bluuebunny/crossref_metadata_2025 huggingface dataset:
Immersive Educational Systems With Procedure-Oriented Combinations of Real and Virtual Environments
Authors: Zhang Zhou , Zhang Shaojin , Zhang Mingshao , Esche Sven K.
Published: January 2019

Virtual reality (VR) is becoming increasingly popular in educational applications, but insufficient users’ feel of immersion often slows the further adoption of VR. Many solutions with a focus on the results rather than the details of the interactions between the objects in the real and virtual worlds have been developed. Therefore, the real procedures are distorted and the users lose their perception of in-person participation.

In order to improve the users’ feel of immersion further and to simulate more realistic operations in VR, a procedure-oriented approach for the combination of real and virtual environments is proposed here. As its name implies, this approach emphasizes the details of the procedures, namely how to capture, track, operate and interoperate the real and virtual objects in a mixed environment. In order to illustrate this idea, a prototype of mixed real and virtual assembly, in con-junction with object recognition and rigid-object tracking functions based on robotic vision techniques, is presented as an example. This prototype is designed based on a game-based virtual laoratory system, and the specific implementation is a planetary gear train experiment. In this experiment, all models of the parts with the information required for the assembly are created, labeled and added to the database of the virtual laboratory system. The physical parts are marked in order to facilitate object recognition and object tracking. During the experiment, the main assembly with one missing planetary gear is accomplished in a purely virtual environment. In the real world, the missing planetary gear is tracked by a Kinect while the user is manipulating this gear. Then, the system recognizes this gear based on the markers and couples the corresponding virtual model of that gear with the avatar’s hand in the virtual environment. Afterward, the cam-era tracks the real part, and the user can adjust its pose and location to finish the final assembly. The main benefit of this implementation is that the user can take advantage of some simple real parts in conjunction with virtual models of sophisticated parts in order to get realistic experience with the assembly process.
Experimental Investigation on Newtonian Drop Formation in Different Continuous Phase Fluids
Authors: Nazari Ashkan , Nazari Arash
Published: January 2019

In this work, formation water drops as a Newtonian fluid in different bulk fluids are investigated. A MATLAB code has been developed to process the images taken via a high speed camera in the lab to measure the contact angle of drop, as well as the drop’s diameter and volume at different stages of formation. It is found that the water drop shows similar behavior when they shaped in the liquid phase bulk fluid with different properties while the drop formation’s behavior is substantially different when water drops are formed in the gas bulk fluid. In addition, it is tried to predict the frequency of drop formation at different flow rates with regard to the inertial and surface tension forces applied to the dispread fluid.
Heat Transfer Analysis of a Low-Temperature Heat Pipe-Assisted Latent Heat Thermal Energy Storage System With Nano-Enhanced PCM
Authors: Mahdavi Mahboobe , Tiari Saeed , Pawar Vivek
Published: January 2019

In the current study, the thermal characteristics of a low-temperature latent heat thermal energy storage system are studied numerically. A cylinder container encloses a paraffin-based PCM, which is heated via a heat transfer fluid passing through a tube at the center. Heat pipes are incorporated into the PCM to enhance the heat transfer rate between the heat transfer fluid and the PCM. In addition, high thermal conductive nanoparticles are dispersed into the PCM to increase its thermal conductivity. A transient model is developed using ANSYS-FLUENT to simulate the charging process and study the impact of heat pipes and nanoparticles on the performance of the system. The effects of different parameters, such as the quantities of heat pipes as well as the nanoparticles types and volume fraction, are investigated.
Compliant Variation Analysis for High-Speed Train With Consideration of Welding Distortion
Authors: Liu Tao , Li Yongjun , Li Baowang , Li Zhimin , Yao Limin , Jin Sun
Published: January 2019

An important goal of the manufacturing process is to achieve high accuracy and reliability of products. For modern equipment manufacturing industries, such as high-speed trains (HST), the assembly performance is guaranteed by the product design and manufacturing technique. Since dimensional control is much related to manufacturing quality, assembly variation analysis methods play an increasingly crucial role in advanced manufacturing industry. Nevertheless, the relationship between welding distortions and tolerance design has not been considered in most existing assembly variation analysis models, which lack of quantitative analysis between precision and performance. In this study, a compliant variation analysis methodology considering both static structural deformation and welding distortion is developed and applied to predict assembly variation of the roof of HST. Firstly, welding simulation is carried out to predict welding shrinkage and angular distortion with different welding configurations. Then, welding distortion is equivalent to dimensional variation and considered in the compliant variation analysis model with offset tolerance technique. Finally, a compliant variation simulation is carried out to investigate the variation propagation influence of welding shrinkage and distortion on the final dimension of assembly. The presented methodology provides an efficient tool for variation analysis of HST, also offers a theoretical basis and experimental support for mechanical properties of compliant assembly.
An Accurate On-Line Correction Strategy for Gravity Compensation Aiming at Teaching by Touch of Collaborative Robots
Authors: Dong Yunfei , Ren Tianyu , Wu Dan , Chen Ken
Published: January 2019

Modern industrial robots are increasing rapidly towards collaborating and physically interacting with people on complex tasks, and away from working in isolated cages that are separated from people. Collaborative robots are usually developed to perform variable stiffness control, teaching by touch, collision detection, and so on. Torque control with accurate gravity compensation becomes necessary.

