bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two-Degree-of-Freedom Control System for Motion Control of Flexible Cartesian Robots
Authors: Sasaki Minoru , Okuda Kouji , Fujisawa Fumio , Okamoto Ryouichi 
Published: July 2023

Abstract
In this paper, a two-degree-of-freedom control system for motion control of a flexible cartesian robot is presented. The two-degree-of-freedom control system consists of a feedback controller and a feedforward controller. The feedback controller is designed based on Lyapunov’s direct method while the feedforward controller is designed based on the inverse system. A feedback control of the tip motion of a flexible system is derived by considering the time rate of change of the total energy of the system. The inverse system consists of finding the feedforward input that needs to be applied at base so that the end point of the arm can follow a desired trajectory. The simulation and experimental results verify that the proposed control system is effective at controlling the tip motion of the flexible cartesian robot.
Performance Limits of Shock Isolation Mounts for Specific Deterministic Inputs
Authors: Ferri Aldo A. , Eshleman Eric D. 
Published: July 2023

Abstract
This paper investigates the optimal isolation mount for specific deterministic inputs. Peak, rather than mean-squared, quantities are used as metrics of optimality. Both active and passive mounts are considered. Two design techniques are evaluated: direct minimization of a performance criterion and use of linear-quadratic-regulator theory. It is shown that for a variety of shock inputs, the optimal isolation mount is a purely passive, ideal friction element. However at times, the friction mount is suboptimal and active mounts are required to minimize the performance criterion.
Experimental Evaluation of Segmented Active Constrained Layer Damping Treatments
Authors: Kapadia Rajiv K. , Kawiecki Grzegorz 
Published: July 2023

Abstract
The objective of this research is to demonstrate the feasibility of segmented Active Constrained Layer Damping treatments to improve low frequency vibrations damping in flexible robotic arms. The Active Constrained Layer Damping treatment, under consideration, consists of a viscoelastic layer sandwiched between two piezoelectric layers. The shear deformation of the viscoelastic layer causes loss of energy and thus damping of vibration.
This paper focuses on the effects of constraining layer segmentation. Experimental results obtained for slender beams partially treated with segmented and unsegmented Active Constrained Layer Damping treatments are presented. Tested specimens have low natural frequencies, typical for flexible robotic manipulator arms. The performance of segmented and unsegmented treatments, as well as the performance of active and passive treatments is compared. Presented results demonstrate that significant improvement in Active Constrained layer treatment performance can be achieved by an appropriate segmentation of the constraining layer.
Smart Structure Technology for Rotor Blade Tip Clearance Control Using a Beam Model
Authors: Lin Y.-J. , Wen C. , Choi B. , Saravanos D. 
Published: July 2023

Abstract
This paper presents the experimental development of a simple and effective vibration control scheme by employing smart structure technology. Due to high accuracy and high slew rate requirements for lightweight structures, vibration control becomes a challenging task. In this paper, it is proposed to actively control rotor blade tip vibration with collocated piezoceramic sensors and actuators. To include the flexible characteristics of rotor blades in our analysis, a flexible cantilever beam is used to simulate the dynamic behavior of the cantilever beam due to external disturbances, generated by a magnetic shaker. The shaker was installed near the tip of the simulated rotor blade to maximize the external excitations. Piezoceramic sensor and actuator were used and evenly distributed as elements of the smart structure. The mathematical model of the smart structure including the piezoceramic sensors and actuators was determined by combining both analytical and experimental schemes. Based on the derived experimental dynamic model, a proportional gain feedback controller was implemented to compensate the vibratory deflections of the underlying structure. The results of the work show that the proposed control methodology along with the smart structure can suppress more than 80% of the measured structural vibration, which is considered satisfactory.
An Electrostatically-Driven Phase Change Actuator for Vibration Control
Authors: Hallinan Kevin P. , Kashani A. Reza , Bartsch Michael 
Published: July 2023

