bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Investigation of Passive Boiling Enhancement Within the Suction-Line Accumulator During Reverse-Cycle Defrost
Authors: Roberts Terrance M. , Nutter Darin W.
Published: March 2022

The heating seasonal performance factor (HSPF) of an air-source heat pump is degraded by the defrost cycle. Investigations have been performed previously which looked at active enhancement within the suction-line accumulator. This paper presents the results of a similar study with the use of passive enhancement techniques in lieu of active. A layer of small 3.6 or 5.0 mm diameter steel spheres was placed at the base of the accumulator and used to increase the rate of refrigerant boiling during the initial few minutes of the reverse-cycle defrost. Components from a 10.6 kW air-source heat pump were used to perform the experimental study.

The accumulator was equipped with a site glass for visualization purposes. Refrigerant-to-water/glycol heat exchangers replaced the refrigerant-to-air heat exchangers and conditions were set to simulate the pre-melt and melt stages of a defrost cycle. Waterside conditions were maintained for the outdoor coil at 0°C and indoor coil at 21.1 °C dry bulb. Overall performance characteristics of particular interest were refrigerant flow rates, compressor power, refrigerant temperatures and refrigerant pressures. Tests with both the 3.6 mm and 5.0 mm diameter steel spheres enhancement showed increased mass and net energy flow rates to the outdoor coil. Compared to baseline tests, peak mass flow rates were increased by up to 16%.
A Numerical Study of Instantaneous Heat Transfer During Compression and Expansion in Piston-Cylinder Geometry
Authors: Catto A. G. , Prata A. T.
Published: March 2022

A numerical analysis of the flow and heat transfer in gas springs is presented. A gas spring is a volume of gas with constant mass confined by a moving piston inside a valveless cylinder. Repeated compression and expansion of the gas in the cylinder causes it to heat up. Although there is a heat transfer to and from the gas at different times during a cycle, there is a net flow of heat out of the gas which is equal in magnitude and opposite in direction to the net work done per cycle on the gas. The net work is not recoverable and is called the hysteresis loss. Furthermore, during compression and expansion the in-cylinder heat transfer is out of phase with the bulk gas-wall temperature difference and the conventional Newton’s law is not applicable. Instead of being proportional to bulk gas-wall temperature difference the heat transfer should also depend on the time derivative of the bulk gas temperature. An understanding of the in-cylinder heat transfer is essential in modeling compressors, internal combustion engines and other reciprocating machines. Gas springing is a starting point in constructing correlations for heat transfer during compression and expansion, and in the present paper the unsteady compressible axisymmetric flow inside the cylinder was modeled using a moving coordinate system and a finite volume methodology. Results for instantaneous temperature, pressure and heat flux are presented and discussed. The existing phase difference between the heat transfer and the gas-wall temperature difference is explored. Available correlations are compared with the numerical results showing that the time variation of the bulk gas temperature plays an important role in the heat transfer, this effect tend to decrease as both the crank shaft speed and the volume ratio increase.
Rocket Noise Propagation
Authors: McInerny S. A. , Wickiser J. K. , Mellen R. H.
Published: March 2022

In this paper, we review known characteristics of rocket noise. These include low peak frequencies, a high radiation efficiency and a large angle of peak directivity relative to that of subsonic and supersonic jets. The extended source region and high temperatures in a rocket plume are discussed. Evidence is presented to support the contention that it is Mach wave radiation from the transonic region of the plume that governs the sound power. We summarize properties of noise measured in the far-field during rocket launches. This high intensity noise is rich in shocks and the time domain data are positively skewed. Far-field noise spectra do not decrease with distance as would be expected on the basis of linear absorption theory. We briefly discuss signal processing techniques that have the potential to better distinguish the unique properties of rocket noise and we explore the idea of using non-linear acoustic propagation codes to better understand these properties. We conclude by soliciting input on the best way to proceed in these research efforts.
Acoustic Scattering by Two Submerged Elastic Spherical Shells: Mutual Validation of the Normal Mode Series and B.E.M. Solutions
Authors: Everstine Gordon C. , Gaunaurd Guillermo C. , Huang Hanson
Published: March 2022

We validate, using a coupled finite element/boundary element computer code, a recently-developed series solution for the structural acoustics problem of scattering from two submerged spherical elastic shells. Although the general purpose computational tools for acoustic scattering have never been restricted to single scatterers, the availability of the series solution provides, for the first time, the mutual validation of both exact and numerical approaches for a multiple elastic scatterer problem. The excellent agreement between the two solutions presented thus allows this problem to be added to the short list of existing benchmark structural acoustics problems possessing an analytic solution. For the purposes of this comparison, the direction of incidence is taken as parallel with the axis joining the two shells. The numerical solution uses the NASHUA code, which couples a finite element shell model of the two shells with a boundary element model of the surrounding fluid. The exact (series) solution is found by expanding in terms of classical modal series and uses the addition theorem for the spherical wave functions. The exact solution requires coupling coefficients that are expressed in terms of sums of products of Wigner 3-j symbols (or Clebsch-Gordan coefficients).
Qualification of the Sound Field in a Metadyne Anechoic Chamber
Authors: Duda John , Hastings Mardi C. , Godfrey Richard D.
Published: March 2022

