bluuebunny/crossref_metadata_2025_split huggingface dataset:
Designing Student-Centered Learning Into a Multimedia Classroom: One Small Step
Authors: Heidler Jeffrey S. , Thompson John C. , Hrinyak Matthew J. , Mistree Farrokh 
Published: March 2021

Abstract
Courses today are instructor-centered in that students rely on the instructor and textbook as knowledge sources and offer themselves as “empty vessels” to be filled with facts and skills. We are interested in exploring student-centered learning using multimedia technology. We want to determine how multimedia can be used to empower students to controltheir own learning. In this paper, we report on a small part of our investigation, namely, the development of a framework for implementing engineering case studies in multimedia to facilitate student-centered learning.
Life Algorithm: Its Concept and Application
Authors: Fukuda Shuichi , Konishi Fumikazu 
Published: March 2021

Abstract
Recently an autonomous system that meets the growing demand for solving a problem in adiversifying environment has been desired, in order to secure more robustness and flexibility. As a first step towards establishing such an autonomous system, we developed Life Algorithm (LA). Life Algorithm is fundamentally an extension of Genetic Algorithm (GA). While the conventional GA approach is based on genes and is homogeneous in its essence, LA is something more like a genome and realizes more diversity. A group of genes with different evaluation function is considered and these constitute agents. Thus, more individuality and more interaction between these agents can be taken into account and more robustness to cope with the widely and quickly changing environment can be realized. This paper demonstrates the usefulness of an LA approach by illustrating the example of power plant operation through simulation and an experiment of a solar cell system.
Direct and Intuitive Input Device for 3-D Shape Design
Authors: Murakami Tamotsu 
Published: March 2021

Abstract
Standard input tools such as the mouse and keyboard do not provide users with a direct and intuitive means of 3-D shape manipulation. This study proposes a new concept of interface system for 3-D shape deformation using a deformable real object as an input tool. By deforming the tool with bare hands with a tactile feedback, users can manipulate a 3-D shape modeled and displayed on a computer screen directly and intuitively. A prototype with a cubical input tool made of electrically conductive polyurethane foam demonstrates the effectiveness and promise of the concept.
Section CAD: A Tool for Rapid Prototyping
Authors: Fukuda Shuichi , Suzuke Daisuke 
Published: March 2021

Abstract
This paper proposes a new methodology for a geometric design. While a conventional 3-D CAD directly treats an object in a 3-D space, Section CAD, which we propose in this paper, treats the object as a set of several discrete sections. Therefore, editing only 2-D information, Section CAD enables a designer to design a topologically complex object more intuitively than conventional ones at the earlier stages of design.
Because Section CAD can interpolate between a few distant sections properly, the designer does not have to edit all sections of the object. In this way, Section CAD provides a very flexible tool for rapid prototyping by generating the whole shape of an object using discrete partial sections.
A Study on Topological Optimization of Structure Using Cantor Function As Teaching Function
Authors: Arakawa Masao , Ohkubo Naoto , Yamakawa Hiroshi 
Published: March 2021

Abstract
In order to obtain better structural designs, it is important to carry out optimization from primary parts of those designs. Especially, designs of topologies of structures were depended on intuition of the designers and they were not always best fitted to the requirements of the structure. These days, designs of topologies of the structures become important to meet those purposes. In this study, we will propose a new method to obtain optimum topology of the structure to satisfy their requirements by growth and degeneration tutored by Cantor function as teaching function. Cantor function is the one which is very famous as an introduction of the fractal. By operating its order, it is very easy to manipulate its division among 0 and 1. We set skipping and restarting rules of growth and degeneration, and criteria of convergence. We applied the proposed method to the problem similar to the one well-known as Mitchell truss problem to compare the results obtained by the proposed method. From these numerical examples, we can obtain quite similar topological results to the homogenization method in small number of iteration. There, the proposed method has advantages in computational time, cost and memory. More over, we can see the growth of the topology. Although we demonstrate the proposed method in a few examples, we can say that the proposed method can derive optimum oriented topology even with this simple scheme efficiently.
Japanese Product Development: Today and Tomorrow
Authors: Fukuda Shuichi 
Published: March 2021

Abstract
The task of creating a common basis among different people becomes more and more important with the increasing complexities and diversification of product, since collaboration becomes inevitable. But Japanese have to develop some new technologies for assisting them, since we communicate non-verbally rather than verbally. Japanese could work together as a team up to now, since there were a clear goal from the first. To cope with the diversification, goal finding will be most important.
VR and multimedia technologies would be very promising, but they have tobe adapted to the Japanese way, where the atmosphere or the sense of sharing the same way of thinking plays a much important role than true production of the real world.
If such technologies could be developed, they will also serve a great deal for attaching values to the processes of design and production. The conventional approach considered values in terms of the performances of the final products alone and the processes to realize them were regarded only as cost inreasing factors. But this situation will surely change if such technologies can be realized.
Design for Maintenance by Constrained Motion Planning
Authors: Li Tsai-Yen , Chang Hsuan 
Published: March 2021