Abstract
Many motion control applications rely on piezoelectric and magnetostrictive type actuation devices to achieve active control or micro-manipulation. These devices have an important drawback. They are limited in their ability to simultaneously provide large force and large displacement.
A new concept electrostatically driven phase-change actuator (EDPA) has been theoretically studied to investigate if the drawbacks inherent to these devices might be overcome. This actuator concept relies upon changes in vapor pressure to expand a pliant membrane enclosing a vapor cavity. Changes in the vapor pressure are achieved by applying an electric field across a dielectric liquid film beneath the vapor space. The field polarizes the liquid molecules reducing the liquid pressure. A reduced liquid pressure produces an associated decrease in the equilibrium vapor pressure at the liquid-vapor interface. The surrounding vapor subsequently condenses causing a reduction in the vapor pressure. As a result, the membrane retracts. When the field is removed, the equilibrium vapor pressure increases above the pressure of the surrounding vapor, causing liquid to evaporate. The evaporation increases the vapor pressure, expanding the membrane.
Simulations of the device performance have shown it capable of producing forces of over 300 N with displacements of up to millimeters and sub-millisecond response time, while maintaining a much smaller package (lengthwise) than possible using stacked magnetostrictive or piezoelectric actuators. However, the transverse dimensions required to produce this force were found to be substantial (20 mm).
Discrete Domain Analysis of Delayed Resonator
Authors: Elmali Hakan , Olgac Nejat 
Published: July 2023

Abstract
The Delayed Resonator (DR) is a new active vibration absorption technique which uses time delayed partial state feedback to generate ideal resonance on a passive vibration absorber. It has many attractive features such as real-time tunability, ease of implementation and total suppression of vibration for tonal frequency disturbances. The DR controller has been developed in continuous domain until now. In this paper discrete domain analysis is presented. Simulation results indicate an expected dependency of stability on the sampling period for this active control strategy. A major advantage of discrete domain analysis is the reduction of characteristic roots from infinite to finite numbers and consequent simplicity in the analysis and design of the controller. It is shown that discrete domain control design for DR yields better vibration suppression considering the sampled control structure in implementations.
Active Structure Vibration Control Using Dynamic Neural Networks: Modeling Error, Nonlinear, Parameter Imprecise and Disturbance
Authors: Lu Zheng , Shi Xizhi , Wang Xuejun , Xu Min 
Published: July 2023

Abstract
In structure vibration control. Most of the results in the past time are based on idealized system description. Structural nonlinearities, modeling error, parameter imprecise and disturbance are four problems which are not solved completely till now. This paper uses a new type of dynamic neural network to control structure vibration. Singular perturbation theory is used and a neurocomputing approach is developed to solve these problems at the same time. Simulation results show that this new method can solve four problems in vibration control to some extent.
Investigation on Decreasing Combustion Noise of D.I. Diesel Engines
Authors: Yuan Xue , Shao-Xi Shi 
Published: July 2023

Abstract
Based on the theory analysis and multi-points measurement of combustion pressure oscillation in D.I. diesel engines, each resonance modes of combustion pressure oscillation are discussed. In the paper, the influence of pressure oscillation on combustion noise is analyzed. The methods of decreasing combustion noise through reducing pressure oscillation are investigated. Resarch results show that combustion noise can be decreased and economy can be improved when some parameters of injection system in D.I.diesel engines are changed.
Fuzzy Logic Identification of Ship Motions in Response to Varying Wave Incidence
Authors: Moore Christopher T. , Telionis Demetri P. 
Published: July 2023

Abstract
A fuzzy logic identification code was prepared. The program was trained with experimental data of pitch and roll of a ship model at various incidences to oncoming waves. The program can then predict the response of the model to any wave and at any incidence.
Development of a Particle-Fluid Model for Transient Analysis of Bubbly Two-Phase Flows in Parallel Channels
Authors: Pokharna H. , Mori M. , Ransom V. H. 
Published: July 2023

