bluuebunny/crossref_metadata_2025_split huggingface dataset:
Target Cascading: A Design Process for Achieving Vehicle Ride and Handling Targets
Authors: Rideout D. Geoff , Stein Jeffrey L. , Ferris John B. 
Published: November 2021

Abstract
Vehicle dynamics are well understood by both academic researchers and automotive industries. And while modeling and simulation tools are still underutilized, they are becoming more frequently used in the vehicle design process. However, there is still lacking an overall design methodology that can link and integrate in a systematic fashion the design tasks of individual components or systems such that the vehicle performs as intended with a minimal number of design iterations. A process called Target Cascading, applied in the early stages of vehicle design, might serve as this systematic design methodology. In this paper, Target Cascading is evaluated for its ability to propagate top-level design specifications down to specifications for various subsystems and components in a vehicle design problem. More specifically, general ride and handling targets are set for a vehicle and these are cascaded down through the suspension, tire pressure and spring design levels by partitioning the original problem into a hierarchical set of subproblems. At a given level, an optimization problem is formulated to minimize deviations from the proposed targets and thus achieve intersystem compatibility. A coordination strategy links all subproblem decisions so that the overall supersystem performance targets are met. Results are presented that demonstrate Target Cascading’s utility in unearthing tradeoffs and incompatibilities among initial targets early in the vehicle development cycle. Throughout the paper, the Target Cascading process is compared to traditional vehicle design strategies for achieving ride and handling targets. Target Cascading appears to be a promising systematic technique for the design of vehicles to meet ride and handling specifications.
Should Adaptive Cruise Control (ACC) Systems Be Designed to Maintain a Constant Time-Gap Between Vehicles?
Authors: Wang Junmin , Rajamani Rajesh 
Published: November 2021

Abstract
This paper addresses the stability of traffic flow on a highway when the vehicles operate under an adaptive cruise control (ACC) system. ACC systems are commonly designed to maintain a constant time-gap between vehicles during vehicle following. Previous researchers in literature have produced contradictory results on whether the traffic flow is stable when the constant time gap spacing policy is used. This paper resolves the contradiction and shows that the boundary conditions used at the inlets and exits influence traffic flow stability in the case of the constant time-gap policy. Further, the paper shows that it is possible to design an unconditionally stable spacing policy, i.e. a spacing policy which guarantees traffic stability under all boundary conditions. The practical implications of instability are shown through traffic simulation results. The advantages of an unconditionally stable spacing policy over the constant time-gap policy are demonstrated. The answer to the question “Should ACC systems be designed to maintain a constant time gap between vehicles?” is NO. It is quite easy to develop alternate spacing policies with superior stability properties.
Networked Control of Distributed Systems: A Testbed
Authors: Stubbs Andrew , Dullerud Geir E. 
Published: November 2021

Abstract
A testbed for networked control of dynamical systems, recently developed by the authors at the University of Illinois, is described. It is comprised of planar aerial vehicles (hovercraft) which use the Bluetooth chipset for wireless communication, and inertial and vision sensing. The testbed is directly connected, via a Linux-based ground station, to a large Internet networking laboratory containing numerous routers, and thus the developed facility has the capability to model numerous wireless and Internet scenarios in networked control.
Stability Analysis of a Shape Memory Alloy Adaptive Tuned Vibration Absorber Under PI Control With Anti-Windup
Authors: Williams Keith A. , Chiu George , Bernhard Robert 
Published: November 2021

Abstract
This paper presents a stability analysis of a continuously controlled adaptive tuned vibration absorber (ATVA) incorporating shape memory alloy (SMA) structural elements to realize attenuation of the vibration of a primary system subject to uncertain tonal excitation. The objective is for the SMA ATVA stiffness to be adapted such that a relative phase angle of −90° is achieved between the vibration of the SMA ATVA and the primary mass. The Lyapunov-based stability analysis indicates that the system is stable under proportional-plus-integral control across the operating range of the SMA ATVA when an integral reset is included in the control algorithm. The integral reset also substantially improves the performance of the system when compared to the original PI controller without reset.
Active Balancing and Optimal Balancing Plane Selection of Rotors During Acceleration
Authors: Zhou Shiyu , Shin Kwang-keun , Dyer Stephen W. , Shi Jianjun , Ni Jun 
Published: November 2021

