bluuebunny/crossref_metadata_2025 huggingface dataset:
A Software “Design Assistant” for Specification Development
Authors: Schuster Helmut R. , Basson Anton H.
Published: February 2021

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

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

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

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.
Timed Petri Nets and Heuristic Search-Based FMS Scheduling
Authors: Dong Ming , Cha Jianzhong
Published: February 2021

In this paper, FMS scheduling problems are modeled by timed Petri nets. The timed Petri nets can model the important characteristics of FMSs such as routing flexibility, shared resources, precedence relationships among operations, concurrency, synchronization and lot sizes. So the Petri net model of an FMS scheduling problem which reflects the given constraints would limit the search within the feasible schedule space. By making use of a heuristic scheduling algorithm which satisfies the lower bound condition of the algorithm A*, the search space can be further reduced and an optimal path can be found. This new scheduling approach which combines Petri net modeling with heuristic search can effectively handle with the structural complexity and computational complexity of FMS scheduling problems.
Product Data Management Using AP203 of Step Standard
Authors: Kim T. S. , Han S.-H. , Shin Y. J.
Published: February 2021

Manufacturing data needs to be shared among functional groups of an enterprise and among its part suppliers and partners. Technological data needs to be shared among different hardware platforms, different data storage devices, and variety of network architectures. A standard specification for manufacturing data is needed that can support the entire product development phases and life-cycle. This paper proposes an information system for sharing product data throughout its life-cycle. It describes how textual information of design can be integrated with geometric data based on AP203 of STEP standard, SDAI, HTML, and object-oriented Tcl/Tk. The prototype information system can modify STEP data, and display parts information and BOM using the network browser - Netscape.
A Development of Wire Path Searching Module Using Extended RCA Method
Authors: Yim Seong-Hyuk , Lee Soo-Hong
Published: February 2021

This study deals with a development of wire path searching module as a part of automotive wire harness design system. Wire path searching module manages the free space, finds transition locations, and creates bundle paths to dramatically reduce a tedious iterative routing process which results in easy optimization of the bundle paths. A prime policy in the system configuration is to compromise between man’s and computer’s ability, and make it possible a designer’s leading role in designing process. Human input is indispensable to cope with the special cases which were not considered in the initial design stage of the system. In this study, we improve the previous shortest-path-finding algorithm (VGraph and RCA method) into a new method called Extended RCA. Bundles, connectors and transitions are handled as objects so one can manage and modify physical properties of the objects easily. Therefore a verification is allowed at any desired stage of design. The reuse of previous result is facilitated by using Dependency Structure, which represents the mutual relations among connectors, transitions, and bundles. Dependency Structure makes it possible the elimination of redundant calculating process, and consequently shorter routing time.
Hierarchical Decomposition Synthesis in Optimal Systems Design
Authors: Krishnamachari Ramprasad S. , Papalambros Panos Y.
Published: February 2021

Optimal design of large systems is easier if the optimization model can be decomposed and solved as a set of smaller, coordinated subproblems. Casting a given design problem into a particular optimization model by selecting objectives and constraints is generally a subjective task. This article describes how such a subjective selection can be made so that the resulting optimal design model can be directly partitioned into an appropriate decomposed form. This process is termed decomposition synthesis. A particular methodology for synthesizing hierarchically decomposed optimal design models is presented together with examples.
An Artificial Intelligence Based Algorithm for Object-Oriented Design
Authors: Segapeli Jean-Luc , Cavarero Annie
Published: February 2021

It is possible to classify the Object-Oriented design methods in two sets. The first set, which is the most numerous, uses an entity relationship approach to build a static class schema. Then this schema is completed by the use of different models (dynamic, functional). The second set tries to obtain a class schema but they don’t provide a guide to build it. So if different designers work on the same application, it is impossible to obtain the same schema.

So, in this paper we want to prove that we have defined a new design process (generalization process) which is based upon a set of rules to guide the users and the designers to build a representation of their application. The originality of our process lays upon works developped in machine learning and artificial intelligence. We try to translate the expertize of users or designers given through examples into a class schema. Therefore we have defined a new algorithm of clustering to organize examples into a hierarchy of classes.

