bluuebunny/crossref_metadata_2025_split huggingface dataset:
Feature-Based Machining Precedence Reasoning and Sequence Planning
Authors: Kim Yong Se , Wang Eric , Lee Choong Soo , Rho Hyung Min 
Published: February 2021

Abstract
This paper presents a feature-based method to support machining sequence planning. Precedence relations among machining operations are systematically generated based on geometric information, tolerance specifications, and machining expertise. The feature recognition method using Alternating Sum of Volumes With Partitioning (ASVP) Decomposition is applied to obtain a Form Feature Decomposition (FFD) of a part model. Form features are classified into a taxonomy of atomic machining features, to which machining process information has been associated. Geometry-based precedence relations between features are systematically generated using the face dependency information obtained by ASVP Decomposition and the features’ associated machining process information. Multiple sets of precedence relations are generated as alternative precedence trees, based on the feature types and machining process considerations. These precedence trees are further enhanced with precedence relations from tolerance specifications and machining expertise. Machining sequence planning is performed for each of these precedence trees, applying a matrix-based method to reduce the search space while minimizing the number of tool changes. The precedence trees may then be evaluated based on machining cost and other criteria. The precedence reasoning module and operation sequence planning module are currently being implemented within a comprehensive Computer-Aided Process Planning system.
Enhancing a Commercial 3D CAD System by CSCW Functionality for Enabling Co-Operative Modelling via WAN
Authors: Stork André , von Lukas Uwe , Schultz Ralph 
Published: February 2021

Abstract
This paper presents results from a joint project with the aim to introduce advanced Computer Supported Co-operative Work (CSCW) technology to a mid-size supplier for the automotive industry by enhancing the 3D CAD system in use by CSCW functionality and enabling distributed, synchronous, co-operative modelling over a wide area network. Beside the realization of the CSCW extension we present first experience from practical use and a cost assessment discussing the rentability of our approach.
Elementary Computer Modeling Applied to TWA800 Fuel Tank Forensic Issues
Authors: Wyczalek Floyd A. 
Published: February 2021

Abstract
The specific mission was to identify the conditions of atmospheric pressure and ambient temperature under which a so-called empty-Boeing model 747-131 fixed wing jet aircraft center wing tank (CWT), containing a residual fuel loading of about 3 kg/m3, less than 100 gallons of aviation kerosene (JetA Athens refinery commercial jet fuel), could form hazardous air/fuel mixtures. The issues are limited to explosion safety concerns relating to certificated fixed wing jet aircraft in regularly scheduled commercial passenger service. It is certain that a combustible mixture does not exist in a fuel tank containing Jet-A type fuel at ambient temperatures below 38°C (100°F), which is the lean limit flash point (LFP) for commercial jet fuel at sea level. Never the less, although not included in this paper, the original study reported by Wyczalek and Suh (1997), identified six highly unlikely, but rationally possible critical conditions which can occur in a combination which may permit a combustible mixture to exist within a jet aircraft fuel tank and pose a potential hazard.
The scope of this paper is limited to mathematical modeling concerns related to fixed wing jet aircraft fuel tanks and commercial jet fuels combustible air-fuel mixture ratios. It was further limited to a historical review of the scientific literature in the public domain from 1950 to the present time, which defined the thermodynamic and minimum ignition energy properties of aviation gasoline and commercial jet fuels; and, to comparisons with new thermodynamic data for JetA Athens flight test samples, released by the National Transportation Safety Board (NTSB) during public hearings on the TWA800 event in Baltimore, Maryland in December 1997. The original work reported by Wyczalek and Suh (1997) conclusively demonstrated that the USAF Wright Air Development Center and the US Bureau of Mines conducted and published comprehensive evaluations of the potential hazards relating to jet aircraft fuel tanks as early as 1952. This historical scientific data and the mathematical models for the new jetA and Athens refinery jetA in this paper, are relevant to pending TWA800 related litigation, and to the future implementation of NTSB recommendations resulting from the TWA800 event.
Steam Turbine Airfoil Design Optimization
Authors: Wang K. D. , Amano R. S. , Hong Chi-An 
Published: February 2021

