bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Chip Morphology in Hard Turning Using Constitutive Models and Material Property Data
Authors: Poulachon Gérard , Moisan Alphonse L. , Jawahir I. S. 
Published: November 2021

Abstract
Modelling of machining operations requires the use of constitutive relations which could represent as close as possible the material behavior in the primary and secondary zones. The knowledge of these behavior laws involves the use of different types of sophisticated mechanical tests which should provide with sufficient accuracy the material behavior for the relevant conditions of machining. In this paper, firstly, the flow stress of 100Cr6 (AISI 52100) bearing steel in its HV730 hardness state has been identified in order to assess the machinability in case of hard turning. With this, the dependence of the flow stress on strain, strain-rate and temperature, which poses significant difficulty, is presented. Secondly, the material machinability is evaluated with a shear instability criterion, enabling the prediction of chip formation with or without the shear localization. Quick-stop tests have been carried out on the bearing steel treated at different hardness values showing the chip formation variation. Micro-hardness tests performed on these quick-stop test samples show the effects of cutting temperature. A greater understanding of applied machinability is gained through this precise study of work material physical properties and behavior.
Extension of Oxley’s Analysis of Machining to Use the Johnson-Cook Material Model
Authors: Adibi-Sedeh Amir H. , Madhavan Vis , Bahr Behnam 
Published: November 2021

Abstract
The aim of the present work is to extend the applicability of Oxley’s analysis of machining to a broader class of materials beyond the hot rolled low-carbon steel used by Oxley and coworkers. The Johnson-Cook material model has been chosen to represent the mechanical properties of the material being machined as a function of strain, strain rate and temperature. Necessary changes have been made to Oxley’s analysis to make it self-consistent for this material model. A new approach has been introduced to calculate the pressure variation along the beta slip lines in the primary shear zone including the effects of both the strain gradient and the thermal gradient along the alpha lines. The shear force along the primary shear zone is calculated in a consistent manner using the energy dissipated in this zone. The thickness of the primary and secondary shear zones, the heat partition at the primary shear zone, the temperature distribution along the chip-tool interface and the shear plane angle are all calculated using Oxley’s original approach. Two constants are used to fine tune the model — the strain in the chip material at the chip tool interface (εint), and the ratio of the average temperature to the maximum temperature at the chip-tool interface (ψ).
The performance of the model has been studied by comparing its predictions with experimental data available in the literature for aluminum 2024-T4. It is found that the model accurately reproduces the dependence of cutting force as a function of depth of cut and cutting speed. The shear plane angle predicted is smaller than that observed in practice. It is also observed that the constant ψ needs to be very small, implying very little increase in the temperature along the chip-tool interface. The model is highly nonlinear in the constant C that relates the length of the primary shear zone to its thickness.
Investigation Into the Tube-Bending Process by Using Elastomer
Authors: Zeng Yuansong , Li Zhiqiang 
Published: November 2021

Abstract
A tube-bending process is presented in the paper, in which an elastomer is employed as an internal pressure transmitting medium. Finite element method is applied to simulate the forming process. Numerical results show that the internal pressure and the friction condition play an important part during the bending process. Experimental research was also performed. It is found that the numerical results are in good agreement with the experimental values, and an aluminum alloy tubular component with relative bend radius equal to 1 was manufactured without wrinkling and fracturing.
An Experimental Investigation of Necking in Thin Sheets
Authors: Tong Wei , Zhang Nian 
Published: November 2021

