bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient Manufacturing Methods for Hybrid Metal-Polymer Components
Authors: Landgrebe Dirk , Müller Roland , Haase Rico , Scholz Peter , Riemer Matthias , Albert Andre , Grützner Raik , Schieck Frank
Published: February 2017

Lightweight design for automotive applications gains more and more importance for future products, independent from the powertrain concept. One of the key issues in lightweight design is to utilize the right material for the right application using the right value at the right place. This results irrevocably in a multi-material design.

In order to increase the efficiency in manufacturing car components, the number of single parts in a component is decreased by increasing the complexity. Examples for the state of the art are tailored welded blanks in cold forming, tailored tempering in press hardening or metallic inlays in injection molding of polymers.

The challenge for future production scenarios of multi-material components is to combine existing technologies for metal- and polymer-based applications in efficient hybrid process chains.

This paper shows initial approaches of hybrid process chains for efficient manufacturing of hybrid metal-polymer components. These concepts are feasible for flat as well as for tubular applications. Beside the creation of the final geometric properties of the component by a forming process, integrated joining operations are increasingly required for the efficiency of the production process and the performance characteristics of the final component. Main target of this production philosophy is to create 100% ready-to-install components. This is shown in three examples for hybrid process combinations.

The first example deals with the combination of metal forming and injection molding of polymers. Example number two is the application of hybrid metal-polymer blanks. Finally, example number three shows the advantages of process integrated forming and joining of single basic components.
Investigating Center-of-Pressure Based Parameters to Quantify Athlete and Non-Athlete Balance
Authors: Thompson Lara A. , Badache Mehdi
Published: February 2017

Through ground reaction (foot) forceplate-based, center-of-pressure (COP) parameters, we aimed to investigate differences in standing balance for young, healthy individuals from both athlete (soccer) and non-athlete subject populations. We investigated five, COP displacement and velocity parameters derived from the COP position time series. Soccer athlete and non-athlete subjects performed standing balance for postural tasks of increasing difficulty levels, by varying visual cues (eyes-open/eyes-closed) and base of support (wide/tandem foot placement), leading to four test conditions: 1) wide/eyes-open, 2) wide/eyes-closed, 3) tandem/eyes-open, 4) tandem/eyes-closed.

By investigating position and velocity characteristics of the COP position time series, we observed that the soccer athletes had generally lower COP displacement and velocity parameters (meaning they were more stable and perhaps better able to control their body sway) than the non-athletes. This study lends new insights as to how parameters derived from the COP position can be utilized to determine differences in balance between normal subject populations (e.g., athletes versus non-athletes).
Analysis of Curved Composite Structures Through Refined 1D Finite Elements With Aerospace Applications
Authors: Carrera Erasmo , García de Miguel Alberto , Pagani Alfonso , Petrolo Marco
Published: February 2017

This paper presents a novel approach to deal with the analysis of composite aerospace structures with curved sections. The Carrera Unified Formulation is exploited to create hierarchical high-order beam models capable of detecting both local and global mechanical behaviors of composite structures. The blending function method is applied to introduce the exact shape of the cross-section boundaries into the mapping functions. Problems at both microstructure scale (fiber-matrix system) and macrostructure scale (whole components) can be studied with no lack of generalization. Several numerical examples of aerospace structures are included and the results are compared against those from the literature, as well as solid solutions obtained through the commercial software MSC Nastran. From this study, it is clear than the present formulation has demonstrated to be a powerful tool for the study of composite structures, enabling to obtain complex 3D-like solutions with a substantial reduction in the computational costs.
Component-Wise Models for the Accurate Dynamic and Buckling Analysis of Composite Wing Structures
Authors: Carrera E. , Pagani A. , Cabral P. H. , Prado A. , Silva G.
Published: February 2017

In the present work, a higher-order beam model able to characterize correctly the three-dimensional strain and stress fields with minimum computational efforts is proposed. One-dimensional models are formulated by employing the Carrera Unified Formulation (CUF), according to which the generic 3D displacement field is expressed as the expansion of the primary mechanical variables. In such a way, by employing a recursive index notation, the governing equations and the related finite element arrays of arbitrarily refined beam models can be written in a very compact and unified manner. A Component-Wise (CW) approach is developed in this work by using Lagrange polynomials as expanding cross-sectional functions. By using the principle of virtual work and CUF, free vibration and linearized buckling analyses of composite aerospace structures are investigated. The capabilities of the proposed methodology and the advantages over the classical methods and state-of-the-art tools are widely demonstrated by numerical results.
A Finite Element Analysis for Thermal Analysis of Laser Cladding of Mild Steel With P420 Steel Powder
Authors: Nazemi Navid , Urbanic Jill
Published: February 2017

