bluuebunny/crossref_metadata_2025_split huggingface dataset:
Near Tip Loss Control With a Winglet Baffle Cavity Tip in a Turbine Cascade
Authors: Li Li , Jiang Dengyu , Zhou Chao , Luo Hualing , Hou Weitao , Chang Qiyue 
Published: March 2021

Abstract
The aerodynamic performance of a winglet baffle cavity tip is investigated at different inlet incidences from −12.5 to +12.5 deg. This blade tip shows a geometry feature with a pressure side winglet and a baffle within the tip cavity. The experimental studies were carried out in a large-scale linear cascade. Numerical methods were also used to obtain the detail flow physics. The baffle on the tip divides the cavity vortex into two main parts, and enhances flow mixing over the tip. As the tip leakage flow exits the tip near the baffle and the cavity corner, flow separation occurs over the suction side and its blockage effect reduces the local tip leakage mass flow rate. The additional pressure side winglet reduces the contraction coefficient on the pressure side squealer. Compared with the squealer tip, the winglet baffle cavity tip reduces the tip leakage mass flow by 12.1% and the near tip loss by 4.2%. Removing the baffle on the tip also results in an increase of the loss. As the incidence of the incoming flow decreases, the loss near the tip reduces mainly due to a reduction of the strength of the passage vortex, which develops from the casing endwall. At all incidences studied, the winglet baffle cavity tip shows better aerodynamic performance than the squealer tip.
The Impact of the Human Body Position Changes During Wheelchair Propelling on Motion Resistance Force: A Preliminary Study
Authors: Wieczorek Bartosz , Kukla Mateusz , Warguła Łukasz , Rybarczyk Dominik , Giedrowicz Marcin , Górecki Jan 
Published: March 2021

Abstract
The aim of this research was to analyze the impact of the human body position changes caused by propelling a wheelchair with the pushrim propulsion on the value of motion resistance force. The discussed research works are in progress; therefore, the presented results should be treated as preliminary. The research was carried out in the group of six volunteers propelling a wheelchair of which frame was inclined, in respect to the horizontal plane, under the angle of 0 deg, 7 deg, and 14 deg. The area of the position variability of the human body center of gravity (COG) and the coefficients of wheelchair rolling resistance have been determined. Based on the measurements conducted, rolling resistance force FT and motion resistance force FR have been defined for three values of frame inclination angle. The determined force of rolling resistance Ft depended on the location of the COG of the human body and the value of the coefficients of rolling resistance of the front and rear wheels of a wheelchair. This force was a component of the resistance to motion FR, which also took into account the influence of gravity resulting from the inclination of the wheelchair on an inclined plane. For the tested inclination angles relative to the horizontal plane, the rolling resistance force ranged from 9.82 N to 22.81 N. Analyzing the variability of the rolling resistance force FT, it was found that for the final phase of the driving motion, it increased by 36% for the inclination angle of 0 deg and 43% for the inclination angle of 7 deg. Its increase was 48% for the inclination angle of 14 deg in relation to the human body position for the beginning of the driving motion. In the case of measuring the value of the resistance to motion FR, it was observed that, depending on the angle of the incline of the wheelchair, it ranged from 14.69 N to 256.33 N. The measurements conducted enabled the derivation of an analytical model for determining rolling resistance force depending on the position of the human body COG and the wheelchair inclination angle. The conducted research demonstrated the impact of the COG position on the changes of motion resistance force, thus expanding the state of knowledge, introducing a new parameter which, like a surface type and wheel type, affects motion resistances.
Statically Balancing a Reconfigurable Mechanism by Using One Passive Energy Element Only: A Case Study
Authors: Kuo Chin-Hsing , Nguyen Vu Linh , Robertson Daniel , Chou Lin-Tien , Herder Just L. 
Published: March 2021