Abstract
Due to its simplicity in instrumentation and data analysis, uniaxial tensile tests are commonly used for determining the plastic stress-strain relation of a sheet metal. However, the tensile stress-strain data obtained using the standard procedure is valid only up to the moderate strain level just before the onset of diffuse necking in the specimen gage section. Once the diffuse necking starts, the plastic deformation of the specimen becomes increasingly non-homogenous within the necked region. Questions arise regarding the validity of extrapolating the uniaxial stress-strain data to very large strains when one analyzes the forming failure of the sheet metal. Here an experimental technique and the related application procedure for obtaining rate-dependent, anisotropic, tensile stress-strain data of sheet metals at large strains up to fracture are described. Detailed plastic strain mapping results of a tapered commercially pure titanium thin sheet specimen are presented to characterize necking of the thin sheet. A brief discussion of a hybrid experimental and numerical methodology for estimating the strain hardening, strain rate sensitivity, and plastic anisotropy of sheet metals at large tensile strains is given. Preliminary results on necking in aluminum alloys, copper alloys, and low-carbon steel thin sheets are also presented.
Formability Enhancement for Tailor-Welded Blanks Using Blank Holding Force Control
Authors: He Sijun , Wu Xin , Hu S. Jack 
Published: November 2021

Abstract
Tailor-welded blanks (TWB) are widely used for stamped auto panels because of their great benefits such as weight and cost reduction. However, the weld line in a tailor-welded blank causes serious concerns in formability because it induces material discontinuity and additional inhomogeneous stress/strain distribution. This paper proposes a blank holding force (BHF) control strategy to control the weld line movement, distribute the deformation more uniformly and improve TWB formability. The control methodology is developed based on a simplified 2-D sectional analytical model that estimates the stress/strain distribution and the required BHFs for each side of flange with dissimilar materials. The model can be further extended to 3-D by superimposing the 2-D sectional analysis results around the entire binder ring and thus determining required BHF for the whole panel. Finite element simulations are performed to study the effects of forming parameters on the weld line movement. Experiments have been conducted to verify the analytical model and partial finite element simulations. Both analysis and experiments demonstrated that a lower BHF should be applied on the thicker blank side to allow more metal to flow in for obtaining more uniform strain distribution. The proposed BHF control is proven to be a good solution to enhance TWB formability.
Plastic Deformation of a Perforated Sheet With Non-Uniform Circular Holes Along the Thickness Direction
Authors: Chen Fuh-Kuo , Lee Yi-Che 
Published: November 2021

Abstract
For a perforated sheet with circular holes, used in shadow masks, the diameter of the circular hole varies through the thickness, and the non-uniform circular holes are arranged in a triangular pattern. In order to simplify the analysis, a perforated sheet with equivalent circular holes of uniform diameter is proposed such that its plastic behavior is similar to that with the given non-uniform circular holes. In this study, a yield criterion is discussed for the perforated sheet with uniform circular holes by employing an equivalent continuum approach, which is then applied to examine the plastic deformation of the perforated sheet with non-uniform circular holes. The analytical results predicted by the theory, including those for the apparent yield stresses and strain ratios, are verified by the results obtained from the finite element analysis and also from experiments.
A New Forming Limit Criterion and Ductile Fracture Prediction in the Forging of Sintered Powder Preforms
Authors: Huang Cheng-Chao , Cheng Jung-Ho 
Published: November 2021

Abstract
The main purpose of this study is to investigate the forgability of sintered powder compacts, including the void evolution and fracture prediction in the forming process. A new ductile fracture criterion for porous media is developed based on the maximum principal strain energy per unit of volume. It demonstrates that the strain energy density is governed by the maximum principal stress in material. Fracture will occur as the accumulation of strain energy density reaches the critical value at that point.
Experiments and Finite element analysis were conducted to establish the models. The material properties of sintered porous preforms were obtained from both the uni-axial tension and compression tests. The finite element models were verified with experiments of upsetting under different frictional conditions. Studies show that the results by the new criterion are more compatible with the experimental data than other previous forms. In addition, voids lead to the degradation of the strength and workability of materials. Friction contributes to the non-uniformity of deformation and density variation that causes the workpiece to fracture.
The 2000 CASA/SME University Lead Award Winning Joint Engineering/Business Masters in Manufacturing Program at Penn State
Authors: Ruud Clayton O. , Hottenstein Michael P. , Winkelblech Cindy K. 
Published: November 2021

