bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prediction of Flow and Heat Transfer Within a Scroll Compressor Working Chamber
Authors: Zhu J. , Ooi K. T. 
Published: March 2022

Abstract
A numerical investigation has been carried out to predict the fluid flow and heat transfer within a scroll compressor working chamber. The “two-boundary” algebraic method was employed to generate the curvilinear and deforming grid systems which can accommodate a range of practical scroll compressor configurations. The computation accounts for the effect of simultaneous change in the instantaneous volume and the moving boundary of the scroll chamber. The convective heat transfer has been calculated through standard k-ε turbulence model with log-law wall function. Fluid flow and heat transfer rate were predicted in consecutive time steps. Results obtained were compared with that predicted using the lumped parameter approach employing the First Law of Thermodynamics, where some commonly used heat transfer empirical correlations were employed. The comparisons show that empirical correlations are inadequate in predicting heat transfer within the scroll compressor chamber. This is due to highly curved geometry of the scroll chamber and results in the existence of the recirculating flow especially in the late period of the compression process. However, reasonably good prediction in pressure history can be obtained using the First Law of Thermodynamics.
Dynamic Simulation of Bearing Forces in Screw Compressors
Authors: Adams Glynn P. , Qin Zhaohui 
Published: March 2022

Abstract
In most current investigations on bearing forces in screw compressors, the supports at the bearings are basically treated as ideal, simply supported boundary conditions [Adams and Soedel, 1995; Qin and Adams, 1996; You et al, 1994]. By using static mechanics, the loads on the rotors are resolved to equivalent loads at the bearings at suction and discharge ends. Studies on rotor dynamics have shown that the characteristics of a rotor bearing system are strongly dependent on thebearings that support the rotor. Therefore, it is important to study the rotor dynamic performance of screw compressors so that the bearing faces can be more accurately described. In this paper, a dynamic model of a rigid compressor rotor supported by two cylindrical roller bearingsand a four point contact ball bearing is developed from basic principles. This model is used to simulate the dynamic response of a typical screw compressor configuration. Under compression loads, the resulting bearing forces in the screw compressor are compared with those obtained by assuming ideal simply supported boundary conditions at the bearings. A more accurate model of the compressor response is believed to be obtained by coupling the global rotor motion with the local dynamics of nonlinear bearings.
Fast Estimation of Space-Time Correlations of Wall Induced Loads on a Cylinder by a Random Acoustic Plane Waves Field: Numerical and Experimental Application to the Supersonic Jet Noise of a Space Launcher During Lift-Off
Authors: Guillermin Bruno , Cléro Franck 
Published: March 2022

Abstract
The computation of the wall induced loads on a cylinder by random acoustic waves is often costly. In order to reduce this duration, an approximated model of diffraction has been developed on the basis of the scattering of a plane wave by an infinite cylinder. It leads to simplified expressions of the power spectrum density and the normalized cross-spectrum density, which are functions of the azimuth of the incident wave and of a non-dimensional variable β = k a sin(θ). This model gives excellent results as in the case of the infinite cylinder, as in the one of finite slim bodies. It has been linked to a jet noise sources model to allow an experimental validation in the complex case of a three engines launcher at lift-off. The results point out a satisfactory level of accuracy in different configurations, as on the amplitude, as on the phase.
Reverberation Room Survey and Qualification According to ASTM C 423
Authors: Hastings Mardi C. , Godfrey Richard D. 
Published: March 2022

Abstract
Results of an experimental performance qualification of a large reverberation room in the Noise and Vibration Control Laboratory at Owens-Corning Science & Technology Center, Granville, Ohio, are reported. The qualification testing was done according to ASTM C 423 – 90a and a proposed revision of ASTM C 423 being developed by Task Group E–33.01–D of ASTM Committee E–33 on Environmental Acoustics. The proposed revision puts requirements on spatial uncertainties in the reverberant field in addition to the uncertainty in the total number of decay rate measurements. Results of the performance qualification show that this room meets or exceeds requirements for a reverberation chamber for measurement of sound absorption and sound absorption coefficients in the 100 to 5000 Hz third-octave bands.
On Calibrated Measuring Microphones and Their Use in Ordinary Sound Fields
Authors: Peppin Richard J. , Hellsund Hans 
Published: March 2022