Abstract
This paper presents an active balancing method to reduce the imbalance-induced vibration of rotating machinery. In this method, the rotor was modeled by influence coefficient and a gain scheduling strategy was proposed to suppress the imbalance-induced vibration during acceleration. Besides the theoretical derivation of this active balancing algorithm, a comprehensive testbed was built to validate this scheme. The validation results were presented. To apply an active balancing scheme, the axial position of the actuator needs to be determined. This paper also presents an optimal balance plane selection procedure. A numerical study shows the effectiveness of this selection method.
The Active Control of Motion in a Composite Structure
Authors: Badea Traian , Chiroiu Veturia , Munteanu Ligia 
Published: November 2021

Abstract
The purpose of this paper is to propose a configuration for a piezoelectric composite structure that can control the motion caused by mechanical loads. The composite structure is composed of two semi-infinite layers: one layer of main material, and another layer of piezoelectric material with Cantor-like structure. We show that the displacement distribution can be controlled actively by applying a voltage to the piezoelectric material.
Disturbance Rejection Using Two Degree of Freedom Repetitive Control Through Mixed Sensitivity Optimization
Authors: Chen Cheng-Lun , Chiu George T.-C. 
Published: November 2021

Abstract
In this paper, a repetitive control based 2 degree-of-freedom (DOF) controller for a SISO motor/gear-train system is proposed. Instead of sequential design, it is shown that the optimal 2 DOF controller for such system can be obtained simultaneously by solving an mixed-sensitivity problem. The simulation results are presented to show the feasibility and effectiveness of the proposed control structure for periodic and non-periodic disturbance reduction for motor/gear-train velocity regulation.
State/Parameter/Disturbance Estimation With an Accelerometer in Precision Motion Control of a Linear Motor
Authors: Lee Dong-Jun , Tomizuka Masayoshi 
Published: November 2021

Abstract
In this paper, the use of an accelerometer in precision motion control of linear motors is investigated. The acceleration measurement can provide several advantages. In particular, it can be used with the position measurement for estimation of the position and velocity based on a kinematic model. It can be further utilized for identification of dynamic parameters such as coulomb friction and cogging force as well as for estimation of disturbance. Experimental results verify the effectiveness of the proposed estimation/identification schemes. These schemes are integrated into a two-degree of freedom control system for precision motion control of linear motors. The proposed schemes are evaluated by experiments performed on a linear permanent-magnet motor.
Logic Control Design and Implementation for a Machining Line Testbed Using Petri Nets
Authors: Gollapudi Chandra , Tilbury Dawn 
Published: November 2021

Abstract
Historically, logic control for machining systems has been programmed in ladder logic. Although this language is very intuitive at a low level, it is difficult to understand the sequencing in a large and complex program. Recently, several different formal languages, such as Petri nets, finite state machines, and real-time temporal logic, have been proposed for logic control design. These languages allow the logic to be formally verified to be correct before it is implemented. The proofs of correctness rely on a set of explicit and implicit assumptions. By implementing these methods on a testbed system, the advantages and limitations can be more easily seen. This paper describes an implementation of a formal method for logic control design using Petri nets on a small-scale testbed at the University of Michigan using software developed at the University of Kentucky.
Kinetostatic Behaviour of the Prismatic Pair With Clearance
Authors: Parenti-Castelli V. , Venanzi S. 
Published: November 2021

