bluuebunny/crossref_metadata_2025_split huggingface dataset:
Foam Extrusion Technology of Microcellular Plastics
Authors: Shimbo Minoru , Nishida Kouji , Nishikawa Shigeo , Sueda Takanori , Eriguti Mitio 
Published: January 2022

Abstract
Processing technology was studied basically for microcellular plastics in this paper. The continuous processing system was constructed using extruder and was verified propriety of this system. In order to investigate cell morphology and cell structure, microcellular polystyrene samples were produced under various conditions by the above processing system. Concretely, foaming die which can be varied pressure in die was prepared. The effect of pressure drop in die on cell morphology of microcellular plastics was examined using this changeable die. In addition, the effect of blowing agent contents, temperature in die and besides additioner on that of microcellular plastics were also investigated.
Polystyrene / Acrylic Blends and Their Application in Foam Production: Part Two — R134a Blowing Agent
Authors: Smith Peter J. , Cross Bernard J. , Corr Stuart , Gendron Richard , Daigneault Louis E. 
Published: January 2022

Abstract
Rheological data, at elevated temperature and pressure, for pure polystyrene, pure acrylic and polystyrene / acrylic blends containing R134a are contrasted with similar data for polymers containing R22 and R142b blowing agents. The variation of polymer melt viscosity with blowing agent concentration (R22, R142b and R134a) is interpreted in terms of equilibrium blowing agent solubility and molecular plasticization effects. Equilibrium solubility data for all blowing agents are presented.
Information on the variation of extruded foam density with blowing agent content for pure polystyrene, pure acrylic and polystyrene / acrylic polymer blends is described. Inclusion of modest quantities (∼10% w/w) of acrylic into the polystyrene is shown to allow the manufacture of reduced density foams using R134a blowing agent. Inclusion of the acrylic also stabilizes extruder pressure profiles and facilitates easier plant operation.
The observed reduced foam density, both with polymer composition and blowing agent content, and easier extruder operation are explained in terms of blowing agent solubility and secondary relaxation processes associated with the acrylic component.
More Experiments on Thermoplastic Foam Sheet Formation
Authors: Lee Shau-Tarng 
Published: January 2022

Abstract
This paper discusses effects of formula/processing parameters of polyethylene foam extrusion on foam sheet characteristics, such as: foaming efficiency and open cell percentage. The former arises economics issue, and the latter performance. Earlier publications suggest that surface to volume ratio has profound impacts on thermal and gas loss to become a key processing factor for foaming efficiency during sheet formation. More experiments were performed to investigate foam density, cell density and open cell percentage. It was found that foam density reaches a minimum then increases as cell density increases. Open cell percentage experiments offers a reasonable correlation between cell density and foam density. Therefore, cell wall strength becomes a limiting factor for optimal foaming, which was confirmed by the take-up speed experiments.
A Reactive Algorithm for Micro-Robotic Vehicles
Authors: Dohner Jeffrey L. 
Published: January 2022

Abstract
In this paper a guidance and control algorithm for a simple robotic vehicle (called a “bug”) cooperatively operating in a swarm of vehicles is presented. A bug is assumed to have limited communication, sensing, memory, and compute capability. Therefore, it is assumed that its behavior is reactive in nature. Bugs travel in swarms and track scent emanating from scent sources in unknown environments.
Since bug behavior is reactive, the guidance and control algorithm which is used to define its motion must not be computationally intensive. The guidance and control algorithm presented in this paper is subdivided into three, simple to implement, non-computationally intensive sub-algorithms. They are a sensory compensation sub-algorithm, a guidance sub-algorithm, and a control sub-algorithm. The sensory compensation sub-algorithm uses a simplified potential model of the local scent environment to cancel discovered scent source effects on its sensory perception, the guidance control algorithm produces a desired trajectory for bug motion which is based on a simplified friction model, and the control sub-algorithm forces the bugs actual trajectory to the desired trajectory. Bug cooperation is performed by using the concepts of social rank.
An Intelligent Tool With Adaptive Structure for L-Bending Process of Sheet Metals
Authors: Yang Ming , Manabe Ken-ichi 
Published: January 2022