Abstract
Measuring microphones come with frequency response curves based on pure tone excitation in well-defined sound fields. Hence microphones have a distinct frequency response curve only for well-defined conditions. These conditions may, in fact, not be met in practice.
People making measurements infrequently use microphones in sound fields that are characterized and known, much less well defined. The location of the sound, the types and effects of reflections, and the exact relationship between the source and microphone are unknown. Hence the data taken may have unknown and unaccounted-for errors.
This paper presents the results of a study that compares the performance of microphones in ordinary and frequently encountered sound measurement situations. These situations consist of a combination of a number of sources, a variety of spaces, and a selection of microphone orientations. In other words, the measurements were made in non-ideal spaces. It is shown that the frequency response of a given measurement in an unknown field is unpredictable for whatever standard microphone used. The continuing efforts to tighten the specifications of instrument tolerances given these real-world errors will not improve reliability of measurements for many situations.
Analysis and Characterization of Ply Lay-Up in Fiber Reinforced Composites Using Ultrasonic Plate Wave Dispersion Curves
Authors: Rao Navin S. , Balasubramaniam Krishnan 
Published: March 2022

Abstract
In this paper, initial efforts on the characterization of the ultrasonic oblique incidence data to obtain the fiber orientation and ply Lay-up properties of orthotropic symmetry material systems, such as fiber reinforced composites, will be discussed. The acoustical data domain used was the plate wave dispersion curves. The influence of ply-Lay-up ordering in cross-ply symmetric graphite/epoxy laminates on leaky plate wave dispersion curves was studied. The Thomson-Haskell Method was implemented to model the reflection factor behavior of fluid-loaded laminated plates and compute the dispersion curves. Two different types of ply ordering — staggered and inverted — were examined. It was found that the all dispersion modes are sensitive to changes in lay-up sequence. Consequently, it was concluded that stacking sequence identification from leaky plate wave dispersion data is indeed possible, provided accurate experimental and robust combinatorial optimization techniques are used. It is further recommended that Genetic Algorithms can be used as the optimization tool for solving the inverse problem of nondestructively obtaining the ply-Lay-up from experimental oblique incidence ultrasonic data on composite materials.
Evaluation of Elastic Properties of a Functionally Graded Composite Using an Elastic-Impact Technique
Authors: Marur Prabhakar R. , Tippur Hareesh V. 
Published: March 2022

Abstract
An experimental technique for evaluating the elastic properties of functionally graded materials (FGM) is proposed. Ultrasonic pulse-echo measurements in conjunction with elastic impact testing permit determination of Young’s modulus, Poisson’s ratio and their longitudinal variation. The details of the formulation of the technique and the implementation issues are discussed in this paper. These techniques have been applied successfully to evaluate the properties of a unidirectionally graded glass-epoxy particulate composite.
Circular Expansion Chambers With Offset Inlet/Outlet
Authors: Selamet A. , Ji Z. L. , Radavich P. M. 
Published: March 2022

Abstract
The acoustic attenuation performance of circular expansion chambers with offset inlet/outlet pipes is investigated. Two approaches are employed to determine the transmission loss: (1) the three-dimensional computational solution based on the boundary element method (BEM); and (2) experiments on an extended impedance tube setup with expansion chambers fabricated with fixed inlet, outlet and chamber diameters, and varying chamber length to diameter ratios for the different relative locations of the inlet/outlet. The results from the two approaches are shown to agree well. The effect of multi-dimensional propagation is discussed in comparison with the classical treatment for the breakdown of planar wave.
Numerical Methods for Modeling and Optimization of Noise Emission Applications
Authors: Guisset Pierre , Tzannetakis Nikolas 
Published: March 2022

