bluuebunny/crossref_metadata_2025_split huggingface dataset:
The PIER Parallel FEA Program Generator
Authors: Sharma Naveen , Wang Paul S. 
Published: March 2021

Abstract
In this paper we describe a coupled symbolic-numeric approach for solving PDE-based mathematical models on sequential and parallel computers. PIER, an experimental software system that we are developing, synthesizes F77 subroutines for finite element modeling directly from very-high level user input specifications. The system is being developed in Common Lisp and uses MAXIMA computer algebra system for symbolic mathematical computations.
PIER input syntax provide high-level statements to specify finite element discretization and methods for solving systems of equations. The user composes the finite element analysis process using MAXIMA input syntax and F77 statements along with these statements. Symbolic quantities for element formulation like shape functions, element equations etc. are automatically derived. The input model characteristics, derived formulae, desired solution methods, and the target machine knowledge are then used to generate numerical code for FEA solution steps.
The benefits of this approach include: 1) substantially reducing the time and effort required to solve mathematical models, 2) ability to solve models in higher-dimensions, and 3) automatic retargeting of numeric computations to multiple parallel architectures. Currently, we are applying the techniques developed in our research to the numeric solution of problems in computational liquid crystal physics and the theory of elasticity. Sequent shared-memory multiprocessor is the current target parallel computer.
The Practical Application of Advanced Statistical Techniques for Computer-Based Quality Control
Authors: Robinson David C. , Mazharsolook Ebrahim , Sanders David A. 
Published: March 2021

Abstract
Innovative methods are explored for computer based quality control of parts manufacture. The approach is based on the use of analysis of variance techniques and regression modelling to formulate a description (model) of the product and process in terms of product quality. This model is then employed in a computer based on-line quality control strategy in which the aim is to optimise manufacturing quality by attempting to compensate for product deviations.
Available quality control software is based on methodologies developed in the 1920s [1]. It is concerned with the presentation of data and off-line analysis rather than the decision making process. By integrating statistics and quality control strategies, computer based decisions can be formulated based on larger quantities of data than a human could assimilate. Such decisions can be made more accurately and in a fraction of the time taken by manual means.
A case study is presented which is concerned with the implementation of computer based on-line quality control of manufacture. This case study was successfully completed with a reduction in the first time reject rate from thirty percent to below four percent. The case study shows the generic nature of the method and also the diversity of application.
Image Stabilization for a Camera on a Moving Platform
Authors: Tucker Joseph C. , de Sam Lazaro Anthony 
Published: March 2021

Abstract
The problem of video tele-operation of a moving vehicle is compounded by the fact that a camera mounted on such a vehicle moves rather violently and randomly depending on the terrain. This contributes to motion sickness of the operator who is controlling the vehicle from a stationary platform. In order to correct this problem, motion of the camera is counteracted by a stabilization routine that can account for all unwanted vibrations. A possibilistic model is described. The experimental set-up and preliminary results are presented.
Artificial Neural Networks Used As a Rule Selector for Fuzzy Logic Controllers
Authors: Huang Shou-Heng , Nelson Ron M. 
Published: March 2021

Abstract
A feedforward, three-layer, partially-connected artificial neural network (ANN) is proposed to be used as a rule selector for a rule-based fuzzy logic controller. This will allow the controller to adapt to various control modes and operating conditions for different plants. A principal advantage of an ANN over a look up table is that the ANN can make good estimates to fill in for missing data. The control modes, operating conditions, and control rule sets are encoded into binary numbers as the inputs and outputs for the ANN. The General Delta Rule is used in the backpropagation learning process to update the ANN weights. The proposed ANN has a simple topological structure and results in a simple analysis and relatively easy implementation. The average square error and the maximal absolute error are used to judge if the correct connections between neurons are set up. Computer simulations are used to demonstrate the effectiveness of this ANN as a rule selector.
Teaching the Finite Element Method As a Design Tool for Mechanical Engineering
Authors: Grimm T. R. 
Published: March 2021

Abstract
The importance of the finite element method as an engineering tool for design and analysis is emphasized in a senior level elective course taught at Michigan Technological University. The course emphasizes hands-on experience with computers and the pre- and post-analysis of results to establish confidence in solutions obtained. The students learn by using the finite element method to “solve” several design projects, rather than by being told about the method without significant actual experience. They also learn about the basis of the method, including formation of the matrix equations required and the numerical methods used in their solution. Intelligent use of the method requires that engineers understand both the mechanics of how to apply the method, i.e modeling requirements, and the limitations imposed by the basic solution process. The course provides the students with important experience in using the powerful finite element method as a design tool. It requires a strong background of fundamentals and stimulates the problem solving thinking skills so essential to industry.
Solving Large Linear Equations Using PVM System
Authors: Li Qiang , Liu Jyh-chum , Yip T. Gary 
Published: March 2021

