved to be an excellent tool to enhance fault diagnosis in rolling element bearings and gears. LRD’s good identification capabilities of fault frequencies are presented which outperform envelope analysis. This is very critical for early fault diagnosis. The case studies were carried out to evaluate the effectiveness of the proposed method. The results of simulated and experimental studies show that LRD is efficient in alleviating the negative effect of noise and transmission path. The results of simulation and experimental tests demonstrated outperformance of LRD compared to classical envelope analysis for fault diagnosis in rolling element bearings and gears, especially when it is applied to the processing of signals with strong background noise.
INTEGRATION FAULT DETECTION AND TOLERANT CONTROL IN MICRO-SATELLITE ATTITUDE PROPULSION MODE APPLICATION
Authors: Shou Ho-Nien
Published: April 2018

The paper refers to a tolerant control method which is reconfigurable to micro-satellites when they are out of order. The integrated approach to the design of thruster control reconfigurable fault-tolerant control system is proposed. The scheme includes a control effectiveness factor and a reconfigurable fault-tolerant controller. The fault detection, diagnosis and controller reconfiguration are carried out using the control effectiveness factor based on the information from a two-stage Kalman filter. By using the two-stage Kalman filter and digital controller, the nonlinear plant will be discretized. We present sufficient conditions under which a discrete-time controller that input-to-state stabilizes an approximate discrete-time model of a nonlinear plant with disturbances. The result shows the method enables us to solve the system faults and meet the requirement when there is a fault in the micro-satellites attitude control system.
RESEARCH AND EXPERIMENT OF THERMAL WATER DE-ICING DEVICE
Authors: Zhu Zicheng , Zhang Xuejun , Wang Qiang , Chu Weijun
Published: April 2018

By analyzing the deficiencies of existing de-icing methods, a new de-icing method which combines thermal de-icing with water-jet cutting de-icing technology is coming into being. This paper introduces the construction of thermal water-jet de-icing equipment. Through repeated experiments, the factors which would affect de-icing have been researched and experimentally verified, including jet pressure, nozzle aperture, standoff, and jet injection angles, etc. Analysis of experimental results shows that this device can perform well and satisfy design requirements.
A CRASHWORTHINESS SIMULATION FOR A LIGHT AIRCRAFT CONSTRUCTED OF COMPOSITE MATERIALS
Authors: Chen Pu-Woei , Chen Kuan-Jung
Published: April 2018

This study analyzes the crashworthiness of a light aircraft that is constructed from composite materials. The finite element method is employed to conduct dynamic impact simulations on carbon fiber composite fuselages. The results show that the safe impact speed for an aluminum alloy cockpit crashed at a 30° impact angle is 9.59 m/s, but a cockpit made of composite material can withstand a speed greater than 18.05 m/s. The safe impact angle for an aluminum alloy cockpit is 16.56°, but that for a composite cockpit is 84.9°. The safety crash zone for a composite material cockpit is 160% greater than that for an aluminum alloy cockpit.