bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integrated Part Feature Modeling and Process Planning for Concurrent Engineering
Authors: Cherng John G. , Shao Xin-yu , Li Pei-gen , Sferro Peter R. 
Published: February 2021

Abstract
This paper presents the methodologies and technologies of integrated part feature modeling and process planning for Concurrent Engineering (CE) applications. The part feature modeling is constructed on the basis of a hierarchical and dynamic structure that consists of feature syntax, feature semantics, and feature operations. A discussion is given on part function representation and function mapping mechanism for CE realization. A CE-oriented Computer-Aided Process Planning (CAPP) is advocated to not only fulfill both variant and generative design tasks, but also perform part manufacturability evaluation by using multi-level knowledge reasoning. The knowledge representation as well as a system structure of integrated part feature modeling and process planning for CE application are discussed.
Relations Between Features: Prototyping Object-Oriented Language Extensions on an Industrial Example
Authors: Brett Brendan D. , Peters Thomas J. , Demurjian Steven A. , Needham Donald M. 
Published: February 2021

Abstract
Feature-based design techniques are being broadly incorporated into supporting CAD/CAM software. Object-oriented methodologies effectively capture parent-child relationships between features. However, realistic design, manufacturing and assembly domains often require more subtle inter-relationships between features, where contemporary object-oriented languages lack capabilities to facilitate such modeling. This research focuses upon prototyping object-oriented techniques to express non-ancestral relationships between features.
This research was undertaken to support an industrial design team and our research goals were to:
• determine critical feature inter-relationships,
• prototype object-oriented software mechanisms for expressing these non-ancestral inter-relationships, and
• equip those mechanisms with methods for change notification.
Using Virtual Node Generation to Speed Up Sheet Metal Bending Operation Planning
Authors: Gupta Satyandra K. , Bourne David A. 
Published: February 2021

Abstract
A large number of manufacturing operation planning problems can be formulated as state-space search problems. In case of sheet-metal bending operation planning, processing a search node involves extensive geometric reasoning and many other types of complex computation steps. Such computation-intensive node-processing limits the number of search nodes that can be expanded in a reasonable amount of time, making it difficult to solve real-life operation planning problems.
In this paper, we describe a scheme to speed up operation planning by virtual generation of state-space nodes. In this scheme, we eliminate unnecessary computation at the time of node generation by extracting the required information from already generated nodes. Although generation of two different search nodes rarely involves identical computation steps, there is considerable overlap in node generation steps. We have divided the node generation step into a number of computation subproblems. When we need to generate a new node, we first try to see if any of the node generation subproblems have been solved for any of the already generated nodes. If any subproblem has already been solved for some other node, then we use the solution of that subproblem to save computation time. In such cases, we do not perform node generation computation steps, and therefore we call such node generation virtual.
The scheme presented in this paper increases the node generation capability and allows us to generate many more search nodes. We believe that the ability to consider more search nodes will help us in solving more complex problems and finding better operation plans.
Optimal Process Planning for Four-Axis Turning Centers
Authors: Veeramani Dharmaraj , Stinnes Andreas H. 
Published: February 2021

Abstract
This paper addresses the problem of process plan generation and optimization for dual-spindle/dual-turret CNC mill-turn centers (commonly referred to as four-axis turning centers) that are capable of both parallel and simultaneous machining modes. The number of alternative process plans for machining a given workpiece on this class of machines can be large, and the process plan optimization problem can, therefore, be complex. Due to the lack of a computer-aided process plan generation and optimization system, these highly flexible machines are being used in industry today as dedicated, mass-production machines. In this paper, we present research (being conducted in close cooperation with industry) on the development of a computer-aided process planning system for four-axis turning centers. In particular, we describe the representation schemes and Tabu Search based strategy for process plan generation and optimization, and present results demonstrating the effectiveness of this approach.
System Behavior Modeling As a Basis for Advanced Failure Modes and Effects Analysis
Authors: Eubanks Charles F. , Kmenta Steven , Ishii Kosuke 
Published: February 2021

Abstract
This paper presents a method for developing a device behavior model to enhance reliability at the early stages of conceptual design. The model facilitates a semi-automated advanced failure modes and effects analysis (FMEA). The model performs analyses and simulations of device behavior, reasons about conditions that depart from desired behaviors, and analyzes the results of those departures. The proposed method rigorously specifies pre- and post-conditions, yet is flexible in the syntax of device operation. The paper shows how the method can capture failures normally missed by existing FMEA methods. An automatic ice maker serves as an example application.
An Approach to Virtual Prototyping for Product Disassembly
Authors: Siddique Zahed , Rosen David W. 
Published: February 2021

