bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generalized Modeling of Milling Mechanics and Dynamics: Part II — Inserted Cutters
Authors: Engin Serafettin , Altintas Yusuf 
Published: December 2021

Abstract
Inserted cutters are widely used in roughing and finishing of parts. The insert geometry and distribution of inserts on the cutter body vary significantly in industry depending on the application. This paper presents a generalized mathematical model of inserted cutters for the purpose of predicting cutting forces, vibrations, dimensional surface finish and stability lobes in milling. In this paper, the edge geometry is defined in the local coordinate system of each insert, and placed and oriented on the cutter body using cutter’s global coordinate system. The cutting edge locations are defined mathematically, and used in predicting the chip thickness distribution along the cutting zone. Each insert may have a different geometry, such as rectangular, convex triangular or a mathematically definable edge. Each insert can be placed on the cutter body mathematically by providing the coordinates of insert center with respect to the cutter body center. The inserts can be oriented by rotating them around the cutter body, thus each insert may be assigned to have different lead and axial rake angles. By solving the mechanics and dynamics of cutting at each edge point, and integrating them over the contact zone, it is shown that the milling process can be predicted for any inserted cutter. A sample of inserted cutter modeling and analysis examples are provided with experimental verifications.
Improved Generalized Intelligent Grinding Advisory System
Authors: Lee Cheol W. , Shin Yung C. 
Published: December 2021

Abstract
The intelligent grinding advisory system (Shin et al., 1992), which was further expanded to the generalized intelligent grinding advisory system (GIGAS) by Vishnupad and Shin (1998), provides a novel way of incorporating heuristic knowledge, analytical equations, experimental data into optimization of grinding processes. The improvement of GIGAS, especially in the solution’s accuracy and convergence property for complex multi-modal processes, is sought in this study. A method of combining fuzzy rules is proposed with other modifications. Simulation studies with numerical examples and a cylindrical grinding process show that the improved fuzzy optimization algorithm can achieve numerical accuracy comparable to that of conventional optimization methods while it retains the benefits of the original GIGAS algorithm in computational efficiency, robustness and the ability to incorporate heuristic knowledge. Finally, the improved GIGAS, constructed by combining the improved optimization algorithm with the generalized grinding models, is presented.
A Strategy for the Sensor Placement Optimization for Machine Thermal Error Compensation
Authors: Ma Youji , Yuan Jingxia , Ni Jun 
Published: December 2021

Abstract
This paper proposes a strategy of optimizing temperature sensor placement for thermal error compensation based on dynamic characteristics of temperature field and thermal deformation of a machine tool structure. A simple example of one-dimensional thermal expansion is given to signify the importance of sensor placement to the accuracy and robustness of thermal error modeling. Time and frequency domain analyses of optimal sensor placement are carried out for the simple one-dimensional thermal expansion and then extended to more complex two and three-dimensional thermal expansions. To apply the strategy to a machine tool, a new method of analyzing machine tool thermal errors called thermal deformation chain analysis is proposed to predetermine the sensor locations on a machine tool structure. The method is very effective in identifying thermal error contributors and their significance, and has been proven to be efficient in choosing sensor locations on a turning center.
System Modeling to Support Variation Reduction in a Sheet Stretch Forming Manufacturing System
Authors: Suri Rajiv , Otto Kevin 
Published: December 2021

Abstract
Quality is a major issue in the production of sheet stretch-formed aircraft skins. A typical stretch-forming system is composed of a series of operations, including heat treatment, stretch forming, chemical milling, and trimming. Each of these operations is subject to significant input and process variation, leading to variation on the work-in-process. This variation then results in fit-up problems at the assembly stage and high scrap or rework cost. In this paper we use a mathematical model of a stretch-forming manufacturing system to aid in reducing end-of-line variation. For the paper we reduce the system to two key operations: heat treatment and stretch forming. Physics-based mathematical models of each are used to derive a variational model of the system, which maps output quality characteristic variations to input variations. This variational model is used to identify the major sources of variation in the system: aging time and forming force. To reduce the effects of these variables, a feed-forward control strategy is proposed, in which aging time is measured after heat treatment and used to determine force during stretch forming. Feedback control is not effective. Analytical expressions are developed to predict the effects of the system control strategy on end-of-line variation. Finally, the results of a shop floor implementation of this strategy are presented, showing a 30% reduction in strain variation on production parts.
Detection of Roller Bearing Conditions Using Mechatronics Approach
Authors: Liu T. I. , Ordukhani F. 
Published: December 2021

