bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Fuzzy Sets Approach to Computational Tools for Preliminary Engineering Design
Authors: Wood K. L. , Antonsson E. K. 
Published: April 2021

Abstract
The primary goal of this research is to provide computational tools, or aids, to engineering designers, particularly for the preliminary phase of design. Such aids will be particularly useful in choosing between alternative technologies. Design choices of this nature are perhaps the most critical, and likely to be the most costly if in error. Our approach has been to aid preliminary design decisions with analysis tools developed for computations on imprecise parameters. Contemporary computers and algorithms are not well suited for manipulating imprecise descriptions of objects. To provide these basic tools, we are applying the mathematics of fuzzy sets. This approach (along with “data-driven programming”) appears to be well suited to our problem and has been applied to similar problems in analyzing civil engineering structures and failures.
Fault Tree Approach for the Reliability Analysis of Gear Trains: Part I — Basic Theory
Authors: Pan T. S. , Rao S. S. 
Published: April 2021

Abstract
The application of fault tree techniques to the analysis of gear trains is considered. The techniques involve the decomposition of the system into a logic diagram or fault tree in which certain basic or primary events lead to a specified top event which signifies the total failure of the system. The fault trees are used to obtain minimal cut sets from which the modes of system failure and, hence, the reliability measure for the top event can be calculated. The method of constructing fault trees and the subsequent estimation of reliability of the system is illustrated through a nine speed compound gear train and a five speed epicyclic gear train.
Position-Sensor-Driven Assembly
Authors: Gordon S. T. , Seering W. P. 
Published: April 2021

Abstract
A sensor based assembly technique is described which uses a part position sensor to locate certain part features prior to a mating operation. The rigid parts assembly process is divided into three phases: part acquisition, alignment and mating. The part position sensor is used to increase the accuracy of the part alignment phase and decrease the system compliance requirements for the mating phase. The system is shown to be relatively insensitive to robot kinematic errors. A prototype system is described which assembles a number of closely fitting parts.
An Expert System for Initial Selection of Dwell Linkages
Authors: Kota S. , Erdman A. G. , Riley D. R. , Esterline A. , Slagle J. R. 
Published: April 2021

Abstract
Dwell linkages have numerous applications in industry, especially in automation. Traditional use of more expensive cams is due to lack of proper design tools for synthesizing dwell linkages. By systematically and extensively studying entire motion characteristics of hundreds of linkages, a comprehensive classification system and heuristics were developed. This qualitative classification scheme led to a finite set of linkage models that cover the entire design space in the sense that any possible design falls under one or more of the models. Our system, called Dwell-Expert, incorporates design expertise to select the best linkage model for a given set of design specifications and to compare that model against alternatives. This new design methodology and its implementation in AGNESS (A Generalized Network-based Expert System Shell) are explained. A design example is presented. Our system can reduce even an experienced designer’s initial-design time from a day or more to a minute or less, assuming specifications have already been formulated. Such results motivate extension of this design methodology to other areas of mechanical design and engineering design in general.
A Hybrid-Type Expert System for the Design of Marine Power Plants Using AI Technique and Design Optimization Method
Authors: Akagi S. , Tanaka T. , Kubonishi H. 
Published: April 2021

Abstract
A hybrid-type expert system is developed for supporting the initial design process of marine power plants. Firstly, discussion is given generally to understand design process in the view point of applying the AI technique effectively to design. Based on the result of the discussion, a hybrid-type expert CAD system with coupling the AI technique and the numerical optimization method is developed. In the system, the design knowledge is represented in the production rules, and the data of machineries consisting the plant are described by the frame-type representation. Through the system execution, it is ascertained that the system is effective not only as the design tool assisting designers but also as the tool instructing inexperienced designers.
Shape Optimum Design of Robotic Manipulators With Static Performance Criteria
Authors: Saravanos D. A. , Lamancusa J. S. , Sommer H. J. 
Published: April 2021

Abstract
The end effector deflections of robotic manipulators may be minimized by optimizing the geometric shape and the dimensions of their links. A multiple posture static performance criterion for the prediction of the shape optimum design is presented. An efficient optimization algorithm is developed for the solution of the problem using finite element modeling to predict the compliance of the robotic arm. The method is applied to an existing robotic arm, and the results demonstrate that simple alterations to the dimensions and the shape of the links can greatly improve, not only the stiffness, but also the stiffness/mass ratio and consequently the vibrational response of the manipulator structure.
Characteristic Surfaces for Three Position Function Generation With Planar Four Bar Mechanisms
Authors: Barker C. R. , Tso P.-L. 
Published: April 2021

