bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation Model for Helical Rotor Expanders
Authors: Simmons Larry D.
Published: April 2021

The objective of this project was to develop a computer model for the helical rotor expander which can be used to determine performance potential and to facilitate optimization of expander design. Testing has shown that this energy conversion device has substantial potential advantages over conventional turbines in very high temperature cycles and for two-phase flow. However, the tests have been limited to particular non-optimized designs, and a model is badly needed to assess viable design improvements and their effects on performance. A computer model was developed to simulate the geometric and thermal/fluid characteristics of the expander to give power output, mass flow rate, and efficiency versus rotational speed for any chosen design configuration. The model has been tested against experimental data from expanders running on nitrogen gas and two-phase steam with good agreement. It is now ready and available for use in developing and evaluating designs for new applications of the helical rotor expander.
Evaluation of Thermal Radiation Simulator Rectangular Pulse Characterization Methods
Authors: Loucks Richard B.
Published: April 2021

The thermal output of an aluminum powder/liquid oxygen Thermal Radiation Simulator (TRS) is approximated to that of a rectangular pulse. The output varies as a function of time. The rise and fall times are not relatively abrupt. The problem is how to quantify the thermal output of the TRS into terms of a rectangular pulse.

Within the nuclear weapons effects community, flux, or the transient intensity of thermal radiation energy onto a surface, and fluence, the total energy irradiated onto a surface over a given time, are the determining parameters for specifying or evaluating an article’s survivability in the thermal environment. Four methods are used to determine the TRS output for these two parameters, assuming the output to be a perfect rectangular pulse. It was essential to determine which of the four methods best quantified the thermal output average flux and fluence. The four methods were compared by a computational experiment run on a personal computer.

The experiment was a simulation of five actual TRS traces irradiated onto a fictitious aluminum plate. The temperature profile of the front surface was computed using a finite difference method calculation. The traces were evaluated using the four characterization methods, generating twenty ideal thermal pulses. The temperature profile of the plate was computed using the twenty ideal thermal pulses. The resulting profiles were compared to profiles generated by the actual data to determine which of the characterization methods best evaluated the TRS output.
Finite Element Method of Flexible Multibody Dynamics Based on a New Kind of Floating Frame
Authors: Lu You-Fang , Qi Zhao-Hui , Wang Bin , Feng Guan-Min
Published: April 2021

A new kind of floating frame whose parameters do not appear in equations of motion as additional unknowns is defined. Numerical analysis of flexible multibody dynamics is much facilitated by using finite-element iteration of the corresponding equations based on this concept.
Automatic Mesh Generation on Annular Profiles With Geometric Constraints
Authors: Sharma M. , Rodriguez J. , Langrana N.
Published: April 2021

The Finite Element Method (FEM) has been recognized as one of the most effective analysis method for complicated domains. Unfortunately, any practical application of FEM requires extensive amount of input data. General pre-processors usually require a large amount of user defined information. Therefore, in some particular applications, where more specific options are needed, a special mesh generator in required. In this paper we present an automatic mesh generator for annular models with inherent geometric constraints, such as fiber orientation in composite-like structures/systems. The developed generator is designed to generate 3-D meshes with minimal users’ input and effort, and it can be used in conjunction with almost any CAD system or FEM software. The code is particularly useful for efficient performance of numerical studies relating mesh density and convergence.
Innovative Approaches for Teaching Descriptive Geometry With CADD
Authors: Cherng John G.
Published: April 2021

This paper presents the innovative approaches that can be implemented in teaching descriptive geometry by using a Computer-Aided-Design-Drafting (CADD) software. Examples of line relations, line/surface relations, and plane/cylindrical solid intersections are given in the paper. The paper first discusses the principles of descriptive geometry, and then focuses on how these principles can be applied in a CADD environment. In addition, new methods that take advantage of CADD are also provided. The paper emphasizes creativity while solving descriptive problems by using a CADD software. Although all examples illustrated in CADKEY, the concepts revealed in this paper can be applied to other 3-D CADD software, such as AutoCAD 10 and will significantly improve the engineering student’s CADD skills.
Computerized Data Acquisition, Reduction and Analysis of a Solar Water Heating System
Authors: Dini Said , Davison Wellen G. , Vaccaro John
Published: April 2021

