bluuebunny/crossref_metadata_2025_split huggingface dataset:
Replication of Sub-Micron Gratings on Plates With Surface Mounted Piezoceramic Patches
Authors: Kurusamy Doraraju G. P. , Joshi S. P. 
Published: November 2021

Abstract
A technique to fabricate gratings on thin PZT (lead zirconate titanate) patches and on the aluminum substrate on which they are mounted has been developed. Due to the fragility and brittleness of thin PZT patches this technique avoids imparting large bending strains on the thin PZT patches. The traditional technique was modified to facilitate application on thin surface mounted PZT patches. The gratings obtained by the technique were of high quality.
Diagnosis of Impact Damage in Composite Structures With Built-In Piezoelectrics Network
Authors: Wang Calvin S. , Chang Fu-Kuo 
Published: November 2021

Abstract
An active diagnostic technique for identifying impact damage in composites is presented. A network of piezoelectric actuators and sensors were built into composites to generate and receive ultrasonic stress waves in the structures. Scattered waves were produced from the damage and were detected by sensors. A signal-processing scheme composed of smoothing filtering and joint time-frequency analysis was applied to minimize noise interference and convert sensor measurements into time-frequency spectrograms for interpretation. An identification method based on time-of-flight information obtained from the spectrograms was developed. Experiments were performed on composites with different configurations. It was demonstrated that the method was able to detect the presence of the damage and characterize the damage to a satisfactory precision. Identification results were verified with X-ray images of the structures.
Active Non-Linear Control of a Buckled Beam
Authors: Pinto Osvaldo C. , Gonçalves Paulo B. 
Published: November 2021

Abstract
Buckled beams have been used in several engineering applications to support lateral loading. These arch-like structures are highly nonlinear and may display several instability phenomena when subjected to dynamic and static loads. In this paper a certain class of optimal non-linear control algorithms is used to control the oscillations of simply supported buckled beams subjected to transversal distributed load. To control the non-linear oscillations of the arch, concentrated moments are applied at suitable points along the beam axis. The results show that the proposed control scheme can not only mitigate the effects of dynamic loading on the vibration amplitudes of the beam but also prevent dangerous instability phenomena. In fact the numerical results indicate that the control algorithm can effectively increase the load-carrying capacity of the beam without demanding large control forces.
Opto-Piezothermoelastic Constitutive Modeling of a New 2-D Photostrictive Composite Plate Actuator
Authors: Shih Hui-Ru , Tzou H. S. 
Published: November 2021

Abstract
Optical actuators can introduce non-contact remote actuation and control effect without any hard-wired connections. In this study, constitutive relations, general opto-piezo(electric)-thermo-elastic equations, and their one-dimensional (1D) form are formulated and applied to a new two-dimensional (2D) planar actuator and composite plates laminated with distributed photostrictive optical actuators. Photodeformation, pyroelectricity, and thermoelasticity are considered in the constitutive relations and coordinate transformations are used to transform the 1D local actuation characteristics to the 2D global actuator coordinate system. Mathematical model and system parameters are then calibrated with experimental data; analytical solution based simulation and experimental results are compared favorably. Thus, the proposed constitutive modeling and governing equations of distributed 2D optical actuators preserve natural photodeformation, pyroelectricity, and thermoelasticity characteristics and applicable to distributed control of 2D continuous systems.
Sound Transmission Loss in Electrorheological Fluids Under DC Voltage
Authors: Szary Marek L. , Noras Maciej 
Published: November 2021

Abstract
Extensive investigations of sound transmission loss (STL) in electrorheological (ER) fluids were conducted in the Acoustics Laboratory in the College of Engineering, Southern Illinois University Carbondale.
The STL was investigated for different kinds of ER suspensions in frequency ranges from 100 Hz to 2kHz. Applied DC voltage to the different electrodes allowed normal and shear stress to develop in the ER fluid respectively. The electric field density was variable. Sound transmission loss was obtained by measurement of the sound pressure level in front of and behind the sample. Under both normal and shear stress in ER fluid, STL decreases with increasing stress. Those properties of ER fluids can be useful in noise and vibration control applications.
Internal Resonance of a Beam/Traveling-Mass System
Authors: Siddiqui S. , Golnaraghi F. , Heppler G. R. 
Published: November 2021

Abstract
The dynamics of a cantilever beam undergoing large amplitude oscillations while experiencing a nonlinear interaction with an attached lumped spring/mass system are investigated. The resulting partial differential equations contain trigonometric non-linearities that are treated using methods of weighted residuals and do not require series expansions about the equilibrium positions. The resulting nonlinear ordinary differential equations are solved using a formulation of the average acceleration method.
Approaches to Reducing Silent Chain Noise of Cab Motorcycles
Authors: Pan M. , Shieh Eddy T. 
Published: November 2021