This process is included in a project called C.O.D. (Class and Object Definition). The project is composed of different processes which take into account the expertize level of the designers and their knowledge about the application domain: specialization process, which is based upon generic application and fuzzy object classes; composition process, which uses a functional application definition with an algorithm to build classes and links between classes; generalization process, which is developed in this paper.
Modelling and Analysis of a Grout Delivery Mechanism in the Remote Spray Lining of Shafts
Authors: Hongzhao Liu , Appleton E.
Published: February 2021

A thorough analysis on the characteristics of a grout delivery mechanism in the lining of shafts has been accomplished. The dynamic equation of this spraying mechanism has been established and can describe the system’s performance properties under different conditions of viscous friction forces. The analysis introduces a combined viscous damping coefficient c* and a ratio λ between viscous friction force and inertia force. It is proved theoretically that the relative velocity of the grout is less than the implicate velocity and the emission angle α described in the paper is always larger than 45 °. Numerical simulations are performed by feeding various different parameters into the model. A full discussion of the effects of different variables is presented. Additionally, a formula for calculating the driving torque and power is developed. These studies provide an understanding of the properties of this mechanism and should prove useful in guiding its design and operation.
Optimum Design of a Planar Robotic Manipulator
Authors: Berner D. F. , Snyman J. A.
Published: February 2021

A general optimization methodology for the optimal design of robotic manipulators is presented and illustrated by its application to a realistic and practical three link re volute-joint planar manipulator. The end-effector carries out a prescribed vertical motion for which the weighted average torque requirement from electrical driving motors is minimized with respect to positional and dimensional design variables. In addition to simple physical bounds placed on the variables the maximum deliverable torques of the driving motors represent further constraints on the system. The optimization is carried out via a penalty function formulation of the constrained problem to which a proven robust unconstrained optimization method is applied. The problem of degeneracy or lock-up, which may occur for certain choices of design variables, is successfully dealt with by means of a specially proposed procedure in which a high artificial objective function value is computed for such “lock-up trajectories”. Designs are obtained that represent substantial reduction in torque requirement in comparison to that of arbitrarily chosen practical designs.
Remote Concrete Spraying in Shafts and Tunnels With Closed Loop Control
Authors: Hongzhao Liu , Appleton E.
Published: February 2021

In this paper, a closed-loop control system for the remote concrete spraying in shafts and tunnels is presented. The design includes a velocity measuring element, a PID controller, and a DC servo-motor drive system which is used to control the relative velocity of the grout, emission velocity, emission angle, and rotation to impact angle. The mathematical model of this system has been established and its transfer function obtained by the Laplace Transformation method. A set of stability conditions for this fourth-order system has been developed by means of the modified Hurwitz criterion. These studies provide the possibility of creating high-performance remote concrete spraying machines that operate in shafts and tunnels and have directional spray capability.
Sensitivity Analysis of Engineering Designs Using Taguchi’s Methodology
Authors: Roy Rajkumar , Parmee Ian C. , Purchase Graham
Published: February 2021

The sensitivity analysis of engineering designs has been performed following Taguchi’s methodology. The technique is reliable and computationally inexpensive, thus suitable for real life problems. The design problem involves a mathematical model of a gas turbine blade cooling hole system. The model includes twelve input variables and three non linear constraints. The orthogonal matrix as suggested by Taguchi and the tolerances on the input design variables are used to define a neighbourhood of a design solution. Three different categories of sensitivity are defined, such as, design solution sensitivity, design variable sensitivity and constraint sensitivity. The sensitivities are defined within the neighbourhood of a design solution. The use of the orthogonal matrix allows an approximate sensitivity analysis without resorting to exhaustive local search. Taguchi’s signal to noise ratio is used to define the design solution sensitivity. Methodology involved in the estimation of factor effects in an experiment is used to calculate the design variable sensitivity. The extents of constraint satisfaction within the neighbourhood of a design solution defines different categories of constraint sensitivity, such as, constraint satisfied, statistically active constraint, quasi-active constraint, peak-active constraint and constraint not satisfied. The paper briefly discusses Taguchi’s methodology and then defines the different sensitivities. Results from the sensitivity analysis of the real life turbine blade cooling hole system are presented and discussed.
Configuring Turbine Propulsion Systems Using Robust Concept Exploration
Authors: Koch Patrick N. , Barlow Andy , Allen Janet K. , Mistree Farrokh
Published: February 2021