Abstract
Particle Fluid Model (PFM) is an intermediate method between the numerically intractable local instant model and the fully averaged two-fluid model for simulating transient two-phase flows. PFM uses a Lagrangian description for the dispersed phase and an Eulerian description for the continuous phase. In this paper an extension of the PFM to multiple channels with merging and branching is reported. As the treatment for boundary conditions for the discrete phase requires the use of an extra cell (ghost cell) at each end of the flow passage, the linking of boundary conditions becomes complicated. This linking process is established by overlapping the ghost cell of a channel with the first real cell of the next channel. Work is currently in progress to model parallel bubbly slug two phase flows merging into a single plenum.
The Influence of Heat Transfer on Two-Phase Flow Behavior During Pipeline Blowdown
Authors: Fairuzov Yuri V. , Erosa Jorge A. , Rosas M. Armando 
Published: July 2023

Abstract
The purpose of this study is to investigate the effect of heat transfer, between the fluid and the pipe wall, on the two-phase flow behavior during the blowdown of a long transmission pipeline. A mathematical model which describes transient two-phase flow and heat transfer in the pipeline was developed. A complete break of a long pipeline containing propane was simulated and ‘hree blowdown conditions were considered. These include (1) the fluid flow is adiabatic, (2) the pipeline is adiabatic, and (3) the pipeline interchanges heat with the surroundings. The model predictions were compared with limited available experimental data. The study revealed that the thermal capacitance of the pipe may have a significant influence on the two-phase flow behavior in the final stage of the blowdown.
Internal Flows by MOC: The Role of Friction
Authors: Wylie E. Benjamin 
Published: July 2023

Abstract
Rapidly-varying unsteady internal flows are commonly analyzed with great success using the method of characteristics. Numerical results are seldom questioned, although there are examples when the accuracy should be challenged. In this study the equations and exciter behavior are non-dimensionalized to provide a unified treatment of a class of problems. This permits statements to be made regarding accuracy and range of validity of a standard solution procedure.
Correlation of Loss Coefficients for 3D Separated Flow Through a Grille
Authors: Smith Brian , Birkett Craig A. , Shack David 
Published: July 2023

Abstract
A study was performed to calculate the loss coefficients for flow through thin grille shapes of various geometries. The grille shapes were stamped sheet sections with holes which caused highly separated flow when flow was applied normal to the surface. Two-dimensional and three-dimensional CFD models were first built of simple shapes and compared with known data. This provided information on mesh density and solution methods required to achieve accurate results. Next, symmetric models were built of a number of grille shapes. Loss coefficients were calculated for several Reynold’s numbers. As expected, loss coefficients were relatively independent of Reynold’s numbers. It was also found that loss coefficients depended to a large degree only on the percent area open to the flow. Thus it was possible to use a single curve to represent losses through the grille for a wide variety of shapes and air speeds. Experimental data were obtained in a wind tunnel for a subset of grille shapes. These results agreed well with the analytical solution.
Spectral Element Calculation of a Von Karman Vortex Street
Authors: Springer Marlow E. 
Published: July 2023

Abstract
This paper presents results for the direct numerical simulation of unsteady two-dimensional incompressible flow past a circular cylinder at a Reynolds number of 140. Conforming and nonconforming formulations of the spectral element method have been employed to compare the grid resolution reqirements for the von Karman vortex street. Results presented include the shedding frequenies, vorticity distributions, drag coefficients, and lift coefficients. Quantitative results published by others from experiments at the Reynolds number of interest were found for the shedding frequencies and drag coefficients. Results presented here are within five percent of published values for the shedding frequency and three percent for the drag coefficient. Qualitative comparisons for the vorticity distributions are made with published flow visualizations.
CFD Simulations in the Design and Evaluation of Heat Sinks
Authors: Nakayama W. , Behnia M. 
Published: July 2023

