bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computerized Design and Generation of a Helical Gear Drive in Substitution of a Worm-Gear Drive
Authors: Litvin Faydor L. , Kim David H. 
Published: March 2021

Abstract
The design and generation of a gear drive formed by an involute helical gear and an involute worm is considered. Such a drive is applied as a low-power one in substitution of a conventional worm-gear drive.
The authors have developed the geometry of the drive, simulated the meshing and contact via a computer program, and have developed the design of the grinding (cutting) wheel for generation of the worm.
A numerical example is provided for illustration of the developed theory.
Computer Aided Collision Control Using Extended Octree Representations
Authors: Bao Zhuojun 
Published: March 2021

Abstract
In this paper a new method for the computer aided collision control between moving bodies is presented. A dynamic and continuous collision control is reduced to static testes by subdividing a given time interval into sufficingly small pieces and the introduction of an effective space (domain) of a moving body for each time interval. Using the recursive hierarchical exdended octree representations the intersection of a body with the effected space of another moving body is reduced to the distance determination between nodes (cubes) of extended octrees. The use of the exdended octree representations leads to a quick elimination of non-relevant nodes. In case of a possible collision the collision zone can be recognized and presented by the intersection between relevant nodes using analytic tests. For this, both a discrete and a continuous collision control are developed. The proposed method is useful for the collision control in robotics, mechanics, manufacturing and assembling process.
Trajectory Generation for High-Speed Machinery With Minimal Residual Vibration Using Low-Harmonic Rational Curves
Authors: Ge Q. J. , Rastegar J. 
Published: March 2021

Abstract
For a given high-speed machinery, a significant source of the internally induced vibrational excitation is the presence of high frequency harmonics in the trajectories that the system is forced to follow. We develop a method for synthesizing a low-harmonic joint trajectory to reduce the potential vibration and related control problems using low-harmonic rational curves. Continuity conditions for these curves are studied and are used to develop a geometric algorithm for designing low-harmonic rational spline curves. Finally, we discuss how these low-harmonic curves may be used for trajectory generation of high-speed machinery with minimal residual vibration.
Contact Stress Analysis in Ball Screw Mechanism Using the Tubular Medial Axis Representation of Contacting Surfaces
Authors: Huang Huai-Te T. , Ravani Bahram 
Published: March 2021

Abstract
A simple method is presented for analysis of contact stresses and deformation conditions between the bearing balls, screw, and nut of the Ball Screw Mechanism. The method is based on representation of contact geometry and curvature analysis of contacting surfaces using a generalization of Medial Axis Transform (MAT) to tubular surfaces developed in this paper. Simplified Hertzian contact solutions are obtained using the curvature relationship in MAT. The results are approximate but do include the effect of complex thread profiles as a result of the helical grooves and are suitable for mechanical design purposes.
A Geometric Inspection of Two 3-R Robots Manipulating a Four-Bar Linkage Payload: The Velocity Problems
Authors: Mattson Keith G. , Pennock Gordon R. 
Published: March 2021

Abstract
This paper presents solutions to the forward and inverse velocity problems of two planar three-degree-of-freedom robots, with all revolute joints, manipulating a planar four-bar linkage payload. These kinematic problems are formulated in terms of two Jacobian matrices: one associated with the independent inputs to the robots, and the other associated with the payload outputs. The paper emphasizes how both Jacobian matrices can be obtained from a geometric inspection of the system. This provides kinematic insight into the system and is believed to be important in the design and control of cooperating robot workcells. The paper also shows that the inverse of the Jacobian matrix associated with the independent inputs can be obtained directly from inspection. The inverse of the Jacobian matrix associated with the outputs is obtained from geometric inspection by considering a four-input mechanism equivalent to the passive part of the system. Choosing one input at a time, the instantaneous centers of zero velocity provide relationships between the outputs of the mechanism and each input. The matrix is then formulated from these relationships using the principle of superposition of the outputs. The paper also presents the singular and stationary configurations associated with the system and emphasizes the geometric interpretation of these configurations. For illustrative purposes, a numerical example is included which shows how singular and stationary configurations effect the solutions to the velocity problems.
Energy Recovery Systems in a Bipedal Walking Robot
Authors: Dhandapani S. , Ogot M. M. 
Published: March 2021