Complex systems are characterized as having multiple interdependent subsystems and requiring the coordination of multiple disciplines to design. Top-level specifications provide the foundation of the conceptual design of such systems. They define system/subsystem concept alternatives, representing the primary descriptors of a complex system. A Robust Concept Exploration Method (RCEM) has been developed to facilitate quick evaluation of different design alternatives and generation of “top-level” design specifications in the early stages of the design of complex systems. Comprehensive exploration of a design space is facilitated through the integration of statistical techniques, robust design simulation, and the compromise DSP. Our focus in this paper is to demonstrate the usefulness of this approach for the conceptual design of a comprehensive and practical industrial example. The preliminary design of a turbine lift engine for Advanced Short Take-Off and Vertical Landing (ASTOVL) fighter aircraft has been defined as a test case through a collaborative project with the Rolls-Royce Atlanta Engineering Group. An overview of our approach is provided; the lift engine example is defined; the steps of this approach, as applied to this example, are detailed and results for different design scenarios are provided and verified.
Combining Interactive Exploration and Optimization for Assembly Design
Authors: Kim Gerard Jounghyun , Szykman Simon
Published: February 2021

This paper presents an integrated framework for assembly design. The framework allows the designer to represent knowledge about the design process and constraints, as well as information about the artifact being designed, design history and rationale. Because the complexity of assembly design leads to extremely large design spaces, adequately supporting design space exploration is a key issue that must be addressed. This is achieved in part by allowing the designer to use both top-down and bottom-up approaches to assembly design. Exploration of the design space is further enabled by incorporating a simulated annealing-based optimization tool that allows the designer to rapidly complete partial designs, refine complete designs, and generate multiple design alternatives.
A New Class of Six-Bar Mechanisms With Symmetrical Coupler Curves
Authors: Shieh W.-B. , Tsai L.-W. , Azarm S. , Tits A. L.
Published: February 2021

A new class of six-bar mechanisms with symmetrical coupler-point curves is presented. This class of mechanisms is made up of a four-bar linkage with an additional dyad to form an embedded regular or skew pantograph. Because the coupler curve generated at an output point is amplified from that of a four-bar, a compact mechanism with a relatively large coupler curve can be obtained. In addition, due to their structure arrangement, the analysis and synthesis of such mechanisms can be easily achieved. It is shown that the admissible range of transmission angle for such mechanisms is smaller than that of a four-bar mechanism. It is also shown that mechanisms with an embedded skew pantograph exhibit better design flexibility than those with an embedded regular pantograph. Finally, an example mechanism from this class is illustrated and compared with a four-bar linkage with the same coupler curve.
Optimal Synthesis of Compliant Mechanisms to Satisfy Kinematic and Structural Requirements: Preliminary Results
Authors: Frecker Mary I. , Kikuchi Noboru , Kota Sridhar
Published: February 2021

Compliant mechanism synthesis is an automated design procedure which allows the designer to systematically generate the optimal structural form for a particular set of loading and motion requirements. The synthesis method presented here solves a particular class of design problems, where the compliant mechanism is required to be both flexible to meet motion requirements, and stiff to withstand external loads. A two-part problem formulation is proposed using mutual and strain energies, whereby the conflicting design objectives of required flexibility and stiffness are handled via multi-criteria optimization. The resulting compliant mechanism topologies satisfy both kinematic and structural requirements. The problem formulation is implemented using a truss ground structure and SLP algorithm. Several design examples are presented to illustrate this method.
Domains of Mobility for a Planar Body Moving Among Obstacles
Authors: Haug Edward J. , Adkins Frederick A. , Coroian Dan I.
Published: February 2021

A formulation is presented for defining domains of mobility for a planar convex body moving with three degrees-of-freedom among convex planar obstacles. Applications included are determination of areas of a factory floor or material storage facility in which objects can be manipulated without impacting fixed obstacles. Mobility of the moving body is defined to encompass (1) dextrous mobility of the body; i.e., points that can be reached by a reference point on the body and at which the body can be rotated through its full range of admissible orientations without penetrating any stationary obstacle, and (2) limited mobility of the body; i.e., points that can be reached by the reference point and at which the body does not penetrate any stationary obstacle, for some admissible orientation. Analytical criteria for points on boundaries of domains of mobility are derived and numerical methods suitable for mapping these boundaries are summarized. An elementary example involving a moving and a stationary ellipse, with and without orientation restrictions, is solved analytically to illustrate the method. A more general application with one moving body and three stationary obstacles is solved numerically.
Reverse Fishbone Diagram: A Tool in Aid of Design for Product Retirement
Authors: Ishii Kosuke , Lee Burton H.
Published: February 2021