Abstract
This paper presents a solution to large simultaneous linear equations on a distributed system. The solution is a parallel version of Gauss-Jordan elimination that runs on a network of workstations. The software platform is the PVM system (Parallel Virtual Machine). The goal is to achieve computational speedup for large tasks by utilizing idle time on available workstations. Since the system is a loosely coupled system, we are not striving for the linear speedup as one would do in the case of a tightly coupled parallel machine. The solution is based on dense coefficient matrices. Gauss-Jordan elimination is nicely parallelized into large grain parallel subtasks suitable for the distributed system. Performance evaluation results are presented.
Hilbert Transform Generalization of a Classical Random Vibration Integral
Authors: Spanos Pol D. , Miller Scott M. 
Published: March 2021

Abstract
Integrals which represent the spectral moments of the stationary response of a linear, time-invariant system under random excitation are considered. It is shown that these integrals can be determined through the solution of linear algebraic equations. These equations are derived by considering differential equations for both the autocorrelation function of the system response and its Hilbert transform. The method can be applied to determine both even order and odd order spectral moments. Furthermore, it provides a potent generalization of a classical formula used in control engineering and applied mathematics. The applicability of the derived formula is demonstrated by considering random excitations with, among others, the white noise, “Gaussian”, and Kanai-Tajimi seismic spectra. The results for the classical problem of a randomly excited single-degree-of-freedom oscillator are given in a concise and readily applicable format.
Linear and Nonlinear Instabilities in a Flexible Mechanism
Authors: Beale David G. , Lee Shyr Wen 
Published: March 2021

Abstract
An analytical and experimental comparison is made between the stability of the linear and nonlinear equation response of a flexible rod in a slider crank mechanism, using a one mode approximation. It is shown that there is strong correlation between the onset of parametric resonance regions from the linear equation and the bifurcation of a stable period 1 solution from the nonlinear equation, both regions plotted on a crank length-crank speed parameter plane. But within the unstable zones, an estimate of response requires a nonlinear equation representation. Amplified oscillations, not associated with any instability and called irregular resonance when pertaining to the nonlinear equations, are also present as harmonics in the linear equation analysis. The nonlinearities effect these resonances by pulling the peak amplification to lower speeds.
Control of Dynamic Systems With Nonlinearities and Time Varying Parameters
Authors: Söffker Dirk , Müller Peter C. 
Published: March 2021

Abstract
The well-known theory of disturbance rejection control and the experience of using a generalized technique with universal fault model for building observers and regulators for the estimation and compensation of disturbances and unmodeled or uncertain effects as well, could be used for controlling dynamic systems with time varying parameters and nonlinearities.
Based on a linear time-invariant model the effects of non-linearities and unmodeled dynamics are estimated by an extended observer scheme. Using this information these dynamic effects will be compensated by the developed compensation scheme.
Here also different compensation techniques of disturbance rejection control are discussed, compared, and modified.
The simulation example of an inverted flexible pendulum shows the efficiency of the method controlling an unstable mechanical system without exact knowledge of structure and parameters of nonlinearity and time-variance.
On Dynamic Stability and Nonlinear Modal Interaction of Parametrically-Excited Rectangular Plates
Authors: Ostiguy Germain L. , Evan-Iwanowski Ross M. 
Published: March 2021

Abstract
The authors review recent developments on the dynamic stability and nonlinear parametric vibrations of general rectangular plates. Emphasis is placed on nonlinear modal interaction in parametncally excited plates and various types of resonances are investigated. Analytical predictions are compared to experimental data to form a qualitative and quantitative verification of the solutions. Experimental results indicate that the presence of initial geometric imperfections can modify considerably the dynamic behavior of the plate and produce various types of resonances highly unpredictable beforehand and differing from those generally assumed in analytical studies.
Modeling of a Finger-Follower Cam System With Verification in Contact Forces
Authors: Hsu Wensyang , Pisano Albert P. 
Published: March 2021