The results of an experimental performance evaluation of a Metadyne chamber in both full anechoic and hemi-anechoic configurations over the frequency range from 60 to 10,000 Hz are presented. The Metadyne anechoic wedge, a fiberglas-filled wedge fully encapsulated in a perforated metal casing, was developed several years ago as an alternative to conventional fiberglas and foam wedges. The results of this evaluation show that the Metadyne chamber meets or exceeds all acoustic performance requirements for proper free field environmental conditions, noise reduction, and inside ambient levels. They also indicate that free field conditions exist much closer than a quarter wavelength from the wedge tips which allows use of nearly all the chamber volume for measurements. This chamber provides an environment for conducting highly accurate sound measurement tests.
Natural Frequencies and Mode Shapes of Composite Plates or Panels With a Central Stiffening Plate Strip
Authors: Yuceoglu U. , Özerciyes V.
Published: March 2022

The problem of the free flextural vibrations of a rectangular, orthotropic composite plate or panel system composed of an orthotropic base plate and a dissimilar central stiffening plate strip joined by a thin adhesive layer, is studied. In the formulation, both plates are assumed to be dissimilar orthotropic plates in the manner of the Mindlin Plate Theory. The composite plate or panel system has two opposite edges as simply supported while the other two opposite edges can have arbitrary support conditions. First, classical “Levy Type Solutions” are used for the displacements angle of rotations and the stress resultants. Then, the resulting governing equations of the problem are integrated by a “Modified Version of the Transfer Matrix Method”. The mode shapes and corresponding natural frequencies of the composite plate system are studied for “hard” and “soft” adhesives. It was shown that the normal mode shapes and natural frequencies are very much influenced by the adhesive layer material constants. Also, some parametric studies are presented.
Low Velocity Impact Response and Nondestructive Evaluation of Sandwich Composite Structures
Authors: Vaidya Uday K. , Palazatto Anthony N. , Gummadi L. N. B.
Published: March 2022

Composite sandwich constructions offer light weight and high bending stiffness advantages for aerospace and automotive applications among other structures. The use of a hollow truss core or z-fiber pin core is a new concept in sandwich composites, where the core is hollow and accessible, thereby providing space advantages for fuel cells and/or electronic assemblies besides from possessing high shear and axial stiffness. The z-fiber pins are oriented at predetermined geometry’s and penetrate into the laminated facesheets making-up the sandwich composite. In the reference (Palazatto et. al, 1997), the low velocity response of hollow truss core composites with z-fiber pins oriented at 10 degree and 20 degree angles with respect to the facesheets were investigated by us. The current paper presents the post-impact microstructure, ultrasonic and vibration based nondestructive evaluation (NDE) studies and compression-after-impact response accompanied by acoustic emission (AE) testing of these composites.
Low-Velocity Impact Response and Evaluation of Delamination Damage in CFRP Laminates
Authors: Hosur Mahesh. V. , Murthy C. R. L. , Ramamurthy T. S.
Published: March 2022

In the current study, extensive experimental investigations were carried out on quasi-isotropic Carbon Fiber Reinforced Plastic (CFRP) composite laminates simulating low-velocity impact. Laminates made of three different layups were subjected to impact in the range of 3–30 Joules and their transient response were measured in the form of displacement, energy, velocity and load as functions of time. From these parameters estimates were made of the energy required to initiate damage, onset of delamination and consequent generation of multiple delaminations and their growth. Further, the laminates were tested using ultrasonic NDE technique to quantitatively determine both projected as well as layerwise delamination. From the results obtained, for the range of impact energies tested, threshold energy value for different layups was found to vary from 1.655 to 2.132 Joules/mm. Further, BVID (energy level at which damage is barely visible at the point of impact) was found to be 2.5 Joules/mm. Qualitative indications of damage were observed from load-time plots by sudden drops in load. Ultrasonic evaluation further confirmed these indications. Accurate measure of delamination distribution was obtained by processing the raw scan data using image processing technique. Based on the quantitative data obtained an empirical relation between impact energy and delamination was established.
Finite Element Modeling and Photoelastic Analysis of an Integral Armor Under Flexural Loading
Authors: Mahfuz H. , Lokesh B. R. , Das P. S. , Vaidya U. , Jeelani S.
Published: March 2022

