bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dexterity of Manipulators at an Operating Point
Authors: Abdelmalek Karim A. 
Published: March 2021

Abstract
This paper presents a method for analyzing dexterity of manipulators comprising spherical wrists. The goal is to provide the user with knowledge of orientability of the end-effector at a target. Wrist accessible output sets are determined analytically by first determining manipulator singularities, followed by back substituting the singularities into the constraint equations to parametrize surfaces. Since regions of a surface may exist inside the wrist accessible output set, and other regions on the boundary, surfaces are segmented into subsurfaces. To determine whether a subsurface is an internal or boundary one, each subsurface is studied for existence inside the wrist accessible output set by perturbing a point along its normal. Closed-form solutions of the boundary of the wrist accessible output set are obtained. A service sphere is located at an operating point in the accessible output set and the sphere is intersected with the boundary sub-surfaces. The intersection curves are computed and projected onto the space of a cylinder, then the cylinder is unrolled to depict a map. Dexterity charts are introduced as maps depicting orientability of the end-effector at a target.
Mass Moment of Inertia of External Geneva Wheels
Authors: Sepahpour Bijan , Fischer Ian S. 
Published: March 2021

Abstract
Equations have been developed and design curves are presented to accurately estimate the mass moment of inertia of the Geneva wheel component in mechanisms used for indexing and intermittent motion applications. The curves are non-dimensionalized so that they can be applied whatever material is used for the Geneva mechanism and whatever units are used for the calculation of the dynamics.
Adaptive Synthesis of Hydraulic Circuits From Design Cases Based on Functional Structure
Authors: Fujita Kikuo , Akagi Shinsuke , Sasaki Makoto 
Published: March 2021

Abstract
An adaptive synthesis method for hydraulic circuits is proposed by using case-based reasoning technique based on their functional structure. Since synthesis of hydraulic circuits is a typical problem of conceptual design and its property is expertise-oriented and combinatorial, it is difficult to declaratively represent useful design knowledge. In our design method, past design cases are afore-stored in the case base, and then a circuit is generated by arranging suitable past cases which are retrieved from the case base in accordance with the difference related to functional structure. In order to measure such functional structure, design specifications are represented with labels. Design cases are adaptively manipulated into a target design with three synthesis strategies, decomposition, series combination and parallel combination, based on surplus or deficit of labels. Moreover, arranged circuits are verified with a logical simulation method based on symbol manipulation. These synthesis and simulation methods are applied to some design problems in order to show their effectiveness and validity.
Probabilistic Design of High Temperature Components Subjected to Low Cycle Fatigue Loads
Authors: Pigott Ronald 
Published: March 2021

Abstract
From the beginning, engineers have focused on the special case of determinism in the design process, and an enormous methodology has been developed to support this approach. Today, however, customers are demanding greater reliability and are imposing greater penalties for failure. In order to achieve higher reliability, and in order to asses risk of failure, probabilistic approaches will almost certainly have to be employed. While designers have always used probability in their work, it has usually been done with risk represented in a single factor of safety. This paper focuses on the application of probability theory to the design of high temperature components which are subjected to low cycle fatigue loads. Creep low cycle fatigue interaction and probabilistic design are both complex subjects. In order to make the probabilistic design of components subjected to creep and low cycle fatigue tractable, the calculation models must be as simple as possible without sacrificing too much on accuracy. In this paper, cumulative damage is determined using Miner’s Rule in conjunction with “range pair” cycle counting. The effect of operation at elevated temperatures is included using Coffin’s frequency modified approach. A first order second moment (FORM) method for including probabilistic effects is developed and some sample calculations are presented. It is shown that the traditional deterministic approach using a single factor of safety does not provide a uniform margin of safety for all design conditions.
Sequential Roundoff for Improving Robot Position Accuracy
Authors: Ji Zhiming 
Published: March 2021

Abstract
A robot can only reach discrete locations within its workspace due to its finite encoder counts. Actual position and orientation reached by end-effectors are therefore the result of roundoff in the encoder counts. Traditionally the roundoff is carried out at the end of inverse kinematics, which produces the propagation and accumulation of the roundoff errors (except for Cartesian type of robot). We proposed a sequential roundoff procedure during the inverse kinematics process to compensate the roundoff errors. Numerical analysis shows that this method can lead to significant improvement in the positioning accuracy. Our study also shows that the sequence with which the inverse is carried out affects the improvement. Selection of sequence for inverse kinematics is discussed.
A Comparison of Architectures of Parallel Mechanisms for Workspace and Kinematic Properties
Authors: Gosselin Clement M. , Ricard Rémi , Nahon Meyer A. 
Published: March 2021

