bluuebunny/crossref_metadata_2025 huggingface dataset:
A Hybrid FEM-Analytical Force and Torque Model for the Electrodynamic Suspension Reaction Sphere
Authors: Chen Anlin , Zhang Ming , Zhu Yu , Huai Zhouyu , Yang Kaiming , Hu Chuxiong
Published: January 2018

The actuator of attitude control system (ACS) is a significant component of the spacecraft. The electrodynamic suspension reaction sphere (EDSRS) is a compact and lightweight actuator of ACS and can control spacecraft attitude in three axes. This paper presents a hybrid FEM-analytical force and torque model for the EDSRS. A motor in the EDSRS is divided into many circular rings which are unfolded along circumference and equivalent to linear induction motors. The magnetic field in each equivalent linear induction motor (ELIM) is derived by the two-dimensional magnetic vector potential method. Based on the magnetic field, the force on the mover of each ELIM is obtained by Maxwell stress tensor method. An analytical force and torque model of the EDSRS is developed according to the force of every ELIM. Furthermore, the errors between the analytical model and three-dimensional FEM simulations are analyzed. With FEM simulations, new correction factors which take the end effects into consideration are obtained. The analytical model is further developed to a hybrid FEM-analytical force and torque model which includes the end effects. Finally, the hybrid FEM-analytical model is verified by FEM simulations and experiments.
Development of AC Magnetic Field Stimulation Bio-Reactor for Three-Dimensional Culture of PC12 Cells
Authors: Sakiyama Ryota , Matsumoto Kazuya , Yamamoto Koji , Morita Yusuke , Nakamachi Eiji
Published: January 2018

Recently, the electromagnetic stimulation method to enhance a nerve axonal extension has been attracting a great attention in the nerve regeneration. In this study, we design and fabricate a new 3D bio-reactor, which can implement uniform AC magnetic field (ACMF) stimulation on PC12 cells. We observe the morphology of PC12 cells using the multi photon microscope and evaluate effectiveness of uniform ACMF stimulation of the nerve axonal extension and the neural network generation.

Firstly, a uniform ACMF stimulation bio-reactor was designed by using the pole piece structure. We searched an optimum structure using the magnetic field finite element analyses to obtain a uniform magnetic flux density in the culture region. Secondly, a chamber for 3D culture of PC12 cells was fabricated. PC12 cells were disseminated into a collagen gel which poured in the chamber. We evaluated the effects of uniform ACMF stimulation to enhance the nerve axonal extension. In our bio-reactor, an increase in axonal extension length and number of dendrites was observed under ACMF stimulation after 7 days culture. Finally, it was concluded that our uniform ACMF stimulation bio-reactor is an effective tool for the nerve axonal extension and the neural network generation.
Design for Manufacturing and Assembly (DFMA) of a Test Bench to Simulate Mechanical Vibrations in Rotating Equipment
Authors: Maradey Lázaro Jessica Gissella , Forero González Carlos Adolfo , Ovalle Silva Germán Andrés
Published: January 2018

In the last decade, the reliability and safety of industrial processes have played a very important role in ensuring competitiveness of national and international companies, requiring on-line and off-line fault detection systems that appear in normal operation, and in other cases, the implementation of more robust methodologies for potential failures.

Two of the problems that usually occur in the rotary equipment are the mechanical misalignment and imbalance caused mainly by errors in the assembly, non-uniformity in the density of the material, tolerance in the manufacture of parts, which cause great damage in the machines and generating vibrations that cause problems such as heating parts, increased hot oil, increased lubricant dripping through seals, premature failure of bearings, seals, shafts and joints, wear and tear of parts, loss of efficiency in the engine, noise and collateral damage among others.

The results of this research provide guidelines for the design, manufacturing and assembly of a test bench to simulate misalignment and imbalance failures under controlled conditions by measuring and monitoring selected variables for study, take into account the benefits of Maintenance Condition Monitoring (CBM) and Design for Manufacturing and Assembly (DFMA) methodology.
The Influence of Sulci Trabeculae in Mitigating Impact Induced TBI
Authors: Hashemi Siavash , Anwar Sharlin , Mansoorbaghaei Shahab , Sadegh Ali M.
Published: January 2018

Traumatic brain injury (TBI) is an intracranial injury caused by impacts or angular accelerations of the head such as a violent blow, a bump, a projectile, or even a blast. TBI is a major problem that accounts for over 1.4 million emergency room visits in US. Thus, it is important to understand and predict the occurrence of TBI. Previous studies have shown that the interaction between the subarachnoid space (SAS) trabeculae and the cerebrospinal fluid (CSF) plays an important role in damping the effect of impacts and reducing the brain injuries. However, the influence of sulci parameters and sulci trabeculae in impact induced TBI is still unexplored. A few studies have shown that inclusion of sulci in brain models alters the brain injuries conclusions, even though those models do not take into account the trabecular tissue present in the sulci.

In this study, to obtain a perspective of the morphology and architecture of the sulci trabeculae at the frontal lobe of the brain, Human cadaver brain of an 87 year old male was used. For the first experiment, several sulci from the frontal lobe were sectioned and measured to find the average sulci depth, using the image processing software called ‘ImageJ’. This experiment was followed by the Scanning Electron Microscopy (SEM) study on the samples prepared from the frontal lobe. Indeed, numerous images were taken at various magnifications to find different trabecular morphology and architecture in the sulci.