A combined Finite Element Analysis (FEA) and photoelastic study is performed on a hybrid composite, integral armor, to investigate its response under flexural loading condition at room temperature. The layered solid brick element, developed on the basis of constant transverse strain distribution through the thickness, has been used to model the complete integral armor. The transverse normal and shear strain distribution through the thickness becomes significant and severe in failure mechanisms, therefore multiple elements are used in the thickness direction to take care of nonlinearity by piecewise representation. Large deformation has been considered in the finite element analysis to account for the non-linearity encountered during the actual test. Photoelastic analysis is conducted on the integral armor to determine the stress-strain distribution through the thickness. A reflection polariscope is used to observe the fringe pattern developed under flexural loading in the photoelastic coating applied on the test specimen surface. Data generated using photoelastic analysis are presented to corroborate the finite element analysis findings, and a comparison in respect of strain behavior is presented. Reasonable correlation between the finite element modeling and photoelastic analysis results has been established.
Combining Adaptive-Passive and Fully Active Noise Control in Ducts
Authors: Kostek Theodore M.
Published: March 2022

Presented in this paper is a hybrid noise control scheme for one dimensional acoustic systems. By-combining fully active noise control with adaptive-passive elements to form a hybrid system, the control effort required for a given reduction in sound pressure level is reduced. The adaptive-passive element is a tunable Helmholtz resonator. While previous work has focused on tuning Helmholtz resonators subjected to pure tone disturbances, this work contains an algorithm which tunes the resonator in the presence of unmeasurable broadband disturbances. Because the disturbance is assumed unmeasureable, the active noise control scheme developed is a fixed filter feedback design (as opposed to adpative feedforward) and uses the dynamics of the acoustic system to achieve performance. Experimental verification is included.
A Formulation of Unequal Impedance Boundary Conditions in Boundary Element Acoustics
Authors: Vlahopoulos Nickolas , Raveendra S. T.
Published: March 2022

The boundary element method (BEM) has been utilized extensively in numerical simulations of engineering acoustics problems. The indirect boundary element formulation (IBEM) allows the simulatneous modeling of the acoustic spaces on both sides of a thin vibrating structure. In order to exploit the full potential of the IBEF a new formulation was developed in this work, allowing the application of separate impedance boundary conditions on each side of the vibrating structure. This situation is often encountered in practical applications (engine enclosures, computer boxes, car bodies, etc.), where noise isolation material is applied on only one side of a vibrating structure.
Overview of Applications for High-Frequency Automotive Noise Prediction Using Statistical Energy Analysis
Authors: Kaminsky Cliff , Bremner Paul , Cimerman Benjamin
Published: March 2022

For all transportation equipment, there is a strong emphasis on reducing weight and cost while improving comfort. Unfortunately, reduced weight is often synonymous with increased sound pressure level (SPL), which is not acceptable from the viewpoint of security and comfort.

In this paper we discuss the application of Statistical Energy Analysis (SEA) to the prediction of noise in vehicles such as passenger cars. After a brief theoretical review of the method, we present simple guidelines for the SEA modeling of automobiles. These guidelines are the result of practical experience in the field, also described here, since SEA is already used at many industrial sites. Finally, we discuss promising new directions in automobile SEA modeling.
An Entropy-Based Index Evaluation Scheme for Multiple Sensor Fusion in Classification Process
Authors: Chen Yubao , Orady Elsayed
Published: March 2022

Sensor fusion aims to identify useful information to facilitate decision-making using data from multiple sensors. Signals from each sensor are usually processed, through feature extraction, into different indices by which knowledge can be better represented. However, cautions should be placed in decision-making when multiple indices are used, since each index may carry different information or different aspects of the knowledge for the process/system umber study. To this end, a practical scheme for index evaluation based on entropy and information gain is presented. This procedure is useful when index ranking is needed in designing a classifier for a complex system or process. Both regional entropy and class entropy are introduced based a set of training data. Application of this scheme is illustrated by using a data set for a tapping process.
A Thermomechanical Model of Machine Tool Spindles for Use in the Design of Reconfigurable Angular Contact Spindle Bearing Load Control Systems
Authors: Gibson Alex O. , Stein Jeffrey L. , Tu Jay F.
Published: March 2022

Thermally induced bearing loads have long been recognized as a key factor impacting the reliability and performance of machine tool spindle systems. This is particularly true for reconfigurable machine tool spindles which may experience a wide range of external loads, processes and spindle speeds. Recent research on a roller bearing spindle has shown that it may be possible to control these loads by controlling the temperature distribution within the spindle housing. As this research focused on thermally induced loads in roller bearings, the bearing load model used was largely limited to a radial heat transfer/thermal expansion model. The purpose of this paper is to present a first step model for developing a methodology for designing bearing load monitoring and control systems for reconfigurable angular contact bearing spindles. The proposed model focuses on the thermally and mechanically induced spindle bearing loads in a back to back angular contact bearing pair that are due to radial and axial thermal expansion as well as the centrifugal forces and moments of the bearing balls. Simulation results demonstrate that the proposed model is capable of predicting the interactions between bearing loads and spindle deflections that are likely to be important in the design of future reconfigurable machine tool spindle bearing load monitoring and control systems.
Integrated Digitizing, Path Planning, and Five-Axis Machining for the Refurbishment of Compressor and Turbine Blades
Authors: Fleisig Robert V. , Spence Allan D.
Published: March 2022