Abstract
This paper presents a unique methodology for applying Numerical Optimization, design of Experiments and Response Surface Model Techniques in conjunction with Finite Element and Boundary Element Models to solve acoustic radiation and transmission optimization problems. Implementations of numerical optimization algorithms, and the finite and boundary element methods along with global design sensitivities are presented. Finally two applications from the automotive industry demonstrate the methodology.
Prediction of Sound Radiation From Vibrating Structures in Motion: Application to Vehicle Pass-By Noises
Authors: Zhou Zhiwei , Wu Sean F. 
Published: March 2022

Abstract
This paper presents an extended Kirchhoff integral formulation for predicting sound radiation from an arbitrarily vibrating structure moving along an infinite baffle. In deriving this integral formulation, the effect of sound reflection from the baffle is taken into account by using the image source theory. Moreover, the effect of source convection motion and that of interaction between motion-induced turbulence and the vibrating surface on the resulting acoustic pressure field are incorporated in the formulation. As an example, this formulation is used to simulate sound radiation from a full-size vehicle driving on an infinite solid ground at various speeds. Sinusoidal forces are assumed to excite the vehicle on its four tires. Vibration responses due to these excitations are calculated using finite element method. Once the normal component of the surface velocity is specified, the radiated acoustic pressure field is obtained numerically using boundary element method. The results show that the effect of source convection motion becomes obvious when the Mach number exceeds 0.1, or equivalently, when a vehicle drives at a speed of 70 mph or higher.
Acoustic Prediction of Sound Insulation Panels Using Asymptotic and Numerical Solutions
Authors: Zhu Jason J. , Coats Timothy J. 
Published: March 2022

Abstract
This paper discusses the basic mechanisms of wave propagation inside sound insulation system based on one modified Biot theory. In particular, this paper concentrates on the determination of the asymptotic solutions to resonance frequencies and on the explanation of the interaction between the structural wave and acoustic wave. Finally, this paper demonstrates a numerical example for simulating sound transmission loss of a three-layer sound insulation system by using SYSNOISE/VIOLINS and compares it with the asymptotic solutions.
A Multi-Purpose Laser Sensor for Cutting Tools
Authors: Ryabov Oleg , Mori Kazuo , Kasashima Nagayoshi 
Published: March 2022

Abstract
This paper presents the application of a laser displacement meter for direct multi-purpose sensing of milling tool conditions. Using a laser displacement meter, a laser beam is projected onto the cutting tool and subsequently reflected. The intensity as well as the angle of the reflected beam are measured. The signals are interpreted for identification of tool geometry, tool whirling, or vibration. Signal processing and analysis depend on the application. A prototype system has been developed to demonstrate the feasibility of various applications, namely, (1) tool setting evaluation, (2) in-process measurement of milling cutter geometry and detection of tool failure, (3) continuous monitoring of milling cutter deterioration, (4) detection and measurement of chatter in milling, (5) measurement of milling tool bending and (6) thermal expansion.
Open Architecture Modular Tool Kit for Motion and Machining Process Control
Authors: Erol N. A. , Altintas Y. 
Published: March 2022

Abstract
An open, reconfigurable and modular monitoring and control system is presented for CNC machine tools. The CNC operating system is a fully integrated an open real-time, preemptive DSP operating system and a Windows NT application. It has vendor neutral architecture, and supports multiple DSP boards and multiple host computers for distributed operation. The system’s transparent communication protocol allows connection between software modules on the same or different DSP boards and host computers. The connections can be set up at runtime via a scripting language. The operating system allows modular integration of new functions developed in C language, and can be reconfigured to control robots, machine tools or processes, using simple script commands. The system can be used as an open architecture, modular operating system for the progressive development of real time signal processing, motion and process control applications running in WINDOWS NT and DSP environments. Sample applications for machine tool control and sensor assisted machining applications are presented.
Prediction of Quasistatic Errors in Three-Axis CNC Machining Centers
Authors: Chen Xiong-Biao , Geddam Aseervadam 
Published: March 2022