This paper describes a schematic representation of product retirement specification that aids in design for recycling and reuse. In the past decade, a graphical representation of the assembly process, called the assembly fishbone diagram, has effectively assisted engineers to conduct design for assembly (DFA) and process failure modes and effects analysis (FMEA). On the other hand, environmentally conscious manufacturing requires engineers to make advanced planning for product retirement. This study investigates the use of the reverse fishbone diagram to model the disassembly and reprocessing sequence of a product at the end of its useful life. An industry-provided student project guided us to an initial definition of the reverse fishbone diagram that effectively led the students to analyze the recyclability and make practical redesign suggestions. The diagram is continuously adding more rigorous definitions and promises to be a central tool for evaluation of recyclability in a simultaneous engineering setting.
Design for Disassembly Methodology for Virtual Prototypes
Authors: Shyamsundar N. , Ashai Zia , Gadh Rajit
Published: February 2021

Design for disassembly involves evaluating the ease/difficulty of disassembling a product composed of multiple components. Existing methods primarily address the problem of disassembly planning and do not quantify the ease or difficulty of disassembly. The current research work specifically addresses the development of a design for disassembly methodology based on the quantitative assessment (i.e. metrics) of the disassemblability of the product. The formulation of the metrics is based on the factors to be considered for disassembling a product. In particular we are considering the potential application of the methodology to robotic disassembly for recycling and maintenance. While designing a product it is necessary to determine the numerical value of the metric in order to arrive at an acceptable design. This facilitates the comparison of different design solutions. The methodology developed in this paper can serve as a basis for identifying the optimal design.
Use of Injection Molding Simulation to Assess Critical Dimensions and Assign Tolerances
Authors: Zemel Marc I. , Otto Kevin N.
Published: February 2021

When a product is certified for production and while its quality is being monitored, it is not economically feasible to watch every dimension of the part. Through the definition of critical dimensions, the amount of measurements necessary for quality control can be limited. However, in order to properly assign tolerances to the critical dimensions, the engineer needs to understand the capability of the process. Unfortunately, the subject of tolerances can be a great source of arguments between design and manufacturing engineers. Concurrent engineering has taken a holistic approach to the problem by forcing manufacturing engineers to get involved earlier in the development process. We propose a methodology that employs injection molding process simulation to track the development of critical dimensions from the design stage to production. This methodology provides a more quantitative approach to the tolerancing of injection molded parts. Furthermore, the application of this methodology will promote better communication between manufacturing and design engineers by giving them a common language, consisting of a software model and data. By gaining an understanding of process variation, the design and manufacturing team will be able to do four things: assess the process capability, determine if the part will function properly through tolerance analysis, assign critical dimensions, and set up a measurement scheme for quality control.
A Parallel Solution Strategy for Finite Element Models
Authors: Cox Jordan J. , Talbert Jeffrey A. , Mulkay Eric
Published: February 2021

This paper presents a method for naturally decomposing finite element models into sub-models which can be solved in a parallel fashion. The unique contribution of this paper is that the decomposition strategy comes from the geometric features used to construct the solid model that the finite element model represents. Domain composition and domain decomposition methods are used to insure global compatibility. These techniques reduce the N2 behavior of traditional matrix solving techniques, where N is the number of degrees of freedom in the global set of matrix equations, to a sum of m matrices with n2 behavior, where n represents the number of degrees of freedom in the smaller sub-model matrix equations.
Common Product/Process Models for Integrating Manufacturing Simulation, Process Planning and Computer Aided Design
Authors: Bryant Robert V. E. , Laliberty Thomas J.
Published: February 2021