The results from the experimental studies were used in our numerical analyses. To do so, the validated global 3D FE model of the human head and neck, created at The City College of New York, were impacted by a rigid barrier on the forehead. The pressure time history, beneath the skull, was calculated during and after the impact. Moreover, a local 3D FE model has been created, having the meninges and the brain with sulci, including the trabeculae and the CSF. The depth of the sulci and the architecture of the trabeculae have been inspired by the imaging and SEM studies. Indeed, the top surface of the local model was subjected to the pressure loading condition obtained from the global model. The results of the finite element simulations reveal that the interaction between the trabeculae and the CSF inside the sulci, would affect and reduce the movement and displacement of gyri and sulci’s walls when the forehead of the head is impacted by an elastic barrier.
Modeling and Control Design for Active Trailer Steering of Heavy Vehicles
Authors: Brown Jesse , He Yuping , Lang Haoxiang
Published: January 2018

This paper presents a linear quadratic regulator (LQR) controller for active trailer steering (ATS) of a tractor-semitrailer. The tractor-semitrailer is modelled as a linear yaw/roll model with 5 Degrees-Of-Freedom (DOF). The linear yaw/roll model is validated with a nonlinear tractor-semitrailer model developed with TruckSim under a simulated single lane-change maneuver. Then, the validated linear yaw/roll model is used to design the LQR controller for ATS. The TruckSim model and the LQR controller are integrated by means of an interface between the software packages of TruckSim and Matlab/Simulink. The LQR controller is assessed using numerical simulation of the TruckSim model with and without the ATS control. Evaluation of the controller is based on the performance measures of the trailer in terms of rearward amplification (RA), peak roll angle, and load transfer ratio (LTR). It is demonstrated that the LQR controller leads to the decrease the peak values of the aforementioned measures by 4.81%, 20.7%, and 33%, respectively.
Large Eddy Simulations of Ventilated Micro Hydrokinetic Turbine
Authors: Daskiran Cosan , Attiya Bashar , Liu I-Han , Riglin Jacob , Oztekin Alparslan
Published: January 2018

Large eddy simulations of pre-designed micro-hydrokinetic turbine were conducted to investigate the oxygen transfer from air to water. Simulations were performed in extreme conditions having a tip-speed ratio of 3.8 that is higher than the tip-speed ratio at turbine’s design point. Air was injected from the turbine hub downstream in axial direction. Both single phase and multiphase simulations were performed to reveal the influence of air admission on the flow structures and the turbine performance. The mixture multiphase model was employed in multiphase simulation. The results indicated that turbine power generation was reduced roughly 10.5% by air admission, however the torque applied on turbine surface in axial direction did not vary significantly by aeration. The aeration assisted in the suppression of vortices within the flow field. The deviation of the power coefficient and the thrust coefficient was reduced roughly 32% through the inclusion of aeration process.
Hybrid Probabilistic Physics of Failure Evaluation of Reliability in MEMS Devices
Authors: Pourgol Mohammad Mohammad , Mobasher Moghaddam Minoo , Soleimani Morteza
Published: January 2018

Reliability is critical in MEMS devices design and production. Probabilistic Physics of Failure is proposed in this research for evaluation of MEMS devices reliability. Failure mechanisms are evaluated for determining the most common failures. Accordingly, a deterministic model is selected for the analysis of the life and reliability for the dominant failure mechanisms. By identification of the uncertainty sources affecting dielectric lifetime, the deterministic model is converted to a probabilistic model. This model is simulated by utilization of the Monte Carlo method. The result of life estimation is then updated using the Bayesian method.

As a case study, a framework is developed for reliability evaluation of the MEMS devices with capacitive RF MEMS switches. Results of FMEA show that stiction caused by dielectric charging, is the main failure mode in RF MEMS capacitive switches due to the presence of a high electric field across the dielectric and existence of point defects in these materials. Finally, the results of life estimation are updated using the Bayesian method.
Bioactive Coating From White Portland Cement Deposited by Pulsed Laser Deposition
Authors: Fialkova Svitlana , Yarmolenko Sergey , Sankar Jagannathan , Ndungu Geoffrey , Wilkinson Kevin
Published: January 2018

Objective. We report the study of feasibility to produce the thing bioactive coating from experimental dental cement using pulsed laser deposition (PLD) technique.

Methods. The targets for PLD system (disks 30 mm in diameter × 5 mm thick) were sintered from micronized powder of set Alborg White Portland cement (WPC). The parameters for sintering process were chosen based thermo-gravimetric analysis and differential scanning calorimetry (TGA/DSC). The coatings were deposited by PLD on silicon substrates. The effect of laser power on coating crystallinity and morphology was evaluated by scanning electron microscope (SEM) and X-ray diffraction (XRD). The material transfer from target to substrate were evaluated by X-ray fluorescence (XRF) and X-ray energy dispersive spectroscopy (EDS).