Abstract
The minimization of energy consumption plays a key role in the design of walking machines. As these vehicles tend to carry their own energy source, a reduction in energy consumption results in machines which can not only travel further, but require smaller actuators that typically yield a reduction in vehicle weight and cost. This paper examines how spring-damper (SD) systems, incorporated within the limbs of walking machines, can be used to transfer a portion of the energy typically dissipated, from one step to the next. Unlike previous efforts which have concentrated on hopping machines, this paper examines walking machines which have a definite multi-limb support phase. Two methods, active and passive locking, are developed and applied to a five-link biped. Dynamic simulations demonstrate that energy consumption can be reduced by 34%.
A Linkage Type Map for Spherical 4 Position Synthesis
Authors: Murray Andrew P. , McCarthy J. Michael 
Published: March 2021

Abstract
This paper classifies and evaluates the solutions to the four orientation synthesis of spherical 4R linkages. Burmester’s result that a one-parameter set of planar RR dyads exists that guide a body through the four planar positions has an analogous form for spherical RR dyads given four orientations. The theory provides a two dimensional set of spherical 4R linkages that can be assembled in each of the four chosen orientations. A map of linkage types is obtained by classifying each spherical mechanism at the vertices of a finite grid on this set; Erdman titles this a “Map of Solutions” for the planar case. Each mechanism is then checked for input drivability, that is, whether or not the input link can drive the coupler smoothly through all four positions. The result is a map of the spherical 4R mechanisms that the designer can use to find practical solutions to the spherical synthesis problems.
A New Algorithm for the Determination of the Workspace of Complex Planar Kinematic Chains
Authors: Lê-Huu Pascal , Gosselin Clément M. 
Published: March 2021

Abstract
A new algorithm for the determination of the workspace of complex planar kinematic chains is presented in this paper. This algorithm is completely general since it can deal with any kind of topological graph and any set of parameters defined in a convention of notation. It uses the numerical solution of the inverse kinematics and is based on a wavefront expansion in the Cartesian space. Three examples are presented here, and lead to a dexterity mapping for two two-degree-of-freedom multi-loop manipulators and a three-degree-of-freedom hybrid manipulator.
An Inverse Dynamic Model of a Spherical Electrohydraulic Actuator for Use in a Dexterous Mechanical Hand
Authors: Sharma Shikha , Ogot Madara M. 
Published: March 2021

Abstract
The purpose of this paper is the development of an inverse dynamic model of a two degree of freedom electrohydraulic actuator. The actuator is to be incorporated at the base of each of three fingers of a nine degree of freedom mechanical hand, currently under development. Motion in the proposed actuator is facilitated about intersecting pitch and yaw axes, thus creating spherical actuation. The dynamic model incorporates frictional and hydraulic losses, commonly overlooked sources of energy dissipation. The model is to be used in the control scheme of the mechanical hand and in the optimal synthesis procedure of the actuator. The latter application, briefly described here, takes into account specified motion and torque requirements, pressure, peak input force and size constraints. Particular attention is paid to traditional performance indices, such as mechanical advantage.
Dynamic Non-Interference Constraints in Goal-Directed Geometry
Authors: Coulter Stewart , Bras Bert , Rosen David 
Published: March 2021

Abstract
Improvements in computer-aided design tools can significantly increase designer productivity. The ability to explore a variety of possible designs quickly and effectively is essential for a designer. In a previous paper, Goal Directed Geometry (GDG) was introduced as a computational framework for preliminary design, aiding the formulation of engineering models with geometric considerations, and the solution of these models with a multi-objective optimization package. The geometric considerations were limited to static noninterference constraints, introducing a metric and method for prevention of geometric interference between two subassemblies. In this paper, this metric and method are expanded to include the prevention of interference between moving subassemblies, or dynamic interference. Based on a series of repetitive static checks, this metric is intended to be accurate and simple for the designer to use. A case study is presented showing the GDG implementation for a linkage design problem, demonstrating the use of this metric. This parametric GDG model is then solved using an existing optimization program called DSIDES.
Finite Element Analysis Improves Design of Hot Metal Ladle Car
Authors: Suchora Daniel H. , Perrine Harry S. , Chamberlain Bradley 
Published: March 2021

Abstract
An electric powered Hot Metal Ladle Car was designed to safely transport a ladle filled with 160 metric tons of molten steel. The ladle geometry and space constraints within the use environment were specified. A final design was prepared and documented which met the design requirements and could be efficiently manufactured.
An initial design was developed using past designs of a similar nature as a basis. By hand stress calculations were performed and the design modified to get stress values to acceptable levels. Preliminary design drawings were developed.
At this stage of the design, some engineering personnel felt that the “by hand” stress analysis was sufBciently accurate to go ahead with fabrication. After much discussion it was decided to perform a Finite Element Analysis (FEA) to verify the design stresses calculated “by hand”. The FEA analysis predicted stresses that were significantly higher than indicated “by hand” in some critical change of section regions. These stress levels were much higher than the allowable stresses for this design.
The difference between the FEA stresses and “by hand” stresses were evaluated. After much discussion and thought an insight to the actual load flow was developed which was consistent with the FEA results.
With this insight, modifications were made to the design and incorporated into the FEA model. These changes needed to be practical from a manufacturing and end use viewpoint. After a few iterations on the design tire FEA stresses were reduced to an acceptable level. These changes were incorporated into the design.
The final design of the ladle car was fabricated. The design was significantly improved due to the ability to accurately calculate stresses in transition regions of the frame where “by hand” methods were not really applicable. The combination of “by hand” methods to ballpark a design and FEA methods to reftne a design proved to be a powerful method to get a truly good design.
On the Safety of Agricultural Disc Mowers
Authors: Brickman Dennis B. 
Published: March 2021