Integrated Product Process Development tools which minimize downstream manufacturing risk at the earliest design stages and avoid costly Design-Build-Test cycles are essential to achieving product profitability and meeting market windows. This paper summarizes initial work performed towards the development of the Manufacturing Simulation Driver (MSD) system which will demonstrate the automatic generation and execution of distributed manufacturing simulations. These simulation models are produced by Computer Aided Process Planning (CAPP) software tools which reason about Computer Aided Design (CAD) product models and produce manufacturing “scripts” from a process and resource model of a manufacturing facility. This capability will enable emerging virtual enterprises conducting collaborative design and manufacturing to simulate and prove out the manufacturing cycle of a product prior to launching production ramp-up. 1
A Blackboard Architecture for Integrated Process Planning/Production Scheduling
Authors: Laliberty Thomas J. , Hildum David W. , Sadeh Norman M. , McA’Nulty John , Kjenstad Dag , Bryant Robert V. E. , Smith Stephen F.
Published: February 2021

As companies increase the level of customization in their products, move towards smaller lot production and experiment with more flexible customer/supplier arrangements such as those made possible by Electronic Data Interchange (EDI), they increasingly require the ability to quickly, accurately and competitively respond to customer requests for bids on new products and efficiently work out supplier/subcontractor arrangements for these new products. This in turn requires the ability to rapidly convert standard-based product specifications into process plans and quickly integrate process plans for new orders into the existing production schedule to best accommodate the current state of the manufacturing enterprise.

This paper describes IP3S, an Integrated Process Planning/Production Scheduling (IP3S) Shell for Agile Manufacturing. The IP3S Shell is designed around a blackboard architecture that emphasizes (1) concurrent development and dynamic revision of integrated process planning/production scheduling solutions, (2) the use of a common representation for exchanging process planning and production scheduling information, (3) coordination with outside information sources such as customer and supplier sites, (4) mixed initiative decision support, enabling the user to interactively explore a number of tradeoffs, and (5) portability and ease of integration with legacy systems. The system is scheduled for initial evaluation in a large and highly dynamic machine shop at Raytheon’s Andover manufacturing facility.
Boundary Representation, Intersection, and Evaluation of Nurb Based Non-Manifold Objects
Authors: Wang Xuefu , Cheng Fuhua (Frank) , Sun Jiaguang , Barsky Brian A.
Published: February 2021

Boundary representation (B-rep), intersection, and evaluation schemes for NURB based non-manifold CSG objects are presented. The B-rep scheme follows a top-down, face-based approach. A definition of non-manifold objects and their set operations are given. The boundary evaluation process follows the intersect-merge-select strategy of Weiler (Weiler 1986). The generation of intersection geometry is performed in a bottom-up strategy. Intersection algorithms between entities of same and different dimensions are studied. The computation of face/face intersection is based on the concept of the marching method (Barnhill et al 1987; Barnhill & Kersey 1990). Several techniques have been developed to enhance the marching process, including the computation of initial points and tracing step sizes, control of intersection precision, and handling of branch points and tangential intersection curves (points). Inconsistency of the intersection results is corrected using criteria based on topological adjacency information. The proposed method finds all internal loops without performing loop detection (Hohmeyer 1991). New topological entities corresponding to the intersection results are created in the parameter space for each entity. These include vertices, edges and faces, but not 3D shells. The creation of topological faces is carried out by generating the boundary of each new face while traverse a net structure created during the intersection geometry generation process. Subsequent classification and selection are performed based on 2D topological entities, instead of 3D shells. The proposed methods has been implemented as the core of a NURB-based non-manifold modeling system.
Etch Rate Modeling in MEMS Design
Authors: Hubbard Ted J. , Antonsson Erik K.
Published: February 2021

This paper presents a model for determining the full three dimensional etch rate behavior of bulk wet etching of silicon from experimentally determined etch rates of four principal planes: (100), (110), (111), and (311). The etch rate for an arbitrary plane is expressed in terms of the measured planes. The model shows excellent agreement with both experimental measurements and values reported in the literature. For MEMS CAD to be able to accurately predict etched shapes, a high quality 3D model of etch rates such as the one reported here is required.
Design Considerations for Manufacturability of MEMS Comb Actuators
Authors: Dixit Hrishikesh , Taylor Dean L. , Kannapan Srikanth
Published: February 2021

