bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Computer-Aided Design Technique for the Synthesis of Planar Four Bar Mechanisms Satisfying Specified Kinematic and Dynamic Conditions
Authors: Rigelman G. A. , Kramer S. N. 
Published: April 2021

Abstract
This paper presents a computer-aided design optimization method for synthesizing planar four bar mechanisms which satisfy specified kinematic and dynamic conditions. The method can be used for path, motion, and function generation as well as for combinations of these. The kinematic conditions consist of combinations of specifications on the position, velocity, and acceleration of the coupler point and the rotations of the coupler and follower links. The dynamic conditions consist of the minimization of the average power consumed by the mechanism as well as a limit on the maximum input torque. The external loads consist of variable forces and moments at the coupler point as well as variable torques on the follower link. The Selective Precision Synthesis (SPS) method is used to express each kinematic condition in terms of a specification plus an allowable deviation or tolerance from the specification. In this manner, the synthesis problem is converted into a nonlinear optimization problem which is solved by using the Generalized Reduced Gradient (GRG) method. In addition, two force balancing routines are included to help the dynamic performance of the mechanism. The mathematical formulation and derivation as well as numerical examples are presented in this paper.
Synthesis of Linkages to Generate Specified Histories of Forces and Torques: The Planar 4R Four-Bar Mechanism
Authors: Bagci C. 
Published: April 2021

Abstract
Analytical precision position and optimum synthesis methods for linkages to generate specified force and torque histories are presented and applied to the planar four-bar mechanism. Mechanical advantage method (MAM) and integration of power equilibrium method (IPEM) are used to develop design equations. MAM yields design equations to use when the torque multiplication factor is defined at discrete number of design positions, as well as in continuous forms. IPEM requires continuous forms, but it reduces the torque generation problem into a function generation problem. Design equations with one, two, three, and four unknowns are developed for precision position synthesis; and they are used to formulate optimum synthesis process using many design positions that requires no iteration. Generation of infinite torque multiplication factor and synthesis of quick-return four-bar mechanism to generate specified advance-to-return time ratio are also considered. The synthesized four-bar mechanisms replace circular and non-circular external and internal gear drives. Several industrial application examples are included. The second part of the article considers the slider-crank mechanism.
Quaternions, Hamilton Operators, and Kinematics of Mechanical Systems
Authors: Agrawal O. P. 
Published: April 2021

Abstract
In this paper, quaternions are briefly reviewed and their associated matrix algebra is developed. Two Hamilton operators are defined and some of their properties are studied. The properties of these operators are then applied to find kinematic relations of a body undergoing spatial rotation and to find a recursive relation for intermediate-axes. The formulation presented provides an easy approach to kinematic analysis of spatial mechanical systems.
Planetary-Gear-Type Second-Harmonic Balancers
Authors: Tasi L. W. , Maki E. R. 
Published: April 2021

Abstract
This paper describes several mechanical balancers, based on the planetary gear trains known as the hypotrochoid and epitrochoid trains, for reducing or eliminating second-order out-of-balance in mechanical systems. It is shown that by proper arrangement of the planetary gear trains, a balancer can be obtained for the elimination of second-order shaking forces or second-order shaking moments or a combination of both shaking forces and moments. The advantage of this type of balancer is that the carrier of the gear train needs only to run at the primary speed of the mechanical system to be balanced. Therefore, the balancer can be designed to be concentric with the primary rotating shaft of the machine using the primary shaft as the carrier. For example, for the balance of the second-order shaking force of an in-line four-cylinder four-stroke internal combustion piston engine, the balancer can be placed on the third main bearing or one on each of the second and fourth main bearings.
Constructive Solid Geometry of the Trihedron
Authors: Wilde D. J. 
Published: April 2021

Abstract
As a first step toward a Constructive Solid Geometry for designing general polyhedra, this paper develops the set theory of the trihedron, loosely speaking any set combination of three planar half spaces (monohedra). The trihedron can be decomposed precisely into its primitive monohedra and its CSG-tree of union or intersection operations with no designer topological input other than the convexity or concavity of each edge, giving a human-computer interface simpler than those for existing right-hand rule boundary representation methods. The somewhat visual trigonometric concepts of classical solid geometry are formulated in terms of vectors and matrices appropriate for numerical computation. This reorganization may be useful not only for designers of CAD systems, but also for educators seeking to strengthen and modernize the geometric education of engineering students wonting to make full use of CAD/CAM technology.
Single Domain Methods for Modeling Objects in the Round for Engineering and Manufacturing Applications
Authors: Cox J. J. , Ferguson H. , Kohkonen K. 
Published: April 2021