The bioactivity of deposited films was evaluated by ability produce the hydroxyapatite (HA) layer on a surface of specimen immersed in a simulated body fluid (Dulbecco’s Phosphate-Buffered Saline (DPBS). The formation of hydroxyapatite was confirmed by SEM, X-ray energy dispersive spectroscopy (EDS), XRD and micro-Raman spectroscopy. The formation of HA was evaluated after 1, 3, 7, 14, and 21 days of immersion. Results. This study demonstrated that White Portland cement can be used as a target material for manufacturing of bio-functional coatings. The films deposited on Si substrates have mainly amorphous structure; the crystallinity of the film can be achieved by increasing the laser power. The biological performance of deposited films was tested by HA forming ability in simulated body fluid. The HA layer was formed on a coated surface after first day of immersion.
Comparative Studies of Wet-Stretched and Non-Stretched Electrospun PVDF-HFP Nanofibers
Authors: Wildgoose Alexander , Najjar Raghid , Dittman Jason , Hones Harrison , Umbach Emily , Muska Benjamin , Conte Adriano , Beachley Vince , Xue Wei
Published: January 2018

The recent growth in portable electronics has sparked a demand for alternative energy sources. Energy harvesters that utilize piezoelectric materials are promising in capturing the mechanical energy from body movement to power portable electronics. This study investigated the characteristics of PVDF-HFP nanofibers created from traditional electrospinning and a novel technique called wet-stretching electrospinning. The solution was initially processed using the traditional method, flat-plate electrospinning, which resulted in a fiber network with random orientations. When performing electrical testing the fibers produced minimal voltage. The solution was then processed utilizing a novel wet-stretching electrospinning technique that allowed for fiber alignment and dynamic stretch ratios. Fibers that underwent this method produced higher voltages than fibers from the traditional electrospinning method. It was observed that fibers processed using the wet-stretching technique with different draw ratios (DR) such as 1 (DR 1) and 2.5 (DR 2.5) showed enhanced piezoelectric properties. This research suggests that the wet-stretched PVDF-HFP nanofibers are better suited for piezoelectric applications than traditionally electrospun nanofibers.
Modeling Multiaxial Fatigue Damage Using Polar Equations
Authors: Albinmousa Jafar , Iftikhar Syed Haris , Al-Samkhan Mustafa
Published: January 2018

It is estimated that more than 70% of failures in engineering components are associated with fatigue loading. Therefore, fatigue is a major design tool for mechanical components. These components are usually subjected to multiaxial cyclic loading. In fact, multiaxial state is very common as tension specimen is under triaxial strain state even though its stress state is uniaxial.

There are three approaches to modeling fatigue damage: stress, strain and energy. Critical plane concept is established based on the fact that fatigue cracks initiate at specific plane(s), therefore, multiaxial fatigue damage parameter is evaluated at these plane(s). Critical plane fatigue models such as Fatemi-Socie is among the popular strain-based models. Because it was shown to provide estimation mostly within two factors of life for different materials and different multiaxial loading conditions.

This paper presents a new method for analyzing critical plane damage parameters. Using plane stress-strain transformation, maximum values of normal and shear stresses and strains from hysteresis loops are obtained at 360 planes. Plotting these values on polar diagrams shows that multiaxial cyclic responses represent polar curves that can successfully be fitted with definitive known polar equations. In principle, this means that both critical plane and fatigue damage can be determined analytically for a given loading path. However, fitting constants must first be determined.

A systematic analysis is performed on different experimental data that were obtained by testing two extruded magnesium alloys at proportional and 90° out of phase loading paths. A closed-form solution for Fatemi-Socie damage parameter is presented for these two loading paths.
Aerodynamic Interactions Study on Low-Re Coaxial and Quad-Rotor Configurations
Authors: Shukla Dhwanil , Hiremath Nandeesh , Patel Sahaj , Komerath Narayanan
Published: January 2018

Unmanned multi-rotor VTOL vehicles have recently gained importance in various applications such as videography, surveillance, search and rescue etc. suited to their small size and relatively cheap construction. Small scale UAVs struggle in providing satisfactory performance in terms of payload, range, and endurance because of higher viscosity-dominated losses, and due to yet to be understood rotor-rotor and rotor-airframe aerodynamic interactions. Viscosity dominated rotational flow field makes most potential flow methods, such as free wake model, invalid. A full N-S based approach for this problem is too expensive. Thus, a multi-rotor aerodynamic interaction study is necessary for understanding crucial phenomena, which will help in developing physics-based models which will be instrumental in multi-rotor UAV performance prediction and design optimization. In present work, a flow visualization and a high-speed stereo Particle Image Velocimetry (SPIV) study is done on two low Reynolds number multi-rotor arrangements with the aim of capturing vortex-vortex, blade-vortex and vortex-duct interactions. The first arrangement is a coaxial rotor in forward flight and another is an in-plane quad-rotor with and without duct. Instantaneous and average PIV data is being presented here with some observations and corresponding interpretations.
Damage Accumulation Modeling and Rate Dependency of Spinal Dura Mater
Authors: Ramo Nicole L. , Shetye Snehal S. , Puttlitz Christian M.
Published: January 2018

As the strongest of the meningeal tissues, the spinal dura mater plays an important role in the overall behavior of the spinal cord-meningeal complex (SCM). It follows that the accumulation of damage affects the dura mater’s ability to protect the cord from excessive mechanical loads. Unfortunately, current computational investigations of spinal cord injury etiology typically do not include post-yield behavior. Therefore, a more detailed description of the material behavior of the spinal dura mater, including characterization of damage accumulation, is required to comprehensively study spinal cord injuries.