A computerized data acquisition system for the solar hot water heating system located in the School of Engineering at Western New England College was designed and implemented. The system consists of three flat plate collectors located on the roof of the building facing south and inclinded at an angle of 40° with the horizontal, a heat exchanger, a storage tank, and an AST computer for data reduction, storage and analysis. The data collection and processing of this system was automated by interfacing a DAS-8 board located in the AST computer and a Metrabyte Exp-16 multiplexer amplifier board with 12 thermocouples and a pyranometer. The data acquisition program was written using GWBASIC along with DAS-8 commands. A program was also written to run the boards and do performance calculations. The program provides the solar radiation data, temperature distribution into the flat plate collector, temperatures in and out of the collector, useful energy gain and the efficiency of the collectors.
Declarative Rule Based Programming for Solving Problems in Kinematics and Dynamics of Machines
Authors: Haque Imtiaz , Huey Cecil O.
Published: April 2021

The required, senior course in kinematics and dynamics of mechanisms at Clemson University is currently being taught using a declarative rule based program as a computational tool for all analytical tasks. This is because of the necessity of numerical techniques for the solution of mechanism problems and the difficulty and inefficiency of programming in Fortran or similar languages. Also, it is felt that introductory course work in any subject should not be tied to specific purpose applications software. The course has been successful in developing sound competency in analysis and design of mechanisms while relying only on a widely available, general purpose computational tool. The overall approach used in the course is described and examples of the work assigned to students are provided.
An Automatic Speech Recognition System for Bedside Data Entry in an Intensive Care Unit
Authors: Petroni M. , Collet C. , Fumai N. , Roger K. , Yien C. , Lam A. , Malowany A. S. , Carnevale F. A. , Gottesman R. D.
Published: April 2021

An automatic speech recognition system is being developed for a patient data management system (PDMS) for the pediatric intensive care unit (ICU) at the Montreal Children’s Hospital. Here, fourteen bedside monitors are linked by a local area network to a personal computer for real-time acquisition of vital sign data and the graphical display of trends. The PDMS also allows for the manual input of data, such as fluid balance data, by means of a keyboard and a pointing device. This paper presents a description of the multimodal human-computer interface of the bedside data entry system, focusing on the speech recognition and generation sub-systems and their integration in the OS/2 Presentation Manager environment.
Shape Interrogation by Medial Axis Transform
Authors: Patrikalakis N. M. , Gursoy H. N.
Published: April 2021

In this paper we develop a new interrogation method based on the medial axis transform to extract some important global shape characteristics from geometric representations. These shape characteristics include constrictions, maximum thickness points, and associated length scales; isolation of holes and their proximity information; and a set of topologically simple subdomains decomposing a complex domain. The algorithm we develop to compute the medial axis transform of planar multiply connected shapes with curved boundaries can automatically identify these characteristics. Higher level algorithms for generation of finite element meshes of planar multiply connected domains, adaptive triangulation and approximation of trimmed curved surface patches and other engineering applications using the medial axis transform are also discussed.
Probabilistic Optimal Design Using Successive Surrogate Probability Density Functions
Authors: Eggert R. J. , Mayne R. W.
Published: April 2021

Probabilistic optimization using the moment matching method and the simulation optimization method are discussed and compared to conventional deterministic optimization. A new approach based on successively approximating probability density functions, using recursive quadratic programming for the optimization process, is described. This approach incorporates the speed and robustness of analytical probability density functions and improves accuracy by considering simulation results. Theoretical considerations and an example problem illustrate the features of the approach. The paper closes with a discussion of an objective function formulation which includes the expected cost of design constraint failure.
Distance Calculations in Motion Planning Problems With Interference Situations
Authors: Liu C. Y. , Mayne R. W.
Published: April 2021

This paper discusses distance calculations for three dimensional polyhedra with the assumption of convex bodies. An n-surface convex polyhedron is viewed as the intersection of n half-spaces and is represented by n linear inequality equations while the square of the distance between two points is of a quadratic form in terms of two sets of x-y-z coordinates. The static distance-to-contact between two non-interfering convex polyhedral shapes is then directly solvable by quadratic programming. Based on the concept of distance-past-contact, distance calculations for situations with interference are presented and tested in optimization based robot path planning examples. The distance evaluation is further investigated for the dynamic situations by a swept volume computation strategy. The approach is illustrated in examples with a moving robot link and a fixed obstacle.
Maximum Intersection of Spherical Polygons and Workpiece Orientation for 4- and 5-Axis Machining
Authors: Tang Kai , Woo Tony , Gan Jacob
Published: April 2021

Orienting the workpiece in such a way as to minimize the number of setups in a 4-axis or a 5-axis Numerical Control (NC) machine is formulated as follows: Given a set of spherical polygons (that are representations of curved surfaces visible to a 3-axis NC machine), find a great circle (the 4th axis) or a band (the 4th and the 5th axes) containing a great circle that intersects the polygons maximally.