The compressor and turbine blades used in jet aircraft engines wear down due to tip rubbing against the outer shroud. To restore the original shape, these blades must be either replaced, or, more economically, refurbished. Refurbishment of blades is accomplished by applying a weld bead to the tip, followed by removal of excess material. This paper describes an overview of an integrated system for accomplishing the material removal step. The separate tasks of digitizing the blade to obtain original shape information, automatically calculating the tool paths, and machining the blades, are combined into a turnkey system implemented using a five-axis machine tool and attached personal computer. Experimental results demonstrate the capability of the system for sample blade shapes.
PC Based Open Architecture Machine Tool Control
Authors: Bailey T. E. , Renton D. D. A. , Elbestawl M. A.
Published: March 2022

This paper describes the design and implementation of a PC based Open Architecture machine tool controller. The PC based OAC is based on a distributed, peer to peer functional model of the entire machine controller system. Machine motion and I/O functionality is provided by a machine server module. The machine server is designed to provide a uniform interface, and layer of abstraction, for user applications to all machine services. A PC based motion and I/O solution was designed to provide an open, standard interface to the machine. The overall cost / performance ratio of the PC based OAC makes it an attractive alternative to conventional machine tool control technologies. Intelligent process monitoring and control strategies are implemented with the OAC on a 3-axis machining centre. Power, force, and vibration monitoring and control applications are discussed in this paper.
Active Structural Control of Vertical Turning Lathe Vibrations
Authors: Miesner John E. , Ghanadan Reza , O’Regan Stephen D.
Published: March 2022

An active control system has been developed to suppress tool vibration on a Vertical Turning Lathe (VTL). This system reduced surface roughness by two-thirds and raised by 23% the metal removal rate achievable before the onset of chatter. The system mechanical and sensor portions are contained completely within the VTL ram envelope. The electronic components are in a separate enclosure which also provides a simple user interface. Accelerometers embedded in the VTL ram sense the ram motion in two directions. Signal conditioning and integration electronics pass the ram velocity to the digital controller which computes the forces needed to reduce the tool tip motion error. Control signals are input to highly-efficient switched-capacitor amplifiers which drive high-force electrostrictive actuators to deliver the required forces in two directions. The controller also executes the system identification programs and tracks the ram length to compensate for resonance changes.
Prediction of Shear Angle in Oblique Cutting With Maximum Shear Stress and Minimum Energy Principles
Authors: Shamoto Eiji , Altintas Yusuf
Published: March 2022

A new shear angle prediction law is proposed for oblique cutting operations. Assuming a thin shear zone model, the oblique cutting mechanics are described by the five angles which show the directions of shear, resultant cutting force and chip flow. Five expressions required to solve the unknown angles are derived from the kinematics of oblique cutting and the physical law of deformation, i.e. either Maximum Shear Stress or Minimum Energy Principle. Unlike the previous solutions which require intuitive or empirical assumptions, the proposed methods use only the tool geometry and the material properties, i.e. shear yield stress and average chip-rake face friction coefficient. The predicted angles and forces agree well with the empirical and experimental results reported in the literature. Furthermore, the proposed models are experimentally verified in predicting forces for practical oblique helical end milling operations.
Development of a Magnetostrictive Torque Sensor for Milling Process Monitoring
Authors: Ohzeki Hiro , Mashine Akihiro , Aoyama Hideki , Inasaki Ichiro
Published: March 2022

This paper deals with a sensor system based on the magnetostrictive effect, which is installed in a tool holder, for sensing cutting torque in order to monitor the milling process. Changes in the magnetic permeability of ferromagnetic alloy layers formed onto a rotating shaft due to torque are detected by coils as changes in impedance without contacting the rotating shaft. By mounting the magnetostrictive sensor on a tool holder, it became possible to detect cutting torque as close to the cutting point as possible. The accuracy of the proposed sensor system was confirmed through static and dynamic evaluation tests. In order to investigate the relationship between tool failure and cutting torque, side milling tests were performed, which bore out the possibility of estimating flank wear and tool fracture from the cutting torque detected by the proposed sensor system.
A Statistical Study of Factors Affecting Surface Finish in Five-Axis Machining
Authors: White Keith A. , Jensen C. Greg , Helquist Chuck , Smalley Troy
Published: March 2022