Laser cladding is a rapid physical metallurgy process with a fast heating-cooling cycle in which different compositions and properties of the alloy are melted on the surface of the substrate by the high-energy laser beams. This fabrication process method is accompanied with complex metallurgy and transformation processes. Numerical simulation tools can simulate the process of laser cladding, and optimize the parameters and predict the potential cladding defects of the cladding. In the present study, a three-dimensional finite element model was built for a powder-feed laser cladding model process. A transient temperature field was built, where the conical Gaussian distribution of moving heat source, conduction, convection, and radiation heat transfer are simulated. In the analysis, the temperature dependent material properties as well as the phase transformation behavior of the materials was taken into account. The addition of material is numerically carried out in a thermal-metallurgical-mechanical coupled manner. As a benchmark to validate the simulated model, experimental Vickers microhardness data was used and the observed bead shape of the specimen was compared to the simulation results. The finite element simulation was conducted by SYSWELD software. This paper will present the results of a study where P420 steel cladding powder (a steel commonly used in injection molding) which is deposited on low/medium carbon structural steel plates (AISI 1018) using the coaxial powder flow laser cladding method. The results reveal how the process parameters affect the distribution of the temperature, bead geometry, and strength.
Is the Maturation of Arteriovenous Fistulas a Mechanical or Biological Problem?
Authors: Jodko Daniel , Obidowski Damian , Reorowicz Piotr , Jozwik Krzysztof
Published: February 2017

During the maturation the high pressure blood from the artery inflows directly to the vein, extends its diameter, and finally the blood flow rate in the vein is even 500-times greater than normal one. The changes of the wall shear stress (WSS) in the vein are thought to play a key role in the remodelling of its wall. However, this process is still not well understood. The aim of this paper is to show an innovative approach for modelling of the vein deformation during the maturation process of a-v fistulas. Dilation of the vein was modelled as two-step complex biomechanical process.

The obtained results concerning final diameter of the vein are compared with average diameter obtained for large group of patients. Moreover, this study shows the changes in the flow rate and the WSS that occur after maturation in the patient-specific fistula.
Numerical Computations of MHD Flow on Hypersonic and Re-Entry Vehicles
Authors: Dias Filipe , Páscoa José , Xisto Carlos
Published: February 2017

In hypersonic flight of reentry vehicles the radio blackout is a typical problem, in particular because it arises during a critical mission operation point. To mitigate this radio blackout the magnetic window concept is proposed. In this work a numerical model is presented to accurately simulate the effect of a magnetic field interacting with ionized plasma surrounding the vehicle. The numerical model is based on the MHD flow equations. Initially, the code is validated for pure hypersonic gas dynamics. Diverse high resolution spatial discretisation schemes, within a Finite Volume framework, are analyzed for robustness. Afterwards, the numerical code is further validated for MHD flows using the well-known Hartmann case. A very good comparison between numerical and analytical results is verified. This allows a proper validation of the method in terms of Lorentz force, in particular under low-magnetic Reynolds number conditions. A very tough test-case is finally computed, being typical of a reentry capsule geometry. The accuracy of the model is then verified for different applied magnetic fields.
Influences of Microstructure Defect Size and Distribution for Performance Optimization of Thermal Barrier Coatings
Authors: Wimmer Stephanie A. , DeGiorgi Virginia G. , Gorzkowski Edward P.
Published: February 2017

Thermal barrier coatings are often used to protect a component by reducing temperature excursions. Such coatings are in use on engineered products such as turbine blades. The work presented is part of a broader effort that is focusing on new and novel processing techniques for thermal barrier coatings. Manufacturing methods are being developed to create microstructures that optimize thermal protection while not degrading the mechanical properties of the coating. Sufficient mechanical properties are necessary so the coatings do not fail as a result of loadings associated with the operation of the component. One fabrication method investigated is the inclusion of spherical micron-sized pores to reflect heat radiation at high temperatures along with nano-sized grains to reflect phonons thus providing thermal protection. Pores are sized and distributed so that sufficient mechanical strength is maintained. In the current work the model material used is a yttria-stabilized zirconia (YSZ). Two-dimensional microstructures representing YSZ are computationally generated. The size and distribution of defects that have been experimentally observed to develop during bulk processing are incorporated into the computationally generated microstructural models. Heat transfer and stress-displacement analyses are performed to determine effective bulk material properties. Comparisons are made to experimental measurements available in the literature as appropriate. The influence that defect dimensions and distributions have on the effective bulk material properties are quantified as a first step understanding the impacts that micron sized pores, voids and cracks have on thermal and mechanical characteristics which will facilitate optimizing the microstructure for thermal protection and strength retention.
Automated Reengineering of Industrial Service-Based Systems
Authors: Agostinho Carlos , Raposo Carlos , Jardim-Goncalves Ricardo
Published: February 2017