Abstract
A lumped/distributed-parameter, dynamic model is developed to investigate the dynamic responses of a finger-follower valve train with the effects of an oscillating pivot, frictional forces between sliding surfaces, and a hydraulic lash adjuster.
Based on the measured force data at low speed, an algorithm is derived to determine the dynamic Coulomb friction coefficients around maximum valve lift simultaneously at three contact points. A constraint equation is formulated to find the contact position between the cam and the follower kinematically. This makes it possible for the model to simulate the dynamic response of the cam system when the pivot is moving. A hydraulic lash adjuster acting as the pivot of the follower is also modeled with the effects of oil compressibility and oil refill mechanism.
The model is numerically integrated and shown to have good agreement between simulation results and experimental data of contact forces at three different speeds. The maximum operating speed is limited by valve toss, loss contact between components. The model predicts toss between the hydraulic lash adjuster and the follower at 2535 rpm, and experiment indicates toss starting at 2520 rpm of camshaft speed.
Steady-State Unbalance Response of Continuous Rotors on Anisotropic Supports
Authors: Curti Graziano , Raffa Francesco A. , Vatta Furio 
Published: March 2021

Abstract
An analytical investigation of the steady-state unbalance response of axisymmetric rotor systems with anisotropic, flexible and damped bearings is presented. According to the exact approach of the dynamic stiffness method, the rotor is modelled by means of continuous beam elements.
In this work, the expression of the 8 × 8 dynamic stiffness matrix of a rotating Timoshenko beam is derived and it is shown that it is related, by means of a simple law, to the previously published 4 × 4 dynamic stiffness matrix, which holds for the isotropic bearings case. The effects of concentrated disks and bearings are included into the formulation; in particular, each bearing is described by eight constant coefficients, according to the well-known linearized model of the bearing forces.
The unbalance response of a typical rotor system taken from the literature is analyzed. A comparison is presented with the finite element results reported by other authors.
An Integrated Approach Toward the Dynamic Analysis of High-Speed Spindles: Part I — System Model
Authors: Chen C. H. , Wang K. W. , Shin Y. C. 
Published: March 2021

Abstract
Experimental evidence [Shin, 1992] has shown that the natural frequencies of high speed spindles with angular contact ball bearings decrease with increasing rotational speed. A recent study [Wang, et al., 1991] illustrated that this phenomenon is caused by stiffness change of the bearings. A simplified approximation was used in the analysis to examine the bearing radial stiffness at high speeds. While the investigation explained the experimental observations in a qualitative sense, the analytical results so far are not sufficient to quantitatively describe the spindle behavior under high speed operations due to the approximations made in the modeling process. This paper presents an integrated approach toward the modelling of flexible spindles with angular contact ball bearings from basic principles. The local dynamics of the bearings are coupled with the global shaft motion. The model derived includes both the longitudinal and transverse vibrations of the shaft interacting with the nonlinear bearings. The influences of shaft speed on the bearing stiffness matrix and the system frequencies have been studied. It is shown that the spindle dynamic behavior can vary substantially as speed increases due to the bearing gyroscopic moment and centrifugal force. These effects have been ignored in most of the previous spindle models. Lab tests were conducted to validate the model. The analytical predictions are quantitatively verified by the experimental results.
Comparison of Linear and Nonlinear Control on a Distributed Parameter System
Authors: Rietz Ralph W. , Inman Daniel J. 
Published: March 2021

Abstract
The performance of a single link, very flexible manipulator using two different position control systems was studied. A standard PD feedback control was considered along with PD plus position times velocity feedback. An analytical model of the plant was identified and computer simulations using the two controllers were performed. The results clearly showed a decrease in control effort for the system using nonlinear control when compared to a similar response for the system using PD control. Experimental results on a slewing beam system verified this result. The system using the proposed nonlinear feedback control required significantly less energy to complete the same maneuver as the system using the standard PD feedback control. Other measures of performance (e.g. rise time, settling time, overshoot) were slightly improved when the nonlinear feedback was added to the controller.
Simultaneous Trajectory Tracking and Vibration Reduction of Distributed Parameter Systems Through Inverse Dynamics
Authors: Ledesma R. , Devasia S. , Bayo E. 
Published: March 2021

Abstract
This paper addresses the problem of inverse dynamics for three-dimensional articulated flexible structures with both lumped and distributed actuators. A recursive procedure is presented for computing the lumped inverse dynamic torques and the distributed piezoelectric actuator inputs for simultaneously tracking a prescribed end-point trajectory and reducing motion-induced vibrations in the articulated structure. The procedure sequentially solves for the non-causal inverse dynamic torques and piezoelectric voltages applied to each link in the open-chain articulated structure, starting from the last element in the chain and proceeding to the base element. The method allows trajectory tracking wherein controllability of the structural vibrations is assured in all possible configurations through the use of only one motor at each intermediate joint and three motors at the ground. Numerical simulation shows that the elastic vibrations can be reduced significantly through the use of distributed actuators while at the same time satisfying the trajectory tracking requirement through the use of inverse dynamics.
System Identification for Boring Bar Chatter Control
Authors: Embry Jonathan A. , Smith Suzanne Weaver , Walcott Bruce L. 
Published: March 2021