Abstract
Silent chains have extensively replaced roller chains in drive systems owing to annoying noise problems. But, for some types of cab-motorcycles, especially sheet-frame cabs, the annoying noise originated from silent chains can still not been accepted. In this study, silent chain noise of cab motorcycles has been well investigated by firstly the order analysis and time-frequency analysis of measured noise, and secondly the analysis of origination and transmission of noise. Therefore, noise mechanism can be precisely uncovered and understood. Some experiments were conducted to discover three primary issues of a noise problem, i.e., noise source, transmission path, and response. In addition, to explain a noise component resulting from structure resonance, the mode shape at 1640 Hz was constructed based on the running mode principle. Different engineering modifications have been validated to reduce this transmission-part noise. Useful proposals can be concluded as design guidelines.
Statistical Investigation of Resistance Spot Welding Quality Using a Two-Stage, Sliding-Level Experiment
Authors: Li Wei , Cheng Shaowei , Hu S. Jack , Shriver Justin 
Published: November 2021

Abstract
Quality variation in resistance spot welding is a major concern in the automotive industry. This paper investigates the weld quality using a newly developed two-sage, sliding-level experiment. Welding current is treated as a “slid factor” and is determined based on the settings of other process variables. Engineering knowledge is applied in statistical model selection. From the analysis, it is found that abnormal process conditions, including axial misalignment, angular misalignment, poor fitup, edge weld, and electrode wear, significantly affect the size of the welds, and thus cause large variations on the weld quality. Although they may help increase the weld size, these abnormal process conditions generally lead to a less robust welding process. Developed initially for this study, the new experimental design and analysis procedures are believed to be generic and can be applied to other processes.
Excimer Laser Micromachining of Silicon and On-Line Machining Depth Discovery Using Laser Interferometry
Authors: Theppakuttai Senthil , Chen Shaochen 
Published: November 2021

Abstract
In this paper a parametric study on the excimer laser micromachining of silicon (Si) is conducted and a Michelson interferometer is used for the in-situ diagnostics of the machining depth on the sub-micron and micron scales. An excimer laser of wave length 308 nm is used for the micromachining process. A He-Ne laser of 632.8 nm wavelength is used as the light source for the interferometer and the setup consists of a beam splitter, beam expander and other optics. The interference patterns caused due to the change in the path length between the two interferometer arms gives the machined depth information. These interference patterns are captured by using a photodiode and an oscilloscope. Results from the interferometer are compared with the actual depth measurements obtained by using a surface profilometer in combination with an optical microscope. It is observed that the depths of machining obtained by the surface profile measurement are in accordance with the interferometer measurements with a very high accuracy. The experimental results demonstrate the feasibility of applying this system for the in-situ monitoring of the micromachining process.
Robust Control of Piezo Actuator for Active Error Compensation in Diamond Turning
Authors: Yu Jianming , Li C. James 
Published: November 2021

Abstract
This paper describes a new control strategy for the micro positioning system used in a diamond turning process to improve workpiece geometry in spite of hysteresis nonlinearity and guideway/spindle errors. The control strategy consists of two nested loops. The inner loop is a model-based robust controller, which compensates for the hysteresis nonlinearity associated with piezo actuators, and the outer loop is a P-integrator learning controller which eliminates the unmodeled error sources such as guideway and spindle errors. This control strategy was applied to the error compensation in a diamond turning process. Cutting tests were conducted and showed an order of magnitude improvement in the workpiece form accuracy from 10 μm to 1μm on an aluminum alloy disk.
Suppressing Cracking in Resistance Welding AA5754 by Mechanical Means
Authors: Zhang Hongyan , Senkara Jacek , Wu Xin 
Published: November 2021

Abstract
In this paper mechanical aspects of cracking during single- and multi-spot welding of AA5754 was investigated by both experimental and analytical approaches. The impact of mechanical loading on crack initiation and propagation was studied with the consideration of various process parameters including the loading imposed by electrodes, the formation of liquid nugget, and constraining factors during and after welding. Tensile properties of AA5754 and their dependence on the temperature were tested at room and up to solidus temperatures, in order to provide a reference of cracking stress. Thermal-mechanical analysis was conducted based on the temperature field around the nugget and the state of stress encountered during welding. This analysis revealed that tensile stress might build up in the vicinity of the nugget during cooling, thus explained the experimental observation. General guidelines for suppressing cracking were proposed, i.e. to provide sufficient constraint around the weld spot during and after welding.
Swept Volume Study and Its Application to Real-Time Simulation of Enhanced Machine Controllers (EMC)
Authors: Wang Karen L. 
Published: November 2021