Complex systems are not of static nature. Most are governed by a particular set of laws and behave accordingly to a certain range of expected inputs and variables, but they can also evolve in response to unforeseen stimulus. The same principle can be applied to industrial information systems. Larger systems such as an entire company or a network of companies may be divided into further subsystems, including information systems, each behaving autonomously but is still under influence of the others, interacting with them in a holistic manner. This paper explores this relationship and proposes a conceptual solution to the strain of sustaining interoperability in complex service-based networks from the domain of manufacturing. To such effect, and in order to tackle the complex relationships and dependencies implicit in web-service environments, information modeling is used, allowing for the optimization of several service engineering activities and enterprise business processes while maximizing the efficiency of system’s interactions. Hence, service modeling and orchestration is here suggested as a baseline to network monitoring, and as a possible approach to automatically handle and recover from erratic behavior, providing systems with adaptive web services and self-organizing capabilities.
Development of a Microfabricated Sensor System to Measure Lumbar Spinal Fusion
Authors: Munro Deborah S. , Tsai Eric C. , Lingley Andrew R. , Khbeis Michael T.
Published: February 2017

Lumbar spinal fusion surgery continues to experience major growth in the United States and worldwide. The surgery is performed by implanting spinal rods and screws within an incision on the lumbar region of the spine. This implanted hardware provides the initial mechanical stiffness until the morselized bone and bone growth factors generate new bone and can provide long term fixation. After surgery, development of the fusion is evaluated with radiographs, but determination of this fusion takes many months as the bone must first mineralize. The early stages are not visible on radiographs; however, this non-mineralized bone does provide substantial mechanical stiffness that could be measured with a sensor. As the spine moves and flexes, it creates a bending moment in the spinal rod, which could be measured as a strain. When initially implanted, this rod would experience its peak strain, but this would decrease as the bone shared some of the load. By periodically sampling the strain with a sensor, a curve could be generated that showed the overall progress of the fusion.

To maximize the output signal, an interdigitated capacitor design was implemented as the most effective way to maximize the capacitance measurement. A design using 51 free-standing, interdigitated fingers resulted in 50 parallel plate capacitors. The interdigitated capacitor was connected to a Low-Z Amplifier circuit and attached to a spinal rod. The rod was then flexed to simulate spinal bending, and the capacitance changed as expected under physiological loads.
Simulation of Lightning-Strike-Induced Thermal Ablation in Unprotected Carbon Fiber Polymer Matrix Composite Laminates
Authors: Wang Yeqing , Zhupanska Olesya I. , Pasiliao Crystal
Published: February 2017

In this work, the influence of lightning-strike-induced electric current and surface heat flux on the thermal response and thermal ablation of a carbon fiber polymer matrix composite laminated panel is studied. A coupled electric-thermal model for an anisotropic plate exposed to the lightning-strike-induced electric current and surface heat flux is formulated. Temperature-dependent material properties of the carbon fiber polymer matrix composites, including electrical conductivity, thermal conductivity, and specific heat, are used. A coupled electric-thermal finite element analysis (FEA) is conducted using a MATLAB-ABAQUS integrated numerical procedure, which enables progressive element deletion to accurately model the lightning-strike-induced continuous surface recession (thermal ablation) in the composite panel. The obtained thermal response and thermal ablation using the proposed numerical procedure are compared with those obtained using existing solution procedures without progressive element deletion.
Tool Pre-Failure Monitoring in Intermittent Cutting Operations
Authors: Hassan M. , Sadek A. , Damir A. , Attia M. H. , Thomson V.
Published: February 2017

Tool failure remains one of the most challenging phenomena in machining that affects the productivity and product quality, and hence the cost. In high feed rough milling operations of hard-to-cut materials, chipping and breakage have been observed as the dominant failure modes of the end mill cutters. Most of the work in the open literature is focusing on either detecting the complete tool breakage after it takes place or detecting the progressive tool wear. Detecting the abrupt/sudden tool failure due to tool chipping before it takes place, which is essential to avoid any damage to the machined part, has not been addressed. Therefore, the main objective of this research work is to investigate the ability of using the process monitoring signals in order to detect the tool pre-failure and failure by chipping/breakage in intermittent cutting operations. A method was devised to induce impact load on the cutting tool tip to study the features of signals collected by various sensors due to unstable crack propagation and chipping, while ensuring minimal tool wear effect. The acoustic emission (AE) signal features were able to successfully capture tool pre-failure, while other signals could detect the failure occurrence only.
Self-Tapping Screw Performance in Aluminum-Steel Joints
Authors: Wu Zhijun , Nassar Sayed A. , Satav Kshitij , Jagatap Shraddha
Published: February 2017