Continuum mechanics-based viscoelastic damage theories have been previously applied to other biological tissues, however the current work is the first to report damage accumulation modeling in a SCM tissue. Longitudinal samples of ovine cervical dura mater were tensioned-to-failure at one of three strain rates (quasi-static, 0.05/sec, and 0.3/sec). The resulting stress-strain data were fit to a hyperelastic continuum damage model to characterize the strain-rate dependent sub-failure and failure behavior. The results show that the damage behavior of the fibrous and matrix components of the dura mater are strain-rate dependent, with distinct behaviors when exposed to strain-rates above that experienced during normal voluntary neck motion suggesting the possible existence of a protective mechanism.
Development of Mg-Based Biodegradable Wires for Bone Fixation Devices
Authors: Xu Zhigang , Guarnizo Mendoza Natalia , Tilley Daniel , Plott Christopher , Yarmolenko Sergey , Pai Devdas , Sankar Jag
Published: January 2018

MgZnCa and MgZnCa-RE (Rare Earth) alloys were developed for biomedical applications. Small wires of the alloys were successfully fabricated from the small rods prepared by hot-extrusion followed by multiple cold-drawing passes with intermittent annealing. It was demonstrated that addition of small amounts of rare earth (RE) elements could effectively enhance the mechanical properties of the wires. The ductility or deformability under twisting test was greatly improved by post annealing at relatively high temperatures.
Development of a Thermo-Metallurgical Model to Predict Heating and Austenitization of 22MnB5 for Hot Forming Die Quenching
Authors: Verma M. , Culham J. R. , Di Ciano M. , Daun K. J.
Published: January 2018

Hot forming die quenching (HFDQ) is used to transform ultrahigh strength steel blanks into martensitic body-in-white components that are lighter than parts made from traditional mild steels, without sacrificing crash performance. The part is sometimes locally reinforced by spot-welding patches to the blanks, but the increased thickness of the patched blanks sometimes results in incomplete austenitization, which can compromise the strength of as-formed parts. This paper presents an integrated thermo-metallurgical model of the austenitization of Al-Si coated 22MnB5 within a roller hearth furnace. While previous models account for the latent heat of austenitization by heuristically adjusting the specific heat, the present model explicitly simulates austenite formation using a first-order metallurgy submodel derived from dilatometry measurements. The model is validated by comparing predicted temperatures to measurements carried out on coupons heated within a lab-scale muffle furnace and full-sized blanks heated in an industrial-scale roller hearth furnace. Finally, the model is used to optimize roller speed based on zone temperatures.
Periodic Motion in a Nonlinear Vibration Isolator Under Harmonic Excitation
Authors: Yu Bo , Luo Albert C. J.
Published: January 2018

In this paper, periodic motions of a periodically forced oscillator with a nonlinear isolator are studied through generalized harmonic balanced method. Both symmetric and asymmetric period-1 motions are obtained. Stability and bifurcation of the periodic motions are determined through eigenvalue analysis. Numerical illustrations of both symmetric and asymmetric are given. From the harmonic amplitude spectrums, the harmonic effects on periodic motions are determined, and the corresponding accuracy of approximate analytical solutions can be observed.
Vibration of Rectangular Single-Layered Black Phosphorus
Authors: Zhang Yiqing , Wang Lifeng
Published: January 2018

Two-dimensional layered crystal material black phosphorus (BP) has attracted extensive attention due to its excellent property and practical applications. Single-layered BP has a characteristic puckered structure which leads to two anisotropic in-plane directions. The vibration properties of this puckered structure material would be very interesting. Thermal vibration of a rectangular single-layered BP is studied by using continuum orthotropic plate models together with molecular dynamics (MD) simulation. Five elastic constants including two bending moduli, two Poisson’s ratios, and one shear modulus of BP are calculated by using MD method. The natural frequencies of BP are obtained by orthotropic plate models and MD simulation via fast Fourier transformation (FFT). The result of MD simulation shows that continuum orthotropic plate models can predict the natural frequencies well.
Feasibility of Past Vertical Forming Utilizing Single Point Incremental Sheet Forming
Authors: Grimm Tyler J. , Ragai Ihab , Roth John T.
Published: January 2018

Incremental forming (IF) is a novel sheet material forming technique typically restricted to drafted geometries. By utilizing tooling which features regions that extend radial from the axis of the tool, it is proposed that this restriction can be eliminated. Additionally, by controlling the rotational motion of the tool, it is proposed that greater levels of detail can be achieved in the IF process. In the following works, the feasibility of utilizing this type of tooling in the IF process is discussed, as well as several variations of such tooling. Validation of the proposed tooling is also presented.
Modeling, Simulation and Analysis of Weld-Induced Thermal Stresses in a Solid Round-on-Flat Plate Fillet Weld
Authors: Ghosh Suhash , Sahay Chittaranjan , Al-Mamoury Haider
Published: January 2018