Abstract
This paper presents a study of the workspace and kinematic properties of four different architectures of six-degree-of-freedom parallel mechanisms. For each architecture, the volume of the Cartesian workspace is computed at different orientations of the moving platform. The distribution of the workspace is also found by computing the 2D sections of the 3D workspace. The rotational workspace is then determined at the reference position of the platform. Finally, the stiffness properties of the architectures are obtained. Normalization factors are then defined to account for the structural differences between the architectures of mechanisms. The comparison of the different architectures of parallel mechanisms has been performed using SIMPA, a specialized CAD tool developed for the kinematic analysis and optimization of parallel manipulators. The results thus obtained illustrate the range of performance which can be expected from different parallel architectures. Although none of the architectures proves to be better than all the others in all respects, particular architectures do excel in particular performance measures. The approach proposed would therefore be useful in further studies relating to the design and optimization of parallel manipulators and mechanisms.
A New Shaft Coupling Design for a High-Speed Rotor Wheel
Authors: Kiss Tibor , Ng Wing-Fai , Mitchell Larry D. 
Published: March 2021

Abstract
A high-speed rotor wheel for a wind-tunnel experiment has been designed. The rotor wheel was similar to one in an axial turbine, except that slender bars replaced the blades. The main parameters of the rotor wheel were an outer diameter of 10“, a maximum rotational speed of 24,000 RPM and a maximum transferred torque of 64 lb-ft. Due to the working environment, the rotor had to be designed with high safety margins. The coupling of the rotor wheel with the shaft was found to be the most critical issue, because of the high stress concentration factors associated with the conventional coupling methods. The efforts to reduce the stress concentrations resulted in an advanced coupling design which is the main subject of the present paper. This new design was a special key coupling in which six dowel pins were used for keys. The key slots, now pin-grooves, were placed in bosses on the inner surface of the hub. The hub of the rotor wheel was relatively long, which allowed for applying the coupling near the end faces of the hub, that is, away from the highly loaded centerplane. The long hub resulted in low radial expansion in the coupling region. Therefore, solid contact between the shaft and the hub could be maintained for all working conditions. To develop and verify the design ideas, stress and deformation analyses were carried out using quasi-two-dimensional finite element models. An overall safety factor of 3.7 resulted. The rotor has been built and successfully accelerated over the design speed in a spin test pit.
Internal Variable Modeling of the Creep of Monolithic Ceramics
Authors: White Charles S. , Hazime Radwan M. 
Published: March 2021

Abstract
Ceramics are assuming an important role for use in power generation. One of the road blocks is a complete characterization of the deformation and life of advanced ceramics at elevated temperatures. Substantial high temperature creep testing has been conducted in recent years. Most commonly, Norton’s law for deformation and the Monkman-Grant relationship for failure have been used to correlate test data.
In this paper, internal variable modeling is discussed as an alternative to Norton’s Law/Monkman-Grant. Through the use of internal variables, micromodeling of the important mechanisms can be extended to the macroscopic behavior. Also, the effects of simultaneous or competing phenomena can be considered. An example is the growth of lenticular cavities on the two grain boundaries of certain silicon nitrides while the grain boundaries are crystallizing. The results of a preliminary internal variable model for HIPed silicon nitride is presented and compared with tensile creep experiments.
Shape Definition of Scarred Boiler Tubes and Geometry-Based Implications for Creep Rupture
Authors: Platfoot Robin A. , Zarrabi Khosrow 
Published: March 2021

Abstract
New life assessment procedures are being developed to determine the optimum time when worn or gouged pressure tubing should be removed from tube banks within industrial steam generators. This paper describes a procedure for modeling the volume loss associated with scars of arbitrary shapes which subsequently provides input data for determining remaining tube life. The procedure is designed so that the input measurements may be made with relative ease, irrespective of the complexity of the shape of the damaged site. The basis for this approach is the assumption that, while the sizes of scarred areas vary with each individual occurrence, the shape or profile of the crater is repeatable on a case by case basis. The analysis code has been developed in conjunction with an extensive experimental program to assess the variety of scar shapes which are encountered on tubes removed from coal fired boilers used in power stations. The paper concludes with some preliminary details of how the temperature varies in the scarred section. The estimation of this temperature variation is important for creep life assessments.
Experimental Analysis of an MMC Military Track Shoe
Authors: Strelow Joseph E. , Simula Glen R. , Hughes Craig F. , Pakkala Edward C. 
Published: March 2021