Abstract
A unique, new joint graduate program in manufacturing engineering and management, was introduced in the fall of 1996 at Penn State. It is an integrated two-semester academic program created at the request of, and with the cooperation of industry. The creation was a joint effort of faculty from the Colleges of Engineering and Business. The courses were all developed specifically for the program, are all required, and taken in lock-step by each class cohort. Faculty members from both colleges teach in the program, often with both being present in the classroom to provide continuous integration of course material. The students have backgrounds in business, engineering, science, and industry and are selected to provide diversity in each cohort class. The degree awarded is a Masters of Manufacturing Management (MMM).
This paper describes the founding principles and curriculum of the program and provides profiles of the five classes of students that have graduated.
Experimental Study of Forming Rene95 Alloy Parts by Laser Cladding
Authors: Deng Qilin , Hu Dejin , Pei Jingyu , Zhang Wenwu , Yao Y. Lawrence 
Published: November 2021

Abstract
In this paper, experimental study of forming metal parts by laser cladding Rene95 alloy powder was reported. The influence of main process parameters, such as laser power, scanning speed and laser beam diameter, on the thickness, width and the angle of the laser cladding track was investigated. The microstructures of laser cladding parts were studied and compared with those of common casting parts. The obtained Rene95 metal parts formed by laser cladding are dense and of high strength.
Laser-Assisted Machining of Reaction Sintered Mullite Ceramics
Authors: Rebro Patrick A. , Shin Yung C. , Incropera Frank P. 
Published: November 2021

Abstract
The present study focuses on the evaluation of the laser-assisted machining (LAM) of pressureless sintered mullite ceramics. Due to mullite’s low thermal diffusivity and tensile strength, a new method for applying laser power is devised to eliminate cracking and fracture of the workpiece during laser heating. The LAM process is characterized by means of cutting force and surface temperature measurements for a variety of operating conditions. Estimated material removal temperatures and the ratio of the feed force to the main cutting force are used to determine material removal mechanisms and regimes for brittle fracture and semi-continuous and continuous chip formation. Surface roughness and subsurface damage are compared for typical parts produced by LAM and grinding. Tool wear characteristics are investigated for variations in laser power, and hence material removal temperature, during LAM of mullite with carbide tools.
Residual Stress Reduction by Pulsed Magnetic Treatment
Authors: Klamecki Barney E. 
Published: November 2021

Abstract
Residual stress relief by pulsed magnetic treatment is attractive since the process is carried out at room temperature and magnetic fields that are easy to produce and control can be used. The extent of residual stress reduction due to a particular pulsed magnetic treatment was determined. Initially curved strip specimens were held flat to produce a known residual stress and then subjected to a pulsed magnetic treatment. Microhardness measurements before and after treatment and a mechanical model relating stress and indentation size were used to specify the change in residual stress due to pulsed magnetic treatment. Changes of stress near the surface of the specimens due to treatment were obtained. Reductions of residual stress of 4%–7% were obtained for the particular pulsed magnetic treatment used on lower initial stress level specimens. For a higher initial stress level stress reductions of 8%–13% were measured.
A Wafer Transfer Technology for MEMS Adaptive Optics
Authors: Yang Eui-Hyeok , Wiberg Dean V. 
Published: November 2021

Abstract
Adaptive optics systems require the combination of several advanced technologies such as precision optics, wavefront sensors, deformable mirrors and lasers with highspeed control systems. The deformable mirror with a continuous membrane is a key component of these systems. This paper describes a new technique for transferring an entire wafer-level silicon membrane from one substrate to another. This technology is developed for the fabrication of a compact deformable mirror with a continuous face sheet. A 1 μm thick silicon membrane, 100 mm in diameter, has been successfully transferred without using adhesives or polymers (i.e. wax, epoxy, or photoresist). Smaller or larger diameter membranes can also be transferred using this technique. The fabricated actuator membrane with an electrode gap of 1.5 μm shows a vertical deflection of 0.37 μm at 55 V. The proposed technique has the following benefits over those previously reported: 1) No post-assembly release process (e.g. using HF) is required, and no wax, photoresist, or epoxy is used for the transfer purpose 2) The bonded interface is completely isolated from any acid, etchant, or solvent, which ensures a clean and flat membrane surface. 3) It offers the capability of transferring wafer-level membranes over deformable actuators.
A New Assembly-Transferred Microwave Switch With Suspended CMOS-Compatible Coplanar Waveguides
Authors: Chen Jen-Yi , Huang Long-Sun , Chu Chia-Hua , Li I-Yin , Kuo Yao-Hui , Chang Peizen 
Published: November 2021