Comb actuators are electrostatic drives commonly used in micro-electromechanical systems (MEMS). These devices are typically fabricated using standard Integrated Circuit (IC) fabrication techniques such as lithography, oxidation, chemical vapor deposition and etching. The design of MEMS devices such as comb actuators is a complex process due to the dimensionality of the parametric design space and the parametric interdependencies imposed by performance, manufacturability and reliability constraints. We present a study aimed at the decomposition and structured organization of the various design and manufacturability considerations for comb actuators. The value of this knowledge organization is illustrated by the formulation and solution of a design problem that ensures optimal parametric design and layout of a comb actuator on a silicon wafer. We combine analytical models and specialized fabrication “design rules” to obtain optimal solutions for two interesting problems in MEMS comb actuator design.
Systematic Process Selection in Mechanical Design
Authors: Esawi Amal M. K. , Ashby Michael F.
Published: February 2021

There has been a recent awareness of the importance of making the right manufacturing decisions early in the design process before the cost penalty of making changes becomes too high. The selection of the most appropriate manufacturing process — of which there are a very large number — is one such decision. It is commonly based on human-resident experience or on established local practice. As such, some potentially-usable processes may be overlooked. This paper explores ways in which process selection might be made more systematic.

It presents a procedure for manufacturing process selection which considers all manufacturing processes and eliminates the ones which cannot satisfy the design requirements. This is achieved using Process Selection Charts in which process capabilities are displayed graphically. A procedure for the ranking of the successful processes based on cost is under development.

The systematic selection procedure lends itself well to computer implementation. A database of manufacturing processes and an advanced user interface thus provide ideal support for designers. Cambridge Materials Selector (CMS) software is currently being applied to manufacturing process selection.
Toolpath Patterns and Their Evaluation Methods in NC Machining
Authors: You Xinnong , Chen Youping , Zhou Zude , Duan Zhengcheng
Published: February 2021

In this paper, various kinds of toolpath patterns are summarized and analyzed systematically for flat convex polygon, pocket with islands and sculptured surfaces. On this basis, the evaluation objectives of toolpath patterns are put forward, and a related fuzzy multi-objective evaluation model is presented to solve the problem of the assessment of alternatives with qualitative and quantitative criteria. At the end, an example of three toolpath patterns for the NC machining of a washer-wave-wheel is given to derive an optimal sorting sequence of them.
New CAD for Rapid Prototyping
Authors: Fukuda Shuichi , Suzuki Daisuke
Published: February 2021

We developed a new CAD tool with special attention paid to rapid prototyping. Most of the present 3-D CAD systems treat geometry with very high accuracy but it is not easy to define or modify geometry as we do in the earlier stages of design. The present CAD systems, we believe, are more oritented toward the detailed design and manufacturing of the final product.

As rapid prototyping itself is intended for the earlier stages of design, such a CAD system that permitts more easy or rough definition and modification of geometry is really desired. Most of the rapid prototyping systems generate 3-D geometry by piling up the 2-D sections layer by layer. So, if we develop such a layer-based CAD system, then we could more easily tranfer CAD data to the prototyping system.

Such an idea was very old, but the traditional ones cannot manipulate geometry with much ease. What we aimed here is to develop a system that a designer can manipuate geometry as freely as he or she wishes. Thus, our system serves as a preprocessor to the present 3-D CAD systems.

We are developing another system which permits to generate 3-D geometry as freely as if we are drawing it using a pen, based on the technology of 3-D measurement device. Couled with this system, the system we are proposing here is expected to tranfer such a 3-D geometry data very rapidly and easily to the prototyping equipment and also can interactively modify thus defined geometry data.
On Synthesis of Electro-Mechanical Assemblies
Authors: Madhusudan T. N. , Sycara Katia , Navin-Chandra D.
Published: February 2021

Research in providing feedback to designers to modify designs of electro-mechanical systems based on assembly and process plans has focused on identifying potential assembly and manufacturing problems during the design phase and providing suggestions to designers to eliminate them. Prototypical software systems provide design suggestions primarily based on the form of the different components in an electro-mechanical assembly thus providing feedback to the designers during the embodiment (form) design phase of the product. It is necessary to extend the feedback notions to other levels of abstraction describing a product i.e. function, behavior and parametric information. Performing such a task requires an understanding of the design process so as to have a better idea of the nature of feedback information required by a designer and its usage in design. In this paper, we outline a framework to integrate design feedback information in the course of the design task. This paper provides a classification of electro-mechanical products based on design requirements and describes a prototypical computational framework for the synthesis of electro-mechanical assemblies. We illustrate how assembly design (configuration design), parametric design and concept design may be integrated in a consistent manner.
“Modessa”: A Computer Aided Conceptual Design System
Authors: Kersten Twan
Published: February 2021