A statistical study of factors affecting the surface finish of parts machined on a five-axis mill was performed. The study was a 23 full factorial experiment. The following factors and levels for each factor were selected: cutter type (flat and filleted end mill), feedrate (12 and 20 inches per minute), and angle of inclination (7 and 15 degrees). All factors were statistically significant. Cutter type was the factor which most significantly affected surface finish, followed by feedrate, and angle of inclination. The effect of cutter type was more than four times greater than the other factors. All two-way interactions were also found to be significant, with the magnitude of the interactions involving cutter type approximately four times greater than the interaction between feedrate and angle of inclination. An acceptable mathematical model for predicting surface finish based on these factors was obtained which can be used in five-axis machining research and applications.
Improving the Accuracy of Microscopic Laser Interferometry System for Precision Surface Measurement by Integrated Scanning Motions
Authors: Moon Kee S. , Wang Yiding
Published: March 2022

A new technique for improving the accuracy of microscopic laser interferometry system for precision surface measurement is presented. Laser interferometry creates a fringe pattern which contains information about the surface texture of the specimen and the method provides nanometer resolution for height axis of the reconstructed surface. The resolutions of the lateral axes of the surface, however, relies only on optical magnification capability of the measurement system and this often results in poor resolution. This paper presents a new technique to improve the interferometric system resolution in lateral axes. This method is based on an integrated scanning motion of the specimen and the obtained multiple sets of scanned data are processed to improve the lateral axes resolution. Computer simulations show that the proposed method can be an effective approach to improve the resolution in the lateral axes for commonly used laser interferometric system. It provides a new principle for the design of modern laser interferometric measurement instruments.
Microstructural Effects on the Machining Performance of Dental Ceramics
Authors: Le D. T. , Qi Lixun , Zhang Guangming , Ng Stanley J.
Published: March 2022

Constraints of mechanical, thermal, and chemical properties are making ceramics the material choice for industrial and dental applications. The quality of a machined surface of ceramics is fundamentally dependent on the response of the material to the machining process. This paper presents a combined analytical and experimental study with focus on optimizing the machining performance of dental ceramics — DICOR/MGC — with three distinguished microstructures. The study starts from analyzing the microstructural characteristics to searching for the machining conditions that provide satisfactory performance in terms of acceptable flexural strength. Evidence gained from the cutting force measurements and evaluation of fracture strength degradation indicates that the control of micro-scale fracture formed on the machined surface, with microstructural characteristics being considered, is the key factor which dominates the machining performance.
Current Deburring Methods Used in Industry
Authors: Gillespie LaRoux K.
Published: March 2022

Deburring involves several aspects often overlooked. While over 100 deburring processes exist there is still no universally accepted definition of what the term “deburred” really implies. Deburring and edge standards are available, but are often ignored. The functional requirement probably is to finish edges as opposed to just deburr. Environmental, health and safety issues are important considerations in the selection and use of any edge finishing process. Many of the deburring processes are still laboratory curiosities at this time.
Investigation of the Lead-On-Chip Package’s Reliability
Authors: Tsao P.-H. , Chang L. C. , Chen T. C. , Haung Chender , Chen C. Z.
Published: March 2022

An assembly test chip (ATC), consisting of varieties of test structures, had been utilized to monitor the package integrity of SOJ lead-on-chip (LOC) packages after various reliability tests. Two different types of epoxy molding compounds, namely biphenyl and EOCN epoxies, were chosen to investigate their effects on package’s reliability. After the reliability tests, silicon chip crack was observed in three test samples due to the existence of a large chip backside chipping (−120 μm). Qualitative study about this failure mechanism was carried out by a finite element analysis, and it was found that, due to the higher flexural modulus and CTE of the biphenyl epoxy, the thermally induced stresses developed in the chip encapsulated by this epoxy during reliability tests were more likely to cause the crack propagation in the silicon chip than those induced by using EOCN type epoxy.
Wafer Surface Measurements Using Shadow Moiré With Talbot Effect
Authors: Wu S. , Wei S. , Kao I. , Chiang F. P.
Published: March 2022

In this paper, a modified shadow moiré technique is applied to measure surface topology of wafers. When a wafer is sliced, either by an inner-diameter (ID) saw or wiresaw, the surface needs to be measured to ensure the consistency of quality. Two important characteristics of the wafer surface measurements are the warpage and total thickness variation (TTV). Currently, the most commonly used method of wafer measurement employs a pair of capacitive measuring probes which sample points on the surface of a rotating wafer to obtain the contours of surface. Many sampling points on the surface are needed for more accurate measurements; however, this will require more time for the inspection of wafers during production. An innovative alternative for full-field, whole-wafer measurement is developed using a laser light source and the modified shadow moiré technique. This methodology enables one to examine the whole wafer surface quickly and simultaneously. In this study, a 1000 lines/inch reference grating is employed as the standard to create a shadow moiré pattern. In addition, the Talbot effect is utilized to adjust the gap, or the so-called Talbot distance, between the grating and the wafer surface such that a fringe pattern of good quality can be obtained. By using the phase shifting technique, the resolution (or sensitivity) can be enhanced by two order of magnitude. The results show that not only the full view of whole wafer surface can be obtained, but also enhanced surface resolution and accuracy can be realized. In addition, warpage due to excessive residual stresses can be observed distinctly with fringe patterns because of the global and interconnected moiré fringes. This process is faster, especially when dealing with wafers with diameter larger than 200mm (8″). Experimental results of both 200mm single crystalline and 100 × 90mm polycrystalline wafers are presented. The system can also be fully automated to become an on-line inspection tool.
Constitutive Modeling of Polymer Films From Viscoelasticity to Viscoplasticity
Authors: Qian Zhengfang , Lu Minfu , Liu Sheng
Published: March 2022