In this paper, development of a finite element model for simulating welding-induced thermal stresses is discussed. This nonlinear FE model employs sequentially coupled three-dimensional thermo-mechanical formulation. A solid three dimensional 20 node brick elements have been used in ABAQUS, a linearly elastic and linearly plastic approach is implemented in the analysis. The effects of key process parameters, viz., power, size and speed of welding has been discussed. Further, the need for interfacial elements, instead of solid mesh elements to simulate molten weld solidification, has been investigated. Model validation with published literature has been employed to determine the appropriate properties for the interfacial element (shear and normal). Due to the nature of the welding process, heat generation from moving heat source, rapid heating and cooling gives rise to high stresses in the weld. These stresses have been observed to be greatly influenced by the process variables as well the properties of the selected interfacial element. Position, orientation and magnitude of the highest residual stress components are discussed.
Case Study of SUV Hatchback: ‘Material-Structure-Process-Performance’ Integration Design and Numerical Verification of Automotive Composite Components
Authors: Zhang Cheng , Kang Ning , Li Lijun , Sun Lingyu
Published: January 2018

Substitution of steel by lightweight resin-matrix composites is an effective way of weight reduction for automobiles. In this paper, an integrated design method involving material property, structural geometry, process formability and resultant performance for automotive composite components is proposed. Referring to the exterior styling and assembly space of original steel reference, the conceptual CAD model is established. For the selected materials, optimization of minimizing the mass is carried out with layer thickness, stacking sequence and dimensions of each composite component as design variables, referring to the regulations requirements on performance of steel benchmark as constraint conditions. Then the resin transfer molding (RTM) process is simulated and optimized to determine the optimal forming parameters. As an example, a SUV hatchback with composite laminate is developed by RTM technique. Finally, the lightweight design of hatchback is achieved under the multiple constraints of static bending, torsion stiffness and vibration frequencies. The results show that the weight of SUV hatchback has been reduced 38.8%, whereas the stiffness and frequency all meet the requirements. When manufacturing with RTM process, the filling time of the final optimized program is 443 s, without any air trap. This instance has validated the effectiveness and feasibility of the integrated design method which is also applicable to other automotive composite components.
Generation of 3D Assemblies From Design Graphs of Gear Trains
Authors: Alicchio Corey J. , Vitiello Justin S. , Taylor Callum R. , Radhakrishnan Pradeep
Published: January 2018

This paper discusses the generation of 3D virtual assemblies from design graphs representing gear-trains. The design graph consists of dimensions, assembly and material details, and design constraints of all the gears and the shafts in the gear-train. This data is extracted and using SolidWorks Application Programming Interfaces (APIs), individual components and the overall assembly are generated. The codebase was also used to develop a standalone tool where users could provide these details for automatically generating gear-train parts and assemblies. The paper will detail the process involved, reasoning behind using SolidWorks, benefits, challenges and the future activities related to the generation of 3D gear-train assemblies.
Uncertainty Propagation of System Parameters to the Dynamic Response: An Application to a Benchtop Pendulum
Authors: Petrushenko David , Khasawneh Firas A.
Published: January 2018

Dynamical systems often involve uncertainties either in their parameters or in their initial conditions. Therefore, in order to reliably compute the system response, it is important to understand and quantify the different sources of uncertainty. This necessitates carefully measuring the system parameters and propagating the associated uncertainty to the system response. In this paper we demonstrate an approach for propagating uncertainties from the system parameters to the output response using a benchtop pendulum system. Since the input parameters are treated as random variables, the output is also reported as a random quantity with appropriate error bounds.
Experimental Investigations of Breaking Wave Impact Forces on a Monopile Substructure for Offshore Wind Turbines Under Regular Breaking Waves
Authors: Chakkurunni Palliyalil Vipin , Rajamanickam Panneer Selvam , Alagan Chella Mayilvahanan , Govindasamy Vijaya Kumar
Published: January 2018

The main objective of the paper is to investigate wave impact forces from breaking waves on a monopile substructure for offshore wind turbine in shallow waters. This study examines the load assessment parameters relevant for breaking wave forces on a vertical circular cylinder subjected to breaking waves. Experiments are conducted in a shallow water flume and the wave generation is based on piston type wave maker. The experiments are performed with a vertical circular cylinder with diameter, D = 0.20m which represents a monopile substructure for offshore wind turbines with regular waves of frequencies around 0.8Hz. The experimental setup consists of a 1/10 slope followed by a horizontal bed portion with a water depth of 0.8m. Plunging breaking waves are generated and free surface elevations are measured at different locations along the wave tank from wave paddle to the cylinder in order to find the breaking characteristics. Wave impact pressures are measured on the cylinder at eight different vertical positions along the height of the cylinder under breaking waves for different environmental conditions. The wave impact pressures and wave surface elevations in the vicinity of the cylinder during the impact for three different wave conditions are presented and discussed.
Effect of Fit of the Clamping Bolts in the Plate-Fixture Assembly on the Natural Frequency of Clamped Rectangular Plate
Authors: Mali Kiran D. , Singru Pravin M.
Published: January 2018