Over the last few decades, lightweight material joints including plastics, aluminum, magnesium and various composites have been widely used in many mechanical and structural applications such as automotive, aircraft and so on, for their high strength-to-weight ratio and the significant improvement for the fuel economy and energy efficiency. Self-tapping screws are one of major technologies to connect the various joints and provide system integrity in ease of system assembly, low cost, etc. In this study, tightening performance of thread cutting screw in aluminum joints is evaluated. Effect of repeated tightening and loosening on the screw performance is investigated for the screw residual torque after environmental thermal cycling. Cyclic temperature fluctuates between 130°C and −20°C in a computer-controlled environmental chamber. Joint coupon materials are steel and aluminum material. Analysis of experimental data provides a useful insight into the self-tapping process into aluminum joints.
Multi Response Optimization of Submerged Friction Stir Welding Process Parameters Using Grey Relational Analysis
Authors: Velukkudi Santhanam Senthil Kumar , Ramaiyan Sankar , Rathinaraj Lokesh , Chandran Rathinasuriyan
Published: February 2017

Friction stir welding (FSW) invented by TWI is a solid-state joining process, which is used to weld high-strength aluminum alloys and other metallic alloys which are non weldable by conventional fusion welding process. In this work, AA6063-O alloy of 150 mm in length, 75 mm in width and 6mm thickness is taken and friction stir welded in submerged condition in order to improve the joint properties. The chosen process parameters are tool pin profiles (cylindrical, threaded and tapered), rotational speed and welding speed. The process parameters are optimized with multi response characteristics including hardness and average grain size at the nugget zone. The traditional Taguchi approach is insufficient to solve a multi response optimization problem. Therefore, Grey Relational Analysis (GRA) is used in this current work. The optimal result indicates that the multi response characteristics of the AA6063-O during the submerged friction stir welding process can be enhanced through Grey Relational Analysis. In order to investigate the significance of process parameters, Analysis of Variance (ANOVA) is carried out. The mechanical properties and microstructure variation of both the normal FSW and submerged FSW joints are compared.
Reliability Based Design of Femoral Locking Plate Systems
Authors: El-Gizawy A. Sherif , Eap Laurent , Ma Xuewei
Published: February 2017

Reliability based design and optimization approach is developed for femoral locking plate systems. The new approach encompasses finite element analysis, advanced probabilistic analysis, and robust design methodology. A three dimensional finite element model of a locking plate system with a supracondylar femoral fracture will be generated to investigate the device performance. The model will include all physiological loading conditions-hip contact, knee contact, and muscle forces-associated with a normal walking gait cycle. In conjunction with probabilistic methods, Taguchi design optimization will be used to optimize implant design to minimize the probability of failure.
Aerothermodynamic Optimization of a TSTO Concept With a Liquid Air Cycle
Authors: Toki Takahiko , Hiremath Nandeesh , Komerath Narayanan
Published: February 2017

Regular, routine and affordable access to low Earth orbit (LEO) with heavy payloads is essential to develop infrastructure beyond Earth. A Space Solar Power system based on the Intensified Conversion architecture gives the market parameters to routinely transfer 25000 kg to and from LEO. An initial analysis combines aerodynamics and aerothermodynamics. A hydrogen-oxygen system which collects the oxygen for the rocket phase in flight. The transonic airliner class carrier with hydrogen-fueled turbofans contains the equipment for oxygen collection during subsonic ascent. The second stage starts as transonic ramjet near 18000m, transitions to supersonic combustion at Mach 5 and then to rocket. Aerodynamic lifting surfaces sized by the second stage landing are used in supersonic ascent. This establishes a new basis to estimate launch cost for large-scale infrastructure development in orbit. The optimization results show that a supersonic carrier to Mach 2 and above, along with a higher release altitude for the second stage, should improve payload, but requires design of a completely new supersonic carrier. The results also show the need for oxygen liquefaction systems optimized for LACE and utilizing the availability of liquid hydrogen at the rate needed by the engines.
Vibration Analysis of a Composite Helicopter Rotor Blade at Hovering Condition
Authors: Sarker Pratik , Theodore Colin R. , Chakravarty Uttam K.
Published: February 2017

The helicopter is an essential and unique means of transport nowadays and needs to hover in space for considerable amount of time. During hovering flight, the rotor blades continuously bend and twist causing an increased vibration level that affects the structural integrity of the rotor blade leading to ultimate blade failure. In order to predict the safe allowable vibration level of the helicopter rotor blade, it is important to properly estimate and monitor the vibration frequencies. Therefore, the mathematical model of a realistic helicopter rotor blade composed of composite material, is developed to estimate the characteristics of free and forced bending-torsion coupled vibration. The cross-sectional properties of the blade are calculated at first and are then included in the governing equations to solve the mathematical model. The natural frequencies and mode shapes of the composite helicopter rotor blade are evaluated for both the nonrotating and rotating cases. The time-varying bending and torsional deflections at the helicopter rotor blade tip are estimated with suitable initial conditions. The validation of the model is carried out by comparing the analytical frequencies with those obtained by the finite element model.
Hybrid Polymer Additive Manufacturing of a Darrieus Type Vertical Axis Wind Turbine Design to Improve Power Generation Efficiency
Authors: Deshpande Sourabh , Rao Nithin , Pradhan Nitin , Irwin John L.
Published: February 2017