Abstract
A thrown object test protocol was developed and performed based on agricultural rotary mower safety standards to analyze the safety of an agricultural disc mower. Test results reveal a relationship between the guard to ground clearance and the quantity of thrown objects striking the operator zone target. Application of the Safety Hierarchy systematically explores safety strategies for mitigating the thrown object danger.
Structural Health Monitoring Using Modal Strain Energy
Authors: Ballinger Robert S. , Herrin David W. 
Published: March 2021

Abstract
This research combines analytical and experimental modal analysis techniques to verify the structural integrity or monitor the “health” of a dynamic structure. Central to the procedure is the development of a baseline dynamic fingerprint model of the structure. The dynamic fingerprint is verified with experimental modal analysis and correlation. After the structure is placed into service, damage can be determined by comparing the current dynamic response with the baseline dynamic fingerprint response. The unique aspect of this procedure is that the current dynamic response is enforced on the undamaged baseline dynamic fingerprint model. Should damage exist, the structure is forced to deform in an unnatural manner, and high strain energy results. Significant differences in the normalized modal or operating strain energy density identify structural regions where a loss of stiffness, weakening of the structure, and/or damage has occurred. This identification of a potentially “unhealthy” structural region allows a quick visual inspection of the region or further analytical and/or experimental submodelling of the area to precisely identify the damage. The method is ideally suited to CAE application. The method is demonstrated analytically and experimentally for two structures: an eight-bay cantilevered truss structure and a rectangular plate with various boundary conditions.
Finite Element Analysis of Dynamic Rigidity of Diesel Engine Housing
Authors: Maslov Igor V. , McCafferty Raymond , Rea James P. 
Published: March 2021

Abstract
High levels of dynamic loads in a modem diesel engine take place at low frequencies and are connected with the forced vibration of the engine under the action of excitation gas and inertia forces. The lower range of these frequencies are equivalent to the speed of the engine (two stroke) and half engine speed (four stroke). They lead to high stress levels and deformations and often cause internal damage or component failure as well as increasing vibration transmitted to the foundation. One of the most important factors in improving the reliability and durability of engine components and reducing the level of vibration is providing sufficient rigidity for the engine housing. Careful choice of the main dimensions and design parameters will greatly influence engine performance.
An engineering approach to the Finite Element analysis of low frequency forced vibration is proposed for the elastic system including crankshaft, engine housing, elastic mounting and foundation. This approach is applied to the analysis of medium speed marine diesel engines with particular attention being paid to the analysis of the rigidity of the engine housing.
A solution procedure is proposed to define the loads transmitted from the crankshaft to the main bearings. The procedure takes into account the reciprocal influence of elastic and inertial characteristics of the crankshaft and the engine housing mounting on the elastic foundation, alteration of load amplitudes according to the angular position of the crankshaft, and hydrodynamic behaviour of the lubricating oil film in the contact zone.
Plastic Deformation of a Solid Cylinder of Temperature Dependent Properties Subjected to Cyclic Loading
Authors: Jahanian Shahriar 
Published: March 2021

Abstract
There are many practical instances of structural behaviors where the incremental increase of deformation occurs under cyclic loading, such as ratcheting in nuclear fuel element cans, incremental growth of pressure vessels or turbine cases, etc. This increase of deformation may lead to the failure of structure. For an incremental collapse to occur, it is necessary for different parts of the structure to yield at different stages of loading and unloading cycle. When the thermal loading is present, the properties of the material are temperature dependent. Accordingly the yielding occur at the earlier stage. The situation may get worse when the thermal loading is coupled with the mechanical one. This paper presents a quasi-static, uncoupled thermo-elastoplastic analysis based on incremental theory of plasticity. The behavior of a solid cylinder subjected to torsion and transient thermal loading for one cycle is investigated. The influence upon behavior of nonlinear-strain hardening in the material is investigated.
A Transient Thermoelastoplastic Solution for a Hollow Sphere of Temperature Dependent Properties
Authors: Jahanian Shahriar 
Published: March 2021