Abstract
An important aspect of Design for the Life Cycle is assessing the disassemblability of products. A product designed for disassembly can be quickly and easily broken down so its components can be recycled or refurbished. The use of virtual prototyping is proposed to aid the assessment of product disassembly by enabling the designer to virtually disassemble the product. A virtual prototype is a model of a product and a process that the product undergoes. Virtual prototyping is defined as the generation of a virtual prototype and its simulation or assessment. Factors involved in generating product disassembly processes include: determining the disassembly sequence of a product, the disassembly paths of components, tool change sequences, etc. In recent years, disassembly processes have been generated either by using interactive or automated approaches, but these have limitations. However, by combining the two approaches, disassembly processes of complex assemblies can be generated without extensive user input. This type of interaction can be facilitated by using virtual prototyping. The purpose of this paper is to illustrate the development of a virtual environment that will support the generation of virtual prototypes for evaluating product disassembly. Issues involved in transformation of CAD models to virtual prototypes for disassembly are also discussed. Application to an automotive center console is illustrated.
Computer Programs for Fire Simulation
Authors: Lilley David G. 
Published: February 2021

Abstract
Computer programs for simulating fire development in a multi-room building complements the experimental approach and/or post-fire on-site investigations. A variety of computer calculations can help to validate or deny a suggested fire scenario and witness statements. Thus they help to discriminate between alternative fire scenarios by evaluating the consequences and comparing them with observations. In this way computer simulation helps to rule in or rule out the suggested ignition and spread of the fire.
Numerical Simulation of Complex Geometries
Authors: Lin Wanlai , Chen Ching Jen 
Published: February 2021

Abstract
The numerical simulation of fluid flows and heat transfer over complex geometries, especially for three dimensional problems, remains a challenging problem in computational fluid dynamics. This paper proposes a method to approximate the contour of irregular geometries in Cartesian coordinates. In order to achieve a smooth boundary representation, both diagonal segments and Cartesian grid lines are utilized in the approximation. When the geometric object is specified with a set of discrete points, the approximate representation of the object contour is drawn based on the local monotonic principle such that the essential topographical character of the object is preserved. The accuracy of approximated contour on the Cartesian coordinate is estimated by the convergence of contour length and normal distance between the approximated and original contour. The proposed techniques is illustrated by the contours of complex lake banks, multi-cylinder, porous media and the sphere, which are often encountered in fluid devices and heat exchangers.
Design and Implementation of a Linear Testbed for Encoder Validation
Authors: Pulanco William Michael , Derby Stephen 
Published: February 2021

Abstract
It was desired to build a test station that would test the maximum operating speed and assist in the adjustment of the potentiometer during assembly of the linear encoders. A linear slide table provides the best linear motion to test encoders. It was also decided that a belt drive system would allow for the desired performance. The belt drive system is connected to a motor which needs some type of control. Many different options were considered for controlling the motor and some tried, but the final solution was to use a stand alone controller that would take input from a control panel. The total test station includes a motor & encoder, controller, amplifier, power supply, and interface board. The controller is a stand alone unit, that is programmed from the RS232 port on a personal computer. The controller can also send data back through the RS232 port for analysis purposes.
Enhancing Mechanism Simulation in Engineering Education by a Hypermedia System
Authors: Giannotti E. , Galletti C. 
Published: February 2021

Abstract
An attempt to focus problems encountered in teaching mechanics of machines to engineering students has stimulated the authors of this paper to develop specific software, lectures and laboratory activities with different emphases and relations between the teacher’s and students’ tasks. A multi-year study has been made to test if and how simulation, based on a hypermedia system, can be used in developing educational tools for this new courseware. As a result, new tools for learning mechanics of machines are proposed.
Dynamic Response of a Generic Vehicle Floor Model to Coupled Transient Loads
Authors: Gupta Aaron D. 
Published: February 2021

Abstract
A dynamic elastic large displacement response analysis of the bottom floor of a generic vehicle hull model subjected to empirically obtained coupled blast and impact loads has been conducted using three-dimensional (3-D) shell elements in the ADINA nonlinear dynamic finite element analysis code. For the impulse-dominated problem, the impact load is a square wave step function concentrated load while the blast loads from the detonation of an explosive are a series of distributed pressure loads approximated as triangular impulse loads with linear decay and varying arrival and duration times.
The 3-D numerical model has been generated using the PATRAN3 modeling code and converted to the ADINA finite element input data deck using the ADINA translator and careful inclusion of appropriate material properties as well as initial and boundary conditions. Monolithic single-layered four-noded quad shell elements were sufficient to model the bottom floor and the left- and right-horizontal and vertical sponsons as well as the lower front glacis.
Although several simplifying assumptions and approximations are made during the generation of the basic floor model, material properties, and the forcing functions, the investigation gives valuable insight into the response behavior of a generic hull bottom floor to externally applied coupled blast and impact loads and provides an inexpensive nondestructive method of evaluation of the structural integrity of modern vehicles subjected to spatially varying transient loads.
A New Finite Element Analysis of Frictional Contact Using Nondifferential Optimization
Authors: Refaat M. H. , Meguid S. A. 
Published: February 2021

