CAD and Optimization of Spur and Helical Gear Sets

1996 ◽  
Author(s):  
Sayed M. Metwalli ◽  
Ehab A. El Danaf
Keyword(s):  
Computer Aided Design ◽  
Full Range ◽  
Optimization Techniques ◽  
Design Stage ◽  
Helical Gears ◽  
Face Width ◽  
Optimum Parameters ◽  
Number Of Teeth ◽  
Wide Range ◽  
The Face

Abstract The present work is an application of Computer Aided Design and optimization techniques to solve the problem of designing a pair of gears. The CAD programs have the initial freedom to change the design variables: the module, the number of teeth, the face width, and the material through a data base display, and a full detailed design stage that applies the AGMA bending and contact number checking criteria, and the bending fatigue strength and the surface endurance strength criteria. Other programs are also linked to optimize spur gears under the objective of minimizing the volume. The design vector is taken to be the module, the number of teeth, and the face width, with the interaction between bending and contact stress constraints. These programs were utilized to study the behavior of the optimum parameters for a full range of cases. Charts of the optimum results are plotted. For optimizing helical gears, the design vector is taken as the module, the number of teeth, the face width, and the helix angle. A comparison is made between values of the objective function and optimum parameters for spur and helical gears for a wide range of cases. A comparison is also made of the results with other previous works of optimization and proved that the approach presented here gives better optimum results for the same loading case.

An Analytical Approach to Tooth Friction Losses in Spur and Helical Gears—Influence of Profile Modifications

2009 ◽  
Vol 131 (10) ◽  
Author(s):  
P. Velex ◽  
F. Ville
Keyword(s):  
Numerical Simulations ◽  
Analytical Approach ◽  
Tooth Profile ◽  
Design Stage ◽  
Power Losses ◽  
Helical Gears ◽  
Friction Power ◽  
Wide Range ◽  
Analytical Formulas ◽  
Displacement Based

An original displacement-based formulation of tooth friction power losses in spur and helical gears is established, which can account for the influence of tooth profile modifications. Several analytical formulas are derived enabling friction losses to be easily estimated for a wide range of gears at the design stage. Numerous comparisons with both the classic formulas in the literature and the results of numerical simulations are presented, which confirm the accuracy of the proposed approach.

An Integrated Approach to the Planning of Manual Assembly Lines

2015 ◽  
Author(s):  
George Pintzos ◽  
Markos Matsas ◽  
Christos Triantafyllou ◽  
Nikolaos Papakostas ◽  
George Chryssolouris
Keyword(s):  
Computer Aided Design ◽  
Manufacturing Systems ◽  
Assembly Line ◽  
Assembly Line Balancing ◽  
Optimization Techniques ◽  
Line Balancing ◽  
Assembly Planning ◽  
Manual Assembly ◽  
Wide Range

Manual assembly planning methodologies have been in the center of industrial and academic research for many decades, since the manual assembly costs may often account for even half of the total manufacturing expenses. The existing and emerging manufacturing trends, such as mass customization and personalization, require fast responses when it comes to the conception and realization of the relevant manufacturing systems. Even though, work methodologies, such as concurrent engineering, have been proposed and applied, gaps still exist among product development, configuration and manufacturing. The Current Product Lifecycle (PLM) systems focus on the coordination of activities among engineers of different disciplines. However, they are unable to provide actual decision support functionality to decision makers. Moreover, solutions for the different phases of assembly planning have been proposed, without nevertheless taking into account the holistic nature of assembly planning that spans the different engineering phases. The study presented in this paper is based on a methodology that integrates three distinct steps, regarding assembly planning; the generation of assembly related information, from the Computer Aided Design (CAD) files of an assembly, the calculation of the relevant process times from functions, generated through empirical measurements and the assembly line balancing of a line, based on the information gathered. The innovative aspect of this approach relies on the advancement of the relevant technologies as well as on their integration into a common working practice. The methodology enables the estimation of production related values in the later phases of product design or in the early phases of manufacturing planning. The generation of assembly precedence diagrams is made in an automatic way through the extraction of information on collision detection and the parts’ relations. This application is developed in the form of an add-on to a commercial CAD software suite. It utilizes features that are available in a wide range of such systems. The second step relies on the identification of specific features of parts, such as dimensions and mass. This information is then used as input in the functions already proposed in the academic literature for the estimation of the relevant process times for each part. Finally, the assembly line balancing is performed through the generation of the precedence diagram and the estimated process times, via a web-based service, which makes use of advanced optimization techniques. In order for this methodology to be evaluated, a case study is presented by using the CAD file of an automotive sub-assembly. The case study demonstrates each step separately, beginning with the generation of the precedence diagram down to the balancing of the assembly line.