Abstract
Swept volume study plays an important role in manufacturing. As an application, a collaborative effort has been made to construct an integrated simulation system to validate the enhanced machine controllers (EMC) developed at the National Institute of Standards and Technology. Commercial NC simulation packages available assume ideal controller behavior, i.e., a linear cut is exactly linear, a circular cut is exactly circulate, and all axes are linear and orthogonal. But for the EMC problem it is an opposite situation: it is assumed that the controller inputs (i.e., numerical control programs) are correct, and the controller itself needs to be proven. In this paper, commercial CAD/CAM packages and research on swept volume are integrated to develop an EMC simulation system in which tool configurations, swept volumes and final machined parts are displayed in a superior 3D graphics environment. Unlike the commercial NC simulation packages, the developed EMC simulation system includes all the effects of the controller and machine tool, so that errors in the trajectory-blending algorithm appear on the stock, improperly tuned servos would show oscillation, and nonlinear axes would show tolerance violation.
New Frontiers in Mold Construction: High Conductivity Materials and Conformal Cooling Channels
Authors: Jacobs Paul F. 
Published: November 2021

Abstract
Why are almost all production plastic injection molding core and cavity inserts made from steel? Steel is certainly NOT the hardest material. Steel is also definitely NOT the most corrosion resistant material. Finally, steel most assuredly is NOT the best conductor of heat. So why are production tools made from steel? The real answer is probably because that’s the way they have been made for many years. People are used to working with steel molds. The results are predictable. However, as two mold case studies, in addition to Finite Element Analysis (FEA) results presented in this paper will show, there are now commercially available inserts that achieve: (1) shorter lead times, (2) faster cycle times, (3) enhanced productivity, (4) lower unit part cost, and (5) reduced part distortion.
Transient Thermal Analysis of an Anisotropic Conductive Film Package Assembly Process
Authors: Chiriac Victor Adrian , Lee Tien-Yu Tom 
Published: November 2021

Abstract
Transient thermal simulation was performed to analyze thermal response of the assembly process for a package using Anisotropic Conductive Film (ACF). Two assembly processes were modeled: a simplified process where the package was fixed at two different temperatures during assembly, and a detailed process where the package experienced a ramping heating process, followed by a constant temperature curing process. A 3D conjugate Computational Fluid Dynamics (CFD) study was first conducted, followed by a 3D conduction-only analysis due to the minimal effect of convection and radiation.
Results from the detailed process modeling indicated that during the initial ramping, within 0.02 second, the die and nozzle head experienced a small temperature drop due to the cooling effect of the ACF material and substrate. The ACF material also displayed a steep increase in temperature after contacting the die, followed by a short decay, then ramped up again. At the end of the 10-second ramping process, the ACF reached a temperature of almost 203°C, while the die was at 206°C. During the 5 seconds of curing, all parts reached steady state in less than 2 seconds.
Thermal Contact Resistance of Phase Change and Grease Type Polymeric Materials
Authors: Prasher Ravi S. , Simmons Craig , Solbrekken Gary 
Published: November 2021

Abstract
Thermal interface material (TIM) between the die and the heat spreader or between the heat spreader and the heat sink in any electronic package plays a very important role in the thermal management of electronic cooling. Due to increased power and power density high-performance TIMs are sought every day. Phase change materials (PCM) seem to be very good alternative to traditionally used thermal greases because of various reasons. These phase change materials also have the advantage of being reworked easily without damaging the die.
Typically these phase change materials are polymer based and are particle laden to enhance their thermal conductivity. The thermal conductivity of these materials is relatively well understood than their contact resistance. Current work focuses on explicitly measuring the contact resistance and the thermal conductivity of a particular phase change TIM and some silicon-based greases. Effect of various parameters, which can affect the contact resistance of theses TIMs and Greases, are also captured. The steady state measurements of the thermal conductivity and the contact resistance was done on an interface tester.
In general the work on the contact resistance of fluid-like polymer based TIM, such as thermal grease or phase change polymer has been experimental in the past. A semi-analytical model, which captures the various parameters affecting the contact resistance of two class of materials; the phase change and the thermal grease is also developed in this paper. This model fits very well with the experimental data.
Incremental Single Point Forming
Authors: Jeswiet J. , Ali A. 
Published: November 2021

Abstract
The process of single point incremental micro-plastic forming is presented. This process is used to form sheet metal into complicated shapes without the use of either a male or female die. The process uses a single point tool which plastically deforms sheet metal to give a local micro-deformation. By doing this incrementally, and controlling the tool path with a CNC mill, the plastically deformed points are, in effect, added as the tool moves to give a final shape. The sheet metal is held in place by a blank-holder which moves in a vertical plane on four posts. Deformation of the strip can be achieved in one of two ways: either with a supporting, fixed tool about which the single point forming tool moves or by inversion of the process in which the supporting, fixed tool is not used. The paper describes experiments with both techniques.
Tractive Kinematic Regression: A Computer Assisted Deep Drawing Method
Authors: Ulintz Peter J. 
Published: November 2021