Abstract
This paper describes the experimental analysis techniques used during the design of a prototype military track shoe utilizing cast metal matrix composite (MMC) material for use on future military vehicles. The program requirements were to retain the same functionality, strength, durability and wear characteristics as production forged steel track shoes, but with a significant weight reduction and comparable cost. In order to achieve these goals with such significant differences in mechanical properties, a thoroughly integrated design phase combining analytical modeling and experimental techniques was used.
Finite element analyses were conducted during the initial design phase to optimize the structure. Various experimental techniques were used to validate the computer models and obtain reliable information in regions not accurately modeled. Destructive tests of the final design were also performed to determine failure loads. Experimental techniques were employed in three distinct phases: reflective photoelasticity and strain gage analysis of an aluminum filled epoxy model for initial analytical verification, transmissive analysis of a 3-D photoelastic model, and finally reflective photoelastic and strain gage analysis of the actual prototype MMC shoe. The results from all phases are discussed, but with greater emphasis on the experimental techniques.
The Criteria Predicting Wrinkling of Thin, Flat, Rectangular Webs
Authors: Lin Chen-Chi , Mote Clayton D. 
Published: March 2021

Abstract
A web is termed wrinkled when one of the in-plane principal stresses is tensile and the other is sufficiently compressive. A criterion is derived that predicts wrinkling of isotropic, compressible rectangular webs under uniform in-plane principal stresses. The compressive stress at impending wrinkling depends on the flexural stiffness, and it equals zero in the case of a membrane. A criterion of wrinkling is also derived using isotropic, incompressible membrane theory. This criterion predicts an infinite number of wrinkle waves in a wrinkled region. With small flexural stiffness, the number of wrinkle waves becomes finite at wrinkling and it is predictable along with the shape and the size of the wrinkled region. The number of the wrinkle waves increases as the aspect ratio of the rectangular web increases, as the in-plane principal tension increases, and as the flexural stiffness decreases. Analyses of wrinkling of a rectangular web under simple shear and uniform longitudinal stretching illustrate the above predictions.
Heat Transfer Finite Element Analysis of an Adhesive Bonding Process
Authors: Veldman Roger L. , VandenBrink Dennis J. 
Published: March 2021

Abstract
The finite element method was used to model an adhesive bonding process between a sheet of glass and a long strip of flexible PVC. The effect of the thickness of the PVC strip, the number of heat sources, the temperature of the heat sources, the size of the heat sources, and convection on the steady state temperature distribution in the adhesive layer was studied. The time required to reach the steady-state condition was also determined.
Finite-Element Study of C-Ring Fracture Specimens for the Determination of Design Strength Data
Authors: Segall A. E. , Jadaan O. , Palko J. 
Published: March 2021

Abstract
To investigate the design implications of using C-ring specimens for evaluating the strength controlling flaw population(s) of ceramics when in tubular form, finite-element analysis (FEA) calculations were performed using the ANSYS code. These calculations focused on the ranges of width-to-thickness ratios required to maintain a plane stress state within the C-ring specimen during fracture. In addition, the validity of the theoretical effective-area (KA) and effective-volume (KV) relations derived during earlier analytical and experimental studies were investigated. Results of the FEA calculations indicated that a wide range of width-to-thickness ratios could be safely used to extract fracture strength design data. Moreover, the calculations confirmed the validity of the theoretical stress-area and stress-volume relations used to correlate strength defining flaw population and determine Weibull parameters. However, a tendency for the computational errors to increase with Weibull modulus was observed during the finite-element based estimations of effective-areas and -volumes.
A Method for Assessing the “Local” Accuracy of Weight Functions for Plates With Embedded Cracks
Authors: Ng S. W. , Lau K. J. 
Published: March 2021

Abstract
In this paper a procedure is developed to assess the “local” accuracy of weight functions for finding stress intensity factors of centrally cracked finite plates given by Tsai and Ma (1989). It is found that the weight functions can be used to calculate stress intensity factors for practical cases, with “local” accuracy being within 6 %. In addition, weight functions generated from two finite element analyses are found to be accurate and may be used to assess new algorithms for finding weight functions.
Thermal Vibrations of Beams With Temperature-Dependent Material Properties
Authors: Masoom Abulkhair M. 
Published: March 2021

Abstract
Thin beams subjected to thermal loads are considered. The formulation includes the temperature dependence of thermal conductivity and elastic modulus as well as coupled theory. A comparison is made between beams made of stainless steel and silicon carbide. Results show that significant differences are possible for temperature and stress solutions when temperature-dependent elasticity and conductivity are used, as opposed to the constant properties evaluated at a reference temperature.
Component Minimum Life Estimation Based on Life Testing Suspended Prior to Failure
Authors: Ehrich Fredric F. 
Published: March 2021