When the method of torque-based impedance force-control is used to achieve teaching by touch, the gravity compensation is added to the joint torque loop directly. As a result, the gravity model should be very accurate, otherwise the robot will not stay still even if no any artificial external force is applied. Unfortunately, it is very difficult to model and identify the robot dynamics such accurately in the whole working space because of the presence of the robot cables, joint and link flexibility, cables or tube of end-effector, the end-effector itself and so on. There are always some regions where the robot will drift due to the error of gravity compensation.

This paper is motivated by the gravity compensation problem of collaborative robots equipped with joint torque sensors, and attempts to propose an accurate on-line correction strategy for gravity compensation especially aiming at the application of teaching by touch. The developed method has been tested on a 7-DOF collaborative robot and shown good performance.
Numerical Modeling of Water Impingement and Heat Transfer With Solid Slabs During Secondary Cooling in a Continuous Caster
Authors: Ma Haibo , Tang Kaile , Liu Rui , Lowry Michael , Silaen Armin , Zhou Chenn
Published: January 2019

In the steel continuous casting process, cooling water is directly injected through multiple rows of nozzles to remove heat from the slab to allow the slab to solidify in secondary cooling. Effective heat removal from the slab without causing slab cracking and deformation is desired. The present study focuses on developing a reliable numerical model which can accurately predict the impingement and heat transfer between water droplet and solid slab. The flat fan atomizer is chosen as a representative nozzle to be simulated. The spray pattern on the slab surface, as well as the impingement behaviors of water droplets, are obtained through an Eulerian-Lagrangian approach. The wall jet model coupled with modified evaporation rate depending on the droplet Weber number has been applied in the numerical model. A series of parametric studies have been performed to investigate the effects of spray direction, standoff distance, and distance between adjacent nozzles on the impingement heat transfer process. Simulation results reveal that intense cooling effects can be found in the center of the spray, where the concentration of droplets is the highest regardless of the spray direction. Double the standoff distance can reduce the heat transfer coefficient on slab surface by 10%. Finally, the distance between two adjacent nozzles should be adjusted to be smaller than the standoff distance in order to avoid the “fountain” effect induced by the collision of the two neighboring wall jets.
The Effects of Single-Walled Carbon Nanotubes and Ionic Liquids in Reduction of Friction and Wear
Authors: Guo Hong , Keil Steven , Ackerman John , Puchades Ivan , Landi Brian , Iglesias Patricia
Published: January 2019

A significant amount of energy dissipates from frictional losses of moving components in machinery and devices in industry. This contact friction leads to the wear and eventual failure of industrial mechanical components over extended time through adhesion, abrasion, fatigue, or corrosion. Frictional losses could be mitigated by utilizing more effective lubricants, which would allow the translating surfaces to slide over one another more fluently. There is reason to study eco-friendly alternatives over traditional lubricants to reduce negative impact to the environment. The implementation of Ionic Liquids (ILs) as additives to oil-based lubricants is a development in tribology with the potential to lower the friction coefficient and reduce wear. When carbon nanotubes are dispersed into these ionic liquids, the reduction of losses due to friction and wear can be even greater. In this experiment, single-walled carbon nanotubes (SWCNTs) of four concentrations, 0 wt.%, 0.01 wt.%, 0.02 wt.%, and 0.03 wt.% were dispersed in a room temperature ionic liquid, Trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl) phosphinate, or [THTDP][Phos] for short, to form four homogeneous mixtures. Then, each mixture was added in 1 wt.% to a base vegetable oil. Friction tests were also conducted with pure vegetable oil for comparative purposes. The experiments consist of a pin-on-disk rotational tribometer and a ball-on-flat reciprocating tribometer both applying a steel-steel (AISI 52100) contact to evaluate the lubricating ability of combining SWCNTs and ILs as lubricant additives. The load, speed, wear radius, sliding distance, and duration of the experiment were held constant to isolate lubrication as the experimental parameter. Optical microscopy (OM), thermogravimetric analysis (TGA), and viscometer analysis were utilized after experimentation to analyze and discuss the wear mechanisms of the worn surfaces. Results differed between rotational and translational experiments, with the rotational results yielding a decrease of 14.21% in wear loss with the VO+1%[THTDP][Phos] lubricant. The translational results yielded a continuous decrease in wear loss with the increase in SWCNT wt.%.
Phase Evolution and Corrosion Performance of Laser Processed Oxide Dispersion Strengthened Ferritic Alloys
Authors: Ettefagh Ali Hemmasian , Wen Hao , Lu Fengyuan , Guo Shengmin
Published: January 2019