Abstract
In designing steam turbine airfoil, a continuous slope (second derivative) is desirable to prevent local flow circulation and a minimum curvature is necessary to decrease turbulence. To meet this requirement, the design program uses fifth and sixth order. Berstein polynomials to define for both the pressure-side and the suction-side profile curves. Two sets of data are required to the design program. The first set of data is relevant to the geometric parameters that include radius of nose and tail, inlet and exit metal angles, length and orientation of chord, throat and pitch, bend angle, and wedge angle. The second set of data consists of five control variables to determine the suction-side profile and three control variables to determine the pressure-side profile. The program was successfully applied to modify an existing airfoil. Geometric parameters were obtained by direct measurement. Trial and error procedures were employed to determine the value of those eight control variables so that the airfoil can be curve-fitted by running the design program. The airfoil reproduced by the design program were continuous smooth, which were utilized in a subsequent computational fluid dynamics performance analysis. A close examination of reproduced airfoil reveals that the curve-fitting result is satisfactory as it eliminates certain discontinuities in the measured data. A more efficient airfoil could then be made by adjusting geometrical parameters and control variables. Results obtained by using this program indicate that it can not only effectively optimize airfoil shape to achieve better aerodynamic performance but also preserve original design intents. Through-flow calculations were also made to determine an optimum flow path of the entire turbine. A viscous flow program was used to aerodynamically analyze the original and the new designs.
The Necessity for Product Knowledge Reuse and Sharing Within Knowledge-Based Engineering Systems
Authors: Sainter P. , Oldham K. , Kneebone S. 
Published: February 2021

Abstract
The deployment of knowledge-based engineering systems is on the increase within engineering industries and, as such, there will be an ever-increasing demand to share a common product representation, which includes design and manufacturing knowledge. At the moment, each commercial knowledge-based engineering system has its own development language and therefore representation language for design and manufacturing knowledge. To date, no work has fully addressed the need to exchange product knowledge as well as product data. It is, therefore, the main aim of this paper to demonstrate the need for a standard product knowledge representation language and how it could be developed by using existing standards, thereby providing the ability to exchange product knowledge as well as product data.
Tolerance Analysis of Deformable Assemblies
Authors: Sellem Eric , Rivière Alain 
Published: February 2021

Abstract
This article describes the use of a mechanical approach taking deformation into account in the computation of tolerances for welded, riveted, bolted or glued assemblies of sheetmetal parts. Integration of the FEM to model the elastic deformability in the assembly process results in a finer and more realistic simulation. Both analysis and synthesis tools can be based on this approach.
Life Estimation of a Spur Gear With a Tooth Cracked at Fillet Region
Authors: Arıkan M. A. Sahir , Tarhan A. Ismail , Yahşi O. Selçuk 
Published: February 2021

Abstract
A computer program is developed to find the dynamic tooth load variation, make growth analysis of the crack at tooth fillet region, and determine the life of a spur gear in terms of load cycles. Variable amplitude-variable position cyclic load on the tooth is found by using a model based on torsional vibrations of gears. Stress intensity factor is determined by assuming small, through face width cracks. Paris-Erdogan crack growth rate equation is used for crack growth analysis. Load interaction effects are taken into consideration by using Willenborg retardation model. Stress intensity factor variation is arranged by using range-pair range cycle counting method. Rack cutter tip fillet radius and rack cutter geometry are taken into consideration in tooth modeling and rack cutters standardized by ISO are used for the analysis. Finite element method is used to find tooth stifnesses. Bending deformations of gear bodies and supporting shafts, bearing deformations, torsional deformations of gear bodies, and contact deformations of teeth are included in stiffness calculations.
Optimal CMM Measurement Locations for Manufactured Part Modeling
Authors: Wang Yu (Michael) , Gupta Shailendra 
Published: February 2021

Abstract
The focus of this paper is to address the problem of optimal measurement location for manufactured part modeling (MPM) with CMM coordinate data. In the manufactured part modeling approach, a shape deviation model parameterized to represent the part’s actual geometric attributes is determined from the measured data. The resulting model parameters are then used to make decisions regarding part acceptability and/or manufacturing process control. The goal of optimal measurement is to ensure the accurate and robust estimation of model parameters. A sensitivity measure that reflects the confidence associated with the estimated values of the parameters and their robustness against singularity is developed as a criterion for choosing measurement point locations.
B2: An Interactive Quality Visualization and Improvement Technique for B-Spline Surfaces
Authors: Chen Yifan , Beier Klaus-Peter 
Published: February 2021

Abstract
A new interactive technique for B-spline surface quality visualization and improvement, called the B2 method, is presented. This method interpolates the control points of a given B-spline surface using a second B-spline surface. If small irregularities exist in the control points of the original surface, they will be magnified through the second B-spline and demonstrated as large distortions in its control points. This facilitates the detection of small surface irregularities. Subsequently, the surface may be improved through direct and interactive adjustment of the second B-spline’s control polyhedron.
Constraint Reordering for Multi-Objective Configuration Design
Authors: Adams Nathan J. , Fadel Georges M. 
Published: February 2021