Abstract
Quasistatic error sources, which include thermal, mechanical loading and geometric error sources, are responsible for a very large proportion (typically, 70%) of the volumetric errors of a CNC machine tool. This paper discusses the development of a general quasistatic error model for multi-axis CNC machining centers using rigid body kinematics. To predict the quasistatic errors at any position in the workspace, a new method was proposed using the meshing concepts developed in the FEM literature. Finally, the spatial rate of change of the error was analyzed. The model and analysis method can be used as the basis of a compensation scheme as well as in budgeting of errors on a machine tool.
Application Specific Calibration of AE Sensors for Machining Monitoring
Authors: Hundt W. , Scheer C. 
Published: March 2022

Abstract
Monitoring of machining processes by the use of acoustic emission (AE) is a common technique. But the relation between the measured AE signal and the machining process is often not obvious. Here we present a method for the determination of the transfer function of the complete signal path between AE source and monitoring device. The signal acquisition system including the AE sensor can thus be “calibrated”, which allows the scaling of the measured signal in physically interpretable units. The method is specially adapted to the situation found in monitoring of machining, where the sensor position is fixed and the signal path is therefore kept constant.
Automatic 5-Axis CNC Feedrate Selection via Discrete Mechanistic and Geometric Model Integration
Authors: Hemmett Jeffrey G. , Fussell Barry K. , Jerard Robert B. 
Published: March 2022

Abstract
The purpose of this research is to determine the feasibility of automatically generating adaptive feedrates for five-axis CNC end milling. The complicated geometries involved with multiaxis machining make it difficult to manually estimate acceptable feedrates without being overly conservative. Our strategy is to use a computer simulation of the machining process to estimate the feeds based on in-process cutting information. The simulation consists of two distinct portions: a discrete geometric model of the material removal process, and a discrete mechanistic model of the cutting forces involved. The mechanistic model estimates cutting forces as a function of material properties of the stock and cutting tool, cut geometry, and feedrate. Used in an inverse manner, the mechanistic model can estimate the feedrates necessary to maintain a constant cutting force. This force may be selected to maintain a desired part tolerance, or to meet some other criteria (e.g. machine constraints). The cut geometry information required by the inverse mechanistic model is provided by the geometric model of the material removal process. The geometric model also dynamically stores in-process stock geometry as the simulation progresses. The results of this research has shown that it is possible to automatically generate adaptive feeds using these combined models.
Accurate Assessment of Flatness Tolerance Using Direct Search Optimization
Authors: Damodarasamy Sampath , Anand Sam 
Published: March 2022

Abstract
This paper presents a new method for determining the minimum zone for flatness of a point set obtained from a coordinate measuring machine. The two parallel planes that enclose the entire point set with minimum separation form the minimum zone for flatness. In this method, parallel planes are formed through each point in the point set for a range of plane orientations. Simplex search is used to determine the orientation of parallel planes that form the minimum zone. This method is applied to six example point sets and results are compared with other methods.
Thermal Performance Evaluation of VBGA Packages
Authors: Zheng Wen C. , Wu Paul Y. F. , Lan James J. D. 
Published: March 2022

Abstract
Photo-imageable-dielectric (PID) materials and the Micro-filled Via (MfVia) technology are utilized to make the ViperBGA (VBGA), a thermally enhanced BGA package substrate. The thermal performance of the VBGA packages was evaluated by wind tunnel tests of JEDEC standard and FEM simulations. It is shown that the thermal resistance Θja of any given package can be approximated by a rational function of the power level and the airflow speed. One advantage of such expression is that the thermal resistance of the package under any condition can be confidently predicted, and the other is that more reliable numerical predictions can be achieved. This paper also describes how to approach a confident FEM modeling of the wind tunnel tests in terms of heat transfer coefficients and other factors.
Two Test Specimens for Determining the Interfacial Fracture Toughness in Flip-Chip Assemblies
Authors: Yan Xiantao , Agarwal Rakesh K. 
Published: March 2022