This paper describes the computer aided design system Modessa. Modessa is developed to support multi-disciplinary design teams in the conceptual design phase. Modessa is based on the “morphological design method” which decomposes the design problem into a number of so called functions. Then several alternatives are identified for each of these functions. These alternatives are visualized using pictures and arranged by function in a matrix which results in a so called “morphological overview”. Finally the alternatives are evaluated based on the customer requirements. The best alternatives for each function are combined to form the optimum solution for the design problem. Modessa supports multi-disciplinary design teams during the conceptual design process by:

- Suggesting known design alternatives for design functions, thus leaving more time for the creation of novel design alternatives.

- Offering a “common language” to objectively evaluate the design alternatives.

- Simplifying the creation and reuse of the conceptual design documentation.

Modessa is general purpose in nature and can be used for a wide variety of design applications. The kernel of Modessa is a design knowledge database that increases continuously as design teams add new functions (problems) and appropriate alternatives (solutions). In this paper the use of Modessa is illustrated by an industrial design example.
Team-Roles in Mechanical Design
Authors: Stetter Ralf , Ullman David G.
Published: February 2021

This paper presents an approach for identifying team-roles. The proposed approach is based on the interpretation of a design process in terms of the behavior of the members of the team. Behavior is codified in terms of the team member’s process and physical activities. In this study a collaborative design process was recorded on video-tape and analyzed in detail. The process was decomposed into distinct sections called events. In every event each team member was assigned a team-role taking into consideration the activity of the team member, i.e. what the team member does, how activity of the team member, i.e. what the team member does, how the team member does it, and the context of the event. A graphical representation of the results called ‘role-profile’ was developed making it possible to clearly identify a basic team-role for every subject in the observed design process.
Multi-Dimensional Mapping of Design Imprecision
Authors: Law William S. , Antonsson Erik K.
Published: February 2021

Preliminary design information is characteristically imprecise or fuzzy: specifications and requirements are subject to change, and the design description is vague and incomplete. The Method of Imprecision uses the mathematics of fuzzy sets to explicitly represent and manipulate imprecise preliminary design information, enabling the designer to better understand the full range of designs and performances that satisfy an imprecise set of specifications and requirements. This paper discusses the foundations of this methodology, and introduces pragmatic extensions that provide computationally tractable methods to map design imprecision from multiple design variables onto multiple performance variables. These methods attempt to minimize the number of function evaluations required while retaining an appropriate level of accuracy. This is achieved by using optimization to obtain extremal points for each performance variable and selectively applying a linear approximation for the mapping from the design variable space (DVS) to the performance variable space (PVS) to interpolate between extremal points. This linear approximation is constructed using regression techniques adapted from experiment design.
On a Mathematical Foundation of Axiomatic Design
Authors: Rudolph Stephan
Published: February 2021

The axiomatic design approach and its two underlying postulates, the independence and the information axiom, introduced by Suh (1990) are based on the fundamental claim that “there are generalizable principles that govern the design process and that these in the form of the design axioms are general principles or self-evident truths that cannot be derived or proven to be true except that there are no counter-examples or exceptions” (adapted from (Suh, 1994)).

This paper shortly describes a mathematical framework which allows replacing the independence and the information axiom with the so-called evaluation hypothesis (Rudolph, 1995a). This evaluation hypothesis is based on the technique of dimensional analysis known from physics and allows the straightforward derivation of expressions that in special cases match the above stated independence axiom. For the information axiom a different mathematical expression is obtained.