Abstract
Configuration design is the process of placing components, without altering their shape or connectivity, into an available space, while satisfying various spatial constraints, such as no component overlap. Minimizing the volume occupied by the components and or maximizing the accessibility of the components are just two examples of the many objectives that can drive a configuration design problem.
For complex configuration designs, there can be many objectives, which can impose spatial constraints among the components and increase the design complexity, cycle cost, and time. An iterative procedure becomes necessary to reconcile these spatial constraints. To reach solutions that are optimal, these constraints must be reordered else combinatorial methods such as Genetic Algorithms that are used for such problems do not converge. Successful reordering can make complex configuration design problems easier to solve by minimizing the iterations necessary to reach an acceptable solution. Minimizing iterations translates into faster convergence and thus savings on time and money.
This paper presents a methodology that can manage the propagation of spatial constraints in complex configuration design problems. Representative examples are shown and results and conclusions are drawn.
An Interactive Multistage ε-Inequality Constraint Method for Multiple Objectives Decision Making
Authors: Palli N. , McCluskey P. , Azarm S. , Sundararajan R. 
Published: February 2021

Abstract
Multiple objectives decision making (MODM) in engineering design involves obtaining a preferred optimal solution in the context of conflicting design objectives. Problems with multiple objectives do not have a unique optimal solution but a set of Pareto optimal solutions. This paper presents a new interactive multistage MODM method which captures a decision maker’s preference structure in order to obtain a preferred Pareto solution even for non-convex problems. Representative subsets of an entire Pareto optimal set are generated and expanded based on the decision maker’s preference. The ε-constraint method is used to constrain the multiple objectives problem based on the decision maker’s feedback. In addition, ideas from an interactive weighted Tchebycheff approach are applied to reduce the feasible region at each stage, ensuring that the process eventually converges to a preferred solution. The method is demonstrated with two examples: (i) a simple two-bar truss design, and (ii) a more complicated problem of power electronic module design.
A Case Retrieving System for Machining Processes of Axisymmetric Parts Based on Geometric Indexing and Process Hierarchical Structure
Authors: Chang Hsin-chi , Lu Wen F. , Liu Xiaoqing Frank 
Published: February 2021

Abstract
To develop a new machining process plan in the competitive global market, one effective way is to retrieve a relevant case similar to the new desired case and then adapt it to meet the new situations. This paper proposes a retrieving system for process planning cases from two aspects — the representation and manufacturing processes of a part. The core of the retrieving system contains 1) the feature-based representation of a part, 2) indexing of a part based on two-dimensional peripheral indexing and feature indexing, 3) a hierarchical structure of cutting processes from part cutting history, 4) a similarity metric. The similarity metric is used to measure the similarity between the new desired part and one old case based on the indexes of the parts. The application domain here is the process planning for axisymmetric parts. The proposed retrieving system is implemented in a Sun workstation using ACIS 3D-Toolkit and C++.
Crossover Strategy for Improved Solution Space Exploration With Genetic Algorithms
Authors: Anderson Kurt S. , Hsu YuHung 
Published: February 2021

Abstract
The following paper presents a modified crossover operator to extend the exploration capability in Genetic Algorithms for high dimensional optimization problems. Traditional strategies apply crossover once on a pair of selected chromosomes to generate two offspring by randomly selecting a single crossover location within the chromosomal length. The proposed method applies crossover once on each separate gene (variable) instead of on the entire chromosome. To further accelerate exploration of the Genetic Algorithm, nonuniform distribution of the respective crossover position on each gene has also been studied. The empirical results show that Genetic Algorithms with the proposed crossover strategies can find optimal or near optimal solutions within fewer generations than traditional single point crossover.
Approximate-Cooperative Design Formulations for Enterprise Design and Integration
Authors: Hernandez Gabriel , Allen Janet K. , Mistree Farrokh 
Published: February 2021

Abstract
Enterprise design is embodied by the notion of integrating the processes of product design, manufacturing process design, and organization design to enhance manufacturing competitiveness. However, because of cognitive and computational limitations, the integration of the enterprise design activities based on large and complex enterprise models is not efficacious. In this paper, we show how to achieve an efficacious integration by promoting a common decision support model across the enterprise and using approximate-cooperative formulations of individual design decisions. The preliminary embodiment of a flywheel produced in a forging process is used to illustrate this perspective.
Topology Design of Truss Structures by Shape Annealing
Authors: Shea Kristina , Cagan Jonathan 
Published: February 2021