In this work, we found out the effect of the size of the bolts or type of the fit obtained due to the clamping bolts on the natural frequency of the rectangular plate. We achieved this by varying the dimensions of the clamping bolts. The solid rectangular plate was clamped on all four edges to the machine bed sandwiched between two fixtures. A set of 12 numbers of bolts were used at a time to secure plate-fixture arrangement to the machine bed. Such three sets of clamping bolts were used in the study. The fundamental frequency of the solid plate (138 mm × 216 mm × 2 mm) was obtained experimentally for each set of the clamping bolts of identical size.
Rotation Accuracy Analysis of Spindle Under Variable Preload
Authors: Zhang Yanfei , Li Xiaohu , Hong Jun , Wang Sun’an , Li Baotong , Sun Yanhui , Zheng Shuai
Published: January 2018

Variable preload technology is used to achieve appropriate preload applied on spindle bearing based on machining conditions. However, the bearing temperature rise will be directly affected by bearing preload as well as bearing rotation accuracy. So, the main objective of this paper is to propose a method to determine the rotation accuracy of the spindle affected by the thermal expensive due to heat generation under variable preloads. Five degrees of freedom (5-DOF) quasi-static model of angular contact ball bearing was established to investigate the internal load distribution of the contact areas between the race way and balls. Then local contact heat generation of the bearing is calculated based on hertz contact theory. Finally, an experimental platform equipped with hydraulic system is designed and fabricated, which is preloaded by a hydraulic chamber. Studies have shown that the rotation accuracy presents drastically with the spindle rotational speed. Moreover, the influence of the bearing preload has a secondary importance. Comparative analysis about the rotation accuracy between starting running state and stable running state after a few hours under the same preload has been investigated. Results show that the accuracy of rotation spindle present no obviously difference when the uneven thermal deformation of parts occurs in the spindle system.
The Research on Routing Optimization Method Using Undirected-Graph in Cable Harness Design
Authors: Han Ning , Guo LianShui
Published: January 2018

In this paper, we propose a novel cable harness routing method based on the main channel path using the top-down design strategy, parts spatial distribution and path definition rules. To obtain cable harness routing, a cable harness path optimization algorithm based on undirected-graphs is also discussed in this paper. First of all, in this algorithm, we consider the closest point to the main channel as the access point of the device. Secondly, we convert the cable path to an undirected-graph automatically according to the main channel path. Furthermore, we find the shortest path for the undirected-graph by saving time and avoiding the closed loop. Finally, the 3D models of cable harnesses are generated automatically for the cable harness routing design. To verify this method, a cable harness design software based on Pro/E is developed in this paper. The results show that the efficiency of spacecraft cable harness design is about 50 percent. It is of great significance to fulfill the electro-mechanical automatic integrated cable design and promote the intelligent computer-aided laying technology.
Hydrodynamic Characterisation of Micro-Gap Geometries for Photonics Cooling Applications
Authors: Carroll Marian , Punch Jeff , Dalton Eric , Richardson Niamh
Published: January 2018

Contemporary Photonic Integrated Circuit (PIC) packages within the communications network infrastructure have reached a thermal limit. Integrated packages involving microfluidic channels are an appealing development to improve the thermal design of future PIC packages, to significantly improve the removal of heat fluxes in order to sustain the expected enhanced data traffic growth. The Thermally Integrated Smart Photonics Systems (TIPS) project aims to develop and demonstrate a thermally enabled integrated platform that is scalable, to meet the predicted data traffic demands. Full system integration requires an integrated pumping solution, therefore a primary heat exchanger that can deliver the required thermal performance with a low pressure drop (ΔP) is needed. A channel containing a single array of cylindrical posts offers a low pressure drop, similar to a large hydraulic diameter minichannel. Local destabilization of the flow would provide heat transfer enhancement. In particular, non-Newtonian fluids have been shown to exhibit significant mixing in such configurations. Micro Particle-Image Velocimetry (μPIV) measurements were taken for Newtonian and viscoelastic fluids within this channel. Instabilities associated with the viscoelastic fluid were recorded immediately upstream of the post array. This flow exhibited almost a four-fold increase in mixing at comparable flow rates to the Newtonian fluid tested. This suggests that the Nusselt number enhancement associated with such flows could increase the heat transfer rates quite significantly in microchannels containing obstructions.
Accumulative Roll Bonding (ARB) Process for Effective Biomedical NiTi Alloys
Authors: Sanusi Kazeem O. , Akinlabi Esther T. , Mwita Wambura W.
Published: January 2018

In this paper, potentials of accumulative roll bonding (ARB) severe plastic deformation (SPD) method to process effective nickel titanium alloys for biomedical application is presented. Effective material properties of biomedical NiTi alloys, including ultra-fine grain microstructure, functional, mechanical, wear and corrosion resistance were highlighted and discussed. Performance and challenges of other SPD methods in the literature have been reviewed and compared to that of ARB. Existing challenges, advantages and recommendation of using ARB to process NiTi alloys with desired properties for biomedical applications are given.
Effective Tools to Learn Lean Thinking and Gather Together Academic and Practice Communities
Authors: Alves Anabela C. , Flumerfelt Shannon , Moreira F. , Leão Celina P.
Published: January 2018

Lean Engineering learning should be compulsory on engineering curricula, and, particularly, on the Industrial Engineering field. Prior to the integration on the Industrial Engineering curriculum, Lean Engineering was already implemented by many organizations and, often, fostered by consulting companies. For this reason, if engineering students were taught about Lean Engineering, they would be better prepared to assume a leadership role in their organizations and/or to better communicate with Lean consultants.