AbstractThis paper presents the static balancing design of a special reconfigurable linkage that can switch between two one-degree-of-freedom (DoF) working configurations. We will show that the studied dual-mode linkage only requires one mechanical spring or one counterweight for completely balancing its gravitational effect in theory at both modes. First, the theoretical models of the spring-based and the counterweight-based designs are derived. The proposed design concepts were then demonstrated by a numerical example and validated by software simulation. Experimental tests on both designs were also performed. The result of this study shows that a reconfigurable mechanism with N working configurations can be completely statically balanced by using less than N passive energy elements.
A Heuristic Application-Specific Path Planner for Robot Motion Planning
Authors: Alciatore David G. 
Published: March 2021

Abstract
This paper presents the development and simulation results of a Heuristic Application-Specific Path Planner (HASPP) that can be used to automatically plan trajectories for a manipulator operating around obstacles. Since the implementation of HASPP is inherently application-specific due to dependence on heuristics, the application of HASPP to an eight degree of freedom Pipe Manipulator is presented as an illustrative example. This development and simulation was implemented on a Silicon Graphics Personal IRIS with the aid of WALKTHRU, a 3-D simulation and animation tool, and software developed in C. HASPP uses extensive knowledge of the manipulator’s workspace and makes certain assumptions about the environment in finding trajectories. The algorithm also makes use of the manipulator’s redundant degrees of freedom to avoid obstacles and joint limits during the trajectory while obtaining a heuristic near-optimal solution. The algorithm is rule-based, governed by heuristics and well-defined geometric tests, providing extremely fast results. It finds “good” trajectories that are optimal within the defined heuristics. When a trajectory is not feasible for the given geometry, the algorithm offers a diagnosis of the limiting constraints.
The Pipe Manipulator HASPP implementation has been tested thoroughly with the computer graphics model and it has demonstrated the ability to reliably determine near-optimal collision-free erection trajectories completely automatically. No other planning techniques available in the literature have demonstrated the ability to solve problems as complex as the example presented here. The use of HASPP with simulation offers many application opportunities including plant design constructability studies, assembly and maintenance planning, pre-planning and pre-programming of equipment tasks, and equipment operator assistance. This work was the result of construction automation research sponsored by the National Science Foundation.
Rapid Prototyping: Cornerstone of the New Design Process
Authors: Ulerich Phillip L. 
Published: March 2021

Abstract
A new design process is being developed incorporating engineers designing in 3D on workstations, solid modeling, computerized design data bases and networks, finite element analysis, rapid prototyping, and rapid tooling, the critical issue for us is to get new product parts and assemblies as soon as possible and the cornerstone of our approach for molded parts is rapid prototyping for the initial parts and short run tooling.
The author discusses his experience over the last three years designing molded case circuit breakers with the new design process, including successes and failures of over 20 stereolithography parts and half a dozen spray metal molds. These processes alone have a significant effect on the design cycle time but the really big payoff comes when they are incorporated in an entirely new approach to mechanical design.
A Method for Selecting Measurement Points on Planar Faces of Objects With Holes
Authors: Vardar Hayri O. , Ozsoy Tulga M. 
Published: March 2021

Abstract
In this paper, a method facilitating the automatic selection of measurement points on planar faces of objects with holes will be presented. The objective is to further automate the process of generation of inspection programs for coordinate measuring machines.
The method developed aims for the creation of candidate points on a planar face of an object and the optimal selection of a required number of measurement points among the candidate points. A triangulation technique based on a finite element mesh generation method has been implemented in creating the candidate points. Except for the special case of four points, a random selection process is utilized for choosing among the candidate points. The effects of randomness are compensated by applying a convex hull computation algorithm to find the set of points among other candidate sets that covers the largest area. The method has been successfully incorporated into a software demonstrating the feasibility of the approach.
Interfacing PATRAN or ANSYS Programs to FIDAP for Analysis of Realistic Engineering Problems
Authors: Jamnia Mohammad Ali , Chu William 
Published: March 2021