While there are potentially infinitely many solutions to this problem, a sphere is partitioned into O(N2) regions based on the N polygons. Within each of these regions, it is shown that it requires O(NlogN) time to determine maximum intersections and all the solutions are congruent. Central projection mapping is employed so as to present the algorithms in the plane.
General Tool Offset Curves and Surfaces
Authors: Brechner Eric L.
Published: April 2021

Offset curves and surfaces are often used to define two- and three-axis tool paths for circular and spherical cutting tools. This paper derives extensions of these curves and surfaces that can define tool paths for general cutting tool shapes. The general tool offsets are based on a study of mathematical envelopes of arbitrary smooth “structuring” surfaces centered on an arbitrary differentiable “foundation” surface. When a part is used for the foundation surface and a cutting tool is used for the structuring surface then the envelope forms a general tool offset. Explicit parameterizations are computed for these envelopes and for their tangents, normals, and curvature matrices in terms of the known respective quantities of the structuring and foundation surfaces.
Design Shell: A Framework for Interactive Parametric Design
Authors: Srinivasan Raman V. , Agrawal Rajiv , Kinzel Gary L.
Published: April 2021

This paper consists of a study of the mechanical engineering design methodology and the development of a computer-based framework for performing design. The framework, known as the Design Shell, provides the essential design tools, such as, constraint manager, nonlinear simultaneous equation solvers, optimizers, sensitivity analyzer, and graphics handler, in an interactive design environment. The design shell attempts to enhance the designer’s understanding of the relationships between the various design parameters and how these affect the overall design. As an illustration of the capabilities of the computer tool, the design of a torsion bar spring is presented in the paper.
Compatibility-Based Design for Contact Stress
Authors: Ishii K. , Klinger J. M. , Hamrock B. J.
Published: April 2021

This paper discusses the combined use of quantitative analysis equations and knowledge-based techniques in the design of machine elements. We introduce the method of design compatibility analysis to 1) guide the application of correct analysis equations, 2) interpret the results of analysis, and 3) suggest modifications to improve the design. As an example vehicle, this paper focuses on design issues related to contact stresses and lubrication between two surfaces. The compatibility approach covers not only quantitative performance measures, but also the qualitative design issues such as suitability of surface materials, machining methods, surface roughness, lubricants, etc. To verify the utility of this concept, we developed DECS (Design Expert for Contact Stress), a PC-based design-aid for contact stresses and lubrication. DECS uses Prolog for top-level management and inference, while C provides and efficient computation of the quantitative equations. DECS also utilizes some recent developments in the computations of contact stress and elastohydrodynamic lubrication. Our method would be useful in many other design applications.
Computational Implementation and Tests of a Sequential Linearization Algorithm for Mixed-Discrete Nonlinear Design Optimization
Authors: Loh Han Tong , Papalambros Panos Y.
Published: April 2021

A previous article gave the theoretical background and motivation for a new sequential linearization approach to the solution of mixed-discrete nonlinear optimal design problems. The present sequel article gives the implementation details of program MINSLIP based on this approach. Illustrative examples, modeling issues, and program parameter selection are discussed. A report on extensive computational results with test problems, as well as comparisons with other methods, shows advantages in both robustness and efficiency. Sample design applications are included.
A Deterministic Global Design Optimization Method for Nonconvex Generalized Polynomial Problems
Authors: Lo Chihsiung , Papalambros Panos Y.
Published: April 2021

A new design optimization method is described for finding global solutions of models with a nonconvex objective function and nonlinear constraints. All functions are assumed to be generalized polynomials. By introducing new variables, the original model is transformed into one with a linear objective function, one convex and one reversed convex constraint. A two-phase algorithm that includes global feasible searches and local optimal searches is used for globally optimizing the transformed model. Several examples illustrate the method.
Remarks on Conditions for the Validity of Parametric Decomposition in Optimal Design
Authors: Rao J. R. Jagannatha , Papalambros Panos Y.
Published: April 2021

Decomposition strategies are used in a variety of practical design optimization applications. Such decompositions are valid, if the solution of the decomposed problem is in fact also the solution to the original one. Conditions for such validity are not always obvious. In the present article, we develop conditions for two-level parametric decomposition under which: (1) isolated minima at the two levels imply an isolated minimum for the original problem; (2) necessary conditions at the two-levels are equivalent to the necessary conditions for the original problem; and, (3) a descent algorithm for computing Karush-Kuhn-Tucker points in decomposition formulations is globally convergent. Since no special problem structure is assumed, the results are general and could be used to evaluate the suitability of a variety of approaches and algorithms for decomposition strategies.
Optimization Formulations for Designs Posed in the Labeled Interval Calculus
Authors: Wilhelm Robert , Ward Allen
Published: April 2021