Abstract
Two test specimens are developed to measure interfacial fracture toughness in flip-chip assemblies. The specimens consist three layers of silicon chip, underfill and circuit board. Two symmetric edge cracks are embedded along the interface either between the chip and the underfill or between the underfill and the circuit board. The specimens are subjected to four-point-bend loading and critical loads are obtained. Analytical solutions for energy release rate have been derived for these two specimens and used to obtain the toughness from the measured critical loads. These specimens have been used to evaluate material combinations of chip passivation, underfill and solder mask for desired interfacial strength.
Multi-Media Developments for a Laser Processing Curriculum
Authors: Kannatey-Asibu Elijah 
Published: March 2022

Abstract
Under the lasers in manufacturing curriculum development, a two-course sequence has been initiated into our curriculum. The courses, “Principles of Industrial Lasers,” and “Laser Materials Processing,” integrate theoretical and experimental research results in laser processing of materials with the fundamental characteristics of lasers. Each course constitutes three hours of lectures a week. Associated with each course is a required term project that involves modeling or analysis, computer simulation, and experimental implementation.
Towards Predictive Modeling and Optimization of Machining Operations
Authors: Jawahir I. S. , Balaji A. K. , Stevenson R. , van Luttervelt C. A. 
Published: March 2022

Abstract
The objective of this paper is to introduce an applied systems approach for prediction and optimization of machining performance. Current techniques for assessing machining performance are highly localized and traditionally biased towards the work material. An integrated systems approach is proposed for a reliable and consistent assessment of applied machining performance (AMP). Three areas, namely: fundamental modeling, applied modeling and optimization, are focused on. Fundamental modeling entails generic predictive models for machining performance measures (cutting forces/torque/power, tool-wear/tool-life, chip form/chip breakability, surface roughness/surface integrity, part accuracy, etc.). Applied modeling involves application of the generic models to a specific machining system, including the interactions of the three major elements: workpiece, machine tool and cutting tool. The subsequent step of optimization predicts the optimized machining performance (OMP).
Chip Formation When Hard Turning Steel
Authors: Vyas Amitabh , Shaw Milton C. 
Published: March 2022

Abstract
Hard turning of machine parts is a production process that holds considerable promise for the future since it is an effective means of increasing productivity. Instead of machining a product in the soft state, hardening the part by heat treatment, and then providing the required finish and dimensional accuracy by grinding the expensive grinding operation is eliminated. This is possible because of the availability of improved hard tool materials (polycrystalline cubic boron nitride and ceramics), and more rigid machine tools. The nature of chip formation in hard turning is quite different than in more conventional machining. As might be expected, fracture plays a much more important role in the machining of very hard materials. As in all facets of production engineering it is important to identify the key element involved in the operation and to give far less attention to secondary effects that tend to cloud an issue. The objective of this paper is to establish the key action involved in hard turning chip formation and then to develop the mechanics involved as far as possible at the moment.
White Layers and Thermal Modeling of Hard Turned Surfaces
Authors: Chou Y. Kevin , Evans Chris J. 
Published: March 2022

Abstract
White layers in hard turned surfaces are identified, characterized and measured as a function of tool flank wear and cutting speed. White layer depth generally increases with flank wear. It also increases with speed, but approaches an asymptote. A thermal model based on Jaeger’s moving heat source problems (Jaeger, 1942) is applied to simulate the temperature field in machined surfaces and to estimate white layer depth in terms of the penetration depth for a given critical temperature. The analysis shows good agreement with the trend in experimental results. White layer formation seems to be dominantly a thermal process, possibly plastic strain activated; flank wear land rubbing may be a primary heat source for white layer formation. A strong material dependence of surface alteration is also observed.