The application of laser processing as a surface treatment method on oxide dispersion strengthened (ODS) Fe-14Cr ferritic alloys, Fe-14Cr-3W-0.3Ti-xY2O3 (x = 0.3, 0.6, 0.9) (wt%), was examined in this paper. The ODS ferritic alloys with different amount of Y2O3 particles were prepared by mechanical milling and subsequently consolidated by spark plasma sintering (SPS). The effect of surface laser processing on the corrosion behavior was investigated for these ODS alloys with different oxide contents. The corrosion behaviors of SPS consolidated ODS samples with subsequent laser melting/solidification were examined by the means of electrochemical tests and compared with the untreated ODS samples in salt water. Results indicated that for samples without laser treatment, powders are mainly in their elemental state. However, after laser processing, the formation of passive layer and the improvement in the corrosion resistance are noticeable. CALculation of PHAse Diagrams (CALPHAD) calculations were used to identify the equilibrium phases and compared well with the experimental results.
Journal Bearing With Controllable Radial Clearance
Authors: Farkhondeh Biabnavi Shahrbanoo , Rashidi Majid
Published: January 2019

This work presents the novel design of a smart hydrodynamic journal bearing with adjustable radial clearance. The dynamic behavior of this bearing was mathematically modeled and examined. Finite Element Analyses were conducted to determine the effort needed to change and maintain a desired value for the radial clearance. First, the bearing set was modelled as a two-degrees-of-freedom dynamic system. For an initial value of a radial clearance of c = 0.0508 mm, the bearing set exhibited an unstable behavior under its postulated operating condition. A Generic Algorithm (GA) was used to define an objective function so that an optimum value of c could be determined in order to ring the bearing into a stable operating condition. The GA determined the value of radial clearance of c = 0.0051 mm for this purpose. Second, a Jeffcott rotor was modeled as an eight-degrees-of-freedom vibratory stem supported by two identical smart bearings. For an initial value of c = 0.025 mm, the disk’s peak-to-peak vibrations amplitude was determined to be 8 × 10−5 meter and 8.5 × 10−5 m along two orthogonal axes of a reference frame respectively. The GA was used to determine a new value for the radial clearance of the supporting bearings in order to reduce the disk’s vibration level. A new value of radial clearance c was determined to be 0.095 mm which in turn reduced the vibrations of the dick from 8 × 10−5 and 8.5 × 10−5 meter to 3.5 × 10−5 and 2.5 × 10−5 m respectively.
Finite Element Simulation of Backward Micro Extrusion for Annealed Copper
Authors: Uddin Md Mosleh , Mondal Debabrata , Herrington Paul D.
Published: January 2019

The growing demand of miniaturized products is tremendously influencing the progress of micro-forming technologies. The implementations of micro technologies in the field of microelectronics, sensors, and medical equipment necessitate versatile micro-forming processes. These processes facilitate the bulk production of micro parts with higher precision, minimum material waste, and better surface finish. However, micro-forming technologies are still expensive due to the limitations of traditional materials and stringent size requirements. Finite element simulations are being widely used to analyze the manufacturing process parameters before going into production. In this research, a backward micro-extrusion process is simulated for annealed copper by using commercial Finite element simulation software. The effects of different punch diameters, friction coefficients, punch velocities on the load-displacement curves and the resulting strain distributions are investigated. To overcome limitations of the post-yield hardening data from the uniaxial compression test, the Ramberg-Osgood model is proposed to predict the responses at the higher plastic strain.
Simultaneously Satisfying Multi-Objective Design of Structural and Control Systems Based on Consideration of Uncertainty by Set-Based Approach
Authors: Ishikawa Haruo , Sasaki Naoko
Published: January 2019

The simultaneous optimum design for structural and control systems is very important to realize better performance, short lead time and low cost in the development of product. Previous researches on the simultaneous optimum design of these systems are mainly based on mathematical optimization or coupled computation by CAE which are based on point-based iterative calculation. On the other hand, it is general and essential that the required performances and the influence factors for them have some kinds of uncertainty especially in the initial design stage of structural design and uncertainty arising from the difference of real structural (mechanical) and mathematical models in the control system. In this research, for the expression of uncertainty, we use set-based method rather than point-based for processing these uncertainties. Also, generally, the design of the system has often multi-performances, whether structural system or control system. Then, how effective the set-based design method is to solve the simultaneous design problem is investigated, using simple examples of classical control and modern control. As a result, it is found that the applicability of the set-based design method is shown.
A Small Radio Frequency Sensor for Microwave Tumor Ablation
Authors: Wang Lulu , Ge Mengke , Qiu Bensheng
Published: January 2019