A unified constitutive model for polymer films is proposed with viscoelastic characterization at small deformation and viscoplastic characterization at large deformation, based on molecular chain deformation mechanisms. The evolution equations and the temperature dependence of drag stress and back stress are well established from molecular network theories. The material constants are then determined by master curves and a consistent procedure. The excellent agreement between experimental data of polycarbonate film tests and model predictions is achieved.
Prediction of the Solder Joint Configuration Under Various Geometric Parameters
Authors: Chen Wei-Long , Shyu Bor-Lin , Chiang Kuo-Ning
Published: March 2022

Prediction of the shape of solder joint has drawn special attention in the development of electronic packaging for it’s practical engineering application. Many solder joint models have been developed based on energy minimization principle or analytical method. These methods are extensively utilized to the shape design of solder joint. However, one would find It is important to find a suitable method in real case application. In this study, numerical methods used to predict the shape of solder joint are investigated and compared. The change of geometric shape with respect to different parameters of solder joint are also discussed in this paper. The influence of the geometric parameters such as volumes of solder joint, package weight, contact angles, pad sizes, solder surface tension, and gravity forces to the shape of solder joint are investigated. Results presented in this study can be used to determined the optimal balanced stand-off height of Single Ball Module (SBM) or Multiple Ball Module (MBM) solder joint models.
Evaluation of Interfacial Fracture Toughness of a Bi-Material System Under Thermal Loading Conditions
Authors: Wang Jianjun , Zou Daqing , Liu Sheng
Published: March 2022

In this paper, the interfacial fracture toughness of a bi-material (molding compound/silicon) specimen subjected to a series of thermal loads was evaluated using a high density laser moiré interferometry coupled with FEA technique. The moiré interferometry technique was used to monitor and measure the crack length during the test. A finite element technique was simultaneously used to determine the near crack tip displacement fields of the bi-material specimen. The interfacial fracture toughness and phase angle were computed by using these near tip displacement variables through the analytical energy release rate and phase angle expressions derived by authors. The results show that the interfacial fracture toughness of the bi-material specimen considered is strongly related to the phase angle in terms of the defined phase angle expression in this paper. The interfacial fracture toughness Gc and the phase angle ϕ of the tested bi-material specimen at the interface corresponding to the crack length a = 3.0mm under the temperature rise thermal load from room temperature (20° C) to 120° C are 13.64 J/m and −54.28° respectively, while the interfacial fracture toughness Gc and the phase angle ϕ of the tested bi-material specimen at the interface of the molding compound/silicon with the crack length a = 3.3mm under the temperature rise thermal load from room temperature (20° C) to 138° C are 20.02 J/m2 and −54.8° respectively.
Interactive Tutorials on Manufacturing Processes Using Java™
Authors: Klamecki Barney E.
Published: March 2022

A series of tutorials describing some engineering science concepts underlying the development of manufacturing process models has been developed. The tutorials are available over networks so that access is easy. There are two unique aspects of the tutorials. One is the use of computer-independent software so that interactive exercises run on the user’s computer. This makes for fast response to user input and so useful interactive exercises are possible. The other different aspect is the presentation of process models in a non-typical way. Interactive exercises which call for the user to vary process parameter values, observe the effects on process performance and deduce the form of the process model are used. An example of one such computer-based tutorial is described — chip formation in machining. A world wide web location of the tutorial is provided so that individuals can use and evaluate the approach taken to presenting engineering science concepts and process models, http://www.menet.umn.edu/klamecki.
Manufacturing Engineering Education Through Industry/University Cooperative Research: Issues, Challenges, and Strategies
Authors: Lee Jay
Published: March 2022

Today’s globalized manufacturing enterprise necessitates a new imperative for the academe to generate internationally astute engineers to enable manufacturing companies to collaborate in a global market in the 21st century. This paper presents author’s perspectives on manufacturing engineering education system in a changing world. First, issues, challenges, and strategies are discussed. Second, various industry/university cooperative research models in the US, Japan, Germany, and Taiwan are examined. Finally, challenges in education system and research collaboration in moving the innovation to a global marketplace is addressed.
Video Based Manufacturing Courses for Electronics
Authors: Fillo John A. , Sahay Chittaranjan , Srihari Krishnaswami
Published: March 2022