Utilizing the advantages of additive manufacturing methods, redesigning, building and testing of an existing integral Savonius / Darrieus “Lenz2 Wing” style vertical axis wind turbine is predicted to improve power generation efficiency. The current wind turbine blades and supports made from aluminum plate and sheet are limiting the power generation due to the overall weight. The new design is predicted to increase power generation when compared to the current design due to the lightweight spiral Darrieus shaped hollow blade made possible by 3D printing, along with an internal Savonius blade made from aluminum sheet and traditional manufacturing techniques. The design constraints include 3D printing the turbine blades in a 0.4 × 0.4 × 0.3 m work envelope while using a Stratasys Fortus 400mc and thus the wind turbine blades are split into multiple parts with dovetail joint features, when bonded together result in a 1.2 m tall working prototype. Appropriate allowance in the mating dovetail joints are considered to facilitate the fit and bonding, as well as angle, size and placement of the dovetail to maximize strength. The spiral shape and Darrieus style cross section of the blade that provides the required lift enabling it to rotate from the static condition are oriented laterally for 3D printing to maximize strength. The bonding of the dovetail joints is carried out effectively using an acetone solution dip. The auxiliary components of the wind turbine which include the center support pole, top and bottom support, and center Savonius blades are manufactured using lightweight aluminum. Design features are included in the 3D printed blade parts so that they can be assembled with the aluminum parts in bolted connections. Analysis of the 3D CAD models show that the hybrid aluminum and hollow 3D printed blade construction provides a 50% cost savings over a 3D printed fully solid blade design while minimizing weight and maximizing the strength where necessary. Analysis of the redesign includes a detailed weight comparison, structural strength and the cost of production. Results include linear static finite element analysis for the strength in dovetail joint bonding and the aluminum to 3D printed connections. Additional data reported are the time frame for the design and manufacturing of the system, budget, and an operational analysis of the wind turbine with concern for safety. Results are analyzed to determine the advantages in utilizing a hybrid additive manufacturing and aluminum construction for producing a more efficient vertical axis wind turbine. Techniques used in the production of this type of wind turbine blade are planned to be utilized in similar applications such as a lightweight hovercraft propeller blade design to be tested in future research projects.
Effect of Axial Sweep and Tip Extension on Performance of an Axial Fan
Authors: Patel Ankit Bhai , Viswanath K. , Nath Dhyanjyoti Deb
Published: February 2017

Performance enhancement in terms of stall margin increment, increased pressure rise coefficient and increased efficiency is of great need for low speed axial fans. Stacking line modifications in terms of sweep, skew, dihedral or combination of these, as well as blade tip geometry modifications are assumed to be one of the ways to achieve finite performance improvement. Non radial stacking of blade profiles modifies secondary flows, tip vortex effects, hub passage vortex and thus affects aerodynamic performance parameters such as stall margin, efficiency, pressure rise, blade loading. In literature many studies have confined to comparison of few cases which led to conflicting results as modification of stacking line may have different effects in different cases. In the present work, comparison of performance of axial fan rotor with three different blade configurations BSL (baseline), SWP (swept blade) and EXTN (swept blade with extended tip) are considered. The BSL configuration is designed on basis of non-free vortex design. The SWP configuration is obtained by shifting radial stacking line of the BSL in axial flow direction by 10° (Forward sweep). The EXTN configuration is obtained by extending tip profile on pressure surface as well as suction surface by 3% locally. Experiments have been conducted on these three configurations to study effects of these modifications on aerodynamic performance. The flow field has been surveyed using Kiel probe, Three hole pressure probe at many flow rates starting from fully open to fully closed. Unsteady flow analysis at exit of rotors of all configurations is carried out using fast response pressure probe. Experimental results show slight performance improvement in terms of increased stall margin, efficiency, as well as total pressure rise for SWP rotor as well as EXTN rotor compared to BSL rotor at low flow coefficients.
Nanofinishing of Copper Using Ball End Magnetorheological Finishing (BEMRF) Process
Authors: Khan Dilshad Ahmad , Alam Zafar , Jha Sunil
Published: February 2017