Abstract
With the recent advances in the various fields of engineering and the fields of computer hardware and software, a large number of computer programs are being used as design tools in the area of manufacturing. These tools generally deal with parameters and variables specific to one particular area. For instance, a solid mechanic code is equipped with means of specifying forces and displacements and a program designed for magnetics analysis can only have input/output related to magnetics. However, in many realistic systems, a number of these various fields are present and effective design requires coupling of these variables.
Best-Estimate Analysis of Loss-of-Coolant Accident in Pressurized Heavy Water Reactors Using Microcomputers
Authors: Saha P. , Das T. K. , Chanda A. , Ray S. 
Published: March 2021

Abstract
The present paper discusses the development of a computer software or code for best-estimate analysis of Loss-of-Coolant Accident (LOCA) in Pressurized Heavy Water Reactor (PHWR) systems. The formulation is comparable to U.S., Canadian, French LOCA codes, namely, TRAC, RELAPS, ATHENA, CATHARE, etc. However, the present software has been developed on Microcomputers, namely, PC-XT and AT, whereas the other softwares were developed and are being used primarily on Mainframes such as CDC-7600, CYBER-176, CRAY, etc.
An Intelligent Mathematical Modelling Assistant for Analysis of Physical Systems
Authors: Finn D. P. , Grimson J. B. , Harty N. M. 
Published: March 2021

Abstract
This paper describes work in progress aimed at developing an intelligent modelling assistant for the mathematical modelling task associated with engineering analysis. Mathematical modelling precedes detailed numerical analysis and involves formulating and evaluating engineering problems with the objective of proposing a candidate mathematical model that meets desired modelling requirements. The approach taken in this work is based on Chandrasekaran’s proposecritique-modify method which is adapted for modelling. The use of this paradigm is justified by viewing the mathematical modelling process as an activity of successive investigation and refinement of candidate mathematical models. The system architecture is based on exploiting a number of artificial intelligence techniques including model based reasoning, case based reasoning and rule based reasoning. A modelling options case base assists engineers in proposing candidate mathematical models. Engineering 1st principles and formulae are utilised within an artificial intelligence framework to provide a means of evaluating and critiquing the candidate mathematical models. The system is integrated with an existing interactive CAD system. The problem domain covered is application independent but will initially focus on the modelling and analysis of heat transfer problems.
Implementation of an Efficient Description of Elastic Properties of a Layered Composite in a Finite Element
Authors: Patton Edward M. 
Published: March 2021

Abstract
A constitutive formulation for a layered composite originally proposed by Christensen (1) is implemented in a displacement-based three dimensional isoparametric finite element. The element is tested against the much studied free-edge stress problem, and is found, in general, to have good agreement with published results using a single element through the thickness of the laminate, even in the vicinity of the free edge. In-plane stresses and through thickness normal stresses agree extremely well with previous results. The results for interlaminar shear stress are, however, somewhat lower than previously published. Reasons for this discrepancy are discussed.
Techniques for the Development of an Audiographic Teleconferencing Course
Authors: Hotchkiss Anthony 
Published: March 2021

Abstract
The development and preparation of course material for audiographic teleconferencing, a form of distance education, is discussed. The Group Teleconferencing System (GTCS), used at the University of Wisconsin-Madison, is described. GTCS allows visual material (slides) to be displayed and annotated interactively, and some techniques for the generation and presentation of the slides are suggested, using a computer-aided-design course as an example.
Effect of Contact Ratio on Spur Gear Dynamic Load
Authors: Liou Chuen-Huei , Lin Hsiang Hsi , Oswald Fred B. , Townsend Dennis P. 
Published: March 2021