Optimization formulations are developed for design problems stated in the labeled interval calculus. The labeled interval calculus is discussed briefly and an example is shown where motors and transmissions must be selected to meet design requirements. Optimization formulations for selection over continuous and discrete ranges are shown. A transformation from the labeled interval calculus to an optimization formulation is then discussed.
Design of Control Systems for Performance: A Constraint Mapping Approach
Authors: Beyers Robert , Desa Subhas
Published: April 2021

This paper is the single-input, single-output frequency domain counterpart of a framework developed by the authors [7] for the design for performance of constrained controlled dynamic systems. Simple s-plane maps are used to graphically reveal interactions of performance requirements and constraints, thus permitting a control system designer to clearly understand performance trade-offs. Two important facts underlie our approach: (a) the dynamic performance of a closed-loop system is limited by certain constraints and (b) successful control system design must explicitly account for these constraints. The approach is applied to second-order linear systems which are the basis for much control system analysis and design of single-input, single-output linear systems.
An Optimization-Based Framework for Simultaneous Plant-Controller Redesign
Authors: Beyers Robert , Desa Subhas
Published: April 2021

In this paper we develop a framework for the redesign of computer-controlled, closed-loop, mechanical systems for improved dynamic performance. A central notion which underlies the redesign framework is that, in order to achieve the best possible performance from a constrained closed-loop system, the plant and controller should be designed simultaneously. The framework is presented as the formulation and solution of a progression of optimization problems which enable the designer to systematically establish the various redesign possibilities. An example clearly demonstrates the underlying ideas as well as the use of the redesign framework for performance improvement.
Dynamic Analysis of Mechanical Systems With Time-Varying Topologies: Part 2 — Global Analysis and Simulation Results
Authors: Wang Yu
Published: April 2021

The discrete time model developed in Part 1 has been applied to the determination of regions of stability. The backward mapping method is applied and the associated numerical properties are discussed. The model is combined with conventional numerical techniques to form a computer simulation system which is more reliable and accurate in handling the topological changes. The simulation results of an example system are presented.
Large Scale Structural Optimization With Linear Goal Programming
Authors: El-Sayed Mohamed E. M. , Jang T. S.
Published: April 2021

This paper presents a method for solving large scale structural optimization problems using linear goal programming techniques. The method can be used as a multicriteria optimization tool since goal programming removes the difficulty of having to define an objective function and constraints. It also has the capacity of handling rank ordered design objectives or goals.

The method uses finite element analysis, linear goal programming techniques and successive linearization to obtain the solution for the nonlinear goal optimization problems. The general formulation of the structural optimization problem into a nonlinear goal programming form is presented. The successive linearization method for the nonlinear goal optimization problem is discussed. To demonstrate the validity of the method, as a design tool, the solution of the minimum weight structural optimization problem with stress constraints for 10, 25 and 200 truss problems are included.
A Multi-Objective Optimization Strategy With Priority Ranking of the Design Objectives
Authors: Matsumoto Masahide , Abe Jumpei , Yoshimura Masataka
Published: April 2021

Generally, two types of priorities are considered among multiple objectives in the design of machine structures. One of these objectives is named the “hard objective”, which is the absolutely indispensable design requirement. The other is called the “soft objective”, which has lower priority order. This paper proposes a multi-objective structural optimization strategy with priority ranking of those design objectives. Further, this strategy is demonstrated on the actual example of a motorcycle frame structural design which has three design objectives, (1) an increase in static torsional rigidity, (2) a reduction of dynamic response level, and (3) a decrease in the weight of the motorcycle frame.
Design Sensitivity Derivatives for Isoparametric Elements As an Integrated Part of Finite Element Analysis
Authors: Zumwalt Kenneth W. , El-Sayed Mohamed E. M.
Published: April 2021

This paper presents an approach for incorporating design sensitivity calculations into the finite element analysis. The formulation depends on the implicit differentiation approach and requires few additional calculations to obtain the design sensitivity derivatives. The implicit differentiation approach is developed and implemented to calculate the design sensitivities for continuum and structural isoparametric elements. To demonstrate the accuracy and robustness of the developed approach some test cases using different structural and continuum element types are presented.
Integrated Strength and Manufacturing Process Design Using a Shape Optimization Approach
Authors: Grandhi Ramana V. , Modukuru Sesha C. , Malas James C.
Published: April 2021

This paper considers a simultaneous design of product and manufacturing process. The product requirements include strength properties, whereas the manufacturing process goals include cost, quality, and microstructure to produce defect-free parts on a repeatable basis. The concept is demonstrated by designing a turbine disk manufactured using a forging process. A simplified analysis is used in forging process simulation. Formulation of the integrated design problem is emphasized.
Workstation-Based Man-in-the-Loop Simulation for Multibody Systems
Authors: Chang J. L. , Kim S. S.
Published: April 2021