Abstract
Basic principles are presented for writing down global parametric equations for a broad class of bounded and closed surfaces embedded in three spatial dimensions. The paper focuses on the topological decomposition and identification of objects into appropriate domains and the development of single-valued maps which take these domains into images of the objects in 3-space. Several examples are presented showing the mapping functions and domains. Heuristics used in the identification of the domains and maps are also discussed. These methods are specifically applied to the engineering design process.
A Strategy for Reducing Turnaround Time in Design Optimization Using a Distributed Computer System
Authors: Young K. C. , Padula S. L. , Rogers J. L. 
Published: April 2021

Abstract
There is a need to explore methods for reducing lengthly computer turnaround or clock time associated with engineering design problems. Different strategies can be employed to reduce this turnaround time. One strategy is the use of a supercomputer, which can be costly in terms of hardware acquisition and software modification. Another strategy is to run validated analysis software on a network of existing smaller computers so that portions of the computation can be done in parallel. This paper focuses on the implementation of this second strategy using two types of problems. The first type is a traditional structural design optimization problem, which is characterized by a simple data flow and a complicated analysis. The second type of problem uses an existing computer program designed to study multilevel optimization techniques. This problem is characterized by complicated data flow and a simple analysis. The paper shows that distributed computing can be a viable means for reducing computational turnaround time for engineering design problems that lend themselves to decomposition. Parallel computing can be accomplished with a minimal cost in terms of hardware and software.
A Modified Game Theory Approach to Multiobjective Optimization
Authors: Freiheit T. I. , Rao S. S. 
Published: April 2021

Abstract
In todays competitive economy, it is no longer possible for the designer to find solutions to conflicting objective problems which are merely adequate. The designer must select the design variables such that there is a superior compromise between the objectives. To this end, a large number of methods have been developed for the solution of multiobjective optimization problems. The earliest reported in-depth work on the formulation of the multiobjective problem is that of Kuhn and Tucker [1]. Reviews of the progress in the field have been published by Hwang and Masud [2], Stadler [3], Evans [4], and Rastrigin and Eiduk [5]. The methods for optimizing multiple objectives may be categorized into two types, leaving the objectives in vector form and scalarizing the objectives into one equation.
Remarks on Sufficiency of Constraint-Bound Solutions in Optimal Design
Authors: Papalambros P. Y. 
Published: April 2021

Abstract
Solution strategies for optimal design problems in nonlinear programming formulations may require verification of optimality for constraint-bound points. These points are candidate solutions where the number of active constraints is equal to the number of design variables. Models leading to such solutions will typically offer little insight to design trade-offs and it would be desirable to identify them early, or exclude them in a strategy using active sets. Potential constrained-bound solutions are usually identified based on the principles of monotonicity analysis. This article discusses some cases where these points are in fact global or local optima.
Optimal Design of Complex Systems Using Decomposition Methods: An Example Application to Electromechanical Control
Authors: McLain T. W. , Free J. C. , Teng A. 
Published: April 2021

Abstract
The utility of the classical optimization and decomposition methods were examined with respect to actuator/control system design. A method of integrating actuator design with control system design to obtain optimal transient response was explored and found to be effective. A test problem consisting of an electromechanical actuator was decomposed and optimized following the strategy proposed by Sobieski [1,2]. A comparison of optimization results from decomposed and undecomposed actuator/control system models was made. The results from the sample problems showed decomposition to be a potentially valuable tool in the optimization of large scale dynamic systems. Methods of discrete optimization techniques to select catalog values for dc motors and gears were examined. In the problems tested, a variation of an exhaustive search was found to be the most reliable method for handling discrete variables since a relatively small number of combinations was involved. A sucessful method for evaluating and optimizing the time response characteristics of dynamic systems was also developed.
Sensitivity Analysis and Optimization of Mechanical System Design
Authors: Langner W. J. 
Published: April 2021

Abstract
The paper follows studies on simulation of three-dimensional mechanical dynamic systems with the help of sparse matrix and stiff integration numerical algorithms.
For sensitivity analyses and the application of numerical optimization procedures it is substantial to calculate the effect of design parameters on the system behaviour by means of derivatives of state variables with respect to the design parameters.
For static and quasi static analyses the computation of these derivatives from the governing equations leads to a linear equation system.
The matrix of this set of linear equations shows to be the Jacobian matrix required in the numerical integration process solving the system of governing equations for the mechanical system. Thus the factorization of the matrix perfomed by the numerical integration algorithm can be reused solving the linear equation system for the state variable sensitivities.
Some example demonstrate the simplicity of building the right hand sides of the linear equation system.
Also it is demonstrated that the procedure proposed neatly fits into a modular concept for simulation model building and analysis.
Sensitivity Analysis of Model Coordination Method of Decomposition in Nonlinear Programming
Authors: Torab H. 
Published: April 2021