Abstract
In designing an assembly product, maintainability is a crucial issue that determines whether certain parts can be accessed for routine maintenance. In the past its study has been largely manual and labor intensive. Either by using physical mockup or computer animation with CAD models of a design, the task relies on human to provide an access path for the part. In this paper we present an automated system that replaces the traditional manual process. By applying results from and developing extensions to the motion planning research in robotics, we demonstrate that this automated system is an effective addition to CAD systems. We specifically describe the extension that accounts for special motion constraints imposed by designers. We also present experimental results from applying such a system to problems in industrial applications. The results show that such an system can not only reduce the turn-around time for checking maintainability of a product but also provide more accurate feedback to the designers on potential maintenance problems.
A Virtual Reality Environment for Synthesizing Spherical Four-Bar Mechanisms
Authors: Osborn Scott W. , Vance Judy M. 
Published: March 2021

Abstract
This paper describes the development of a virtual reality environment which facilitates the design of spherical four-bar mechanisms. The virtual environment allows the user to naturally interact with the input data and specify the design parameters while operating in a three-dimensional environment. We see this development as a logical extension of existing graphics-based spatial design software. The need for a three-dimensional design space is driven by the difficulty in specifying design inputs and constraints for a spatial problem using a two-dimensional interface. In addition, once the mechanism has been created, the virtual environment provides the opportunity for the user to visually verify that the mechanism will perform the desired three-dimensional motion.
Shape Similarity Assessment of Mechanical Parts Based on Solid Models
Authors: Sun Tien-Lung , Su Chuan-Jun , Mayer Richard J. , Wysk Richard A. 
Published: March 2021

Abstract
Previous research toward part similarity assessment has been based on two kinds of symbolic part representation schemes, i.e., GT coding schemes and form feature based descriptions. The performance of these approaches is limited because the symbolic part representation is information incomplete and ambiguous. A solid model, on the other hand, is an unambiguous and information complete computer representation for 3D objects. In this work, the shape similarity between two polyhedra is formalized based on isomorphic subgraphs of graph representations extracted from their boundary models. A novel approach is proposed to match subgraphs. Input to the proposed methodology consists of two types of solid models, i.e., the boundary model and a CSG representation called the TO tree. The TO tree is used to derive a set of major sweep directions for a part. Using the matched major sweep directions as probes, a generate-and-test strategy is applied to find the matched subgraphs. A prototype system based on the proposed methodology has been implemented. The prototype system was programmed in AutoLisp© and is interfaced to the AME© solid modeler of AutoCAD©. Shape similarity comparison between various mechanical parts with intersecting features has been successfully accomplished by the system.
Multibody Modeling of Vehicles in a Virtual Prototyping Environment
Authors: Vejju Kishore Sai , Freeman Jeffrey S. 
Published: March 2021

Abstract
This paper presents concepts involved in the theory and implementation of a vehicle body and suspension modeling tool as part of the software development for the National Advanced Driving Simulator (NADS). The NADS will be a state-of-the-art, operator-in-the-loop ground vehicle simulator, which can be applied to both human factors and vehicle virtual prototyping studies. By applying the modeling tool developed in this study, vehicle kinematic models can be easily created and tested, either using off-line engineering analysis packages or using operator-in-the-loop simulators, such as the NADS.
Vehicles are complex systems containing multiple bodies, joints and force generating elements. Manually modeling these systems for kinematic and/or dynamic analysis is tedious and prone to errors. This creates a need for a modeling tool which reduces modeling time, increases modeling accuracy and is easy to use. This paper discusses the concepts involved in developing a modeling tool for the topology analysis and assembly of the multibody vehicle model. Suspension system modeling is briefly described, along with an example employing the US Army HMMWV vehicle.
Consistency Management in Feature-Based Parametric Design
Authors: Vieira Ana Sofia 
Published: March 2021

Abstract
One of the main problems to be solved in design-by-features is to preserve the semantic correctness of feature-based models. Currently, feature-based parametric design (FbPD) is being used as one of the most powerful approaches for solving this problem. In this paper, a fundamental principle of this approach is introduced. Three aspects stated, are: FbPD deals with functional design primitives, it solves the automatic generation of model variations, and it offers the basis for the development of a mechanism to check the semantic correctness of feature-based models. Several concepts for the definition of semantic constraints are presented. They instigate the classification of semantic constraints in four different categories, based on the constraint evaluation-time, purpose, behaviour, and representation. Sinfonia, a system for feature-based parametric design, is presented as a testbed environment for design-by-features applications. One of its modules, the Consistency Handler, uses the constraint concepts introduced in order to preserve the semantic consistency of the models. Several examples illustrate the different types of constraints. In addition, an algorithm applied for the process of a consistent feature modification is presented.
Joint Optimization of Functional Performance and Production Costs Based Upon Mechanical Features and Tolerances
Authors: Xue D. , Rousseau J. H. , Dong Z. 
Published: March 2021