Abstract
Current solution schemes of variational inequalities arising in frictional contact problems adopt penalty and regularization techniques. The convergence and accuracy of these schemes are governed by user-defined parameters. To overcome the difficulties associated with the ad hoc use of such parameters, the variational inequality of the general frictional contact problem is treated in this paper using mathematical programming. A new non-differential optimization (NDO) technique, in association with quadratic programming, is used to treat the resulting variational inequalities.
Determination of Reflection and Transmission Coefficients in Rigidly Connected Beams Using Timoshenko Beam Theory
Authors: Stolte James , Santiago Joseph M. 
Published: February 2021

Abstract
Knowledge of the behavior of a wave incident at a joint is necessary to properly analyze the vibration of a structure. We need to know how much energy is reflected and transmitted and also the type of wave carrying the energy. Typically, Euler beam theory is used to derive the reflection and transmission coefficients at high frequencies. Errors can become unacceptably large in the frequency range currently being analyzed using Statistical Energy Analysis (SEA) and the Power Flow Finite Element Method (PFFEM). We derive reflection and transmission coefficients due to a bending wave incident on a rigid joint between two infinitely long beams using Timoshenko theory and compare results to those obtained using Euler theory. We also compute the reflection and transmission efficiencies that determine the amount of power carried by each wave.
Blending Hierarchical Economic Decision Matrices (EDM) With FE and Stochastic Modeling: I — Methodology and Refining EDM
Authors: Majerus J. N. , Jannone J. A. , Lanphear S. P. , Tenney D. A. 
Published: February 2021

Abstract
This paper introduces the concept of a three-level hierarchy of economic-decision matrices (EDM) and discusses how finite element (FE) and stochastic modeling can be coupled in decisions on quality control. A disadvantage of the deterministic-engineering approach is that quality control cannot be properly accessed by a corresponding EDM. A five-step design-strategy is outlined and various suggestions associated with these steps are presented in the paper. This design-strategy is then quantified by the consideration of a hypothetical reverse-engineering problem involving a U-shaped bracket with cut-outs and holes. The paper presents the results of numerical experiments (sensitivity study) involving six preliminary variates (Yield Strength, Young’s Modulus, thicknesses, magnitude and phase of the forces, and displacement B.C). The final primary variates are assumed to be governed by a Gaussian distribution, and the methodology of applying the classical Z-statistic method to the FE results are presented.
Blending Hierarchical Economic Decision Matrices (EDM) With FE and Stochastic Modeling: II — Detailing EDM
Authors: Majerus J. N. , Tenney D. A. , Mimnagh M. L. , Lamphear S. P. , Jannone J. A. 
Published: February 2021

Abstract
The purpose of the Detailing EDM is to “fine-tune” a previously ameliorated design. First, in order to determine the best fillet radius for formability, forging simulations are conducted using commercial software. Once the fillet dimension is ascertained, the 3-D model is generated and maximum stresses determined for a trial force. Two different commercial programs were used to determine the three dimensional stresses. The only statistical quantities involve the loading (Gaussian distribution), the material “strength” in the Analytical Criteria for Failure (ACF), and possibly, the boundary conditions in the 3-D models. This paper considers the ACF to be the resistance to fatigue-fracture under complete reversal of loads at 5 × 108 cycles. The paper overviews three different methods of combining stochastic behaviour with FE analysis, and presents a methodology for using the interference-method with non-symmetrical distributions. The EDM are then presented for the three Product Criteria of forging — formability, Prime cost and 3-D reliability with respect to the selected ACF.
Time Integration of Impact Phenomena in Solid Mechanics: A One-Dimensional Model Problem
Authors: Chawla V. , Laursen T. A. 
Published: February 2021

Abstract
1D impact between two identical bars is modeled as a simple spring-mass system as would be generated by a finite element discretization. Some commonly used time integrators are applied to the system to demonstrate defects in the numerical solution as compared to the exact analytical solution. Using energy conservation as the criterion for stability, a new time integration scheme is proposed that imposes a persistency condition for dynamic contact. Finite element simulation with Lagrange multipliers for enforcing the contact constraints shows exact energy and momentum conservation.
A Multi-Index Variable Time Step Method for the Dynamic Simulation of Multibody Systems
Authors: Cardenal Jesús , Cuadrado Javier , Bayo Eduardo 
Published: February 2021