Abstract
This paper presents a computer simulation showing how the gear contact ratio affects the dynamic load on a spur gear transmission. The contact ratio can be affected by the tooth addendum, the pressure angle, the tooth size (diametral pitch), and the center distance. The analysis presented in this paper was performed by using the NASA gear dynamics code DANST. In the analysis the contact ratio was varied over the range 1.20 to 2.40 by changing the length of the tooth addendum. In order to simplify the analysis, other parameters related to contact ratio were held constant.
The contact ratio was found to have a significant influence on gear dynamics. Over a wide range of operating speeds a contact ratio close to 2.0 minimized dynamic load. For low-contact-ratio gears (contact ratio less than 2.0), increasing the contact ratio reduced the gear dynamic load. For high-contact-ratio gears (contact ratio equal to or greater than 2.0), the selection of contact ratio should take into consideration the intended operating speeds. In general, high-contact-ratio gears minimized dynamic load better than low-contact-ratio gears.
Studies on the Dynamic Performance of a Spur Gear With Hollow Teeth
Authors: Ramamohana Rao A. , Srinivasulu B. 
Published: March 2021

Abstract
Performance of spur gears largely depends on the magnitude and nature of variation of dynamic loads occuring between mating teeth. Variable tooth mesh stiffness is one of the primary sources causing parametric excitations resulting in dynamic loads. The usual method of varying the mesh stiffness to reduce dynamic loads is to use high contact ratio and profile modified gears. In this paper, a new type of tooth design to improve the dynamic performance of spur gears is presented. In this, a through hole is drilled in each tooth in a direction parallel to the gear axis. The diameter of the hole and its position on the tooth centre line are variable. Such a gear is called a hollow gear. Dynamic analysis is carried out for the mesh of hollow pinions mating with solid gears. The results are compared with solid pinions (no holes in teeth) meshing with solid gears. Finite element method is used for the analysis.
For estimation of the dynamic load variation in hollow-solid and solid-solid gear meshes, a model incorporating the varying mesh stiffness and damping of gear teeth is used. Governing differential equations are solved using unconditionally stable Newmark-beta algorithm. The dynamic loads obtained are used as an input time varying loads for the determination of dynamic fillet and hole stress response of solid and hollow gear teeth whichever is applicable. Modal superposition technique is used for transient response analysis. The study shows that for the same damping ratio, dynamic loads in hollow-solid meshes are nearly the same as in a solid-solid mesh. In reality, the dynamic loads in a hollow-solid mesh are less than a solid-solid mesh due to its inherent higher material damping.
Gear Tooth Stress Measurements of Two Helicopter Planetary Stages
Authors: Krantz Timothy L. 
Published: March 2021

Abstract
Two versions of the planetary reduction stages from U.S. Army OH-58 helicopter main rotor transmissions were tested at the NASA Lewis Research Center. One sequential and one nonsequential planetary were tested. Sun gear and ring gear teeth strains were measured, and stresses were calculated from the strains. The alternating stress at the fillet of both the loaded and unloaded sides of the teeth and at the root of the sun gear teeth are reported. Typical stress variations as the gear tooth moves through the mesh are illustrated. At the tooth root location of the thin-rimmed sun gear, a significant stress was produced by a phenomenon other than the passing of a planet gear. The load variation among the planets was studied. Each planet produced its own distinctive load distribution on the ring and sun gears. The load variation was less for a three-planet, nonsequential design as compared to that of a four-planet, sequential design. The results reported enhance the data base for gear stress levels and provide data for the validation of analytical methods.
Transmission Analysis: Automatic Derivation of Relationships
Authors: Hedman Anders 
Published: March 2021

Abstract
A method for derivation of relationships for general mechanical transmission systems is given. The method is adapted for computer aided analysis and synthesis of the kinematics, loads and power flows. Losses are included. All relationships are handled by a computer program. No manual formulation and elimination of equations are necessary. The user only needs to describe the transmission system:
1. The transmission units, e.g. gear transmissions, planetary gear trains, clutches, input and output shafts.
2. How the shafts of those units are connected.
Then, the computer program formulates and arranges the relationships. After that, a commercial program, “Maple”, performs the algebraic eliminations. Relationships between the speeds and/or torques of two arbitrary shafts can be derived, e.g. an algebraic relationship for the overall efficiency. Different power flows are possible in split-power transmissions. Special algorithms handle that. The method is a useful tool. It saves time and eliminates the risk for human errors.
Effects of Assembly and Manufacturing Errors on Transmission Error of Planetary Gears
Authors: Ishida Takeshi , Hidaka Teruaki 
Published: March 2021