Abstract
Shape annealing is a design technique that combines grammatical transformation with simulated annealing to generate optimally directed discrete structures. The primary advantage of shape annealing over other discrete methods is the introduction of new joints and members, using a shape grammar, to enable simultaneous optimization of topology, shape, and sizing. This approach makes the exploration of truss topologies that are not constrained to a pre-defined grid possible. While details of the method have been presented (Reddy and Cagan, 1995; Shea et al., 1997), this paper provides an overview of the current implementation and validation through a comparison of results for least-weight design problems to both grid-based solutions and previously reported shape annealing solutions. These comparisons illustrate the capability of shape annealing in generating optimal designs and the advantages of not restricting topology optimization to a grid-based design universe. Comparing new results to those previously reported shows improvement in solution quality and extensions for practical multiobjective design. Finally, solutions to a dome problem illustrate the inherent ease in extending the method to three-dimensional design and multiple loading conditions. These examples demonstrate that shape annealing is effective for exploring topology design of truss structures for both least-weight and multiobjective design problems.
3D Spatial Layouts Using A-Teams
Authors: Sachdev Sanjay , Paredis Christiaan J. J. , Gupta Satyandra K. , Talukdar Sarosh N. 
Published: February 2021

Abstract
Spatial layout is the problem of arranging a set of components in an enclosure such that a set of objectives and constraints is satisfied. The constraints may include non-interference of objects, accessibility requirements and connection cost limits. Spatial layout problems are found primarily in the domains of electrical engineering and mechanical engineering in the design of integrated circuits and mechanical or electromechanical artifacts. Traditional approaches include ad-hoc (or specialized) heuristics, Genetic Algorithms and Simulated Annealing. The A-Teams approach provides a way of synergistically combining these approaches in a modular agent based fashion. A-Teams are also open to the addition of new agents. Modifications in the task requirements translate to modifications in the agent mix. In this paper we describe how modular A-Team based optimization can be used to solve 3 dimensional spatial layout problems.
Modelling and Simulation of a Multiloop Flexible High-Speed Mechanism Bending Out of the Plane of Motion
Authors: Fanghella Pietro , Galletti Carlo , Fiorini Valerio 
Published: February 2021

Abstract
A case study of dynamic simulation of a high-speed mechanism driven by three cams is presented. Starting from a planar inverse dynamic model, the following types of 3-D elastic and non-linear effects are taken into account to obtain an accurate model: a) deformations of the revolutes connecting the bodies; b) deformations and clearances in the couplings between cams and rollers; c) deformations of the bodies. Various types of models with up to six simultaneous flexible bodies have been developed by using a commercial multibody code (DADS) and the corresponding results are reported. The choice of the modal forms of the flexible bodies is discussed and the contributions of various effects to the dynamic behaviour of the system are analyzed. The paper shows that classical design techniques based on planar modelling yield unacceptable performances of the actual system.
Optimal Layout and Sizing of Ejector Pins for Injection Mold Design
Authors: Kwak Seongjoon , Lee Kunwoo 
Published: February 2021

Abstract
Injection molding is the most prevalent technology used for processing thermoplastic polymers. At the end of the injection molding cycle, the plastic molded part should be ejected when the injection mold opens. Complex moldings with bosses, ribs, or other features are generally ejected by ejector pins because they are economical and easy to be installed. However, the ejector pins can cause high local stresses and strains in the molding at the stage of ejection leading to the part deformation and damage. This paper proposes a method to determine the layout and size of the ejector pins required to eject thermoplastic moldings with minimizing the part deformation and damage. The proposed method calculates the distribution of the necessary ejecting forces to overcome the friction between the part and its mold. Then, it transforms the ejecting forces into a certain number of representative forces by the wavelet transform. Finally, we can get the location and size of the ejector pins corresponding to the discrete ejecting forces with the help of a rule-based system. The proposed method helps an injection mold designer to systematically obtain an optimum ejector design.
Optimization of Functional Distribution of Materials to Minimize Weight and Cost of Machine Elements Using Genetic Algorithm
Authors: Ohtani Yukio , Shoji Tetsuo 
Published: February 2021

Abstract
This paper proposes an optimizing design method which uses Genetic Algorithm (GA) to reduce both weight and cost of machine elements based on a methodology to optimize “functional distribution of materials”. According to this methodology, machine elements are fabricated of combined plural common materials, and selection and distribution of each material are optimized to satisfy the function to a minimum degree required for each part of the given machine element.
A piston pin for an air compressor and a spur gear for an industrial robot were chosen as examples of this study. Optimal structures of both elements were the multi-layered ones composed of two kinds of materials. The elements fabricated by the proposed optimization procedure showed remarkable reduction both in weight and cost as well as sufficient operational performance.