Based on a literature review and on the authors’ practice, this paper discuss some approaches that have been used for Lean Engineering learning. Some learning experiences implemented in an engineering master’s degree are presented which make use of effective educational tools based on active methodologies, such as hands-on simulation, Problem or Project-Based Learning (PBL), Conceive-Design-Implement and Operate (CDIO) initiative, among others. This paper also presents these tools and how they address Lean Engineering learning through the lens of Lean Thinking principles. Their advantages in Lean Engineering learning are discussed by gathering the academic and practitioners’ communities opinions. These are based on final year projects’ reports, feedback from students and from organization supervisors.
A Study of a Cell Mechanosensing System Under Mechanical Vibration Considering its Modes of Vibration and Calcium Ion Response
Authors: Nakamura Yuki , Shiraishi Toshihiko
Published: January 2018

It was reported that osteoblastic cells respond to mechanical vibration and generate the bone mass with a peak at a specific frequency like a resonance curve [1]. There seems to be an analogy between its cell response and the resonance of a cell as a mechanical system. This paper describes a novel method to measure the cellular modes of vibration of a cell and its calcium ion response under mechanical vibration, and the evaluation of the obtained results to clarify the mechanism of the cell mechanosensing. Nuclei and calcium ion in osteoblastic cells were visualized with fluorescent labelling. Mechanical vibration was applied to cells in a dish in the horizontal direction under a confocal laser scanning microscope by an exciter. Since the fluorescent intensity was very weak due to high frame rate to capture moving cells under Mechanical vibration, we used a high-speed and high-sensitive camera adjusting various conditions such as exposure time. We realized the spatial resolution of approximately 2 μm in the captured micrographs even under mechanical vibration using the experimental setup. As a result, the modes of vibration of nuclei was not obtained in this resolution. We found that the intracellular calcium ion concentration began to increase in a few seconds after mechanical vibration was applied. This experimental result indicates that applying mechanical vibration to cells can produce calcium signals as a second messenger by causing the entry of the ion.
Atomistic Simulation of Hydrogen Diffusion in Palladium Nanoparticles Using a Diffusive Molecular Dynamics Method
Authors: Sun Xingsheng , Ariza Pilar , Ortiz Michael , Wang Kevin G.
Published: January 2018

Understanding the transport of hydrogen within metals is crucial for the advancement of energy storage and the mitigation of hydrogen embrittlement. Using nanosized palladium particles as a model, recent experimental studies have revealed several highly nonlinear phenomena that occur over a long period of time. The time scale of these phenomena is beyond the capability of established atomistic models. In this work, we present the application of a new model, referred to as diffusive molecular dynamics (DMD), to simulating long-term diffusive mass transport at atomistic length scale. Specifically, we validate the model for the long-term dynamics of a single hydrogen atom on palladium lattice. We show that the DMD result is in satisfactory agreement with the result of the classical random walk model. Then, we apply the DMD model to simulate the absorption of hydrogen by a palladium nanocube with an edge length of 16 nm. We show that the absorption process is dominated by the propagation of a sharp, coherent α/β hydride phase boundary. We also characterize the local lattice deformation near the dynamic phase boundary using the mean positions of the palladium and hydrogen atoms.
Identification of Non-Linear Parameters of a Nuclear Fuel Rod
Authors: Ferrari Giovanni , Le Guisquet Stanislas , Balasubramanian Prabakaran , Amabili Marco , Painter Brian , Karazis Kostas
Published: January 2018

In Pressurized Water Reactors (PWR), fuel assemblies are made up of fuel rods, long slender tubes filled with uranium pellets, bundled together using spacer grids. These structures are subjected to fluid-structure interactions, due to the flowing coolant surrounding the fuel assemblies inside the core, coupled with large-amplitude vibrations in case of external seismic excitation. Therefore, understanding the nonlinear response of the structure, and, particularly, its dissipation, is of paramount importance for the choice of safety margins, in the design of fuel assemblies, to ensure their functionality and safety in the worst external condition scenarios.

To model the nonlinear dynamic response of fuel rods, the identification of the nonlinear stiffness and damping parameters is required. A tool based on harmonic balance method was developed to identify these parameters from the experimentally obtained force-response curves, considering one-to-one internal resonance phenomenon present in axisymmetric structures such as cylindrical tubes and shells. To validate the tool, it was applied to the reference case of circular cylindrical shell filled with water, which revealed an increase of damping with the excitation amplitude.