Two product-oriented manufacturing courses, Printed Wire Board Manufacturing and Processes for Electronic Manufacturing have been developed. The mode of delivery is original and unique, pairing manufacturing experts from industry and university faculty to develop video based instructional materials based on real industrial operations and processes. The final product is a new generation of “text books” in the form of video modules for the rapid dissemination of dynamic types of information as encountered in manufacturing. The goal is to educate both defense and commercial sectors to current practices in packaging manufacturing as well as those students who will make up the next work force.
Teaching Manufacturing and Design for Manufacturability to Mechanical Engineering Students
Authors: Nesbit Steven M. , Comer Jess J.
Published: March 2022

The Department of Mechanical Engineering at Lafayette College has implemented an innovative manufacturing laboratory course as part of its mechanical design sequence to give its students a basic understanding of engineering design and the influence of manufacturing in the design process. The course, which is required for all junior mechanical engineering students, teaches basic manufacturing skills and concepts, and design for manufacturability. The laboratory is co-taught by the mechanical engineering faculty and the engineering technicians. The course takes a hands-on approach to teaching these subjects and incorporates two interrelated projects; the manufacture of a pre-designed mechanical system, and the design, manufacture, evaluation, and competition of a semester long design project. This paper discusses the format of the course, the two projects, the role of the faculty and engineering technicians, and how these fit together to create an effective learning experience.
Manufacturing Processes Course With Emphasis on Modeling, Experimentation, and Design
Authors: Moller James C.
Published: March 2022

A sophomore-level Manufacturing Processes course is described. It is the second course in a Design for Manufacturing sequence in the Manufacturing Engineering degree curriculum. Emphasis is placed on prediction of manufacturing results prior to lab sessions to build student confidence with process modeling as well as an understanding of the relations among process conditions and part attributes. The laboratory experience focuses on understanding processes by rational selection of conditions and measurement of attributes for a variety of conditions. The course culminated with a process design project in which teams manufactured product components to be assembled in a subsequent course.
A Continuum Mechanics Model to Predict Shear Angle and Cutting Forces in Orthogonal Cutting
Authors: Zheng Y. , Sutherland J. W. , Olson W. W.
Published: March 2022

The mechanics of the orthogonal cutting process are examined. Under an assumed streamline and shear plane curvilinear system, the Eulerian strain and strain rate tensor in the primary deformation zone are obtained analytically. When the material behavior is dependent on strain, strain rate and temperature, the temperature distribution in machining is numerically estimated using an iterative incremental method. The results obtained are compared with those from the classical shear plane theory. The shear angle as a function of undeformed chip thickness and cutting velocity, and cutting forces in orthogonal cutting are predicted by the total work minimization principle and are seem to agree with the experimental results from the literature.
Dynamic Indentation Hardness of Metals and its Implications to High Speed Machining
Authors: Subhash Ghatu , Koeppel Brian J. , Chandra Abhijit , Huang Yonggang Y.
Published: March 2022

A novel experimental technique for determining the dynamic indentation hardness of materials is described. Unlike the traditional static hardness measurements, the dynamic hardness measurements can capture the inherent rate dependent material response that is germane to high strain rate processes such as high speed machining and impact. The current technique also offers several advantages over the existing dynamic hardness testers. The dynamic hardness of several commonly used engineering materials is found to be greater than the static hardness. The percentage increase in dynamic hardness over its static counterpart is found to be strongly dependent on the crystal structure of the materials used in this study. The significance of dynamic hardness and its implications on high speed machining characteristics of metals is explored.
A Simulation System for Feasibility Study of Single Set-Up Fixtures in Milling and Drilling
Authors: Li Xiaoping , Nee Andrew Y. C.
Published: March 2022

Single set-up fixtures in milling and drilling processes are usually desired because of its high efficiency. One of the main difficulties in designing such fixtures is to estimate the deformation corresponding to the processes under consideration. In this aspect, theoretical calculation of the workpiece deformation has hardly been achieved due to the complication caused by interactions between the cutting forces and clamping forces on the workpiece. Traditionally the workpiece deformation under a fixture is estimated approximately based on the designer’s experience. In this paper, a system for simulation of workpiece deformation in end milling and drilling processes is developed. In the system, from a given plan of fixture setup and machining conditions, the cutting forces and clamping forces acting on the workpiece are firstly predicted using theoretical and empirical models, then the corresponding deformations throughout the workpiece are calculated from the forces and workpiece material properties using the finite element method. As a case study, the system is used to investigate workpiece deformation in end milling a slot and drilling a hole on a workpiece with different configurations of single set-up fixture. It is shown that by using the simulation system the effect of different configurations of single set-up fixture on the deflections of the workpiece can be accurately estimated. In this way the feasibility of a single set-up fixture design can be studied and the design can be optimized on a scientific basis.
Automated Modular Fixture Planning: Accuracy, Clamping, and Accessibility Analysis
Authors: Wu Yufeng , Rong Yiming (Kevin) , Ma Weidong , LeClair Steven R.
Published: March 2022