Abstract
An on-line monitoring and diagnostic system is needed to detect faulty bearings. In this work, by applying the feature selection technique to the data obtained from vibration signals, six indices were selected. Artificial neural networks were used for nonlinear pattern recognition. An attempt was made to distinguish between normal and defective bearings.
Counterpropagation neural networks with various network sizes were trained for these tasks. The counterpropagation neural networks were able to recognize a normal from a defective bearing with the success rate between 88.3% to 100%. The best results were obtained when all the six indices were used for the on-line classification of roller bearings.
Effect of Cutting-Edge Geometry and Workpiece Hardness on Surface Residual Stresses in Finish Hard Turning of AISI 52100 Steel
Authors: Thiele Jeffrey D. , Melkote Shreyes N. , Peascoe Roberta A. , Watkins Thomas R. 
Published: December 2021

Abstract
An experimental investigation was conducted to determine the effects of tool cutting-edge geometry and workpiece hardness on surface residual stresses for finish hard turning of through-hardened AISI 52100 steel. Polycrystalline cubic boron nitride (PCBN) inserts with representative types of edge geometry including “up-sharp” edges, edge hones, and chamfers, were used as the cutting tools in this study. This study shows that tool edge geometry is highly influential with respect to surface residual stresses, which were measured using x-ray diffraction. In general, compressive surface residual stresses in the axial and circumferential directions were generated by large edge hone tools, for longitudinal turning operations. Residual stresses in the axial and circumferential directions generated by small edge hone tools are typically more tensile than stresses produced by large edge hone tools. Microstructural analysis shows that thermal effects are significant at high feed rates, based on the presence of phase changes on the workpiece surface. At high feed rates, compressive stresses correlate with continuous white layers and tensile stresses correlate with over-tempered regions on the surface of the workpiece. Mechanical effects play a larger role at low feed rates, where phase changes are not observed to a significant degree. For these cases, large edge hone tools generally produce more compressive values of residual stress than small edge hone tools.
Machine-Tool Chatter Suppression by Multi-Level Random Spindle Speed Variation
Authors: Yilmaz Alpay , AL-Regib Emad , Ni Jun 
Published: December 2021

Abstract
This paper presents a new method for varying the spindle speed to suppress chatter in machining. The spindle speed is varied in pseudo-random fashion within the bandwidth of the spindle system. Both implementation issues and spindle system responses to such signals are investigated. A new method to analyze the stability of machining systems with varying spindle speed is also introduced. The effectiveness and advantages of the random spindle speed variation in chatter suppression is verified using numerical simulations and experiments.
On Simulation of Bend/Reverse Bend of Sheet Metals
Authors: Zhao K. M. , Lee J. K. 
Published: December 2021

Abstract
Bend/reverse bend tests are performed with a three-point bend test apparatus on two types of sheet metals, mild steel and high strength steel. The bend/reverse bend process tends to a steady cycle upon applying repeated cycles of displacements. Strain hardening and Bauschinger effects for both materials are detected. Three different hardening laws are used to simulate the bend process numerically. Isotropic hardening law overestimates the hardening component and by missing the Bauschinger effect and the plastic shakedown. Kinematic hardening rule underestimates the hardening component and exaggerates the Bauschinger effect. The combination of isotropic and nonlinear kinematic hardening predicts accurately both the Bauschinger effect and the plastic shakedown. The hardening parameters in the combined model are identified inversely by using micro genetic algorithm.
Design and Control of a Spherical Air Bearing System for Multi-DOF Ball-Joint-Like Actuators
Authors: Lee Kok-Meng , Ezenekwe Dan E. , He Tian 
Published: December 2021