Abstract
The roles of CFD simulations in the design of heat sinks are discussed drawing two examples, one is the plate-fin array cooled by planar impinging air flow, and the other is the grooved heat transfer surface of a simulated chip cooled by dielectric coolant. In both examples the CFD analysis is performed to clarify the details of coolant flow and heat transfer in narrow channels which are difficult to capture by experimantal means. The experiments, which were conducted in parallel with the CFD analyses, provide the benchmarks for the CFD. It is emphasized that, in an endeavor to develop thermal design codes, the CFD simulation and the experiment are complementary to each other.
Offset Crush Analysis and its Applications
Authors: Mahmood Hikmat F. , Wheatley Donald , El-Hor Hassan H. , Hammoud Hassen 
Published: July 2023

Abstract
Until recently, frontal crash analysis and tests were performed to predict the performance and behavior of cars to meet full frontal crash safety requirements. Little has been done so far to control the energy absorption during an offset frontal crash. This topic has become a very interesting and challenging issue since it will be included in the federal regulations in the coming years.
In offset crash, the load is applied to one side of the front end, leaving the other side partially unloaded. In light of this situation, cross-members have to be carefully designed in order to absorb and safely transmit part of the offset crash load to the opposite side.
This paper will describe the theoretical performance of the front structure under an offset crash and at the same time identify all related parameters that influence this behavior. A computerized analysis of the single, full and offset crash will be performed and results and comparisons will be tabulated and graphed.
Comparison of Different Material Models in Simulating Compression and Energy Absorption of Bumper Foam During Low Speed Impact
Authors: Chen Ping , Alavandi Bhimaraddi , Saha Nripen K. 
Published: July 2023

Abstract
In this paper an analytical modeling of foam material using four different formulations is considered. Four material models considered here (MATERIAL LAWS 10, 21, 28 and 35) are available in RADIOSS (commercial non-linear finite element analysis code). All four models are used in simulating the deformation of structures consisting of foam components. Static compression test data, on foam cube samples of different densities, are first validated to arrive at the material parameters required as input to RADIOSS. Then, an application of foam material in an energy absorbing front bumper structure is studied. Comparison of these material models in low speed impact testing is carried out. Based upon the experience gained on material modeling of foam. Material Law 10 or 28 (preferably 28) is recommended to simulate low speed impact testing.
A Micro/Macro Solidification Model for Columnar Eutectic Alloys With Velocity-Dependent Freezing Temperatures
Authors: Judson Ward M. , Paolucci Samuel 
Published: July 2023

Abstract
A general multidimensional model for a solidifying columnar eutectic alloy is presented in which a velocity-dependent freezing temperature is coupled with the macroscale energy equation. At solidification rates (∼ 1–10 mm/s) that are representative of gravity permanent mold and die casting processes, near-eutectic alloys freeze with a macroscopically discrete solid-liquid interface at a temperature below the equilibrium eutectic temperature which can impact the heat transfer process.
The model is illustrated with one-dimensional solidification in a finite domain and solved numerically with a Galerkin finite element method. By nondimensionalizing the governing equations the effect of coupled eutectic growth on heat transport is clearly identified so that the model’s sensitivity to important parameters can be investigated. Additionally, the average eutectic spacing can be determined with the temperature field, rather than post-determination from a standard, uncoupled solution of the energy equation. The eutectic coupling results indicate that the eutectic interface location lags behind the uncoupled solution; therefore, decreasing the amount of solid formed, increasing the total solidification time, and increasing the average eutectic spacing.
On the Prediction of Weld Pool Size and Heat Affected Zone in Shallow-Pool Welding
Authors: Bos Jeannine A. , Chen Michael M. 
Published: July 2023

Abstract
Numerical modeling of the Weld pool has been pursued by many investigators over the last decade. Most of these efforts have focused on the details of fluid flow and heat transfer in the weld pool. These efforts have not addressed the important practical issues of the welding engineer which include reliable prediction of the weld pool dimensions and the size of the heat affected zone based on welding parameters such as power and speed. A consequence of this is that available prediction methods are still based on heat conduction considerations without any input from weld pool convection analysis. In the present paper it is shown that the dependence of weld dimensions on power and speed are relatively insensitive to the details of the flow and are primarily influenced by the aspect ratio of the weld pool. It is possible to divide the prediction of weld dimensions into two separate tasks. One task is the prediction of the pool aspect ratio. This is the role of weld pool convection studies. The other is the prediction of weld dimensions based on given aspect ratios and welding parameters. This is accomplished through heat conduction analysis outside the weld pool. Numerical computations for the latter have been carried out and the results are presented in correlations which are convenient for prediction purposes. Sample calculations to illustrate the use of the results are also given.
Magnetic Field Effects on a Laterally Vibrating Magnetic Liquid Column
Authors: Ohaba M. , Saito S. , Sudo S. , Sawada T. , Tanahashi T. 
Published: July 2023