This paper presents a general approach to achieving real-time man-in-the-loop simulation for multibody dynamic systems. Emerging real-time dynamic simulation methods are used to demonstrate the potential for creating interactive design workstations with a human operator in the control loop. The recursive formulation of multibody system dynamics with relative coordinates is employed for efficient numerical analysis and implementation on parallel computer. A workstation-based simulator is developed by integrating the real-time dynamics program, a realistic graphics display, and the operator’s control interface. High speed computer graphics techniques are employed to create realistic visual cues for the simulator. Real-time man-in-the-loop simulation is analyzed, as regards the goal of real clock time, not only with respect to dynamic simulation but also with respect to graphics display and the operator interface. Synchronization of the simulation is found to be most important for realism of the simulator. A backhoe simulation is implemented to demonstrate the capability for man-in-the-loop simulation. The backhoe simulator is developed by modeling backhoe dynamics and hydraulic systems with the recursive formulation to achieve real-time simulation, developing an interactive graphics program for visual cues, and interfacing the operator’s control action with the dynamic simulation through a pair of joysticks.
The Generation of Contact Surfaces of Indexing Cam Mechanisms: A Unified Approach
Authors: Gonzalez-Palacios M. A. , Angeles J. , Cai Ch.
Published: April 2021

In this paper the ruled surfaces of two rigid bodies that are in contact while moving with a prescribed time-varying angular-velocity ratio are generated. These are then used as the contact surfaces of indexing cam mechanisms. In this way, planar, spherical and spatial mechanisms can be synthesized in a unified framework. The approach is illustrated with various examples.
An Energy Efficient Quadruped With Two-Stage Equilibrator
Authors: Shin E. , Streit D. A.
Published: April 2021

A first consideration of the applications of mechanical equilibrators to legged locomotion is presented. Equilibrators are shown to eliminate “geometric work” while allowing simultaneous dual actuation of each leg joint of a quadruped. Gravitational forces on both the vehicle body and legs are decoupled from actuator force/torque requirements. In addition, for slow speeds and when leg kinetic energy is ignored, both joint actuator torques and joint actuator work approach zero. Dynamic simulation demonstrates that proper equilibrator design can reduce peak torque of leg actuators by more than 90% and offer a vehicle specific resistance 70% smaller than that of tracked vehicles.
Design of Cartesian Trajectories and Model Based Control for Robotic Manipulators
Authors: Balkan Tuna , Kaftanoglu Bilgin
Published: April 2021

In this study, design and calculation of Cartesian trajectories for robotic manipulators are discussed with a model-based control system at the joint level. The synthetic generation of the continuous path is described and from a predetermined velocity profile and evaluated path length, the time frame of the motion is computed. In the definition of end-effector orientations, instead of using impractical Euler angles, a practical method suitable to industrial applications is given. The trajectory generation and control algorithms are applied to a computer model of a PUMA type manipulator following a three dimensional path. Open-loop joint variable torques are plotted for the given scenerio. Joint variable position and velocity errors are discussed when certain simplifications are performed on the control law for on-line control of manipulators.
A Relative Coordinate Formulation for Variational Solid Modeling
Authors: Fogle Martin A. , Wu J. Kirk
Published: April 2021

A minimal formulation using relative coordinates is presented for variational solid modeling. Computational methods developed for the kinematic modeling of mechanical systems are used to derive a minimal problem formulation. First, the concept of arbitrary coordinates is introduced to reduce the dimension of the constraint vector. Next, the variational problem is divided into two sub-problems. This is done by modeling the problem as a graph, which is then analyzed to identify open loops and decoupled loops. The third method used to reduce the size of the variational problem is to transform the sub-problems from a Cartesian coordinate formulation to a relative coordinate formulation. Once identified, the open loop sub-problem is solved trivially. Finally, the decoupled loop sub-problem is solved by optimization techniques which minimize the total constraint violation. Compared to the traditional approach, the relative coordinate method has a much smaller formulation, is highly convergent, and is able to evaluate under constrained geometry.
An Intelligent Interactive Layout CAD System for Industrial Plants
Authors: Kameyama Ken-ichi , Kondo Koichi , Ohtomi Koichi
Published: April 2021

This paper describes an industrial plant layout system with an intelligent interactive user-interface. This system offers a powerful design environment, in which a designer can concurrently draw and check a layout plan, which can not be realized on a conventional plant layout CAD system. The major function of the system is the automatic constraint checking of each designer’s drafting action. This function is achieved by the integration of a geometric modeler, frame representation, and production rules. The geometric modeler is used for extracting the information for data updating and constraint checking from graphical objects, which are directly manipulated by a designer. Frame representation is used for representing the attributes of the equipments and the areas, and these attributes are handled by production rules. Production rules are used for representing the constraint checking and data updating procedures, and can be executed as required.
Proving the Labeled Interval Calculus for Inferences on Catalogs
Authors: Habib Walid , Ward Allen C.
Published: April 2021