Abstract
In order to make mechanisms work the presence of clearance in kinematic pairs may be unavoidable. As a major consequence position and orientation errors of the output link occur when loads are applied to the mechanism. This paper focusses on the effect of clearance on the dislocation of the pairing elements of the prismatic pair. A kinetostatic model of the prismatic pair with clearance is presented and contact modes of the pairing elements are found. A particular geometry of the prismatic pair is considered to illustrate the proposed approach which can be used, in principle, for any pair geometry. The proposed model may be implemented in kinematic, kinetostatic and dynamic analyses as well, for the purpose of computing the influence of clearance on position-orientation errors of any link of the mechanism. Finally a numerical example is reported.
Investigation and Comparison of Possible Boundary Conditions and System Vibration Modes in Two-Link Flexible Manipulators
Authors: Cheong Joono , Youm Youngil , Chung Wan Kyun 
Published: November 2021

Abstract
In the slewing multi-link flexible robot systems, the natural frequencies and mode shapes have been determined using the assumed component mode method with clamped-joint condition, in which the system modes is reconstructed by the series of assumed modes of each link. This method, however, requires large number of assumed modes to accurately describe the system and even more, sometimes, the results are erroneous. The direct analytic solution of entire system vibration mode which is a comparative concept of assumed mode method can accurately account for the entire vibration with a few number of significant modes.
This paper deals with system vibration modes of two-link flexible robot and their appropriate boundary conditions. There are four possible set of boundary conditions, that is, clamped-clamped, clamped-spring, spring-clamped, spring-spring, according to joint servo condition, and we compare mode shapes and modal frequencies of each case by numerical and experimental results. We also provide important characteristics of natural mode when imposed certain kind of boundary conditions.
On the Use of the Level Set Method With Unstructured Grids
Authors: Shepel Sergey V. , Paolucci Samuel 
Published: November 2021

Abstract
A mass preserving finite element formulation of the Level Set method is presented. The formulation is based on the discontinuous representation of the level set function and involves the Runge-Kutta Discontinuous Galerkin (RKDG) finite element method. The resulting formulation has the flexibility of treating a complicated geometry by using arbitrary triangulation. The performance of the scheme is demonstrated on a number of two-dimensional re-distance and coupled advection-redistance problems. The results indicate that the RKDG finite element formulation provides accurate solutions of the Level Set problem and has great potential in fluid dynamics applications.
Numerical Simulation of Methane-Air Nozzle Burners for Aluminum Remelt Furnaces
Authors: Mukhopadhyay Achintya , Puri Ishwar K. , Zelepouga Serguei , Rue David M. 
Published: November 2021

Abstract
A turbulent nozzle-mix burner, suitable for industrial use in aluminum remelt furnaces has been numerically simulated using FLUENT software. The burner has been modeled as a vertical axisymmetric arrangement of fuel duct at the center, surrounded by a coaxial annular duct of air. The ducts discharge into a confined environment, formed by a chimney, placed coaxially with the ducts. The effects of fuel velocity and air coflow velocity ratio on the flame height have been investigated. The flame height is found to increase with increase in fuel velocity for a given air-fuel velocity ratio and with decrease in air velocity for a given fuel velocity. The different flame height definitions found in literature give nearly identical flame heights for all the cases studied.
Simulation of Multi-Phase Glass-Melt Flows in a Glass Melter
Authors: Chang S. L. , Zhou C. Q. , Golchert B. , Petrick M. 
Published: November 2021

Abstract
A typical glass furnace consists of a combustion space and a melter. The intense heat, generated from the combustion of fuel and air/oxygen in the combustion space, is transferred mainly by radiation to the melter where the melt sand and cullet (scrap glass) are melted, creating molten glass. The melter flow is a complex multi-phase flow including solid batches of sand/cullet and molten glass. Proper modeling of the flow patterns of the solid batch and liquid glass is a key to determining the glass quality and furnace efficiency. A multi-phase CFD code has been developed to simulate glass melter flow. It uses an Eulerian approach for both the solid batch and the liquid glass-melt flows. The mass, momentum, and energy conservation equations of the batch flow are used to solve for local batch particle number density, velocity, and temperature. In a similar manner, the conservation equations of mass, momentum, and energy of the glass-melt flow are used to solve for local liquid molten glass pressure, velocity, and temperature. The solid batch is melted on the top by the heat from the combustion space and from below by heat from the glass-melt flow. The heat transfer rate from the combustion space is calculated from a radiation model calculation while the heat transfer rate from the glass-melt flow to the solid batch is calculated from a model based on local particle number density and glass-melt temperature. Energy and mass are balanced between the batch and the glass-melt. Batch coverage is determined from local particle number density and velocity. A commercial-scale glass melter has been simulated at different operating/design conditions.
Temporally Resolved Radiation Spectra From a Sooting, Turbulent Pool Fire
Authors: Kearney Sean P. 
Published: November 2021