Abstract
The paper reports a new, transferred micromachined microwave switch on top of suspended transmission lines for high performance and Si-based CMOS compatibility. The micro assembly transfer technique is used to integrate functional complex structures of the mircomachined microwave switch and suspended coplanar waveguides. The electrostatically actuated torsional switch has been successfully driven in a low voltage of 17 volt. Furthermore, the resonance of its dynamic behavior is numerically calculated as 2.6 KHz. In summary, the new microwave switch with suspended Si-based coplanar waveguides presents low driving voltage, CMOS-process compatibility and potentially high transmission efficiency on a lossy Si-based substrate.
Micromechanical Clamps for Optical Fiber Packaging of High Aspect Ratio MEMS Devices
Authors: Beamesderfer Michael A. , Litcher Ed , DeVoe Don L. 
Published: November 2021

Abstract
This paper describes the design and characterization of monolithic clamping structures for mechanical packaging of optical fibers in optical MEMS devices. Both single crystal silicon and nickel LIGA components have been investigated [1,2]. Mechanical clamping methods for optical fiber integration were perused both for on-chip attachment as well as alignment-assist in conjunction with other packaging methods. Arrays clamps with normal clamping forces ranging from 3mN to 375mN were designed, fabricated and characterized. A detailed theoretical analysis of clamping force for each design is presented and compared to measured results from fabricated devices. The clamps were evaluated on their ability to maintain alignment under a range of mechanical and thermal loads. Four arrays of eight clamp sets with varying applied normal clamping forces were designed by varying the deflection of 10μm and 20μm cantilever beams, and arranged in single-clamp and double-clamp configurations. A 100μm moment arm, integrated into the clamp structure, permitted the cantilevers to be initially deflected by the inserted fiber face during the fiber channel population. The populated test clamp arrays were heated from ambient conditions to 55 degrees Celsius to assess their stability under thermal strain, and monitored with an integrated Fabry-Perot whitelight interferometer. The maximum induced axial misalignment did not exceed 3μm. In addition to current theoretical and experimental results, alternative mechanical fiber clamp designs for both silicon and nickel microfabrication are presented and analyzed.
Processing of Ceramic Tapes Into 3-D Shells and its Application to a Small Spherical Stepper Motor
Authors: Li Jun , Ananthasuresh G. K. 
Published: November 2021

Abstract
Low Temperature Co-fired Ceramic (LTCC) tapes (DuPont, 951 series), originally developed for monolithic packaging of interconnects and hybrid microelectronic circuitry, have been used in the last four years to develop a meso-scale integrated fluidic technology. The LTCC fluidic technology is shown to be versatile, inexpensive, fast, and free of packaging problems. The manufacturing basis for this technology is patterning of individual tapes, which are laminated and co-fired to create a layered 3-D structure. In this paper, we present another attractive facet of this technology by creating 3-D shell structures with a single layer of LTCC tape. The processing technique is illustrated with hemispherical and cylindrical shells that have internal 3-D conduits. A novel three degree-of-freedom spherical stepper motor is also presented as an application of an active device using magneto-statically actuated curved LTCC shells.
3 KHz Servo Bandwidth Demonstration by HDD Tracking Microactuator
Authors: Hirano Toshiki , White Matthew , Yang Xin H. , Semba Tetsuo , Shum Victor , Pattanaik Surya , Arya Satya , Kercher Dan , Fan Long-Sheng 
Published: November 2021