This paper presents a small radio frequency sensor namely multi-slot antenna for liver tumor ablation at microwave spectrum. A computer simulation model was developed to validate the proposed antenna. The authors tested the proposed antenna on pig liver tissue samples. Both simulation and experimental results showed that the proposed multi-slot antenna has the potential for liver cancer treatment in the future.
Optimal Design of a Conventional and Magnetorheological Fluid Brakes Using Sensitivity Analysis and Taguchi Method
Authors: Khafaji Salwan Obaid Waheed , Manring Noah D. , Al-Mudhafar Mohammed
Published: January 2019

Drum brakes have dominated the braking industry for many years due to their low cost and adequate operating performance. In this paper, the authors present the first example of studying the sensitivity analysis of a magnetorheological fluid (MRF) and a conventional frictional brake by using first order Tayler series expansion. Nondimensional analyses are carried out to generalize the analyses for every brake configuration. This paper seeks to step away from the complexity of the numerical models for these brakes. Taylor series expansion is used to examine the effects of perturbing dimensionless design parameters on the braking torque. In addition, Taguchi approach is applied for the brakes to study the contribution of the design parameters on the braking torque and to obtain the optimal design. It is shown in this paper that braking torque for magnetorheological fluid brake is dependent on seven dimensionless groups while the frictional brake is dependent upon only four dimensionless groups. Four groups of the MRF brake and two groups for the frictional brake dominate the physics of braking. The sensitivity analysis has identified the key parameters that must be adjusted in order to increase braking torque. Furthermore, Taguchi approach has showed the how the variations of input variables affect the variations of the output variable and stated the optimal levels of the design parameters that achieve the optimal design.
Develop a Flexible Regenerative Exoskeleton to Assist Walking
Authors: Xie Longhan , Li Xiaodong
Published: January 2019

During walking, human lower limbs accelerate and decelerate alternately, during which period the human body does positive and negative work, respectively. Muscles provide power to all motions and cost metabolic energy both in accelerating and decelerating the lower limbs. In this work, the lower-limb biomechanics of walking was analyzed and it revealed that if the negative work performed during deceleration can be harnessed using some assisting device to then assist the acceleration movement of the lower limb, the total metabolic cost of the human body during walking can be reduced. A flexible lower-limb exoskeleton was then proposed; it is worn in parallel to the lower limbs to assist human walking without consuming external power. The flexible exoskeleton consists of elastic and damping components that are similar to physiological structure of a human lower limb. When worn on the lower limb, the exoskeleton can partly replace the function of the lower limb muscles and scavenge kinetic energy during lower limb deceleration to assist the acceleration movement. Besides, the generator in the exoskeleton, serving as a damping component, can harvest kinetic energy to produce electricity. A prototype of the flexible exoskeleton was developed, and experiments were carried out to validate the analysis. The experiments showed that the exoskeleton could reduce the metabolic cost by 3.12% at the walking speed of 4.5 km/h.
Advanced Zig-Zag Beam Theories for Sandwich Structures Analyses
Authors: Filippi Matteo , Carrera Erasmo
Published: January 2019

This work aims at evaluating the capabilities of several higher-order beam formulations for stress and dynamic analyses of layered sandwich structures. The structural models are conceived within the framework of the Carrera Unified Formulation (CUF) that allows one to generate (and compare) an infinite number of displacement fields. The number and the type of functions that are selected to generate the kinematic expansions are input parameters of the problem. Besides the well-known Taylor- and Lagrange-type expansions, great attention is paid to a new class of advanced higher-order zig-zag theories, which are written as combinations of continuous piecewise polynomial functions. Numerical simulations are performed on laminated and sandwich beams with very low length-to-depth ratio values. Also, structures with soft layers made of viscoelastic materials are considered to investigate the different dissipation mechanisms.
Nonlinear Dynamics of Rotating Structures and Helicopter Blades
Authors: Filippi Matteo , Pagani Alfonso , Carrera Erasmo
Published: January 2019

This work explores the effects of geometrical nonlinearities in the vibration analysis of rotating structures and helicopter blades. Structures are modelled via higher-order beam theories with variable kinematics. These theories fall in the domain of the Carrera Unified Formulation (CUF), according to which the nonlinear equations of motion of rotating blades can be written in terms of fundamental nuclei, whose formalism is an invariant of the theory approximation. The inherent three-dimensional nature of CUF enables one to include all Green-Lagrange strain components as well as all coupling effects due to the geometrical features and the three-dimensional constitutive law. Numerical solutions are considered and opportunely discussed. Also, linearized and full nonlinear solutions for vibrating rotating blades are compared both in case of small amplitudes and in the large deflections/rotations regime.
A New Incremental Bending System to Form Curved Metal Plate by Experiment and Finite Element Simulation
Authors: Dang Xiaobing , He Kai , Zhang Feifei , Zuo Qiyang , Du Ruxu
Published: January 2019