Abstract
Infrared radiation spectra from a 1-m diameter, JP-8-fueled, liquid pool fire in nominally quiescent surroundings have been acquired using a novel IR spectrometer. Data were acquired at a rate of 390 spectra/sec allowing for a time-resolved description of the radiation from the fully turbulent fire plume. Results are discussed in terms of an effective homogeneous pathlength and both gray and nongray spectral models, of which the gray model surprisingly fits the data in the soot-dominated regions of the spectrum more effectively. The results from the gray model are used to provide statistical descriptions of the heat transfer from the fire plume in terms of probability density functions (PDFs) of the effective fire temperature and emissivity.
Radiation Heat Transfer to the Leeward Side of a Massive Object Suspended Over a Pool Fire
Authors: Kramer M. Alex , Greiner Miles , Koski J. A. 
Published: November 2021

Abstract
A series of large-scale experiments were recently performed to measure heat transfer to a massive cylindrical calorimeter engulfed in a 30-minute circular-pool fire [1]. The calorimeter inner surface temperature was measured at several locations and an inverse conduction technique was used to determine the net heat flux. The flame emissive heat flux was measured at several locations around the calorimeter. Light winds of around 2 m/s blew across the calorimeter axis at the beginning of the test but diminished and stopped as the test continued. The winds tilted the fire so that the windward side of the calorimeter was only intermittently engulfed. As a result, the measured flame emissive power near the windward side was substantially less than the leeward surface. The variation of calorimeter temperature and heat flux was closely correlated with the measured flame emissive power.
Using Artificial Neural Networks to Develop a Predictive Method From Complex Experimental Heat Transfer Data
Authors: Kelleher Matthew D. , Cronley Thomas J. , Yang K. T. , Sen Mihir 
Published: November 2021

Abstract
Artificial neural networks are employed to develop a predictive algorithm using experimental heat transfer data for a complex situation. The data of Marto and Anderson has used to illustrate the process. This data is from a series of experiments investigating the boiling heat transfer from a vertical bank of tubes in refrigerant 114 with variable amounts of oil present. Both finned and unfinned tubes were investigated. The network was trained with a partial set of the available data. The prediction obtained using the trained network was then compared to the remaining experimental data. The artificial neural network provided an excellent predictive method.
Studies on Natural Convection Induced Flow and Thermal Behavior Inside Electronic Equipment Cabinet Model
Authors: Ishizuka Masaru , Peng Guoyi , Hayama Shinji 
Published: November 2021

Abstract
In the present work, an important basic flow phenomena, the natural convection induced flow, is studied numerically. Three-dimensional Navier-Stokes equations along with the temperature equation are solved on the basis of finite difference method. Generalized coordinate system is used so that sufficient grid resolution could be achieved in the body surface boundary layer region. Differential terms with respect to time are approximated by forward differences, diffusions terms are approximated by the implicit Euler form, convection terms in the Navier-Stokes equations are approximated by the third order upwind difference scheme. The heat flux at the body surface of heater is specified. The results of calculation showed a satisfactory agreement with the measured data and led to a good understanding of the overall flow and thermal behavior inside electronic equipment cabinet model which is very difficult, if not impossible, to gather by experiment.
A Simplified Numerical Model to Predict the Velocity Field in a Catalytic Cracking Unity in Oil Refineries
Authors: Souza J. A. , Vargas J. V. C. , von Meien O. F. , Vlassov D. I. 
Published: November 2021