Abstract
Transforming 2K-H type planetary gears with three planet gears into an equivalent model with many degrees of freedom, in a plane perpendicular to the input and output shafts, the loci of the displacement of a floating sun gear were analyzed theoretically by using the equivalent model. The theoretical locus of the displacement of the sun gear was nearly identical to the experimental one.
K-H-V type planetary gears have been used as the reduction gears in the industrial robot, and have desired to decrease the transmission error between the input and output shafts for increasing the positioning accuracy of the robot. The K-H-V type planetary gears composed of a sun gear for the input, three planet gears, three crankshafts, two disks with cycloidal teeth, an internal gear with pin type teeth, and a carrier for the output were also transformed into the equivalent model in the same manner as the 2K-H planetary gears, and the effects of manufacturing and assembly errors of elements on the transmission error were determined theoretically.
A Study of Transmission Error in Timing Belt Drives: Effect of Production Error in Polychloroprene Rubber Belt
Authors: Kagotani Masanori , Koyama Tomio , Ueda Hiroyuki 
Published: March 2021

Abstract
Experiments on a transmission error, having a period of one revolution of the belt in polychloroprene rubber timing belts, were performed under a quasi-static condition and an initial tension. The experimental results were compared with the computed results obtained using the measurement results of the production error in the belt. It was confirmed that the transmission error was mainly caused by a single pitch error, a change in cross-sectional area of the load carrying cords and a change in modulus of elasticity for one revolution of the belt. As the experimental results coincided quite well with the computed ones, it was concluded that the measurement methods for the single pitch error and the belt elongation factor, and the arrangement methods of these values used to compute the transmission error were right. Further, it was found that the transmission error due to the production error in the belt lessens when the initial tension becomes smaller.
A Globoidal-Cam Type Gearing
Authors: Oizumi Tetusya , Emura Takashi 
Published: March 2021

Abstract
This paper describes a globoidal-cam type gearing with roller-wheel composed of two lines of roller followers to obtain a no-backlash reduction gearing. A principal advantage of this system is the reduction of backlash of the gearing by holding the cam’s rib with the roller followers of each line. We suggest that the roller’s axis should make a reasonable angle to the wheel’s axis. By setting this angle to a suitable amount, the power loss of the gearing will be reduced significantly. The gearing of which roller’s axes are inclined can be applied to high speed and large torque gearing indicating a remarkable improvement upon roller-wheel gearing. A typical globoidal-cam type gearing is analyzed geometrically, its frictional loss of power in meshing is calculated, and a substantial reduction of friction loss was resulted. Additionally, the stiffness of the roller-wheel was estimated and is practically sufficient for our application.
Surface Failure and Durability of Induction-Hardened Sintered Powder Metal Rollers and Gears With Various Hardened Depths
Authors: Yoshida Akira , Ohue Yuji , Karasuno Isamu 
Published: March 2021

Abstract
In this study, the effect of hardened depth on failure modes and fatigue strengths of induction-hardened sintered powder metal test rollers and spur gears is elucidated also with the effect of relative radius of curvature of the test rollers. These experimental results are discussed by an amplitude of ratio of orthogonal shear stress to Vickers hardness. Failure mode of the test rollers was spelling due to subsurface origin crack with slight micropits and that of the test gears was pitting due to surface origin crack with spall near the pitch point independent of the hardened depth. The depths of spalling cracks agreed almost with the occurring depths of peak amplitude of the ratio of orthogonal shear stress to Vickers hardness. Surface durability of the test rollers increased as the surface hardness increased and the relative radius of curvature decreased almost independent of the hardened depth. Surface fatigue life of the test gears was hardly influenced by the hardened depth.