Abstract
In this study, an intelligent tool system for flexible L-bending of sheet metals is developed. The punch and die are adaptively actuated by hydraulic cylinders incorporated in the punch and die, respectively. An adaptive structure with high stiffness and motion accuracy is designed and compared with a formerly developed one. The tool system can basically change the profile of the tools and pressure distribution along the workpiece during the L-bending process. The system is characterized by its capability to bend the workpiece to various bending radii and bend angles for different materials without tool change. Process control paths for obtaining desired bend radii and angles are determined off-line by a numerical simulation using the elasto-plastic model. The paths are stacked into a simulation database and used for real-time control of the L-bending process. The measured data from the sensors are input into a computer for controlling the actuators and learning the control model by comparing it with the simulated data. Several experiments have been carried out for obtaining various bend radii using two kinds of materials, SPC and aluminum alloy. The experimental results corresponded not only to various bending radii but also different materials. In addition, higher accuracy of the process control has been achieved by improving the structure of the tool system and learning the process control model. These results prove the validity and reliability of the proposed intelligent tool system.
Performance Comparison of Magnetorheological and Electrorheological Materials in Adaptive Structural Applications
Authors: Yalcintas Melek , Dai Heming 
Published: January 2022

Abstract
Magnetorheological (MR) and electrorheological (ER) materials show variations in their rheological properties when subjected to varying magnetic and electric fields respectively. They have quick time response, in the order of milliseconds, and thus are potentially applicable to structures and devices when tunable system response is required. When incorporated into an adaptive structural system, they can yield higher variations in the dynamic response of the structure. This study presents a detailed analysis of vibration control capabilities of adaptive structures based on MR and ER materials, and compares their vibration minimization rates, time responses, and energy consumption rates. Homogenous one-dimensional MR and ER adaptive beam configurations were considered. Structural dynamic modeling approach was discussed, and vibration characteristics of MR and ER adaptive beams were predicted for different magnetic and electric field levels. In addition to the model predictions, actual MR and ER adaptive beams were fabricated and tested. Both studies illustrated the vibration minimization capabilities of the MR and ER adaptive beams at different rates and environmental conditions. The relative performances of both MR and ER adaptive beams were discussed in detail and their advantages and disadvantages were listed.
Dynamic Characterization of Grid Stiffened Composite Panels for Active Structural-Acoustic Control
Authors: Newbury Kenneth , Glaese Roger , Leo Donald , Anderson Eric 
Published: January 2022

Abstract
This paper presents a dynamic characterization of a sample plate of a grid stiffened composite material being developed for use in launch vehicle payload fairings. First, experimental modal analysis is performed to identify the plate’s global modes. The global modes are used for finite element model correlation and for a sound power radiation study which identifies the dominant radiator modes. Next is a strain transfer study using piezoceramic actuators bonded to the plate surface and to the stiffener ribs. Efforts are focused on the ability to sense and excite the dominant radiator modes using the piezoceramic actuators.
Enhanced Piezoelectric Shunt Design
Authors: Park Chul H. , Kabeya Kazuhisa , Inman Daniel J. 
Published: January 2022

Abstract
Piezo ceramic patches connected to electronic shunt circuits have formed successful vibration reduction devices. Here a new shunt circuit design with additional capacitors is presented. One drawback of existing electronic shunt circuits is the large inductance required when suppressing low frequency vibration. Also, the large internal resistance associated with this high inductance value exceeds the optimal design resistance needed for vibration suppression. To solve these problems, a modified and improved piezoelectric shunt circuit is designed by connecting additional capacitors in parallel. This design is experimentally demonstrated for a desired tuned mode of an aluminum beam. The results indicate that improved electronic passive damping can significantly reduce the structural vibration response with half of the inductance previously required.
Adaptive Shape Control of Precision Membrane Antennae and Reflectors
Authors: Jenkins C. H. , Kalanovic V. D. , Faisal S. M. , Padmanabhan K. , Tampi M. 
Published: January 2022

Abstract
A resurgence of interest in membrane structures in space is developing after a brief period of activity about two decades ago. This renewal is motivated in large part by the great potential for reduced launch mass and stowed volume that membrane structures can afford. Applications for such structures range from planar configurations in solar sails, concentrators, and shields, to inflatable lenticulars for radar, radio, and optical purposes. Three key factors are paramount for the success and user acceptance of this technology: deployment, longevity, and performance. Performance hinges critically on the precision of the membrane surface.
Nonlinear controllers developed to improve performance of such systems are often dependent on state estimation and parameter identification procedures. The existence of these procedures, within the control strategy, increases the size of the algorithms, limiting the system performance in real-time. The research presented has as a main objective to create an intelligent controller, based on feedback error learning, which is capable of extracting performance information from precision large membrane deployables, and subsequently using this information to achieve maximum surface precision.
This paper addresses the problem of modeling and controlling a class of nonlinear systems that can be considered as highly compliant structures, specifically planar and inflatable membranes, which are represented by complex nonlinear multi-variable models. Methods of noncontact local state estimation are considered in order to provide feedback on the membrane shape, which would then be coupled with a mathematical model of boundary perturbation and/or thermal effects for control efforts.
Robust Position Control of Flexible Adaptive Structures With Embedded PZT Actuators
Authors: Wilson D. G. , Parker G. G. , Starr G. P. , Robinett R. D. 
Published: January 2022