Abstract
This paper considers the relationship between the three position function generation problem and the solution space for planar four bar mechanisms. The two infinities of solutions possible are mapped in a plane to determine the locations where particular types of mechanisms occur. It is possible to generate a contour in the mapping plane which joins together all solutions which possess a common characteristic in regard to their link lengths. This same contour can be displayed in the solution space to ascertain the overall characteristics of potential solutions to the design problem. A numerical example is used for illustrative purposes, but the results can be applied to any three position function generation problem.
Synthesis and Balancing of Cam-Modulated Linkages
Authors: Pracht P. , Minotti P. , Dahan M. 
Published: April 2021

Abstract
Linkages are inherently light, inexpensive, strong, adaptable to high speeds and have little friction. Moreover the class of functions suitable for linkage representation is large. For all these reasons numerous recent works deal with the problem of design mechanisms for robotic applications, but very often in terms of components such as gripper, transmission, balancing.
We investigate a new application for linkages, using them to design industrial manipulator. The selected mechanism for this application is a four bar linkage with an adjustable lengh for exact path generation. This adjustment is performed by a track or cam which is substituted to a bar. By this mean, we define a cam-modulated linkage which possess superior accuracy potential and is capable of accomodating of industrial design restrictions.
Such a kinematic chain is free from structural error for path generation and the presence of the track introduces the flexibility and versality in the usefull four bar chain. The synthesis technique of cam modulated linkage utilizes loop closure equations, envelop theory to find the centerline and the profile of the track. These techniques provide a systematic approach to the design of mechanism for path generation when extreme accuracy is required.
In order to complete an contribution, we take in consideration the static balancing of the synthesized manipulator. To achieve static mass balancing we use the potential energy storage capabilities of linear springs, and integrated it with the non-linear motion of mechanism to provide an exact value of the desired counter loading functions.
Examples are worked to demonstrate applications of these procedures and to illustrate the industrial potential of spring balancing and cam-modulated linkage.
Singularities in Motion and Displacement Functions for RCRCR, RCRRC and RSRC Linkages: Part III — RCRRC Linkage
Authors: Litvin F. L. , Fanghella P. 
Published: April 2021

Abstract
The general approach for the determination of singularities in motion and displacement functions for spatial linkages has been developed by Litvin, et al. (1986b) and also represented in the first part of this paper. Applications of the developed methods for the RCRRC linkage are given in this paper. The authors determined the singularities in motion, displacement functions and the configurations of the linkage. Numerical examples are given.
Simulation of Planar Dynamic Mechanical Systems With Changing Topologies: Part II — Implementation Strategy and Simulation Results for Example Dynamic Systems
Authors: Gilmore B. J. , Cipra R. J. 
Published: April 2021

Abstract
Part II presents a technique which uses the general point to line kinematic constraint equation presented in Part I coupled with an incidence matrix to automatically formulate the kinematic constraint equations between contacting rigid bodies and solve the resulting dynamic equations of motion. The automatic determination of system connectivity coupled with impulse-momentum theory enables the strategy to handle impact between rigid bodies in line contact or between rigid bodies in topologically complex systems. The characterizations of the changes in the kinematic constraints, as described by Part I, are combined with the incidence matrix and impact analysis to form an automatic dynamic simulation strategy. The strategy automatically predicts, detects, and determines the changes in the system topology and then reformulates the equations of motion without the user specifying the kinematic constraint changes and resulting system topology. The simulation results of two example systems are presented. The examples illustrate the effect the boundaries have on a system’s motion and show that the only connectivity data required by the strategy is the initial system topology.
An Experimental Investigation of the Static and Elastodynamic Responses of an Industrial Robotic Manipulator
Authors: Choi S. B. , Sun F. , Gandhi M. V. , Thompson B. S. 
Published: April 2021

Abstract
A methodology is presented herein for experimentally evaluating the static and elastodynamic responses of industrial robotic manipulators. The procedure enables estimates of the principal characteristics of these machines to be quantified in order to identify limitations in the structural elements of these designs. Furthermore, the proposed approach also provides experimental data with which to evaluate the predictive capabilities of the various mathematical models proposed in the literature for predicting the static and elastodynamic behavior of these systems. In order to demonstrate the test procedure, a General Electric Company P50 articulating robot was subjected to evaluation, the error sources identified and the associated errors quantified.
A Constrained Search Technique for Motion Generator Pivot Location
Authors: Lawley T. J. , Nambiar R. V. , Nisbett J. K. , Prince S. , Zarefar H. 
Published: April 2021