The ball end magnetorheological finishing (BEMRF) is an advanced nanofinishing process for flat, curved and freeform surfaces of ferromagnetic as well as diamagnetic materials. While finishing copper (diamagnetic material) by this process, a low finishing effect is obtained as its surface repels the externally applied magnetic field. In this work a magnetic simulation is carried out over both copper and ferromagnetic material. For the ferromagnetic material the simulation result shows a high flux density region below the tool tip. However in case of copper the magnetic flux density is too low for finishing. It is also observed through simulations that when copper workpiece is placed on a mild steel base the flux density improves marginally. This led to the idea of using a permanent magnet (in place of mild steel) as a base for finishing of copper using the BEMRF process. Using this technique copper was finished and the experimental results indicate that this method can realize ultra-precision finishing of copper.
Development of the Working Fluid With Blood Viscosity for Evaluating Ablation Catheter in In Vitro System
Authors: Yu Kaihong , Takahashi Ren , Ohta Makoto
Published: February 2017

The purpose of this study was to develop a working fluid with the proper viscosity to mimic blood flow to evaluate an ablation catheter. We proposed a working fluid that matches the blood viscosity, using glycerol-saline solution or xanthan gum (XG)-saline solution. We compared the two solution mixtures at various concentrations (for glycerol-saline solution, 10%, 30%, and 50%; for XG-saline solution, 0.10%, 0.11%, 0.12%, and 0.13%) by measuring their temperature dependence on viscosity. To test the developed working fluids, RF ablations were performed with both solutions, and the flow around the catheter during ablation was observed by particle image velocimetry (PIV) method. In addition, to test the efficacy of the solution mixtures, myocardium was observed after it was soaked separately in the two solution mixtures. The viscosity of both kinds of solution mixtures increased at higher concentrations and decreased with increasing temperatures. At 37°C, the viscosities of 50% glycerol-saline solution and 0.11%–0.13% XG-saline solution were 3–4 mPa·s, a value that is similar to the viscosity of blood. The upward flow resulting from heat convection by ablation was observed around the catheter in the PIV analysis using an in vitro model without flow. The solution mixture with the higher viscosity flowed at a lower velocity around the catheter, and the myocardium soaked in 50% glycerol-saline solution shrunk into a black and tough tissue. On the other hand, the myocardium soaked in XG-saline solution showed no change in color or shape. In conclusion, the XG-saline solution is a superior option for evaluating ablation catheters.
Hybrid Rapid Spinning and Incremental Sheet Metal Forming of Extra Deep Drawing (EDD) Steel
Authors: Regalla Srinivasa Prakash , Suresh Kurra
Published: February 2017

In this work, investigation into a two-stage hybrid and integrated incremental sheet metal processing of EDD sheet has been carried out. EDD steel was chosen for its excellent formability. The hybrid process consists of two stages, the first stage is the conventional spinning process and the second stage is the asymmetric incremental sheet metal forming (AISF) process. The objectives of the proposed hybrid process are reduction of manufacturing time and improved surface finish, in comparison to AISF process alone. In the proposed hybrid process, the geometry of sheet metal part was sub-divided into two groups of features. The first group of axisymmetric features was obtained by spinning process, on top of which, in the second stage, the second group of asymmetric features was superimposed by AISF process. The hybrid process for studying the manufacturing time consisted of negative AISF in the second stage. A substantial overall reduction in manufacturing time was observed. The hybrid process for studying improved surface finish consisted of, on the other hand, positive AISF in the second stage, in which the experiments were carried out using four different lubricants, namely plain canola oil and three different additives in canola oil, namely, molybdenum disulphide, boric acid and maleic anhydride. The surface topography of the sheet in the two stages of hybrid process was determined using a profilometer. It is found that canola oil with molybdenum disulphide gives the best surface quality.
Analysis of Preload Loss With Corrosion Protection Layers in the Flow of Force
Authors: Isele D. , Friedrich C. , Isele A.
Published: February 2017

This contribution investigates the tightening behavior and preload loss of bolted joints with painted coating systems for corrosion protection of components. Friction coefficients are measured with test stand, preload loss is measured by strain gauges. Further evaluation is done with optical roughness measurement to see damage of the painted surfaces in contact areas. Resulting from this hints for applications get obvious. Research progress focuses the quantification of preload loss in different applications. Mechanical loads are neglected at that stage because of minor influence as the temperature.

To sum up, it can be formulated that the tested, robust coating systems can endure yield-point-tightening of high-strength screws and also exist as a complete and coherent layer after the loosening. Therefore corrosion protection could be guaranteed also after a yield-point-tightening, especially underneath the screw head. This is in particular relevant for applications which require repeated tightening of the same screw.

Corrosion protection layers within the flow of force usually change the friction coefficients compared with bare material. This effect influences the assembly of bolted connections dominantly. Controlling the assembly process is getting more difficult because of the increasing scattering from steering parameters, like torque or angle. There might be huge deviations, up to a factor of 6.2, between torque values of a similar assembly process. Therefore process safety cannot be guaranteed, especially if their values miss originally defined tolerances.