Abstract
The boring bar is used to provide smooth, accurate cuts in materials. However, when the length to diameter (L/D) ratio of the boring bar becomes large, low-frequency vibration, or chatter, results. Initial attempts to control this unwanted vibration with an active absorber have been successful, but in some configurations problems remain. In this paper, algorithms for flexible structure identification widely used in the aerospace industry are applied to a number of boring bar setups to identify the vibration characteristics of each system. Emphasis is placed on one class of methods which includes the Eigensystem Realization Algorithm (ERA), developed for identification of flexible space structures. The resulting identified characteristics are compared and contrasted. Results are also compared to finite element analysis predictions. From the current identification results, implications for chatter control are discussed, including the possibility of nonlinear modal interactions.
The Origins of Engineering Design
Authors: Dimarogonas Andrew D. 
Published: March 2021

Abstract
Engineering is distinguished from craft or invention by systematic development and use of intelligence and scientific knowledge. Elements of engineering design can be found in the great Potamic civilizations but systematic engineering design activity started in the ancient Greek and Hellenistic world and matured under the Romans. The renaissance and the industrial revolution revived Engineering and modern engineering design was eventually defined during the 19th Century.
On the Dynamics of a Rotary Compressor: Part 2 — Experimental Validation and Sensitivity Analysis
Authors: Padhy Sisir K. 
Published: March 2021

Abstract
This paper describes the experimental validation of the rotary compressor dynamics model [1]. Roller velocity is measured using video technology and a very good agreement is found with the theoretical results. A sensitivity study using different variables that affect the compressor dynamics is also carried out. It is found that the coefficient of friction at the vane and roller plays an important role in roller velocity. The dynamics of roller is influenced by the clearances, the roller radius, the vane radius, eccentricity of the shaft, the frictional behavior between the roller ends and the bearing plates, the discharge pressure of the compressor as well as the moment of inertia of roller.
An Improved Model for the Dynamics of Spur Gear Systems With Backlash Consideration
Authors: Shing Tai-Kang , Tsai Lung-Wen , Krishnaprasad P. S. 
Published: March 2021

Abstract
An improved model which accounts for backlash effects is proposed for the dynamics of spur gear systems. This dynamic model is mainly developed for the purpose of real time control. The complicated variation of the meshing stiffness as a function of contact point along the line of action is studied. Then the mean value is used as the stiffness constant in the improved model. Two simulations, free vibration and constant load operation, are performed to illustrate the effects of backlash on gear dynamics. Also given are comparisons of the simulation results with that of the Yang and Sun’s model. This model is judged to be more realistic which can be used in real time control to achieve high precision.
Development and Real Time Implementation of a Collision Detection Algorithm for an Automated Guided Vehicle
Authors: Majumder Indranil , Naganathan Nagi G. , Kim Young-Gon 
Published: March 2021

Abstract
An algorithm has been developed for detecting a collision-free path for an Automated Guided Vehicle (AGV) when it is required to navigate in an unstructured environment. Real time implementation issues are discussed and investigated experimentally using an ultrasonic sensor system. Concepts of obstacle matrix and path penalty are used in the guidance of the vehicle in a work area discretized as matrix cells. Two search methods namely, the arc searching method and obstacle crawling method, are developed for the AGV to facilitate navigation. The algorithm is capable of admitting the appropriate search method depending on the nature of the obstacles in the work area. Case studies using real time data from ultrasonic sensors demonstrate an excellent level of performance for the algorithm.
Shape Optimization Using a Variable Number of Conic Patches
Authors: Widmann James M. , Sheppard Sheri D. 
Published: March 2021

Abstract
Shape Optimization is a branch of structural optimization in which the boundaries of geometry are varied. The shape of the boundary is determined by optimizing a set of design variables that form the geometric description of the shape. This paper presents a method of two dimensional shape optimization in which the number of design variables is allowed to change during the optimization process. First an initial design representation is chosen and optimized. Next a new mathematical description of the optimized design is created with an increased number of design variables. This new design is subsequently optimized. This allows the optimization process to work within a larger design space that includes a greater variety of shapes. The process of adding design variables is repeated until no additional improvements in the design are made. Several design examples are solved with this procedure and presented.