The “labeled interval calculus” is a formal system that performs quantitative inferences about sets of artifacts under sets of operating conditions. It refines and extends the idea of interval constraint propagation, and has been used as the basis of a program called a “mechanical design compiler,” which provides the user with a “high level language” in which design problems for systems to be built of cataloged components can be quickly and easily formulated. The compiler then selects optimal combinations of catalog numbers. Previous work has tested the calculus empirically, but only parts of the calculus have been proven mathematically. This paper presents a new version of the calculus and shows how to extend the earlier proofs to prove the entire system. It formalizes the effects of toleranced manufacturing processes through the concept of a “selectable subset” of the artifacts under consideration. It demonstrates the utility of distinguishing between statements which are true for all artifacts under consideration, and statements which are merely true for some artifact in each selectable subset.
Generalized Measures of Manufacturability
Authors: Jansson David G. , Shankar Srinivasa Ravi , Polisetty Francis S. K.
Published: April 2021

This paper reports on the development of a framework for the evaluation of design concepts early in the design process through the use of a set of Generalized Manufacturabi1ity Indices (GMI). The indices are aimed at providing designers with a deeper insight into design issues which affect manufacturabi1ity than is available from a pure cost estimate. It is argued that at very early stages of design, cost estimates are inappropriate. Also, the GMI’s provide a more quantitative estimate of the manufacturability of a design than the use of design guidelines. The generalized nature of the GMI’s enables application of this approach to very dissimilar designs. The merging of manufacturing issues upstream in the design process through the framework presented here, is expected to increase both the speed and quality of product design.
Two Robust, Point-in-Polygon Tests Based on the 4 × 4 Determinant Method
Authors: Yamaguchi Fujio , Niizeki Masatoshi , Fukunaga Hiroyuki
Published: April 2021

Two new, contrastive point-in-polygon algorithms based on the 4 × 4 determinant method are proposed. By employing the error-free computations of the 4 × 4 determinant method, the algorithms can be very robust. First, a brief introduction to the 4 × 4 determinant method is presented. Secondly, the ideas of reconstructing, in two contrastive ways, a polygon from a sequence of point data are explained and then two algorithms derived from the ideas are presented. Thirdly, characteristics of both algorithms are discussed and compared. The complete programs of the two algorithms are shown.
Recognizing Novel Uses for Familiar Plans
Authors: Adelson Beth
Published: April 2021

Analogical design and invention is a central task in human cognition. Often during the process the designer/inventor gets stuck; backs off from the problem; and only later, after having put the problem aside, discovers that some familiar plan can be used in a novel way to solve the problem. We describe a system which uses a causal case memory to check the side effects, preconditions, etc. of incoming events in order to model this phenomenon.
Research in Design Theory and Methodology in West Germany
Authors: Hundal M. S.
Published: April 2021

Current research in design methods in the Federal Republic of Germany is reviewed. VDI guideline 2221 is discussed. The paper looks at basic research in design theory and methodology, application of the methodology to computer-aided conceptual and embodiment design, development of intelligent CAD systems, use of expert systems in CAD, and understanding thought processes in designing. References to the publications of the past three years are given.
A Formal Approach to Structural Design Automation Using Predicate Logic
Authors: Lakmazaheri Sivand , Rasdorf William J.
Published: April 2021

The common approach to engineering software development involves the identification of relevant concepts, relations between concepts, and strategies for manipulating concepts and relations in an informal manner. We believe that although the informal approach to the identification and utilization of engineering knowledge may be sufficient for a certain class of problems, it fails to systematically support the development and study of complex automated (intelligent) engineering systems. Therefore, a formal approach is needed for such developments and studies.