Abstract
Burmester’s solution to the problem of guiding a body through four precision points has been extended to find planar mechanisms that have their pivots located inside prescribed regions. The complex number formulation has been used to generate the Burmester curves. A random search technique was developed to choose a new set of precision points that lie within user specified limits, in order to find a set of curves that pass through the desired regions. A computer program was written to generate Burmester curves that lie within the desired regions, while maintaining a coupler motion within satisfactory limits. An automobile suspension linkage was successfully designed using this program.
Synthesis of Harmonic Motion Generating Linkages: Part I — Function Generation
Authors: Farhang K. , Midha A. , Bajaj A. K. 
Published: April 2021

Abstract
This paper deals with the first- and higher-order function generation problems in the synthesis of linkages with relatively small input cranks. Such linkages tend to produce nearly simple harmonic motions at the output members. Owing to this distinction, the generality of the conventional synthesis techniques is no longer applicable. Thus, in function generation, only harmonic functions of the input motion may be expected to be synthesized for output motions.
Synthesis of Harmonic Motion Generating Linkages: Part II — Path and Motion Generation
Authors: Farhang K. , Midha A. , Hall A. S. 
Published: April 2021

Abstract
This paper, a sequel to a companion paper on function generation, discusses the path and motion generation problems in the synthesis of linages with relatively small input cranks. The point on the floating link (i.e., the coupler of a crank-rocker linkage point on connecting rod in a slider-crank linkage) traces an approximate ellipse. This fact serves as a major distinction between the method described herein and the conventional, more general, synthesis techniques. In other words, only elliptical paths may be generated by the path (or coupler) points in the synthesis of linkages with small cranks. Higher order path and motion generation, in which velocity, acceleration, slope and the rate of change of slope of the coupler path may be specified, are also addressed in this paper.
The Evaluation of Moments of Bounded Regions Using Spline Approximations of the Boundary
Authors: Angeles J. , Chaoming Z. , Duarte R. , Ning H. 
Published: April 2021

Abstract
The subject of this paper is the computation of the first three moments of bounded regions imbedded in 2- and 3-dimensional Euclidean spaces. The method adopted here is based upon formulae derived elsewhere, that permit the computation of the said moments — volume, vector first moment and inertia tensor — via integration along the boundary. This is accomplished by the application of Gauss Divergence Theorem to planar and axially-symmetric 3-D regions. It is shown that a spline approximation of the boundary leads to explicit, readily implementable formulae. Two examples are included to illustrate the applicability of the procedure.
A New Dynamic Basis Algorithm for Solving Linear Programming Problems for Engineering Design
Authors: Wang Y. , Sandgren E. 
Published: April 2021

Abstract
A new linear programming algorithm is proposed which has significant advantages compared to the traditional simplex method. The search direction generated which is always along a common edge of the active constraint set, is used to locate candidate constraints, and can be used to modify the current basis. The dimension of the basis begins at one and dynamically increases but remains less than or equal to the number of design variables. This is true regardless of the number of inequality constraints present including upper and lower bounds. The proposed method can operate equally well from a feasible or infeasible point. The pivot operation and artificial variable strategy of the simplex method are not used. Examples are presented and results are compared with a traditional revised simplex method.
A Modification of Feasible Direction Optimization Method for Handling Equality Constraints
Authors: Chen Yong , Li Bailin 
Published: April 2021

Abstract
The Feasible Direction Method of Zoutendijk has proven to be one of the efficient algorithm currently available for solving nonlinear programming problems with only inequality type constraints. Since in the case of having equality type constraints, there does not exist nonzero direction close to the feasible region, the traditional algorithm can not work properly. In this paper, a modified feasible direction finding technique has been proposed in order to handle nonlinear equality constraints for the Feasible Direction Method. The algorithm is based on searching along directions intersecting the tangent of the equality constraints at some angle which makes the move toward the interior of the feasible region.
On the Design of Wire Rope
Authors: Velinsky S. A. 
Published: April 2021

Abstract
In recent work, Velinsky (1988) has developed a design methodology for multi-lay wire strands. The current paper expands on this work to study wire ropes in which the strand is a basic component. Wire ropes with the three types of cores, independent-wire-rope-core (IWRC), fiber-core (FC), and wire-strand-core (WSC), are considered. This work further generalizes the previously developed linearized theory which, through substantiation with experiment, is felt to be reasonably accurate for most wire rope behavior. The theory is then utilized to examine various parameters in the design of wire ropes.
Workspace Analysis of Multibody Mechanical Systems Using Continuation Methods
Authors: Jo D.-Y. , Haug E. J. 
Published: April 2021