Bending curved metal plate is an important process for many heavy industries such as shipbuilding. It is a basic process to manufacture hull surface. The conventional method is the so-called line heating method, which is not only labor intensive but also inefficient and error-prone. We have presented a new method of incremental bending. In this paper the incremental bending system is explained from its hardware and software. A kind of curved metal plate is formed by experiment and finite element simulation. The manufactured workpiece is of high quality with smooth surface. The presented method can be successfully used to form curved metal plate. It is a highly flexible forming method. It would have a wide application in industry.
The Impact of the Wind Power Plant on the Air Radars Functioning
Authors: Radulescu Victorita
Published: January 2019

Nowadays a large interest in the public and private sector is dedicated in generating electricity using renewable resources. Thus, over 60,000 MW is produced worldwide by using the wind energy. These systems are generally composed of power plants formed from 2–3 to several tens, hundreds of wind turbines with rotating blades that reach heights over 160m. The number, the height, and the rotation of these wind turbines represent technical challenges for the radar system efficiency and accuracy. They should be assessed carefully, in each case, to ensure that it maintains an acceptable level of the air space surveillance capability. The research paper presents the influence of the wind power farms on the air radars especially in cases of surveillance area, both for the primary radars and the secondary radars. There are differences between the interference between the wind turbines and radars functioning, depending on the types of radars. In the last decades in Romania is a permanent effort to increase the number the wind farms built, or in the process of being built, but also referring at the number of wind turbines in these parks and their physical dimensions. This paper focuses on the effects of the wind farms on the radars efficiency, and their potential impact on the ability of airspace surveillance. This results in a concise and transparent reference guide for developers of wind farms when assessing the impact of wind turbines on aerial surveillance systems. Specialists are relatively unanimous in their opinion that, in order to make an assessment of the impact of the wind farms on the radars must be defined at least three areas corresponding to different levels of the technical expertise. They must be combined with the influence of the wind farms on the ability of the radar to fulfill the mission, why they were installed, assuming that it is necessary to create an exclusive protection area. First, are discussed briefly the principles of the radar’s operation, depending on their type: primary and secondary surveillance radars. Further, are estimated the induced reflections by the wind power plant on the radar system. If the number of false targets generated by the reflections from wind turbines is too big, so it exceeds the processing capacity of the radar, the operational capacity will suffer. There are presented some theoretical aspects, followed by some cases where the proper functioning of the primary and secondary radars is affected. The model is tested in field, at two different distances, with airplanes and helicopter flying at different altitudes, with radar placed near the wind power plant Fantanele – Cogelac, the biggest in Romania. Finally, is estimated the area necessary to assure proper functioning of radars. Some conclusions and references are presented.
Periodic Motions in a Van Der Pol Oscillator
Authors: Xu Yeyin , Luo Albert C. J.
Published: January 2019

This paper develops semi-analytical solutions of periodic motions of the van der Pol oscillator. The van der Pol system is discretized to form implicit mappings. Based on specific mapping structures, the semi-analytical solutions are obtained accurately, and the independent bifurcation branches of periodic motions are also presented for a better understanding of the nonlinear characteristics of the van der Pol oscillator. Stability and bifurcations are carried out though eigenvalue analysis. For comparison of analytical and numerical solutions, numerical simulation is completed and displacement and trajectories are presented.
Performance Comparison and Parametric Analysis of sCO2 Power Cycles Configurations
Authors: Alsagri Ali S. , Chiasson Andrew , Aljabr Ahmad
Published: January 2019

A thermodynamic analysis and optimization of four supercritical CO2 Brayton cycles were conducted in this study in order to improve calculation accuracy; the feasibility of the cycles; and compare the cycles’ design points. In particular, the overall thermal efficiency and the power output are the main targets in the optimization study. With respect to improving the accuracy of the analytical model, a computationally efficient technique using constant conductance (UA) to represent heat exchanger performances is executed. Four Brayton cycles involved in this compression analysis, simple recaptured, recompression, pre-compression, and split expansion. The four cycle configurations were thermodynamically modeled and optimized based on a genetic algorithm (GA) using an Engineering Equation Solver (EES) software. Results show that at any operating condition under 600 °C inlet turbine temperature, the recompression sCO2 Brayton cycle achieves the highest thermal efficiency. Also, the findings show that the simple recuperated cycle has the highest specific power output in spite of its simplicity.
Determination of Key Influencing Factors on Thermal Conductivity Enhancement of Graphene Nano-Platelets Reinforced Epoxy
Authors: Rieger Maximilian , Nagarajan Balakrishnan , Vollmer Mario , Mertiny Pierre
Published: January 2019