In this paper a formal theory that captures the knowledge associated with the physical behavior of structural systems is formulated. The physical behavior of structural systems is defined as the response (member displacements and member forces) of the structure to its environment (applied loads and boundary conditions). Predicate logic is used as the underlying formal language of the theory and the resolution theorem proving strategy is used for reasoning about the theory. The use of the formal theory for the analysis and synthesis of structural systems is illustrated and several research areas where the formal approach shows promise are discussed.
Most-Probable-Point-Locus Reliability Method in Standard Normal Space
Authors: Khalessi M. R. , Wu Y.-T. , Torng T. Y.
Published: April 2021

This paper describes a new structural reliability analysis iteration procedure based on the concept of most probable point locus (MPPL). Using a new quadratic search algorithm, the proposed procedure examines the global behavior of the limit-state function, g, along the MPPL in the standard normal space in search of the most probable point (MPP) on the g = o surface, and identifies unusual conditions such as multiple MPPs. During the iteration procedure, the generated information is updated after each sensitivity analysis. This action helps the analyst to minimize the number of computer runs and determine the next step. By adopting two efficient convergence criteria, the proposed procedure is demonstrated to be significantly more efficient than the commonly used reliability analysis procedures, and is suitable to be integrated with existing general-purpose finite element computer programs for nondeterministic structural analysis.
Probabilistic Stress Analysis Methods
Authors: Weber M. A. , Penny R. K.
Published: April 2021

The paper starts by reviewing some of the current concepts in assessing the effects of uncertainty in structural components — particularly those of Monte Carlo simulation methods and stochastic finite element methods. The review is followed by results of Monte Carlo simulations of thin shell components, initially designed deterministically, and of a built-in beam, analysed using both simulation and stochastic methods. Typical examples which are considered are a sphere/cylinder nozzle intersection with elastic and creep loading and a built-in beam with a central load. The results allow the evaluation of the most sensitive parameters and the assessment of their effects on the component response to be made.
Exact Elasticity Solutions for Stresses and Deflections in Curved Beams and Rings of Exponential and T-Sections
Authors: Bagci Cemil
Published: April 2021

Exact elasticity solutions for stresses and deflections (displacements) in curved beams and rings of varying thicknesses are developed using polar elasticity and state of plane stress. Basic forms of differential equations of equilibrium, stress functions, and differential equations of compatibility are given. They are solved to develop expressions for radial, tangential, and shearing stresses for moment, force, and combined loadings. Neutral axis location for each type of loading is determined. Expressions for displacements are developed utilizing strain-displacement relationships of polar elasticity satisfying boundary conditions on displacements. In case of full rings stresses are as in curved beams with properly defined moment loading, but displacements differ satisfying different boundary conditions. The developments for constant thicknesses are used to develop solutions for curved beams and rings with T-sections. Comparative numerical results are given.
The Use of Qualitative Physics for Integrated Design Object Modeling
Authors: Kiriyama Takashi , Tomiyama Tetsuo , Yoshikawa Hiroyuki
Published: April 2021

This paper discusses a theory and its implementation of integrated design object modeling for intelligent CAD. Models from different aspects must be correlated at the level of their background theories, so that the system can derive relationships among models from knowledge about the physical world. The metamodel concept proposed in this paper is a framework for integrating design object models in this manner. In order to implement the metamodel, we need representations of concepts about physical phenomena and a method for reasoning out the relationships among the concepts. Qualitative physics plays two roles for this purpose. The first role is to serve as a representation framework of concepts and their relationships. The second role is to serve as a reasoning method for generating aspect models and deriving qualitative behaviors from the aspect models. The idea of the metamodel is demonstrated by a design system, which provides the designer with physical features to build a primary model, helps to generate aspect models from the primary model, and maintains consistency among the aspect models.
Design for Die Casting: A Group Technology Based Approach
Authors: Poli Corrado , Shanmugasundaram Shyam
Published: April 2021

This paper describes an alternative approach to the rules-of-thumb based design of die castings. It describes a systematic, knowledge-based approach for drawing a designer’s attention to those features of a die casting which tend to increase manufacturing cost, so that designers can minimize difficult to produce features. Unlike the heuristic rules-of-thumb approach found in handbooks and textbooks, the knowledge-based approach discussed here provides both qualitative as well as quantitative feedback concerning a proposed design. An example illustrates use of the system.
Making Sense of Prototyping Technologies for Product Design
Authors: Wall Matthew B. , Ulrich Karl T. , Flowers Woodie C.
Published: April 2021

Firms that design mechanical and electro-mechanical products confront a variety of difficult issues in their prototyping activities. For a given part, how can a choice among fabrication technologies be made? Where should investments in new prototyping technology be focused? How can new and existing prototyping technologies be evaluated? Our primary goal has been to develop a systematic method of evaluating prototyping processes in order to determine the best process for a given situation. This paper reports on a field study conducted at the Kodak Apparatus Division. Our data is drawn from (1) a user survey of prototyping perceptions and needs, (2) a survey to determine the importance of various prototype part performance attributes, and (3) estimates of the fabrication time, cost, and part performance for 104 parts and four prototyping processes.
In Search of QFD
Authors: Steiner Mark W.
Published: April 2021