Abstract
This paper presents an analytical investigation on the design method and modeling of an air bearing system for ball-joint-like actuators. It addresses the method of regulating the three DOF translations of the rotor introduced by the air bearing system and thereby improving the dynamic performance of the orientation motion manipulation. The kinematics, which relates the rotor displacement and the air gaps, are essential for design optimization, dynamic simulation and motion control, are derived in closed-form. With a detailed modeling of the pressure-flow relationship as a function of the rotor position, the forces and dynamics of the system are formulated, and design methods of regulating the rotor displacement have been explored analytically. Simulation results suggest that the fluid forces could be generated to passively stabilize the otherwise open loop unstable electromagnetic system. It is expected that this research will be a basis for designing and evaluating an improved VR spherical motor with enhanced torque capability by eliminating mechanical friction.
Transport Phenomena in Heterogeneous Media: Experimental Data Reduction and Analysis
Authors: Travkin V. S. , Catton I. , Hu K. , Ponomarenko A. T. , Shevchenko V. G. 
Published: December 2021

Abstract
Volume averaging theory (VAT) is used to bring a consistent basis to experimental data reduction and analysis by examples in several areas of transport phenomena. Many common correlations, and their weaknesses, are examined using a unified scaling procedure that allows them to be compared to one another. Momentum resistance and internal heat transfer dependencies are analyzed and compared. VAT based analysis is shown to reveal the influence of morphological characteristics of the media, to suggest scaling parameters that allow a wide variety of different porous media morphologies to be normalized, often eliminating the need for further experimental efforts, and to clarify the relationships between differing experimental configurations. The origin, and insufficiency, of electrical conductivity and momentum transport “cross-correlation” approaches in efforts to find analogies by mathematical comparison without examining the physical foundations of phenomena are described and explained.
Mesoscale Combustor/Evaporator Development
Authors: Brooks Kriston P. , Martin Peter M. , Drost M. Kevin , Call Charles J. 
Published: December 2021

Abstract
Battelle has developed a mesoscale combustor/evaporator that provides a lightweight and compact source of heating, cooling, or energy generation for both man-portable and stationary applications. The device uses microscale flow channels that increase the available surface area for heat transfer and reduce the fluid boundary layer. These characteristics in turn result in heat fluxes for hydrocarbon/air combustion in excess of 25 W/cm2 and thermal efficiencies of 80 to 90%. Furthermore, high heat transfer rates allow for short channels and reduced pressure drops.
Recent development efforts have focused on obtaining low emissions and improving the combustor/evaporator fabrication process. By using spatially varying stoichiometry inside the combustor, catalyst coated microchannels, and increased coolant temperature, the combustor’s CO and NOx emissions were reduced to below California standards for hot water heaters and boilers. The fabrication process photochemically machines thin metal laminates and then uses diffusion bonding to form a monolithic component. This approach is capable of high fin aspect ratios and can be scaled up for mass production.
Thermo-Electro-Mechanical Refrigeration Based on Transient Thermoelectric Effects
Authors: Miner Andrew , Majumdar Arun , Ghoshal Uttam 
Published: December 2021

Abstract
This paper introduces the concept of a thermo-electro-mechanical cooler (TEMC), which modifies a traditional thermoelectric cooler (TEC) by using intermittent contact of a mechanical element synchronized with an applied pulsed current. Using Bi2Te3 as the thermoelectric material, it is predicted that the maximum temperature drop across a TEMC may be as much as 35 percent higher than that of a TEC in low heat flux applications. This effectively increases the figure of merit by a factor of 1.8.
Heat Recovery Enhancement and Operational Issues of a 200 kWe Fuel Cell Cogeneration Plant
Authors: Söderlund Erika , Martin Andrew R. , Alvfors Per , Forsman Jonas , Sarközi Laszlo 
Published: December 2021