Abstract
One possible approach to life extension of aerospace components is to take those parts or subsystems that have run the limited initial life estimate and been removed from service, and to operate them in simulated service for periods of time beyond the initial life estimate. It is often the case that such testing must be suspended before the part reaches the point of actual failure. A need therefore exists to use such suspended test data to infer a life limit.
The standard deviation of the estimated life can generally be reliably quantified by applying results from laboratory material tests and information on the variability of the unit’s dimensions. The derived life estimate must therefore be consistent with the known standard deviation.
The problem is structured as a variational one, that is, a problem of finding the values of a set of variables — the hypothetical duration of the individual suspended tests if they had been continued to failure — subject to the constraints that the period of continuation must be equal to or greater that zero, and that the standard deviation of the average value of the life of the sample set be equal to the known, predetermined value. The problem is made determinate by applying the conservative requirement that calculated average life of the sample set be the lowest possible value.
Although the problem is nonlinear and not amenable to traditional linear programming solution, a very simple pair of algorithms have been identified which permit exact solution for all ranges of objective standard deviation. Solutions to typical problems are given to illustrate the utility of the procedure.
Firmware Design Capture
Authors: Viste Michael J. , Cannon David M. 
Published: March 2021

Abstract
One of Allen-Bradley’s goals is leveraging — taking better advantage of existing resources. We are developing a methodology and supporting tools that help engineers share and reuse (i.e., leverage) their firmware design and development work. Writing reusable firmware source code is especially difficult due to the tight constraints in most embedded systems — code must usually be written for product specific hardware needs and resources. Reuse of engineering work at the design level is a more effective approach.
With this in mind, we have been working with Allen-Bradley Power Products engineers and managers to pilot a Firmware Design Capture (FDC) system. In a FDC system, engineers work in their own paper or electronic workbooks compiling descriptions of their domains’ technologies and algorithms in loosely structured electronic document sets called technology books. Product-specific information is placed in complementary document sets called product books. Engineers can access this growing body of ‘Strategic Design Information’ that they and others have created; freely drawing from, commenting on, or adding to it. Key characteristics of this FDC system are:
• A focus on collecting reusable and accessible design information
• Incremental, small-grained development of documents during design activity
• Electronic format of documents, for ease of refinement and access
• Unobtrusive tools and methods, determined through frequent user feedback
We expect this methodology to help engineers improve schedule predictability and reduce the firmware development life cycle, better retain vital technologies and product data, and increase product quality. Feedback from our initial work supports these expectations.
The Creation of a Taxonomy for Manufacturability Design Requirements
Authors: Gershenson John A. , Stauffer Larry A. 
Published: March 2021

Abstract
In this paper, we present a taxonomy of manufacturing issues used in the design process. The purpose of this taxonomy is to serve as a checklist of issues about manufacturing that can be considered during the product definition process. Such a taxonomy helps designers to incorporate manufacturing considerations in conceptual and detail design. In this paper, we also present the taxonomy’s development. A study was conducted to improve our initial taxonomy by soliciting reviews from experienced, practicing engineers. In this way, we hope to assure that the taxonomy is useful in an industrial design context.
A Model of Information Exchange in the Design Process
Authors: Christian Andrew D. , Seering Warren P. 
Published: March 2021

Abstract
This paper describes a method of modeling the engineering design process and a simulation that implements the model. The model explicitly represents the communication requirements of interdependent design projects and the assigned roles of individuals. The simulation uses computer agents to represent individuals working within a design environment, exchanging information, and making decisions based on a limited rationality model of human behavior. This paper describes how the model and simulation can be used to make predictions about design team performance.
Modeling Uncertainty in Preliminary Design: A Short Review
Authors: Butler A. C. , Coates G. R. , Rao S. S. , Sadeghi F. , LeClair S. R. 
Published: March 2021

Abstract
Several mathematical theories exist for modeling uncertainty, and this paper explores the use of three different techniques for modeling judgment in preliminary engineering design. The relative advantages and disadvantages of each theory are discussed from an applied perspective based on experience with prototype systems. These techniques include the Dempster-Shafer theory, Bayesian Belief Networks, and Fuzzy Systems. Additionally, the relative merits and limitations of each technique are discussed in a qualitative manner drawing on experience gained with each model. Conclusions are drawn about the effectiveness of these techniques for representing uncertainty in preliminary engineering design.
Design for Product Variety: Key to Product Line Structuring
Authors: Ishii Kosuke , Juengel Cheryl , Eubanks C. Fritz 
Published: March 2021

Abstract
This study develops a method to capture the broadest customer preference in a product line while minimizing the life-cycle cost of providing variety. The paper begins with an overview of product variety and its importance in overhead costs: supply chain, equipment and tooling, service, and recycling. After defining the product structure graph as a representation of variety, the paper introduces an approximate measure for the customer importance and life-cycle cost of product variety The cost measure utilizes the concept of late point identification which urges standardization early in the manufacturing process and differentiation at the end of the process. The variety importance-cost map allows engineers to identify cost drivers in the design of the product or the manufacturing system and seek improvements. The refrigerator door example illustrates the concept. On-going work seeks to validate and enhance the method with several companies from different industries.