Abstract
A methodology in sensitivity analysis of the Model Coordination Method (MCM) of Decomposition in Nonlinear Programming is discussed. Under the Model Coordination Method, the optimization of an engineering system is divided into two levels. In the first level, each component is analysed and optimized independently. This is done through separation of variables into two groups of local and coordinating variables. At the second level, the coordinating variables are determined so that the interaction between the components provides an optimal performance of the system. This study focuses on sensitivity analysis for the Model Coordination Method.
Automated Design of a Turbocharged, Fueled, Four-Stroke Engine for Minimum Fuel Consumption
Authors: Woodard J. K. , Johnson G. E. , Lott R. L. 
Published: April 2021

Abstract
The design of a turbocharged, gasoline fueled, four-stroke engine is considered with the goal of selecting design and operating variables to minimize fuel consumption. The development of the engine simulation code and the effect of model assumptions on the results are presented. The optimization includes constraints on detonation, exhaust emissions, and torque. Variables are bounded to assure the validity of the simulation. A number of observations about the interaction between the thermo-fluid model and the nonlinear programming algorithm are made and general strategies to enhance the optimization under such circumstances are discussed. The method is illustrated by exploring the design of a turbocharged Buick V-6 engine on an IBM PC/AT personal computer.
Stock design variables, and operating variables that provided a design away from the constraints imposed by torque, emission, and detonation were chosen as the starting point for the optimization. Application of the optimization strategy resulted in an 18 percent reduction in predicted fuel consumption at 50 miles per hour. Significant specific recommendations included a reduction in combustion chamber volume, an increase in intake manifold pressure, an increase in intake duration, a decrease in exhaust duration, and relatively small changes in valve geometry. The paper clearly demonstrates that it is feasible to do relatively sophisticated engineering design and optimization on personal computers, and it sets the stage for further work in this area.
On the Experimental vs. Numerical Shape Optimization of a Hole in a Tall Beam
Authors: Azarm S. , Bhandarkar S. M. , Durelli A. J. 
Published: April 2021

Abstract
This paper describes and compares an experimental and a numerical method for shape optimization of continuum structures. The experimental method is based on a systematic application of photoelasticity. The numerical method is based on coupling of a finite element analysis and an optimizer. The paper demonstrate several means used for interactive communication between the designer and the (experimental or numerical) shape optimization process. The discussion is made taking shape optimization of a hole in a tall beam as an example.
Compromise: An Effective Approach for Designing Composite Conical Shell Structures
Authors: Fuchs W. J. , Karandikar H. M. , Mistree F. , Eschenauer H. A. 
Published: April 2021

Abstract
The layout of fiber composite structures compared to that of structures made from conventional homogenous isotropic materials is far more difficult, because a fiber composite (laminate) is built up of several unidirectional layers (UD-layers) with fibers set at different angles. A contribution to the structural analysis and preliminary design of a fiber-reinforced conical shell is made in this paper. The equations of the membrane theory are used for analyzing the shell behavior. The design, with the objective of obtaining minimal deformation at minimal weight, subject to a set of failure constraints, is achieved by formulating and solving a compromise Decision Support Problem. Some designs of a fiber reinforced conical shell subjected to pressure load and temperature are presented.
Building an Expert System for Engineering Design Based on the Object-Oriented Knowledge Representation Concept
Authors: Akagi S. , Fujita K. 
Published: April 2021

Abstract
An expert system is developed for engineering design based on object-oriented knowledge representation concept. The design process is understood as determining design variables and their relationships which compose design model. The design model is represented as a network in the computer system using the object-oriented knowledge representation. The system built with the above concept provides the following abilities: 1) flexible model building and easy modification, 2) effective diagnosis of the design process, 3) supporting method for redesign, 4) a hybrid function with numerical computations and graphics, and 5) applicability for various design problems. Finally, it is applied to the basic design of a ship.
Composite Drive Shaft Coupling for Future Rotorcraft: A 3D Finite-Element Analysis
Authors: Margasahayam R. N. , Faust H. S. 
Published: April 2021

Abstract
A finite-element stress analysis of a one-piece, integrated, all-composite shaft and coupling is presented. In addition to a brief discussion of design-driving parameters, some limitations of the analytical techniques used for design development are described. The 3D finite-element method (FEM) was then used to evaluate critical stresses and strains experienced by the shaft coupling. A comparison of the results from the finite-element analysis and those from static bending, axial, and torsional tests conducted on these prototype shafts yielded excellent correlation. Some important considerations in the development of the FE model and the correlation of results with tests, especially in the design of composite materials, are addressed.
A New Synthesis Method for Cam-Follower Systems Using Finite Series
Authors: Berzak N. 
Published: April 2021