Abstract
A demonstration of a closed loop system with a 3 kHz 0 dB open loop crossover using a microactuator in an HDD is reported. An electrostatic rotational microactuator is placed between the suspension beam and the slider, and moves the slider relative to the suspension. A new suspension with extra leads that provide signal to the microactuator was also developed. These leads are electrically connected by a micro-scale solder-ball reflow process. The dual-stage servo experiment was carried out in an HDD and a 3 kHz servo bandwidth was achieved, which is more than twice as high as a conventional servo system. The error rejection function also shows that this dual-stage servo system has superior error rejection capability over the conventional VCM-only servo system. Simulation shows that the bandwidth can be as high as 44 kHz, if a continuous-time servo is used.
Microscale Liquid Impingement Cooling
Authors: Zhang Lian , Wang Evelyn N. , Koch Jon D. , Liu Jonathan T. C. , Koo Jae-Mo , Jiang Linan , Goodson Kenneth E. , Santiago Juan G. , Kenny Thomas W. 
Published: November 2021

Abstract
Impingement cooling is an attractive method for individual IC cooling because of the uniformity and high values of the expected heat transfer coefficient. This paper presents spatially-averaged temperature measurements for DI water impingement from single micro jets with diameters smaller than 50 μm. The jets are circular orifices plasma etched into silicon. A heater chip is fabricated to simulate a high power IC while simultaneously measuring the temperature distribution around the impingement region. A hydrodynamic model is proposed for determining the pressure drop associated with jet formation. With a single 50 μm diameter DI water jet at 3.5 ml/min flow rate, up to 45 W/cm2 heat flux has been removed with 80 °C chip temperature rise. This research provides the first study of microscale liquid impingement cooling down to 14 μm diameter jets.
A Thermomechanical Model for Adhesion Reduction of MEMS Microcantilevers
Authors: Rogers James W. , Mackin Thomas J. , Phinney Leslie M. 
Published: November 2021

Abstract
We present a model for reducing adhesion in MEMS structures using laser heating and compare the model to experimental results. Using a fracture mechanics model, the interface between the stiction-failed microcantilever and the substrate is treated as a crack, and the energy release rate is calculated using elastic theory. In order to include the effect of laser irradiation of the microcantilevers, an associated thermal strain energy is included in the fracture model. As the beam peels, the free length reaches a critical value where the beam buckles, decreasing the energy of the system. The results of the model predict a temperature difference of 100 K is able to repair microcantilevers as long as 600 μm. Experiments are performed that demonstrate the peeling of stiction-failed beams from the substrate after laser irradiation as predicted by the thermomechanical model.
Design of MEMS Resonators for Tuning With Selective Polysilicon Deposition
Authors: Joachim Daphne , Lin Liwei 
Published: November 2021

Abstract
Variations in micromachining processes cause sub-micron differences in the size of MEMS devices, which leads to frequency scatter in resonators. A post-fabrication process was developed to tune the frequency of a comb-drive resonator by selectively adding polysilicon to the rotor. The resonator was designed using finite element simulations, to withstand the thermal stresses of the deposition process and have initial frequency in a desirable range. Experimental results show a permanent increase of 2.6% in the resonant frequency of a special comb-drive resonator after a deposition process time of 15 minutes.
Splitting a Liquid Droplet for Electrowetting-Based Microfluidics
Authors: Cho Sung Kwon , Moon Hyejin , Fowler Jesse , Kim Chang-Jin “CJ” 
Published: November 2021

Abstract
This paper deals with the physical analysis and the experimental verification of splitting a droplet in an open microchannel (i.e., in a gap between two plates) by electrowetting forces. We discovered there exist criteria beyond which the droplet simply cannot be split by controlling the electrowetting. Based on the criteria, we fabricated the testing devices where an electrowetting principle was used to split a liquid droplet and made the experimental verification for the criteria. The channel gap size, the droplet size, and the contact angle change by electrowetting are important parameters in splitting a droplet. The small channel gap enhances the necking of the droplet, helping the splitting process. Higher applied voltage induces larger change in contact angle and consequently enhances the splitting process as well. Most importantly, the droplet cannot be split if the channel gap is too large for the given droplet size and EWOD mechanism.