In the following paper, the more realistic case of a single fuel rod with clamped-clamped boundary condition was investigated by applying harmonic excitation at various force levels. The nonlinear parameters including damping were extracted from experimental results by means of the adapted tool. An increase in damping with excitation amplitude has been shown according to earlier studies.
PIV and LIF Measurements in Aortic Dissection Models
Authors: Salameh Elie , Khoury Wadih , Saade Charbel , Oweis Ghanem F.
Published: January 2018

In this work an in-vitro flow experiment is conducted to elucidate the flow behavior in simplified aortic dissection (AD) disease geometries. In AD, the innermost layer of the aortic wall is locally and partially torn allowing blood to flow between the wall layers forming a parallel blood stream in what is known as the false lumen. The aim of this work is to elucidate the disease flow physics, and to provide guidance in diagnostic radiology, particularly contrast injected computed tomography (CT), where understanding flow patterns and mixing behavior is important for accurate diagnosis. In contrast-CT, dye is injected in the peripheral blood stream to illuminate the blood vessels and identify vascular abnormalities. The flow patterns and the dye transport dynamics impact the nature of the CT images and their interpretation. Particle image velocimetry (PIV) is used to quantify the AD flow fields, and laser-induced fluorescence (LIF) is implemented to visualize and assess the mixing behavior of dye in the false and true lumens. Interesting flow patterns are revealed and discussed in the context of their possible contribution to tear expansion and flapping, and to the elevated mean pressure in the false lumen that is reported in the literature.
Design of a Robotic Catch and Release Manipulation Architecture (CARMA)
Authors: Johnson Shannon , Stroup Robert , Gainer John J. , DeVries Levi D. , Kutzer Michael D.
Published: January 2018

The exponential growth of commercially available unmanned aerial systems (UAVs) provides a reliable, low-cost platform for mobile sensor deployment. Extensive work exists leveraging large numbers of these platforms for intelligence, surveillance, and reconnaissance (ISR) applications ranging from search and rescue to plume detection and tracking. The proposed Robotic Catch And Release Manipulation Architecture (CARMA) is designed to address flight time limitations of small UAVs, leveraging a robotic manipulation and computer vision to actively compensate for perturbations of the UAV in flight (caused by environmental conditions such as wind) and movements of the recharging station (cause by movement over rough terrain, sea state in maritime applications, etc.). CARMA leverages an industrial robotic manipulator to create a robust system capable of capturing multi-rotor UAVs in an agitated hover. Using a custom-designed end-effector incorporating a monocular camera system, CARMA employs a closed-loop control strategy informed by a relative position and orientation estimate of the UAV using an active marker approach. Results demonstrate UAV tracking accuracy sufficient for capture of a small, CrazyFlie 2.0 UAV. The architecture is deployed on the Universal Robots UR10 manipulator which is able to successfully track the Crazyflie for capture.
Observing Fluid Flow Through Carbon Nanotube Arrays and Nanoporous Membranes
Authors: Jensen Anna , Schrlau Michael G.
Published: January 2018

Arrays of carbon nanotubes (CNTs) have shown significant promise for delivering biomolecules into cells with high efficiency and low toxicity. In these applications, biomolecules are flowed from a large fluid reservoir, through the lumens of vertically-aligned, open-ended CNTs, and into cells cultured over top of the CNTs on the other side. Over the course of several transfection experiments, it was discovered that biomolecule delivery varied considerably depending on the type of biomolecule being delivered. It was also inferred that the number of CNTs the cells covered would affect the transfection rate. In this work, an experiment was designed and conducted to visually characterize fluid flow through these CNT arrays and other nanoporous membranes. The experiment utilizes a 3D printed flow device consisting of anodized alumina oxide (AAO) membranes and restricts flow to a predefined circular area. Flow data was taken by measuring the intensity of fluorescent dye as it diffused through the AAO membrane. The intensity measurements were then plotted as a function of time from which diffusion times constants were calculated. This work establishes a platform technique for visualizing fluid transport through AAO membranes, which can be applied to CNT arrays, and allow for the testing of the effects of other parameters on flow.
Cellulose Nanocrystals Assisted Preparation of Electrochemical Energy Storage Electrodes
Authors: Illera Danny , Fontalvo Victor , Gomez Humberto
Published: January 2018

Renewable energy sources demands sustainable energy storage technologies through the incorporation of low-cost and environment-friendly materials. In this regard, cellulose nanocrystals (CN), which are needle-shaped nanostructure derived from cellulose-rich resources, are extracted by sulfuric acid hydrolysis of biomass and used as both template and binder for the construction of electrochemical capacitors electrodes. A composite material is synthetized comprising CN and a conjugated electroactive polymer (CEP) to overcome the electrical insulating properties of cellulose as well as to exploit enhanced electrochemical activity by increased electrode surface-area. A one-step in-situ film synthesis protocol is evaluated by performing simultaneous polymerization and film deposition. The effect of proportion of starting components are evaluated through statistical Response Surface Methodology towards optimizing the electrochemical performance. Depending on the mass proportion of the starting components, a conducting network could be created by surface coating of the CEP on the whiskers during polymerization. Electrochemical measurements suggest an increase in specific surface area by at least a factor of two relative to bare CEP as a consequence of the template role of cellulose. Therefore, adjustment of the proposed one-step synthesis parameters allows tuning the material properties to meet specific application requirements regarding electrochemical performance.