Abstract
A method for jointly evaluating and optimizing the functional performance and production costs of a design is introduced to produce high quality designs with better life-cycle performance and shorten product development lead-times. Various design approaches considering both functional performance and production costs are investigated. A method for associating performance with costs based upon a combined feature, tolerance and production process model is introduced. The methods are illustrated using a typical design example of the hole feature. The study contributes to optimal design theory, and forms the basis for integrated concurrent engineering design.
Gravitational Effects on Two Link. Flexible Multibody Systems
Authors: Smart David W. , Wiens Gloria J. 
Published: March 2021

Abstract
Few flexible multibody studies have been conducted in which gravity is included in the analysis and of these, none include the axial component of the gravitational loading. However, as multibody systems become increasingly more flexible, the axial loads induced by gravity are playing an increasingly more important role in the elastic characteristics of multibody systems, especially in the ground testing of those for space applications. In an effort to minimize the unreliable aspects in ground testing, the research presented here provides a relatively simple theoretical model based on the quasi-dynamics of two link multibody systems with an arbitrary orientation within the gravitational field. The theoretical model has shown gravity does play a significant role in predicting accurate first and second frequencies and the static deflections of such systems. Experimental verification of the theoretical results is presented.
Elastic Robot Arms With Variable Length: Part I — A Systematic Nonlinear Modeling Approach
Authors: Söffker Dirk 
Published: March 2021

Abstract
In this paper modeling of a geometric nonlinear beam and the corresponding matrix representation of the model of 3rd order is considered. Especially in the case of lightweight robots for space applications undergoing large reference motion, the nonlinear dynamic behaviour of the beam should be modeled as exact as possible. Here coupling effects betweeen the elastic variables due to the geometric nonlinear beam kinematic are important. ‘Stiffning effects’ and parametrically excited effects between longitudinal and bending vibrations e.g., should also be considered.
Starting with the nonlinear beam kinematics, all equations up to terms of second order are considered. Using the principal of virtual work, nonlinear equations are given, which are discretized by Hermite polynomials in the next step. Considering also terms of second order in the elastic variables, a special technique handling this equations in the usual structural dynamics matrix representation is developed to preserve the couplings of higher order in contrast to the usual linearization. Additionally, the length-variability is considered. So the clearness and effectiveness of matrix methods is combined with beam theory of 3rd. order, this means quadratic terms for the elastic variables axe considered building up state-dependend matrices. The importance of the effects of those couplings axe shown by two simulation examples of a planar and a spatial lightweight, very flexible telescopic robot arm for space operations. It can be shown clearly, that beside the known stiffning effects due to nominal axial loads, effects of higher order may weaken the structure up to failure of the structure.
Numerical Study of an Impact Oscillator
Authors: Marudachalam Kannan , Bursal Faruk H. 
Published: March 2021

Abstract
Systems with discontinuous dynamics can be found in diverse disciplines. Meshing gears with backlash, impact dampers, relative motion of components that exhibit stick-slip phenomena axe but a few examples from mechanical systems. These form a class of dynamical systems where the nonlinearity is so severe that analysis becomes formidable, especially when global behavior needs to be known. Only recently have researchers attempted to investigate such systems in terms of modern dynamical systems theory.
In this work, an impact oscillator with two-sided rigid constraints is used as a paradigm for studying the characteristics of discontinuous dynamical systems. The oscillator has zero stiffness and is subjected to harmonic excitation. The system is linear without impacts. However, the impacts introduce nonlinearity and dissipation (assuming inelastic impacts). A numerical algorithm is developed for studying the global dynamics of the system. A peculiar type of solution in which the trajectories in phase space from a certain set of initial conditions merge in finite time, making the dynamics non-invertible, is investigated. Also, the effect of “grazing,” a behavior common to constrained systems, on the dynamics of the system is studied.
Based on the experience gained in studying this system, the need for an efficient general-purpose numerical algorithm for solving discontinuous dynamical systems is motivated. Investigation of stress, vibration, wear, noise, etc. that are associated with impact phenomena can benefit greatly from such an algorithm.
Impacts With Friction
Authors: Pfeiffer Friedrich , Glocker Christoph 
Published: March 2021