Abstract
A general method for design cam-follower systems with desired kinematic and dynamic properties is presented. In this method, an output motion is defined as a sum of two series and satisfies prescribed terminal conditions as well as constraints directly related to the characteristics of the system. Approximation of such characteristics was based on certain properties of the series. The method is suitable for polynomials as well as finite trigonometric series or a combination of both. The application of this method is demonstrated for output motion expressed by polynomials.
Fuzzy Set Based Models in Design Optimization
Authors: Diaz A. R. 
Published: April 2021

Abstract
A formulation for multiobjective optimization for engineering design based on fuzzy sets is presented. Models for the optimization problem and operations to introduce model variations are described formally. Under a reasonable set of rules it is shown that solutions to fuzzy multiobjective problems are weakly efficient and can reproduce solutions obtained by traditional methods such as compromise and goal programming. Results are easily implemented in computations.
Pattern of upper limb amputation associated with lower limb amputation: the UK military experience from Iraq and Afghanistan
Authors: McMenemy Louise , Mondini V , Roberts D C , Kedgley A , Clasper J C , Stapley S A 
Published: April 2021

IntroductionThe conflicts in Iraq and Afghanistan resulted in large numbers of personnel sustaining extremity injuries. In the context of polytrauma, partial hand amputation is often unrecorded. The aim of this work was to quantify the burden of upper limb (UL) amputation at any level occurring concurrently with a major (ankle and proximal) lower limb (LL) amputation. Knowledge of this cohort could aid in prosthetic modification to further improve quality of life outcomes in a population with dexterity loss.MethodA trauma database search was undertaken for all UK military LL amputees from the conflicts in Iraq and Afghanistan. A manual search method was employed to identify from the major LL amputees those who had a concurrent UL amputation at any level (including isolated finger amputation). Demographics, level of amputation, and injury profile data were recorded.ResultsSixty-eight individuals were identified; the most prevalent population was bilateral LL with a unilateral UL amputation (60%). Most UL amputations were partial hand (75%). The was no statistically significant difference between left or right side (p=0.13). On the left side, correlation was found between amputation of the thumb and third digit (rho=0.34; p=0.005) not seen on the right.ConclusionWe have determined the rate of UL amputation at any level, in combination with LL amputation as a result of blast injury. Knowledge of these combinations enables further research to support anecdotal evidence that there is a need for tailored prosthetics in the context of potential dexterity loss making donning and doffing problematic.
Nature and type of patient-reported safety incidents in primary care: cross-sectional survey of patients from Australia and England
Authors: Hernan Andrea L , Giles Sally J , Carson-Stevens Andrew , Morgan Mark , Lewis Penny , Hind James , Versace Vincent 
Published: April 2021

BackgroundPatient engagement in safety has shown positive effects in preventing or reducing adverse events and potential safety risks. Capturing and utilising patient-reported safety incident data can be used for service learning and improvement.ObjectiveThe aim of this study was to characterise the nature of patient-reported safety incidents in primary care.DesignSecondary analysis of two cross sectional studies.ParticipantsAdult patients from Australian and English primary care settings.MeasuresPatients’ self-reported experiences of safety incidents were captured using the validated Primary Care Patient Measure of Safety questionnaire. Qualitative responses to survey items were analysed and categorised using the Primary Care Patient Safety Classification System. The frequency and type of safety incidents, contributory factors, and patient and system level outcomes are presented.ResultsA total of 1329 patients (n=490, England; n=839, Australia) completed the questionnaire. Overall, 5.3% (n=69) of patients reported a safety incident over the preceding 12 months. The most common incident types were administration incidents (n=27, 31%) (mainly delays in accessing a physician) and incidents involving diagnosis and assessment (n=16, 18.4%). Organisation of care accounted for 27.6% (n=29) of the contributory factors identified in the safety incidents. Staff factors (n=13, 12.4%) was the second most commonly reported contributory factor. Where an outcome could be determined, patient inconvenience (n=24, 28.6%) and clinical harm (n=21, 25%) (psychological distress and unpleasant experience) were the most frequent.ConclusionsThe nature and outcomes of patient-reported incidents differ markedly from those identified in studies of staff-reported incidents. The findings from this study emphasise the importance of capturing patient-reported safety incidents in the primary care setting. The patient perspective can complement existing sources of safety intelligence with the potential for service improvement.