Automated fixture design has become a research focus in process planning and CAD/CAM integration. An automated fixture configuration design system has been developed where when fixturing surfaces and points are specified, modular fixture components can be automatically selected and placed into position with satisfying assemble conditions. A geometric analysis has been conducted to determine the fixturing surfaces and points which provide feasible geometric constraints and assembly relationships with modular fixtures. This paper presents analyses on fixturing accuracy, clamp planning, fixturing accessibility, and clamping stability. When a fixture planning is determined, the analysis results can be applied to verify the performance of the fixture design.
A Systematic Approach for Fixture Design and Analysis: A Workholding Illustration of Truck Differential Carrier
Authors: Hou Jiang Liang , Trappey Amy J. C.
Published: March 2022

Many factors such as process planning and fixture design contribute to the machining quality of products. Based on the determined operating sequences and the corresponding cutting path and force distribution, fixture design and analysis are proceeded. Further, the result of fixture design and analysis can provide additional information or constraints to be fed-back to the process planning so that the process can be further improved. In this paper, fixture planning of a truck differential carrier is taken as a case study to illustrate how the fixture design and process planning act interactively. By finite element analysis and loading-strain experiments, we explore the effects of fixture system and the dimensional variation of workparts on machining accuracy. The deformation effects of fixturing force are analyzed so that the process planning can be modified for more accurate machining. Moreover, in fixture hardware design, the functional behavior of fixture is verified to ensure the functional requirements are satisfied. Combining the computer-aided engineering (CAE) with experimental verification, this paper presents a systematic approach of fixture design to ensure the workholding accuracy and reliability.
Optimal Selection of Tooling and Cutting Conditions for End Milling Using Microgenetic Algorithms
Authors: Strenkowski John S. , Wei Yi-Min
Published: March 2022

In this paper, a new method is presented for the optimal selection of cutting tools and operating conditions for end milling. An end milling model developed by Armarego is used to determine the cutting forces and power. This model is coupled with a microgenetic algorithm to determine the optimal tooling and operating conditions. Unlike other more conventional optimization techniques, genetic algorithms can be used for discrete data. In this paper, the optimal tool is identified from a manufacturer’s catalog of milling cutters along with the optimal speed and feed to achieve both minimum production cost and minimum production time criteria. In addition, constraints are imposed on the cutting speed, feed, maximum cutting force, and available power to simulate realistic machine tool constraints.
Correlation of Measured Shoe Forces and Surface Quality in Centerless Grinding
Authors: Monahan Richard W. , McFarland D. Michael
Published: March 2022

The objective of this research was to experimentally study the forces imparted on the workpiece during a typical shoe centerless grinding cycle on a flat (unprofiled) outer diameter. The data obtained provide insight into the forces developed between the machine structure and workpiece during both idling and steady-state grinding. These workpiece-machine structure interactions involve the grinding wheel, support shoes, and magnetic driver plate. The influence of the work-piece rotational center offset on the resultant shoe forces was examined by varying the workpiece rotational center relative to the fixed rotational center of the magnetic driver plate. The magnitude and direction of the resultant force and its effect on the final workpiece surface finish quality were examined.
Improving Gear Profile With an Electroplated CBN Wheel for High Accuracy Gear Profile Grinding & the Development of a Truing Machine for High Accuracy Wheel Grinding
Authors: Masaki Ryuzo , Nagata Hiroshi , Hisada Jiro
Published: March 2022

Load capacity of gears could be remarkably improved by making their tooth surface roughness smaller than 1μm Ry. In order to produce such gears, the authors developed a precision CNC gear grinding machine of the forming type. The shortcomings in using the above grinding machine was that the productivity of grinding with a conventional wheel was low, and the layer below the ground surface was occasionally damaged by a residual tensile stress.

Consequently, to supplement the precision grinding process, the authors also developed a microtruing machine which creates a high accuracy profile and a uniform grain height of the electroplated cBN grinding wheel.

The machine realized an axial stiffness of 300N / μm on the wheel spindle, and a positioning accuracy of about 50 ran. A conventional wheel was microtrued on the microtruing machine and tested for grinding a gear. The gear profile error, was 1 μm.
Chatter Suppression via an Oscillating Cutter
Authors: Yang Fulun , Zhang Bi , Yu Junyi
Published: March 2022

Chatter is one of the critical issues in a machining process since it deteriorates the surface quality of a workpiece and reduces machining efficiency. A new method is developed to suppress chatter in which an oscillating cutter is used to machine the workpiece through a stepping motor and a transmission mechanism so as to vary tool rake angle continuously and periodically in process. Theoretical analyses are performed on the stability of the cutting system, and verified by the experimental studies. Both theoretical analyses and experimental results indicate that the method can suppress chatter effectively. With the application of an oscillating cutter, the amplitude can be reduced by 80% in cutting a steel workpiece.