Abstract
Mechanically impacts with friction include questions of relative kinematics and of constraint dynamics both in normal and in tangential directions. In addition both directions are of course coupled because impulses in one direction influence the behaviour in the other direction, especially when considering the normal impulses stored at the end of the compression phase. Together with the stored tangential impulses it governs the expansion phase. Paper presents a model of such impacts with friction considering a compression and an expansion phase. Some examples illustrate the practical relevancy of the theory.
Experimental Investigation of the Dynamics and Bifurcations of an Impacting Spherical Pendulum
Authors: Garza S. , Ertas A. 
Published: March 2021

Abstract
An experimental investigation was performed to determine the dynamics of an inverted, impacting spherical pendulum with large deflection and vertical parametric forcing. The pendulum system was studied with nine different bob and two different base configurations, for twenty times the natural frequency at shaker powers of 0 to 125 mm-hz. It was found that sustained conical motions did not naturally occur. The spherical pendulum system was analyzed to determine under what conditions the onset of Type I and sustainable Type II responses occurred.
Frictional Impact of an Elastic Body
Authors: Marghitu Dan B. 
Published: March 2021

Abstract
A model is presented for the impact with friction of a flexible beam in translational and rotational motions. This model enables one to predict the rigid body motion as well as the elastic after the impact. The system of equations is written in the Lagrangean formalism using a set of coupled reference position and local elastic generalized coordinates. The model uses an experimental dynamic coefficient of friction and an experimental co-efficient of restitution. We introduce a finite number of vibrational modes to take into account the vibrational behavior of the beam during impact.
Control of Nonlinear Parametrically Excited Beam Vibrations
Authors: Schlacher Kurt , Irschik Hans , Kugi Andreas 
Published: March 2021

Abstract
A straight composite beam under the action of a harmonic axial support motion is considered. Piezoelectric layers are used to control the parametrically excited vibrations. A nonlinear initial-boundary-value problem for the deflection is derived, which is approximated by a set of nonlinear ordinary differential equations. The controller design is based on the differential geometric approach by extending the method of input output linearization to the time variant case. Controllers with different zero dynamics are presented to show that the approximating system can be stabilized by a proper choice of the virtual output function.
Techniques for Periodic Control of Flapping of a Helicopter Blade
Authors: Pandiyan R. , Sinha S. C. 
Published: March 2021

Abstract
The primary objective of this paper is to present new periodic control strategies for the control of flapping motion of an individual helicopter rotor blade in forward flight which is represented by a differential equation with periodic coefficients. First, an algebraic procedure based on Chebyshev polynomial expansion is employed to control the periodic flapping motion. In this approach, the state vector and the elements of the periodic system matrix have been expanded in terms of shifted Chebyshev polynomials of the first kind over the principal period. Later, optimal control theory in conjunction with Floquet Theory has been used to design full state and observer state feedback controllers. In the second method, the feedback controllers have been designed in the time-invariant domain through an application of a linear, invertible, periodic transformation known as Liapunov-Floquet (L-F) transformation to the periodic system model. It is shown that by using both the methods the periodic control gains can be obtained as explicit functions of time and therefore, a control scheme more suitable for real-time implementation can be achieved. The design procedures have been found to be much simpler in character when compared to those techniques that have been appeared in the literature.
In-Plane Vibration of High-Speed Spur Gear Webs
Authors: Arakere Nagaraj K. , Nataraj C. 
Published: March 2021

Abstract
High cycle fatigue loading of gear webs due to in-plane stresses, caused by forced excitation resulting from centrifugal loading and dynamic tooth loads, has been known to cause radial fatigue cracks. This is especially prevalent in high-speed gears used in aerospace applications, with small web thickness, for weight reduction. Radial cracks have also been observed to originate at the outer edge of lightening holes machined in gear webs for weight reduction. This paper presents an analytical treatment of the in-plane vibration of high-speed gear webs resulting from rotational effects and periodic excitation from dynamic tooth loading. Dynamic tooth loads result from the combined effect of inertia forces of gear wheels which are significant at high speeds, the periodic variation of gear mesh stiffness, and involute tooth profile errors.
The gear web is modeled as a thin rotating disc and the governing differential equations of motion and the associated boundary conditions are derived from first principles. A comprehensive tooth stiffness model for spur gears is used that accounts for periodic variation of mesh stiffness. The dynamic tooth loads are obtained by solving the pertinent equations of motion, using a collocation method, that yields a closed-form expression for the periodic excitation, that is used as an input for the in-plane vibration problem. The in-plane vibration equations are solved by an approximate method of weighted residuals. It is found that the displacement fields and the resulting stresses can be significant under certain speeds and loading conditions. The in-plane stresses leading to high cycle fatigue loading, and frequency components of the resulting response are discussed in detail.