Dispersing micro and nanoparticles into polymeric materials has proven to induce multifunctional properties in polymer composites, including their magnetic, electrical, thermal and mechanical characteristics. Adding carbon-based nanoparticle inclusions such as Graphene Nano-Platelets (GNP) to polymeric materials typically leads to thermal, electrical and mechanical property enhancements. Raising thermal conductivity by adding highly thermally conductive fillers particularly harbors great potential given diverse possible applications, such as in the electronics industry. In this study, the focus is on increasing the thermal conductivity of an epoxy by dispersing GNP in the pre-polymer. The influence of various process parameters such as filler loading, influence of swelling, use of solvent and additives, sonication time and amplitude, as well as curing cycle were determined. By means of a Design of Experiments approach the parameters which have the greatest effect on thermal conductivity enhancement were identified. Through this study a better understanding of the influence of process parameters was achieved in a qualitative and quantitative manner. The study further aids in selecting ideal process parameters for maximum thermal conductivity enhancements.
Finite Element Models of One Dimensional Flows With Node-Dependent Accuracy
Authors: Guarnera Daniele , Zappino Enrico , Pagani Alfonso , Carrera Erasmo
Published: January 2019

The formulation of simplified models in the description of flow fields can be highly interesting in many complex network such as the circulatory system. This work presents a refined one-dimensional finite element model with node-dependent kinematics applied to incompressible and laminar flows. In the framework of 1D-FE modelling, this methodology is a new development of the Carrera Unified Formulation (CUF), which is largely employed in structural mechanics. According to the CUF, the weak formulation of the Stokes problem is expressed in terms of fundamental nuclei and, in this novel implementation, the kinematics can be defined node by node, realizing different levels of refinements within the main direction of the pipe. Such feature allows to increase the accuracy of the model only in the areas of the domain where it is required, i.e. particular boundary condition, barriers or sudden expansion. Some typical CFD examples are proposed to validate this novel technique, including Stokes flows in uniform and non-uniform domains. For each numerical example, different combinations of 1D models have been considered to account for different kinematic approximations of flows, and in particular, models based on Taylor and Lagrange expansion have been used. The results, compared with ones obtained from uniform kinematics 1D models and with those come from available tools, highlight the capability of the proposed model in handling non-conventional boundary conditions with ease and in preserving the computational cost without any accuracy loss.
Experimental Investigating the Impact of Ionic Liquid on PET’s Properties
Authors: Ahmed Waleed K.
Published: January 2019

This study presents an experimental laboratory investigation done on the Polyethylene terephthalate – PET that is used for food grade (water bottle) by mixing with ionic liquid. Both thermal and mechanical properties with a varying weight percentage of ionic liquid are investigated. Mainly, at different mixing ratios of PET-Ionic liquid of (2, 3, 5, 7 and 10%), impact of the ionic liquid on the characteristics of the PET are examined through MFI (melt flow index), differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), nanoindentation methods as well as Fourier Transform Infrared (FTIR) spectroscopy. In general, the estimated results indicated that the stiffness as well as the hardness acquired from nanoindentation test for the PET blends, decrease as long as the concentration increases.
Simulation of Liquid Crystal Polymer Directionality During Cast Film Extrusion
Authors: Sullivan Anthony , Saigal Anil , Zimmerman Michael A.
Published: January 2019

Liquid crystal polymers (LCP’s) comprise a class of melt-processable materials that derive specialized mechanical, chemical, and electrical properties from long-range molecular ordering. This unique microstructure gives rise to anisotropic bulk behavior that can be problematic for industrial applications, and thus the ability to model the orientation state in the polymer is necessary for the design of isotropic material manufacturing processes. Previous efforts to model LCP directionality have been primarily restricted to structured grids and simple geometries that demonstrate the underlying theory, but fall short of simulating realistic manufacturing geometries. In this investigation, a practical methodology is proposed to simulate the director field in full-scale melt-processing set-ups, specifically cast film extrusion, to predict the bulk material orientation state. The hybrid approach utilizes separate simulations for the polymer flow with commercial computational fluid dynamics (CFD) software, and the material directionality through a user-defined post-processing script. Wide-angle x-ray scattering (WAXS) is used to experimentally validate the simulated directionality during extrusion processing. It is shown that the model is capable of predicting both the direction and degree of orientation in the polymer resulting from processing, and the model produces strong agreement with experimental measurement of the polymer orientation state.
Development of Soft Body Rescue-Bot Using 3D Printing
Authors: Lewis Cody , Legg Jared , Shin Minchul
Published: January 2019

The use of robots in search and rescue operations has increased dramatically over the years. A robot is able to detect survivors of a dangerous situation, like an earthquake, without putting the operator’s life in danger as well. There are many types of robots being developed for search and rescue purposes, but a smaller and more durable robot will be beneficial for designs in the future.