To overcome these difficulties it is necessary to use the right assembly method as well as the right coating system. After our opinion the yield-point controlled tightening is the only method which leads to a safe assembly preload, even with coated parts. If the preload loss will be acceptable depends on the coating system and the external conditions.
Design of a Highly Loaded Turbine Exit Case Airfoil With Active Flow Control
Authors: Kurz Julia , Hoeger Martin , Niehuis Reinhard
Published: February 2017

In this paper a design process of a highly loaded profile for a turbine exit case (TEC) application is described. The profile has an increased pitch to chord ratio which is approximately 50% higher compared to conventional airfoils. For the design of the airfoil a two-dimensional (2D) computational fluid dynamics (CFD) prediction method was used in addition to in-house design rules and low Reynolds number experience from previous experiments. Furthermore, common knowledge from turbine and compressor design as well as turbine exit guide vane studies was evaluated and taken as basis for the new design.

To verify the highly loaded design, the profile was tested over a wide Reynolds number range in the high speed cascade wind tunnel of the Institute of Jet Propulsion (ISA) at the University of the German armed forces in Munich.

The experiments showed a very good agreement between the CFD predictions and the measurements for high Reynolds numbers. In the low Reynolds number regime the tendency to massive flow separation was slightly underestimated by the CFD predictions. It is particularly challenging as the CFD predictions still have problems to calculate open separation bubbles. Active flow control (AFC) by fluidic oscillators was also part of the design process and successfully applied on the profile.
Study of Surface Quality and Cutting Parameter Optimization in Side Milling CFRP With Diamond Coated Carbide Tool
Authors: Liu Weiwei , Hu Yuan , Zhou Jianwu , Lu Renjie , Wang Chengzhou
Published: February 2017

Composite machining is one of the hot researches currently, and optimal cutting parameters are particularly important to get ideal surface and reduce processing cost of workpiece. By comparison, the present paper selects the surface root mean square deviation Sq as the three-dimensional evaluation parameter of surface roughness to reflect the special appearance after cutting accurately. The single-factor experiment and orthogonal experiment were conducted to study the machining defects emerged and effect of parameters on surface roughness when side milling CFRP (Carbon Fiber Reinforced Plastics) with diamond coated carbide tool. The mapping relationship between cutting parameters and surface roughness was established based on the experiment results. Then, the cutting parameters were optimized by using genetic algorithm with two conflicting objectives: material removal rate and surface roughness. The experiment results show that the proposed method is feasible and effective, and can provide references for the actual processing of CFRP.
Finite Element Modeling and Simulation of Inconel 718 Using WEDM
Authors: Karidkar S. S. , Dabade U. A.
Published: February 2017

Wire Electrical Discharge Machining (WEDM) is a versatile process to generate intricate and complex shapes on conductive work material with high dimensional accuracy and surface finish. Since the process is stochastic, its input parameters play critical role for achieving desired accuracy and precision of the component. Inconel 718, High-Strength-Temperature-Resistant (HSTR) material, has wide applications in the field of aerospace, automobile, mould making and medical industries. Hence, machining of Inconel 718 using WEDM is a challenging task. Also experimentation on Inconel 718 with WEDM is costly as well as time consuming process. Therefore to study the behavior of WEDM process with different process parameters for effective and efficient operation, process modeling and simulation using appropriate software is highly essential. In the present investigation, a 3-D single spark finite element thermal model for WEDM process has been developed using ANSYS software. This model has some more realistic assumptions like heat flux following Gaussian distribution and spark radius as a function of time and energy. Plasma incident region is meshed by keeping elemental size equal to one tenth of entire plasma radius, so that exact ten elements can be fitted. Identified elements were thermally loaded by applying element wise different temperatures for getting more accurate temperature distribution profile. This profile was found to be having crater shape matching with earlier Finite Element Models (FEM) available in the literature. Along with the shape, it also helps to decide the elements having temperatures greater or equal to melting point leading to estimate Material Removal Rate (MRR). Later on single spark MRR can be used to estimate multi-discharge-MRR by calculating pulse rate. Model MRR is validated with the experimental MRR which show a very good agreement, but little variation. This variation in the modeling could possibly due to assumptions like no delay in ignition, non-deposition of recast layer (100% flushing efficiency), etc. The factors like incomplete flushing of debris and inter-electrode gap arcing cause the variation in machining conditions thus reducing the actual MRR. In the present investigation, the use of dielectric is considered only for convection, but in reality, it acts as an insulator, coolant and also as debris remover. Melting and vaporization of material is the main phenomena for material removal. Dielectric fluid partially removes the molten metal because at the same time, the molten metal is under very high pressure due to plasma channel. Its adhesive property resists the material removal. It is very difficult to incorporate all real effects in the model, however the obtained results in the present study show good agreement between model MRR and experimental MRR within 10% variation.
A Coupled Shear Stress-Diffusion Model for Adhesively Bonded Single Lap Joints
Authors: Nassar Sayed A. , Mazhari Emad
Published: February 2017