Abstract
This paper presents a new multi-index variable time step method for the integration of the equations of motion of constrained multibody systems in descriptor form. The basis of the method is the augmented Lagrangian formulation with projections in index-3 and index-1. The new method takes advantage of the better performance of the index-3 formulation for large time steps and of the stability of the index-1 for low time steps, and automatically switches from one method to the other depending on the required accuracy and values of the time step.
The modification of time steps is accomplished through the use of a global system invariant such as the kinetic energy stored in the penalty system. This energy provides a good measure of the global error introduced by the numerical integration during the simulation process, and permits a simple and reliable strategy for varying the time step. Overall, the new method is quite efficient and robust: it is suitable for stiff and non-stiff systems, it is robust for all time step sizes, it works for singular configurations, redundant constraints and topology changes. Also, the constraints in positions, velocities and accelerations are satisfied to machine precision during the simulation process. The method is always more accurate as the time step size decreases.
Checking Geometric Constraints in Layout Design Using Primitives
Authors: Yim H. , Butler A. C. 
Published: February 2021

Abstract
The use of geometric primitives provides representation of objects in layout design at an appropriate level of abstraction, and it allows the use of two new algorithms which permit improvements in computational speed for constraint checking. These algorithms detect intersections between two rectangles and between a rectangle and circle with improved computational efficiency. The use of this pair of algorithms is demonstrated on test problems executed on a parallel computer, and conclusions are drawn regarding the use of geometric primitives for constraint checking in layout design.
A Software “Design Assistant” for Specification Development
Authors: Schuster Helmut R. , Basson Anton H. 
Published: February 2021

Abstract
The Design Assistant is primarily a computer-based tool for teaching a systematic mechanical design procedure and improving a novice designer’s productivity while doing so. Provision is made for recording experienced designers’ intent for education through case studies. Record is kept of the relationships amongst design decisions to ensure consistency. QFD and techniques suggested by Pahl and Beitz are adapted for the specification development procedure employed in the Design Assistant. The implementation details of the Windows-based software, including ease of use, hypertext-based help, and relational database issues, are discussed. Practical evaluation of the Design Assistant is underway.
General Form Tolerance Evaluation Using Non-Uniform Rational B-Splines
Authors: Yau Hong-Tzong , Chen Kuei-Wu 
Published: February 2021

Abstract
Tolerance evaluation is critical to quality assurance in modern manufacturing. In contrast to traditional measurement which relies on specific hard gauges, coordinate measuring machines provide more flexibility for dimensional measurement and tolerance evaluations. To fully automate CMM inspection and tolerance evaluation, CAD/CMM integration is an important key. Although the subject of CAD-directed inspection has been widely researched, CAD model-based tolerance evaluation has received less attention. This paper presents a CAD model-based approach for evaluating general form tolerances using non-uniform rational B-splines. Unlike classical methods which construct substitute geometric features from the measurement data, this method evaluates form tolerances by comparing the measurement data with a nominal CAD model. Nonuniform rational B-splines (NURBS) is used to represent general form features since NURBS offers a common format for modeling precisely all the different form features. With this unified database, a general best-fit algorithm is developed that can be applied to the evaluation of various form tolerances. Computer simulations have been performed on different form features to study the robustness and efficiency of the algorithm. Application to the measurement of turbine wheel die segment is also presented.
Computer-Aided Modelling of Cloth Deformation
Authors: Zhao Y. F. , Tan S. T. , Wong T. N. , Chen W. J. 
Published: February 2021

Abstract
A constrained finite element method for modelling cloth deformation is developed. The bending deformation and the geometric constraint of developable surfaces of the cloth objects are considered. The representation of large rotation and the motion of rigid body are described using the current coordinates with the geometric constraint. The effectiveness of the present method is verified by comparing the thread deformation with the exact solution of catenary. Several examples are given to show that the proposed method converges quickly and is thus computationally efficient.
Model Abstraction Techniques for Virtual Prototyping
Authors: Chen Jyun-Ming , Hsieh Chih-Chang 
Published: February 2021

Abstract
The incorporation of VR (virtual reality) technology in the CAD/CAM community shows a promising future. Virtual prototyping uses VR techniques to simulate various functionalities of a candidate design. Downstream aspects of the product can be examined early at the design stage, saving the time and money required for repetitive design iterations.
Real-time rendering is essential for interactive VR applications. This is especially challenging when dealing with complex geometric databases. Various methods have been proposed in the literature to tackle this problem. Level-of-details is a methodology that incorporates multiple representations of a model in the viewing environment. It reduces the rendering load by presenting the model in the most appropriate level of detail. However, these simplified representations often require laborious redesign efforts. In this paper, several model simplification techniques are reviewed. An automatic simplification procedure for CSG models is also devised. This method incorporates both the geometric simplification and the dimensional reduction schemes. Implemented on a non-manifold topological kernel, the system has been shown to produce promising results.