Abstract
A new approach to numerical analysis of workspaces of multibody mechanical systems is developed. Numerical techniques that are based on manifold theory and utilize continuation methods are presented and applied to a variety of mechanical systems, including closed-loop mechanisms. Generalized coordinates that define kinematics of a system are classified and interpreted from an input-output point of view. Boundaries of workspaces, which depend on the classification of generalized coordinates, are defined as sets of singular points of Jacobians of the kinematic equations. Numerical methods for tracing one dimensional trajectories on a workspace boundary are outlined and example are analyzed using one dimensional manifold mapping computer programs, such as PITCON and AUTO.
A Network Implementation of Real-Time Dynamic Simulation With Interactive Animated Graphics
Authors: Dubetz M. W. , Kuhl J. G. , Haug E. J. 
Published: April 2021

Abstract
This paper presents a network based implementation of real-time dynamic simulation methods. An interactive animated graphics environment is presented that permits the engineer to view high quality animated graphics rendering of dynamic performance, to interact with the simulation, and to study the effects of design variations, while the simulation is being carried out. An industry standard network computing system is employed to interface the parallel processor that carries out the dynamic simulation and a high speed graphics processor that creates and displays animated graphics. Multi-windowing and graphics processing methods that are employed to provide visualization and operator control of the simulation are presented. A vehicle dynamics application is used to illustrate the methods developed and to analyze communication bandwidth requirements for implementation with a compute server that is remote from the graphics workstation. It is shown that, while massive data sets are generated on the parallel processor during realtime dynamic simulation and extensive graphics data are generated on the workstation during rendering and display, data communication requirements between the compute server and the workstation are well within the capability of existing networks.
A Vehicle Handling Model With Active Suspensions
Authors: Shannan J. E. , Vanderploeg M. J. 
Published: April 2021

Abstract
This paper presents two different vehicle models used to investigate the effects of active suspensions. One is a linear seven degree of freedom ride model. The second is a nonlinear ten degree of freedom ride and handling model. Full state feedback optimal control algorithms are developed for both models. The seven degree of freedom model is used to study ride effects. The active suspension substantially reduced the motions of the sprung mass. The ten degree of freedom model is used to study the effects of the active suspension on the directional response characteristics of the vehicle. The handling characteristics exhibited by the active suspension are very similar to those of the passive suspension. However, the active suspension did significantly reduce sprung mass motions during the handling maneuvers. It is then illustrated that by altering various feedback gains, active suspensions can be made to change the handling characteristics in the nonlinear range.
Mental health after paediatric concussion: a systematic review and meta-analysis
Authors: Gornall Alice , Takagi Michael , Morawakage Thilanka , Liu Xiaomin , Anderson Vicki 
Published: April 2021

ObjectiveThis systematic review and meta-analysis sought to rigorously examine mental health outcomes following paediatric concussion. To date, heterogeneous findings and methodologies have limited clinicians’ and researchers’ ability to meaningfully synthesise existing literature. In this context, there is a need to clarify mental health outcomes in a homogeneous sample, controlling for key methodological differences and applying a consistent definition of concussion across studies.DesignSystematic review and meta-analysis.Data sourcesWe searched Medline, Embase, PsycINFO, CINAHL, SportDiscus, Scopus and PubMed.EligibilityPeer-reviewed studies published between 1980 and June 2020 that prospectively examined mental health outcomes after paediatric concussion, defined as per the Berlin Consensus Statement on Concussion in Sport.ResultsSixty-nine articles characterising 60 unique samples met inclusion criteria, representing 89 114 children with concussion. Forty articles (33 studies) contributed to a random effects meta-analysis of internalising (withdrawal, anxiety, depression, post-traumatic stress), externalising (conduct problems, aggression, attention, hyperactivity) and total mental health difficulties across three time points post-injury (acute, persisting and chronic). Overall, children with concussion (n=6819) experienced significantly higher levels of internalising (g=0.41–0.46), externalising (g=0.25–0.46) and overall mental health difficulties compared with controls (g=0.18–0.49; n=56 271), with effects decreasing over time.Summary/conclusionsOur review highlights that mental health is central to concussion recovery. Assessment, prevention and intervention of mental health status should be integrated into standard follow-up procedures. Further research is needed to clarify the mechanisms underlying observed relationships between mental health, post-concussion symptoms and other psychosocial factors. Results suggest that concussion may both precipitate and exacerbate mental health difficulties, thus impacting delayed recovery and psychosocial outcomes.