Abstract
The magnetic field effects on both the static stability limit and the resonance frequency of a magnetic liquid column are examined theoretically and experimentally. We first derived the theoretical resonance frequency of a column using linear potential theory. Then, in the experiment, a vertical cylindrical magnetic liquid column was formed between two electromagnets. As the magnetic field intensity was decreased, the column’s diameter exhibited hysteresis, such that its stability limit extended to a smaller diameter range due to the coaxial magnetic field. The column was also subjected to lateral excitation and the surface frequency response of the non-axisymmetric first two modes were observed. It was found that the resonance frequency of the column increases with increasing magnetic field intensity and decreases with an increase in the aspect ratio of the column (mean diameter / height). The resonance frequency of the first mode was in qualitative agreement with the theory.
Semiconductor Deposition Profile Simulation Using Direct Simulation Monte Carlo Method
Authors: Ikegawa Masato , Kobayashi Jun’ichi , Maruko Morihisa 
Published: July 2023

Abstract
As integrated circuits are advancing towards smaller device features, step-coverage in submicron trenches and holes in thin film deposition is becoming concern. Deposition consists of gas flow in the vapor phase and film growth in the solid phase. A deposition profile simulator using the direct simulation Monte Carlo method has been developed to investigate deposition profile characteristics on small trenches which have nearly the same dimension as the mean free path of molecules. This simulator can be applied to several deposition processes such as sputter deposition, and atmospheric- or low-pressure chemical vapor deposition. In case of low-pressure processes such as sputter deposition, upstream boundary conditions of the trenches can be calculated by means of rarefied gas flow analysis in the reactor. The effects of upstream boundary conditions, molecular collisions, sticking coefficients and surface migration on deposition profiles in the trenches were clarified.
Modeling of Multiphase Transport During Solidification of Metal-Matrix Particulate Composites
Authors: Feller Robert J. , Beckermann Christoph 
Published: July 2023

Abstract
A multiphase model for the solidification of metal-matrix particulate composites is developed that accounts for macroscopic particle segregation due to liquid-particle flow and particle-solid interactions. Macroscopic transport equations are written for each phase with unknown parameters modeled through supplementary relations pertinent to the solidification of a binary alloy containing a stationary solid phase and generally non-stationary spherical particles. Model validation is performed through comparison of one-dimensional simulation results to experimental sedimentation and composite solidification results in which good agreement is found. One-dimensional case studies demonstrate the effect of cooling rate and direction, particle packing, clustering, and particle rejection on the final particle distribution in various Al-Si/SiC castings.
Flat Heads for High-Speed, Contact Tape Recording: Experimental Evaluation and Theoretical Analysis
Authors: Müftü Sinan , Hinteregger Hans F. 
Published: July 2023

Abstract
We report on an investigation of the mechanics and tribology of a flat head for high-speed, contact tape recording. We found that a self-acting negative air-bearing (suction) created near the leading wrapped corner is responsible for stable low-pressure contact over a wide range of speed, wrap angle, tension and tape thickness. This suction is caused by the expansion of air into the diverging gap on the upstream side of the head-tape interface which is unique to this wrap geometry. Experiments performed on a “row-bar” of thin film disk heads where the tape is wrapped only on the edge opposite to the heads showed the gap spacing to be stable in the 0.5–8m/s speed range with less than 4nm of wear on the read elements. A bi-directional version of a flat head geometry is analyzed via a model and suggestions are made for that design.