Abstract
In this paper we present a hybrid Sliding Mode Control (SMC) and Constant Amplitude Feedback Control (CAFC) architecture for a slewing flexible adaptive structure. The SMC controller is used to servo the adaptive structure and the CAFC is used to suppress vibrations of the flexible structure. In addition a traditional Linear-Quadratic Regulator (LQR) controller was developed and tested. This system consists of 1) a single-axis servo DC motor and encoder for large angle slewing and 2) a graphite/epoxy composite structure with embedded strain sensors/actuators for active vibration suppression. The results of this study include the analytical development and numerical simulation verification. Minimum time maneuvers based on an equivalent rigid structure are used to slew the flexible active structure. Numerical simulation studies were performed to compare the SMC/CAFC controller with the LQR controller. A nonlinear optimization algorithm was used to determine optimal component weights for the LQR control weighting matrices Q and R. Both controllers were also compared to a passive SMC case to show benefits of using active vibration control. Several case studies are reviewed that involve minimizing tracking and residual tip deflection errors. The results showed a reduction in residual vibration for both cases studied. A final test was performed that investigated the robustness to parameter variations by increasing the tip mass. Both control architectures showed favorable results, but the LQR controller required larger control effort.
Quantization Effects on Digital Control of Structural Vibration
Authors: Sun Jian , Shahin Ali. R. 
Published: January 2022

Abstract
The implementation of a digital control system for the response of a structure will introduce nonlinearities due to the finite-word-length effects. This paper investigates regions of stability, possible existence of limit-cycles and unstable regions for a SISO digital control system for structural vibrations due to quantizer. A cantilever plate is modeled by the finite element method and controlled by a digital control system.
Crash Analysis of Two Vehicles in Frontal Impact Using Adaptive Artificial Neural Networks
Authors: Omar Tarek A. , Eskandarian Azim , Bedewi Nabih E. 
Published: January 2022

Abstract
An advanced recurrent Artificial Neural Network (ANN) was developed and used to model and analyze the frontal impact of two different vehicles. The main factors affecting the vehicle response — in case of frontal impacts — are the impact velocity and the structural characteristics of the vehicle. Each vehicle was represented by a corresponding ANN, and the mutual interaction between the two vehicles during the impact was considered in the ANN input. An adaptive learning technique was used to correct both the connections’ weights and the steepness factor of the neurons’ continuous activation functions to reduce the computation time during the supervised learning phase.
Nonlinear finite element (FE) simulations were performed for two different vehicle models in frontal impact scenarios using different impact velocities. The results obtained by the FE simulations were used in training and testing the proposed ANN model. The passenger compartment acceleration of the vehicle during the first 100 ms of the impact event was the main criteria considered in the crash analysis. The performance of the proposed ANN configuration was very good in both training and testing phases. The proposed technique explained the ability of the adapted ANNs to store the nonlinear structural characteristics of the two vehicles after a successful training phase. These two networks were then used together to predict a new different impact scenario. The predicted velocity and acceleration curves for the new impact scenario correlated well with the corresponding curves obtained from the FE simulation.
The current technique was applied only for frontal impact scenario, however, further research will be considered to extend the methodology to be applicable for both offset and oblique impact scenarios.
Sensitivity Analysis of Static Side Door Intrusion
Authors: ElHor Hassan H. , May Thomas A. , Jurosek Mike L. 
Published: January 2022

Abstract
This paper identifies the most important parameters that contribute to the strength of the door in a static intrusion, in order to satisfy the FMVSS 214 Standards. Side door intrusion requires the door to resist three stages of loading at several crash distances: initial (6″), intermediate (12″) and peak (18″). Thickness, shape and material of the side door beam are among the most important parameters considered in this study, latch and hinge strengths are also included.
A sensitivity evaluation analysis is performed where the main objective is to investigate the sensitivity of those parameters to changes, and their impact on the structural performance of the side door and its resistance. The various results are presented in tables and graphs to show the effect of each of those parameters.
Numerical Simulation on Turbulent Buoyant Jets in a Flowing Stratified Ambient
Authors: Hwang Robert R. , Chiang T. P. 
Published: January 2022