Abstract
In this paper an analysis based on incremental theory of plasticity is formulated to predict the thermoelastoplastic stresses in a hollow sphere. The properties of the material are assumed to be temperature dependent, and the material was characterized by linear strain hardening. Mendeson’s method of successive elastic solution is presented for the analysis. The analysis shows that the stresses are not monotonic function of radius or temperature, they strongly depend on history of temperature distribution. In this analysis the problem is treated in a uncoupled, and quasi-static sense. The plastic stress and strain distribution on loading and the residual stress distribution on unloading is presented. The results are compared with the results of other investigators who used a different theory and a reasonable agreement is observed.
Estimating Errors in Concept Selection
Authors: Otto K. N. , Wood Kristin L. 
Published: March 2021

Abstract
Numerical concept selection methods are used throughout industry to determine which among several design alternatives should be further developed. The results, however, are rarely believed at face value. Uncertainties (or errors) in subjective choices, modeling assumptions, and measurement are fundamental causes of this disbelief. This paper describes a methodology developed to predict overall error ranges, in addition to estimating a confidence measure in the numerical evaluation results. Each numerical assignment is given an associated error tolerance, and then treated as a probability error to create a simple means to propagate the uncertainties. A degree of confidence is also derived, similar to a statistical t-test, to indicate an induced confidence level in the final decision. Two preliminary concept selections are shown, to illustrate the methodology. Results from these concept selections indicate that (1) uncertainties can be suitably captured and quantified; (2) critical design questions are addressed during the process of numerical concept selection with error propagation; and (3) designers can make more informed and confident decisions through error estimation.
A Jungian Theory for Constructing Creative Design Teams
Authors: Wilde Douglass J. , Berberet John 
Published: March 2021

Abstract
A novel coordinate system is proposed for the four-dimensional space of scores from the Myers-Briggs Type Indicator (MBTI), a psychological questionnaire increasingly used in education and business as well as in psycholgical counseling. The new normal orthogonal basis proposed is consistent with the Jungian personality theory upon which the MBTI is based. The immediate motive is to find ways of improving the composition of student design teams.
Elementary Education and Engineering Design: Concrete Experiences in Mathematics and Science
Authors: Crawford Richard H. , Wood Kristin L. , Fowler Marilyn L. 
Published: March 2021

Abstract
The education community has focused attention recently on a number of initiatives to evolve, and perhaps revolutionize, approaches for teaching science, mathematics, and engineering. In this paper, we present a new engineering and design technology program, initiated in 1992 and referred to as DTEACh, that focuses on the elementary grades. Two components comprise this new program: (1) open-ended design and exploration lessons that use hands-on models to teach integrated mathematics and science principles, and (2) a two-part teacher preparation program to provide teachers with the necessary engineering, mathematics, and science fundamentals for DTEACh. In this paper, we focus on a description of the teacher preparation program, including discussions of a novel teaching model, the subject matter for engineering and design fundamentals, and evaluation of the program. Results of the evaluation that teachers are more confident and equipped to facilitate the instruction of mathematics, science, and engineering principles.
Modeling the Information Access Methods of Engineering Designers
Authors: Court Andrew W. , Culley Stephen J. , McMahon Christopher A. 
Published: March 2021

Abstract
An information modeling approach is used to gain an understanding of the methods that engineering designers use when accessing design information. A new technique is presented that attempts to represent the key information sources used and to identify the information access paths or routes most frequently undertaken by engineering designers. This technique is termed Information Access Diagrams (IADs). Elements of the IADs were derived firstly, from observations of engineering designers in practice, and secondly, from the use of the IDEF1X modeling technique.
Using twenty case studies, the diagrams are demonstrated in real design situations. In particular, the paper focuses on the access paths or routes undertaken during a number of different design activities; for example, original, adaptive and variant design; simple and complex designs, design and selection tasks; and new and previously done designs. Subsequent observations are used to recommend areas for future research.
Engineering Decision Support System (EDSS)
Authors: Herling Derald , Ullman David G. , D’Ambrosio Bruce 
Published: March 2021

Abstract
Engineers, as well as other decision makers, are required to make many decisions as they are designing a product or resolving a problem. At these decision points there are many alternatives and criteria to be considered. Studies of design sessions show that most decisions made during these times are in an ad hoc manner. Greater understanding of the mechanical design process, data representation for collaborative design and probabilistic inferences have allowed the creation of a computer decision support program, called Engineering Decision Support System (EDSS), that addresses the special needs of design engineers.1 This paper introduces this work, which is still in the developmental stages.