Development and application of new design methodologies to improve product and process is not foreign to GE. Yet, when Don Clausing and representatives from FORD introduced us to QFD, we were puzzled by the level of interest on the part of these people and others. Much of what we heard sounded like practical common sense methods. What visible evidence existed of QFD was manifested in strange, complicated charts that appeared to be in direct conflict with current efforts within GE to reduce bureaucracy and paperwork. QFD sounded like just another three letter acronym. Its direct translation into words (ie. Quality Function Deployment) provided little insight into why anyone should use it.
Design Through Selection: The Use of QFD in the Attribute Generation Process
Authors: Bascaran Eduardo
Published: April 2021

Selection problems in conceptual design arise whenever one out of a number of possible solutions has to be chosen based on multiple criteria. Among the variety of approaches that have been suggested in the literature to tackle engineering selection problems, in this paper we focus on the approach proposed by Kuppuraju et al. (1985). The approach involves: the generation of solution concepts, the selection of the “most-likely-to-succeed” concepts for further development into feasible alternatives and the formulation and solution of selection decision support problems (DSP) to rank the alternatives in order of preference using multiple attributes. In this paper we propose to enhance the process of formulating a selection DSP by introducing the use of the Quality Function Deployment (QFD) as an auxiliary technique to aid in the identification of attributes. An example problem is presented to illustrate the material.
Evaluation of Group Design in Engineering
Authors: McMahon Edward H.
Published: April 2021

In group design simultaneous input from multiple individuals, communications between group members, and management of the group effort make the process difficult to study. This paper describes the preliminary results of a computer-based system which was developed to study group design in engineering.

Three groups of engineering designers were studied using the computer based group design system (GDS). Observations were made regarding the impact of management style (methodology) on the design process, the impact of communications on the overall group activity, the sequence of transactions leading to the conceptual design decision, and the involvement of group members. The use of systematic procedures appears to encourage more equal participation, a decision less influenced by individual choice, and reduced authority hierarchy.
Towards a New Science of Functional Design
Authors: French Michael
Published: April 2021

This paper maintains that there should be a science of functional design, based upon all the design ideas developed by engineers and others over the centuries, ordered, generalised and combined into a coherent system. It sketches some ways in which such an ordered system of design knowledge might be built up, the study of design principles (such as kinematic design), systematic invention by the study of known means, and the study of limits.
Cumulative Results of Concept Generation by Individuals in a Mechanical Design Class
Authors: Kicher Thomas P. , Robie Bruce H.
Published: April 2021

A study of the concept generation abilities of individuals in a senior level mechanical engineering design class was performed. The study also examined the number of subjects identifying each concept. Results from two tests were standardized based on the number of distinct concepts identified by the sample. Sixty-five students participated. Tests were scored based on the number of concepts generated. Concepts were defined based on a categorization scheme (Pahl and Beitz, 1988).

Counting the number of concepts generated and standardizing based on the sample provide measures for the study of concept generation methodologies. Between sixty and seventy percent of all concepts were identified by less than ten percent of the sample. Concepts generated by fewer than ten percent of the sample were termed uncommon and were generated by most of the sample. Design groups may generate more concepts if the each individual’s uncommon concepts are accepted by the group.
Design Optimization for Robustness Using Performance Simulation Programs
Authors: Sundaresan Sivakumar , Ishii Kosuke , Houser Donald R.
Published: April 2021

This paper presents a methodology to incorporate manufacturing and operational variances in the design optimization stage to achieve robust and optimal performance. The procedure uses Taguchi’s orthogonal arrays to approximate the expected value of performance during optimization. This approach reduces the number of function evaluations in problems that use computationally expensive performance simulation programs. Hence, the method allows incorporation of variances on many variables simultaneously. This paper uses two illustrative examples: 1) Design of helical gears that have minimum transmission error and at the same time are less sensitive to manufacturing errors, 2) Design of beverage cans where we minimize the effects of errors in tooling on can weight and structural requirements. The optimal robust design shows a considerable decrease in sensitivity to manufacturing and operational variances and, at the same time, has good performance.
Automatic Generation of Well Structured Meshes Using Medial Axis and Surface Subdivision
Authors: Armstrong C. G. , Tam T. K. H. , Robinson D. J. , McKeag R. M. , Price M. A.
Published: April 2021

This paper reports on a project in which automatic mesh generation is divided into two phases. In the first phase feature recognition and shape grammar techniques, based on the medial axis of a 2D region, are employed to decompose a complex component into a number of simple subregions. In the second phase the subregions are meshed to a controlled density using conventional mapped mesh methods. The advantage of this approach is that good quality meshes of quadrilateral elements can be generated in 2D and, potentially, meshes of hexahedral elements in 3D. A parallel program of work has concentrated on the analysis of errors: different methods for error estimation and for providing transitions in mesh density have been compared.