The purpose of our project is to research and design a soft body robot that is capable of locating individuals in search and rescue operations. The robot has a design similar to a car which will allow the control of the robot to be easy to use. It has been designed with a self-righting mechanism in case the vehicle flips over or gets stuck. The robot has a small size so that it can fit through small holes that a person could not enter. The robot will be capable of traversing over uneven terrain, including small ledges through an actuator. The actuator will be designed to cause the robot to spring over or on a ledge. According to simulations from SolidWorks, the wheels of the robot can also withstand a drop from 2 meters. The design and material of the wheels will be further tested and changed to increase the performance of the wheel. Once a design has been chosen, the body of the robot will be designed. Current designs of ground rescue robots will be studied in order to attain a better understanding on what designs work best. The hope is to make the robot more durable than previous designs using a soft material as the outer shell of the robot. A soft material should allow the robot to be able to absorb impacts from falling debris or unexpected falls.

Once the design of the robot has been optimized, a prototype will be created. The next step will be to code the robot so that it can be controlled with a remote. The current proposal is to use an Arduino board to send and receive signals from that remote. Then a camera will be attached to the robot which will allow the operator to see where the robot is and where the survivors are located.
Period Motions and Stability in a Nonlinear Spring Pendulum
Authors: Luo Albert C. J. , Yuan Yaoguang
Published: January 2019

In this paper, period-1 motions varying with excitation frequency in a periodically forced, nonlinear spring pendulum system are predicted by a semi-analytic method. The harmonic frequency-amplitude for periodical motions are analyzed from the finite discrete Fourier series. The stability of the periodical solutions are shown on the bifurcation trees as well. From the analytical prediction, numerical illustrations of periodic motions are given, the comparison of numerical solution and analytical solution are given.
Vibration of Curvilinearly Stiffened Plates Using Ritz Method With Orthogonal Jacobi Polynomials
Authors: Alanbay Berkan , Singh Karanpreet , Kapania Rakesh K.
Published: January 2019

This paper presents a general approach for the free vibration analysis of curvilinearly stiffened rectangular and quadrilateral plates using Ritz method employing classical orthogonal Jacobi polynomials. Both the plate and stiffeners are modeled using first-order shear deformation theory (FSDT). The displacement and rotations of the plate and a stiffener are approximated by separate sets of Jacobi polynomials. The ease of modification of the Jacobi polynomials enables the Jacobi weight function to satisfy geometric boundary conditions without loss of orthogonality. The distinctive advantage of Jacobi polynomials, over other polynomial-based trial functions, lies in that their use eliminates the well-known ill-conditioning issues when a high number of terms are used in the Ritz method; e.g., to obtain higher modes required for vibro-acoustic analysis. In this paper, numerous case studies are undertaken by considering various sets of boundary conditions. The results are verified both with the detailed Finite Element Analysis (FEA) using commercial software MSC.NASTRAN and for some cases, and with those available in the open literature for others. Convergence studies are presented for studying the effect of the number of terms used on the accuracy of the solution. The paper also discusses the effects of stiffener and plate geometric dimensions on the dynamic characteristics of the structure. The method also has an advantage of saving significant computational time during optimization of such structures as changing the placement and shape of stiffeners does not require repeated calculation of plate mass and stiffness matrices as the stiffener shapes are changed.
Improving the Heat Dissipation From a Pressure Wheel of a Laser Robotic End-of-Arm Tooling Using Different Geometrical Designs and Materials
Authors: Hamieh Abdallah , Kheirallah Mike A. , Jawad Badih , Liu Liping , Fernandez Vernon
Published: January 2019

The automotive industry corporations noticed the advantages of automated laser welding. Robot laser welding systems have immediately attracted their interests for bringing down the production costs and delivering higher-quality items. The objective of this research is to study how to enhance heat dissipation to endorse a better performance of the pressure wheel, and help achieve a longer life cycle. Transient thermal analysis of the pressure wheel was conducted using ANSYS workbench. The work studied the effects of different design models and materials on the thermal performance of pressure wheel assembly during the cooling period. Numerical simulations were performed on both solid and geometrically ventilated wheels for enhancing the heat dissipation performance of the wheel. Different materials were also be tested and compared. The analysis will support the design process by monitoring different parameters in terms of performance, heat loss and manufacturing cost.

A comparison was made for two different designs each with three different materials and the best design was selected. The simulation results in a period of 50 seconds cooling time showed that the temperature dropped with the 1st design (full solid wheel) made of tungsten from an initial temperature Ti = 500 K to a final temperature of Tf = 434.5 K. Tungsten was found to have better heat dissipation compared to stainless steel and cast iron. For the 2nd design (geometrically ventilated wheel) made of tungsten, the temperature drops from Ti = 500 K to Tf = 422.1 K. Comparing the two designs, the geometrically ventilated wheel was proved to be cooled faster. The present work will help improve the performance of pressure wheel in the welding industry by providing computational results for successive design testing and data validation.
On-Board State of Health Estimation of Lithium Ion Batteries With Incremental Capacity Analysis Based on Gaussian Function
Authors: Liang Tongyi , Song Lingjun
Published: January 2019