Abstract
In this study, an investigation using a 3-D numerical model, which treats conservation of mass, momentum and salinity simultaneously, was carried out to study the detailed flow field of a buoyant jet in a uniform cross-stream of stable linearly stratified environment. A k-ε turbulence model was used to simulate the turbulent phenomena and close the solving problem. Results indicate that the numerical computation simulates satisfactorily the plume behavior in a stratified crossflow. The ambient stratification tends to inhibit the flow development by inducing pairs of vortex as the plume flowing downstream and results in causing the jet-flow oscillation from its maximum height-of-rise.
Application of Embedded Parallelism to Large Scale Computations of Complex Industrial Flows
Authors: Tafti D. K. , Wang G. 
Published: January 2022

Abstract
The paper combines advances in computational fluid dynamics with advances in computer architectures and programming paradigms to extend the state-of-the-art in large-scale computations of complex industrial flows. The present work combines traditional distributed memory programming with shared memory programming, and hence has the advantage of imposed data locality of the former as well as the ease and flexibility of the latter. Conceptually, it manifests the architectural features of Distributed Shared Memory (DSM) and complements the concept of hierarchical domain decomposition for cache friendly algorithms on microprocessor based parallel systems. We demonstrate this concept through three-dimensional simulations of developing flow and heat transfer in a multilouvered fin array.
Isothermal Flow Distribution in Coupled Manifolds: Comparison of Results From CFD and an Integral Model
Authors: Jones G. F. , Galliera J. M. 
Published: January 2022

Abstract
Isothermal, incompressible flow distribution in the coupled manifold continues to be of interest to the industrial, engineering, and scientific communities. Several investigations carried out in the past have considered the suitability of a CFD code (Fluent) for predicting detailed velocity and pressure distributions for three dimensional dividing flow in a 90° tee junction. Results from these cast doubt on the successful use of CFD to model the complex flow in a tee. The focus of the present work is to determine if the same code can accurately predict the larger-scale features of three dimensional branching flows and in a coupled manifold having three risers. Simulations were performed for flow in the coupled manifold and for both laminar and turbulent, dividing and combining flow in a tee section for a broad range of flow branching conditions. The ratio of riser diameter to manifold diameter is fixed at 0.75 for this study. The turbulent models used are the standard and renormalization group k-ϵ models. All constants in these models are set to their respective default values. Static pressure re-gain factors are calculated from the results of CFD simulations and are favorably compared with the data of others. These data are then used in an existing integral model for flow in coupled manifolds. The good agreement between the results from the integral model and the CFD model for flow in the coupled manifold attests to the suitability of the integral model for this problem. The advantage of the integral approach is the speed at which the problem can be solved by the computer, and the fact that there is no need for the time-consuming and expensive geometrical modeling and mesh generation normally associated with finite element and finite difference models.
Skin Friction Measurement in Low Reynolds Number Shallow Open Channel Flows
Authors: Ramachandran Shyam S. , Balachandar Ram 
Published: January 2022

Abstract
The present study was conducted to measure skin friction in shallow open channel flows at low Reynolds numbers. The study was aimed at extending the database towards lower values of Reynolds number (180 ≤ Reθ ≤ 480) based on the momentum thickness. The validity of the semi-empirical laws characterizing the turbulent boundary layer is examined. The method for accurately determining the wall shear stress and hence the skin-friction coefficient in an open channel is verified.
Integration Methodology for Implementing a Teleservice Engineering System
Authors: Lee Jay , Tsai John 
Published: January 2022

Abstract
Machine maintenance is a critical task to assure operations’ efficiency, reliability, and safety. As manufacturing becomes more globalized, the challenge is how to leverage information technologies to sustain high-quality and just-in,-time maintenance services to global facilities.
This paper introduces a methodology for implementing a teleservice engineering system. This methodology provides manufacturers with a multi-level systematic framework to monitor any highly complex manufacturing system such as a distributed automated storage and retrieval or materials handling system.
A Mechanistic Force Model for Contour Turning
Authors: Gajjela Rohit R. , Kapoor Shiv G. , DeVor Richard E. 
Published: January 2022

Abstract
In this paper a mechanistic model for contour turning is presented. A chip load model is developed for general contour turning process. Analytical expressions are derived for chip thickness and chip load in a simple case of contour turning. A generalized numerical procedure is also developed for evaluation of various cutting parameters like cutting velocity, effective lead angle, chip thickness, chip load, normal rake angle, and chip flow angle. The effects of these parameter variations on the cutting forces are analyzed. As a special case hemispherical turning is considered for model validation. Simple straight turning tests are employed for model calibration. The interference between tool and workpiece and ploughing are identified as possible causes for an abrupt increase observed in the cutting forces. Use of circular inserts with large nose radius eliminates this problem. Experimental validation is done with circular inserts.