Abstract
This study presents some of the experiences gained during a two year operational period of a decentralized fuel cell cogeneration plant installed in southern Sweden. Various modifications to the system are described, most notably a plume eliminator for the reduction of an undesirable vapor cloud emitted by the original system. Aside from vapor cloud elimination, the plume eliminator allows for more efficient plant operation, as a larger fraction of the system cooling requirements can be shifted to the district heating system. In-field measurements show a 17 to 26% increase in district heat production with use of the plume eliminator, depending upon the season of operation (winter or summer). The study also presents two options for added heat recovery, which are employed in conjunction with the plume eliminator: an air preheater module; and an air preheater/humidifier module. Calculations show that air preheating has a small but measurable impact on heat recovery (an additional 8% gain), while combined air preheating and humidification allows for nearly a 50% increase in district heat production.
Predicting the Effect of Gas-Flow Channel Spacing on Current Density in PEM Fuel Cells
Authors: Naseri-Neshat Hamid , Shimpalee Sirivatch , Dutta Sandip , Lee Woo-kum , Van Zee J. W. 
Published: December 2021

Abstract
The effects of change in diffusion layer width for constant diffusion layer thickness and constant gas-flow channel width are investigated with a straight channel model of a Proton Exchange Membrane (PEM) fuel cell. A three-dimensional 10-cm long straight channel model of the PEM fuel cell is presented. The geometrical model includes diffusion layers on both the anode and cathode sides and the numerical model couples three-dimensional Navier-Stokes flow with electro-chemical reactions occurring in the fuel cell. Contours of the current density, anode water vapor concentration, anode water activity, water molecules per proton flux, and secondary flow velocity vectors at different cross sections are presented for the two diffusion layer widths. For the particular conditions and properties used for this study, the results show a marked difference between the base case (0.16-cm) and the wide (0.72-cm) diffusion layer. The current density is quite uniform at different axial cross sections and cross-flow sections for the 0.16-cm wide diffusion layer. However, for the 0.72-cm wide diffusion layer, the current density decreases more significantly in the axial direction near the edges of the diffusion layer. Numerical predictions of the water transport between cathode and anode across the width of the MEA show the delicate balance of diffusion and electro-osmosis and their effect on the current distribution along channel.
Evaluation of Insulated Pressure Vessels for Cryogenic Hydrogen Storage
Authors: Aceves Salvador M. , Martinez-Frias J. , Garcia-Villazana O. 
Published: December 2021

Abstract
This paper presents an analytical and experimental evaluation of the applicability of insulated pressure vessels for hydrogen-fueled light-duty vehicles. Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH2) or ambient-temperature compressed hydrogen (CH2). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (lower energy requirement for hydrogen liquefaction and reduced evaporative losses).
The purpose of this work is to verify that commercially available aluminum-lined, fiber-wrapped vessels can be used for cryogenic hydrogen storage. The paper reports on previous and ongoing tests and analyses that have the purpose of improving the system design and assure its safety.
The analytical and experimental results carried out until now indicate that it may be possible to use fiber-wrapped aluminum-lined vessels for operation at LH2 temperature and high pressure. Required future tests are described that will assure vessel safety under daily operating conditions.
Operating Characteristics of Natural Gas Fueled Homogeneous Charge Compression Ignition Engine
Authors: Kawabata Y. , Nakagawa K. , Shoji F. 
Published: December 2021

Abstract
Recently, a new design of engine combustion that achieves higher efficiency and less NOx emission has been proposed. Some researchers have started studying the concept, which is called Homogeneous Charge Compression Ignition (HCCI), but there have been few reports on investigations using a future prospective alternative fuel, natural gas.
In this study, natural gas fueled operation of HCCI using a single cylinder gas engine was conducted. Operating and exhaust characteristics were obtained. Experimental data confirmed the potential of higher efficiency and less NOx emission, though THC and CO were higher. Based on these data, the feasibility of this concept for gas engines is also examined.
Thermodynamic and Hydraulic Testing of Cryogenic Turbines
Authors: LeGoy Philip R. , Cengel Yunus A. 
Published: December 2021