In this study, a coupled shear stress-diffusion model is developed for the analysis of adhesively bonded single lap joints by applying Fickian diffusion model to the adhesive layer. Differential equations of equilibrium are formulated in terms of adhesive material properties that are time and location-dependent. By invoking a Volkersen approach on the equilibrium equations, a shear stress differential equation is formulated, and numerically solved. Several scenarios are considered for investigating the effect of diffusion on shear stress distribution in adhesively bonded single lap joints. Detailed discussion of the results is presented.
Correlating Tri-Accelerometer Swallowing Vibrations and Hyoid Bone Movement in Patients With Dysphagia
Authors: Zahnd Etienne , Movahedi Faezeh , Coyle James L. , Sejdić Ervin , Menon Prahlad G.
Published: February 2017

Swallowing accelerometry has been recently investigated as a potential non-invasive tool for dysphagia screening. This method is based on the translation of vibrations recorded from the upper aerodigestive tract structure during swallowing into a voltage signal. Some studies hypothesize the hyoid bone movement during swallowing as the source of swallow vibrations, as it is an essential component of swallowing function that contributes to protection of the airway during the swallow. However, there is still an open question about the physiological source of swallowing vibrations. In this paper, we investigate the correlation between the swallowing vibrations recorded by the tri-axial accelerometer and hyoid bone kinetics observed in video-fluoroscopic swallow imaging studies. Further, this is a first of its kind study investigating this correlation with vibration signals measured in the medial-lateral plane of accelerometry. Our hypothesis is that there exists a correlation between the recorded swallowing vibrations in three axes and hyoid bone kinetics in videofluoroscopic images.
Effect of Cutting Conditions on Dimensional Accuracy and Surface Roughness in Traditional Milling of Steel
Authors: Stringer Brian , Liu Rui , Fuentes Aznar Alfonso , Iglesias Patricia
Published: February 2017

Gear milling is one of the common gear manufacturing processes. In gear milling, the cutting edge of the cutting tool has an identical profile with the profile between gear teeth, and the cutting tool travels along the axial direction of the gear blank to produce the gear tooth by tooth. Due to the high requirements about the dimensional accuracy and the surface roughness during the gear manufacturing process, it is very crucial to understand the influences of cutting conditions on those requirements to improve the quality of the product and increase the production rate. In this study, a machined gear blank made from 1018 cold-rolled steel was subjected to variable speed and feed-rates in a traditional milling operation using a standard gear-milling cutter. The effect of the variable speed and feed-rates were analyzed by measuring the total lead (helix) error, total profile (involute) error, and surface finish of each gear tooth subjected to the variable cutting conditions. The objective is to experimentally investigate the correlation between the cutting conditions, i.e. cutting speed and feed, with the accuracy and quality of the machined surface during the gear milling process.
Development of Wire 3D (Wir3D) Printing Parameters
Authors: Hunko Wesley S. , Payton Lewis N.
Published: February 2017

Currently additive manufacturing techniques offer great detail in small, difficult to produce parts. They are also relatively slow, limited in scale and very expensive (especially so in the additive manufacturing of metals realm). Wire and arc additive manufacturing enables manufacturers to build parts by depositing metal in layers using welding techniques. The extremely inexpensive Wire 3D (Wir3D) printing process, in development by the authors, uses an electric arc to melt metals at higher deposition rates than other additive techniques in metals. Large parts can be created quicker with less material waste or total machining time than subtractive manufacturing. Unique metal alloys can also be quickly and economically produced without worry of tool wear and the other drawbacks that are related to super alloy manufacturing as with subtractive techniques. A Wir3D additive machine was designed, constructed and evaluated at Auburn University. The wire deposition machine features a modular, open frame design allowing for easy access and continuous upgrades. The machine, which is based upon gas metal arc welding (GMAW) technology, is extremely rapid compared to other additive processes currently available at producing metal objects. Although it cannot currently compete with laser or electron beam additive methods in terms of resolution, these methods will never be able to compete with Wir3D in terms of speed for bulky print jobs, or especially material costs. During the literature review of this emerging technology, it became apparent that a standard reporting format would greatly increase future developments in the field by all researchers. A standard parametric data sheet was developed to establish a common data set for future researchers (included at end) during the experiments’ execution incorporating all of the parameters reported variously in the scattered literature. The printer described in this paper constructed for very little money by students working together. In the development, voltage and current requirements for different wire diameters were analyzed along with resulting wall widths and heights. The tensile strengths of deposited steel structures were measured in multiple orientations achieving up to 90% of standard material values in one orientation. Deposited steel structures were found to be heat treatable. With improved controls and in-process feedback, one-off castings can be easily replaced using this process in a wide array of metals. The wire 3D printing process is a viable option for low cost and rapid manufacturing of metallic objects [1].