Abstract
This paper introduces a general computational model for determining the velocity field in either reacting or non-reacting duct flows. The model is then applied to a catalytic cracking unit (FCC) of an oil refinery, to determine the velocity field inside the riser, where reactions take place to convert heavy petroleum fractions in lighter products, like middle distillates and light olefins, with high rates of conversion and productivity. The correct approach to simulate this process is to avoid the plug flow assumption and to solve the full fluid flow problem, based on the mass and momentum conservation equations in a complete formulation, which are shown in the literature to be computationally very expensive and time consuming, mainly in a three-dimensional (3-D) simulation. Since, the main objective of the simulation is the accurate determination of the concentration of the noble products, a very accurate velocity field is not mandatory. Therefore, bidimensional flow is assumed, and a modified set of unsteady mass and momentum conservation equations is proposed and the resulting 2-D differential equations are discretized in space using an upwind cell centered finite differences method, and the equations integrated in time with an implicit backward Euler scheme. The coarsest possible mesh is determined such that the solution relative error is within 5 % when compared to a steady state accurate finite element solution, which was obtained with a 2-D isoparametric, four-noded, linear element that was implemented to solve the complete Navier-Stokes equations for the finite element analysis program, FEAP [1]. The objective of this work is to propose an alternative technique that gives a simplified treatment to the velocity field, to make possible the numerical calculation of the products concentrations in the riser and future application in optimization and real time control. Each cell, in this specific situation, can be understood as a perfect mixing reactor.
Radiation and Induced Convection in Ventilated Enclosures
Authors: Ziskind G. , Dubovsky V. , Letan R. 
Published: November 2021

Abstract
The paper presents a thorough numerical investigation of the effects of radiation and induced convection inside an enclosure. The objective is to assess the interaction of these two mechanisms in real size buildings with heating elements inside.
As a first step, a small size model is studied. The investigation is performed for closed and partially open enclosures. Temperature distributions and flow fields inside the enclosure are obtained for different values of the heat-transfer parameters, like emissivity of the hot element and the walls, and the thermal resistance of the walls. It is shown that radiation can considerably affect the air flow inside the enclosure. Real-size structures, where turbulent flow prevails, are compared to the model.
Three-dimensional simulations are performed. The influence of grid refinement on the results is discussed. The results obtained for a uniform grid are compared to those for a non-uniform one, having higher density at the boundaries. Special attention is paid to the radiation modeling, where the influence of angular discretization is important.
Quantitative Validation of Mathematical Models
Authors: Dowding Kevin 
Published: November 2021

Abstract
Validation is a process to compare a mathematical model with a set of physical experiment to quantify the accuracy of the model to represent the physical world (experiment). Because the goal is to use experiments to quantify the accuracy of the mathematical model, the interaction of the model and experiment must be carefully studied. Advancing the comparison beyond a qualitative nature requires consideration of the errors in the process and the effect of these errors on the comparison. The mathematical model, in conjunction with sensitivity analysis, uncertainty analysis, and statistical analysis are tools for studying the interaction of the model and experiment and quantifying the effect of errors. A model for steady state heat conduction is used to discuss issues associated with the errors in the validation process and demonstrate a quantitative process to study validation of mathematical models.
Simultaneous Determination of Steady Temperatures and Heat Fluxes on Surfaces of Three Dimensional Objects Using FEM
Authors: Dennis Brian H. , Dulikravich George S. 
Published: November 2021

Abstract
A finite element method (FEM) formulation is presented for the prediction of unknown steady boundary conditions in heat conduction on multiply connected three-dimensional solid objects. The present FEM formulation is capable of determining temperatures and heat fluxes on the boundaries where such quantities are unknown or inaccessible, provided such quantities are sufficiently over-specified on other boundaries. Details of the discretization, linear system solution techniques, regularization, and sample results for 3-D problems are presented.