Abstract
Thermodynamic and hydraulic testing of the newly developed Cryogenic Hydraulic Radial Turbine-Generator assembly was successfully performed. It is an alternative to the conventional Joule-Thompson valve used in Cryogenic Liquefaction plants.
Included in this process was the complete design and manufacture of the first turbine of this kind from concept to the prototype turbine, the creation of a test bed and the development of algorithms for the analysis.
Significant power recovery and refrigeration were demonstrated by testing. This is an advantage over the Joule-Thompson valve, which wastes power potential and adds to the refrigeration load. Up to 78% isentropic efficiency for the Turbine-Generator assembly and up to 0.84°C temperature drop across the turbine are calculated from test data.
A “rule of thumb” is presented to identify conditions under which the use of a turboexpander is justified.
The Application of Multi-Zone Thermal Radiation Models to Investigate the Energy Efficiency of a Metal Reheating Furnace Under Start Up Conditions
Authors: Ward John , Correia Sara A. C. , Sousa João L. V. A. 
Published: December 2021

Abstract
The zone method of radiation analysis has been widely used in mathematical models of a range of industrial heating processes. This paper is thus concerned with the use of a two-dimensional, multi-zone model to predict fuel consumptions, heating rates and load temperatures following the “cold start up” of a gas-fired furnace heating steel bars to a nominal discharge temperature of 1250°C. The model takes into account variations in the flows of the combustion products and in particular examines the influence of the re-circulation of these hot gases within the furnace chamber. The predictions of this complex two-dimensional model are compared with those of a one-dimensional so-called “long furnace model” to illustrate the differences resulting from the use of a more sophisticated multi-zone model.
Analysis of Nonlinear Flexural Behavior of Thick Composites With Fiber Waviness
Authors: Chun H.-J. , Lee S. W. , Daniel I. M. 
Published: December 2021

Abstract
A finite element analysis model was developed to predict flexural behavior of thick composites with uniform, graded and localized fiber waviness. In the analyses, material and geometrical nonlinearties due to fiber waviness were incorporated into the model utilizing energy density and an incremental method. In the model, two kinds of geometrical nonlinearity were considered, one due to reorientation of fibers and the other due to difference of curvatures from one finite element to another during deformation. The finite element analyses utilize the iterative mapping method to incorporate these geometrical nonlinear factors. The model was used to predict not only the flexural behavior of a flat thick composite plate but also of a thick composite plate with initial curvature. Flat composite specimens with various degrees of fiber waviness were fabricated and four-point flexural tests were conducted. The predicted nonlinear behavior by the current model was compared with results from the thin slice model [7] and experiments. Good agreement was observed among them.
Dynamic Behavior of Fiber Reinforced Composites Under Multiaxial Compression
Authors: Oguni Kenji , Ravichandran G. 
Published: December 2021

Abstract
Results from an experimental investigation on the mechanical behavior of a unidirectional reinforced polymer composite with 50% volume fraction E-glass/vinylester under uniaxial and proportional multiaxial compression are presented. Specimens are loaded in the fiber direction using a servo-hydraulic material testing system for low strain rates and a Kolsky (split Hopkinson) pressure bar for high strain rates, up to 3000 s−1. The results indicate that the compressive strength of the composite increases with increasing levels of confinement and increasing strain rates. Post-test optical and scanning electron microscopy is used to identify the failure modes. The failure mode that is observed in unconfined specimen is axial splitting followed by fiber kink band formation. At high levels of confinement, the failure mode transitions from axial splitting to kink band formation and fiber failure. Also, a new energy based analytic model for studying axial splitting phenomenon in unidirectional fiber-reinforced composites is presented.