Accurately online state of health estimation is one of the key issues in battery management system (BMS), which enable the batteries function safely and efficiently. With excellent performance in in-situ degradation modes detection and precise state of health estimation modeling ability, incremental capacity (IC) analysis is widely used to analyze the situation of aged batteries. This paper discussed the difficulties in IC analysis application at first, and a robust method is then proposed, which parameterize the IC curve with Gaussian function. Battery cycle life experiment is conduced to validate the feasibility and accuracy of the proposed method. A capacity is constructed based the parameters of Gaussian function in each peak. The results show that the model estimation error is less than 3% of normalized capacity in each aging state, promising to be implemented in real BMS.
Tube Buckling: An Advantage to Tube Shaping
Authors: Nikhare Chetan P.
Published: January 2019

Tube forming is one of the most common manufacturing processes to shape the tubes. Within tube forming operations the general practice is to expand and reduce the tube end cross-section and bend the tube by means of a solid mandrel. Mostly the mandrel is rigid bodies. To reduce the friction between the tube and the tool, tube hydroforming process was evolved in which the fluid was highly pressurized to expand the tube shape to the desired shape. By reducing the friction more uniform thickness could be achieved and thus increase in formability. One of the process within tube end forming process is flaring which is the focus of this paper. In tube flaring process the conical shape rigid tool flares the end of the tube. While flaring the tube, the tube buckles if proper consideration would not have been taken. In this paper, various influencing parameters such as outer diameter to tube thickness ratio, length or the tube, the strength coefficient of the tube and conical angle of the tool were analyzed. It was noted that the most important factor affect the buckling of the tube is its strength coefficient. Considering this parameter the buckling was carried out in a set die and a tube shape was formed. The advantages of this process over similar processes were discussed.
A Comparative Assessment of the Structural, Elastic and Electronic Properties of Nb3Pt and NbPt3 Phases Through First-Principles Study
Authors: Fono-Tamo R. S. , Tien-Chien Jen , Bhila O.
Published: January 2019

Two phases of the Nb-Pt system namely Nb3Pt and NbPt3 have been studied using first principles approach in CASTEP. Structural, elastic and electronic properties of the concerned binary alloys were determined and examined against each other. Although both alloys have the same structure, it was observed that the percentage difference in the change of lattice parameters varied. Nb3Pt exhibited a 0.073% change while NbPt3 had a 14.809% change making Nb3Pt more stable structurally than NbPt3. The elastic properties showed that both binaries are ductile materials but NbPt3 proved to be more ductile than Nb3Pt based on Born, Pugh’s and Frantsevich’s criteria. Through the electronic properties, both binaries were proven to be conducting and their bonding nature seen as a combination of ionic metallic and covalent bond.
Study of Energy Absorption Characteristics of Square Tube With Composite Cellular Core
Authors: Ali Muhammad , Ohioma Eboreime , Alam Khairul
Published: January 2019

Square tubes are primarily used in automotive structures to absorb energy in the event of an accident. The energy absorption capacity of these structural members depends on several parameters such as tube material, wall thickness, axial length, deformation modes, locking strain, crushing stress, etc. In this paper, the work presented is a continuation of research conducted on exploring the effects of the introduction of cellular core in tubular structures under axial compressive loading. Here, the crushing response of composite cellular core tube was numerically studied using ABAQUS/Explicit module. The energy absorbing characteristics such as deformation or collapsing modes, crushing/ reactive force, crushing stroke, and energy curves were discussed. The composite cellular core tube shows promise for improving the crashworthiness of automobiles.
Studies on Cryogenic Treated Drills Under Nano-Fluid Based Reduced Quantity Lubrication Conditions for Machining Ti6Al4V
Authors: Raj D. Samuel , Praveen C. Jerome Arul , Kumaran Aarthi S.
Published: January 2019

Minimum quantity lubrication (MQL) machining is gaining wide acceptance because of the need to make machining more environment friendly. With cutting fluids contributing more than 10–15% of the manufacturing costs, economics of MQL is also gaining interest. The initial cost of commercial MQL systems is one of the limiting factors hindering their adoption in small and medium scale industries. This study, uses a simple commercial paint sprayer with a portable compressor (with a total cost < $125) to produce an MQL like spray with a slightly higher flow rate as compared to MQL (and is thus called reduced quantity lubrication) in drilling Ti6Al4V. Tungsten carbide drills of 7 mm diameter were subjected to deep cryogenic treatment, which has been acknowledged as a means of improving tool wear resistance. There was a marginal improvement in drill microhardness as a result of cryogenic treatment. The performance of untreated and cryo-treated drills was compared for tool wear, hole surface roughness and cutting forces. In addition to the normal air-coolant mist, the effect of adding nano-particles in the coolant was also studied. It is found that cryo-treated drills under nano-fluid based reduced quantity lubrication (RQL) conditions performed better than untreated drills and conventional cutting fluids, in terms of all the three measured parameters. This can be attributed to the higher thermal conductivity of nano-fluid based coolants and their ability to reduce the coefficient of friction at the chip-tool interface.