Abstract
Combining today’s computer technology with new generation, multiple-action, hydraulic press equipment, has created a new process opportunity in deep drawing. Integrating these modern machine and computer controls with innovative programming and tool designs, has led to the development of a production process that produces a double reverse-drawn, cylindrical shell that significantly exceeds traditional Limiting Drawing Ratios (LDR). The method used to produce these shells employs a recently developed technique, herein referred to as Tractive Kinematic Regression, or more simply, the TKR process.
The TKR process promotes material flow by “feeding” material into the die cavity, as opposed to the punch having to “draw” or “pull” in the flange. This is accomplished through the use of concurrent - but unequal - force and motion curves of a forward moving punch and a regressing (reverse moving) die ring. The computer controlled kinematics, forces and motion curves resulted in less material straining and thereby, provided increased formability and improved LDR.
Stress and Strain Histories of Multiple Bending-Unbending Springback Process
Authors: Huang H.-M. , Liu S.-D. , Jiang S. 
Published: November 2021

Abstract
A drawbead model with sheet metal passing through multiple bending-unbending processes was employed in this study to understand the springback phenomenon and to develop a numerical simulation technique for more accurate prediction of the springback process. The deformation process is simulated using an implicit Finite Element Modeling code. The predicted results were compared with the physically measured ones, including clamping and restraining forces, thickness strains and the curvatures of the deformed sheets. Consideration of the Bauschinger effect and employment of a combined isotropic and kinematic hardening models greatly improve the prediction accuracy. Stress and strain histories under various conditions during the drawing process are studied in detail in an attempt to provide a better basis for comparison for dynamic explicit solutions.
Three-Dimensional Tube Geometry Control for Rotary Draw Tube Bending: Part 1—Bend Angle and Overall Tube Geometry Control
Authors: Lou Huazhou , Stelson Kim A. 
Published: November 2021

Abstract
Traditional trial-and-error springback compensation methods have the problems of high scrap rate, low efficiency, high cost of fixtures and operator experience dependency. The method presented in this paper uses on-line measured springback data from the same batch to predict and compensate for springback. Because there are no springback data for the first bend, bend-rebend control is used to make the first bend to eliminate trial tubes. In addition to springback, relaxation and radial growth are also estimated and compensated for to make a bend more accurate. A process control method is developed to optimize the overall control strategy such that the overall tube error is minimized without increasing the required hardware accuracy. The optimal process control strategy has significantly higher accuracy than the traditional trial-and-error method. The details of statistical analysis of tube tolerance and adaptive bend correction algorithm are presented in part 2 of the paper.
Measurement of the Material State Including the Effects of Recovery and Recrystallization
Authors: Bange M. E. , Beaudoin A. J. , Stout M. G. , MacEwen S. R. 
Published: November 2021

Abstract
Deformation at elevated temperatures in combination with high strain rates leads to recovery and recrystallization in aluminum alloys. Previous work in recrystallization has emphasized the detailing of microstructural trend in progression from the deformed to the annealed state. In the following, we examine the effect of rate dependence on deformation on AA 5182 and AA 6061. It is demonstrated that identification of underlying microstructural mechanisms is critical. An experimental program is then outlined for characterization of recovery and recrystallization of AA 5182. Instantaneous hardening rate and flow stress are developed from interrupted compression tests. These data are used to establish a quantitative measure of recovery through evaluation of a state variable for work hardening, the mechanical threshold. It is intended that the results serve as a foundation for development of relations for evolution of a mechanical state variable in the presence of recrystallization. Such a framework is necessary for the practical prediction of interstand recrystallization in hot rolling operations.
Modeling of Plastic Behavior of Anisotropic Sheet Metals With Voids
Authors: Chien W. Y. , Pan J. , Tang S. C. 
Published: November 2021

Abstract
The influence of plastic anisotropy on the plastic behavior of porous ductile materials is investigated by a three-dimensional finite element analysis. A unit cell of cube containing a spherical void is modeled. The Hill quadratic anisotropic yield criterion is used to describe the matrix normal anisotropy and planar isotropy. The matrix material is assumed to be elastic perfectly plastic. Macroscopically uniform displacements are applied to the faces of the cube. The finite element computational results are compared with those based on the closed-form anisotropic Gurson yield criterion suggested in Liao et al. (Mechanics of Materials, 1997, pp. 213-226). Three fitting parameters are suggested in the closed-form yield criterion to fit the results based on the modified yield criterion to those of finite element computations.