The new theoretical approach has the advantage of possessing an epistemological foundation in form of four fundamental requirements for the evaluation model of a design object which can be motivated through a rational thought process. The two different model assumptions are compared, discussed and illustrated using a published axiomatic design reference example.
Enhancing Design Education With Practical Knowledge Needed in Industry
Authors: Pattison Will
Published: February 2021

Education in design has become a major priority in modern mechanical engineering curriculums. In particular, design education has focused on using good design methodology to produce optimum solutions, promote innovation, and encourage creativity in the engineer. There are other facets of the design engineer’s position that should also be emphasized at the education level. First, design engineers must be aware of the manufacturing processes that will be used to turn their concepts into working solutions. Second, they must understand how prototypes of those solutions fit into the overall product development process, and how new technologies such as Rapid Prototyping can enhance it. Finally, they must be able to effectively communicate their design intent, both graphically, verbally, and in writing, at all stages of the product development process. These three essential engineering skills, with special emphasis given to the last two and their place in design education, are covered in this paper.
Design and Implementation of an Object-Oriented Cooperative Distributed Problem Solving Shell
Authors: Yang Feng-Chao , Ho Yu-Kuen
Published: February 2021

In this paper an Object-Oriented Cooperative Distributed Problem Solving Shell (OOCDPSS) is presented. It is a convenient and effective building tool for the cooperative multi-agent application systems under distributed computer environment. By the Distributed Artificial Intelligence technique and the Object-Oriented concept, each agent is constructed by multi-layer structure to reduce the design complexity and give more flexibility, and they are arranged as a recurrent group structure for run-time effective management. Additionally, the idea of mediator is adopted to integrate new information systems with the existing inflexible legacy system, and the distributed whiteboard agent is used for the information interchange among the agents. This prototype system has been completed and used as the test bed of our other laboratory projects.
Effects of Collocation on the Integrated Product Team and the Impact on Cost, Schedule, and Risk
Authors: Rumpf Richard L. , Gindele Mark E.
Published: February 2021

Program Managers need to look beyond the veil of potential benefits to assess the risks of contractor proposed concurrent engineering efforts. The mere mention of concurrent engineering or its synonym, integrated product team, does not in itself reduce program schedule and cost. Evaluations should center upon the offeror’s past success with these initiatives and the fundamental steps leading to their implementation.

In a recent study of several programs involving the manufacture of Aircraft Launch and Recovery Equipment (ALRE) and support equipment, the effects of integrated product teams were assessed. Several of the programs studied had been competitively awarded to contractors that subsequently defaulted on their contract. The equipment programs were then successfully manufactured by the Prototyping and Manufacturing department at Naval Air Warfare Center, Lakehurst, NJ.

Data from the study indicated the success of the manufacture was directly attributable to the use of integrated product teams. Extensive communication between engineering, manufacturing, and testing teams led to the resolution of problems quickly. Face to face meetings were frequent and issues were resolved in minutes without resorting to technical memorandums or other protracted written documents. Collocation of the team members was considered the most critical factor to gaining any benefits from concurrent engineering.

Further evidence indicated the more complex a system, the more collocation was critical to its successful completion. Complexity, when measured by the number of parts, critical interfaces, and final testing requirements, was assessed for each program. The more complex programs had employed more frequent and local communication.
A New Crossover Operator for Assembly Sequence Planning by Genetic Algorithms
Authors: Sebaaly Milad Fares , Fujimoto Hideo
Published: February 2021

Assembly Sequence Planning (ASP) is the generation of the best or optimal sequence to assemble a certain product, given its design files. Although many planners were introduced in research to solve this problem automatically, it is still solved manually in many advanced assembly firms. The reason behind this is that most introduced planners are very sensitive to large increases in product parts. In fact, most of these planners seek the exact solution, while performing a part basis decision process. As a result, they are trapped in tedious and exhaustive search procedures, which make them inefficient and sometimes obsolete. To overcome these difficulties, Sebaaly and Fujimoto (1996) introduced a new concept of ASP based on Genetic Algorithms application, where the search procedure is performed on a sequence population basis rather than a part basis, and a best sequence is generated without searching the complete set of potential candidates. This paper addresses the problem of improving the GA performance for assembly application, by introducing a new crossover operator. The genetic material can be divided and classified as ‘good’ or ‘bad’. The new crossover insures the maximum transmission of ‘good’ features from one generation to another. This results in a faster GA convergence. The performance of the new algorithm is compared with that of the ordinary matrix crossover for a modified industrial example, where it proved to be faster and more efficient.