Load Sharing Based Fillet Stress Analysis of Involute Helical Gears

2013 ◽  
Vol 465-466 ◽  
pp. 1234-1238
Author(s):  
R. Prabhu Sekar ◽  
G. Muthuveerappan
Keyword(s):  
Load Sharing ◽  
Accurate Estimation ◽  
The Finite Element Method ◽  
Helical Gears ◽  
Critical Loading ◽  
Face Width ◽  
Tooth Fracture ◽  
The Face ◽  
Gear Drives ◽  
Tip Radius

The tooth fracture occurs due to high fillet stress developed at the root fillet region along the face width, when the tooth is normally loaded. Hence, an accurate estimation of critical loading position on the tooth along the line of contact for maximum fillet stress and its location along the face width become important to reduce the tooth fracture. In the present work, the maximum fillet stress is evaluated based on load sharing ratio using the finite element method through the multi pair loaded model and using the results, the influence of cutter tip radius and addendum height on the load sharing ratio and respective maximum fillet stress is evaluated. The maximum fillet stress is lesser in the gear drives which is generated by the full round cutter and it increases due to increase the addendum height. The location at which the maximum fillet stress occurs along the face width is determined, when the load is applied at the critical loading position in the helical gear drive.

Alloplastic Facial Implants

2021 ◽  
Author(s):  
Tsung-yen Hsieh ◽  
Karan Dhir ◽  
William J. Binder ◽  
Peter Andrew Hilger
Keyword(s):  
Computer Aided Design ◽  
Aging Process ◽  
Soft Tissues ◽  
Patient Specific ◽  
Advantages And Disadvantages ◽  
Alloplastic Implants ◽  
Wide Range ◽  
Facial Plastic ◽  
The Face ◽  
Facial Augmentation

AbstractAs the face ages, there is thinning of the epidermis, volume loss and rearrangement of the soft tissues, and malabsorption of the skeletal framework. It is essential to have a thorough understanding of the aging process for successful facial augmentation and rejuvenation. Alloplastic implants can be used to provide a long-lasting solution for augmentation of skeletal deficiencies, restoration of facial irregularities, and rejuvenation of the face. In this study, we describe the ideal implant characteristics along with the advantages and disadvantages of various implant materials. We also present techniques in nasal and premaxillary augmentation, midface augmentation, mandibular augmentation, and lip augmentation. Additionally, computer-aided design and manufacturing as well as bioprinting are emerging technologies with growing applications in facial plastic and reconstructive surgery. We discuss their role in the creation of patient-specific custom implants. The overall goal of facial rejuvenation is to address multiple aspects of the facial aging process including deficiencies in the skin, soft tissues, and skeletal framework. The use of alloplastic implants alone or synergistically with additional surgical procedures can restore a wide range of anatomical deficits that occur with age.

Experiments on Root Stresses of Helical Gears With Lead Crown and Misalignments

2008 ◽  
Vol 130 (7) ◽  
Author(s):  
M. Hotait ◽  
A. Kahraman
Keyword(s):  
Helical Gear ◽  
Strain Gages ◽  
Helical Gears ◽  
Gear Teeth ◽  
Face Width ◽  
The Face ◽  
Bending Stresses ◽  
Contact Models ◽  
Gear Contact ◽  
Different Levels

In this study, the results of an experimental parametric study of the combined influence of shaft misalignments and gear lead modifications on the load distribution and tooth bending stresses of helical gear pairs are presented. A set of helical gear pairs having various amounts of total lead crown was operated under loaded, low-speed conditions with varying amounts of tightly controlled shaft misalignments. Gear teeth were instrumented through strips of strain gages along the face width of gears at the tooth fillet region at a roll angle that is near the start of the active profile. Variations of root strains along the face width were quantified for different levels of shaft misalignments and gear lead crown. The results presented demonstrate the direct link between the lead crown and gear misalignments as well as the effectiveness of the lead crown in preventing edge loading conditions due to misalignment. The results presented here form a database that should be available for a validation of gear contact models in terms of their ability to simulate misalignments.

scholarly journals CONTENT OF DESIGN STAGE IN LIFE CYCLE OF THE MACHINE FOR MANUFACTURING OPTICAL DEVICES AND SYSTEMS

2020 ◽  
Vol 6 (2) ◽  
pp. 8-13
Author(s):  
Alexandr U. Lepen ◽  
Aelita V. Shaburova
Keyword(s):  
Life Cycle ◽  
Computer Aided Design ◽  
Information Technologies ◽  
3D Visualization ◽  
Computer Experiment ◽  
Information Support ◽  
Design Stage ◽  
Product Lifecycle ◽  
Wide Range ◽  
Design Solutions

"Product lifecycle" is a comprehensive indicator of the entire product lifecycle. Today, there is a need to solve the problem of improving the efficiency of equipment development at the design stage, which determines the main technical characteristics, manufacturability, ease of operation and repair. Also, due to the wide range of used modern and technological computer-aided design systems and other information technologies, the process of developing a new product is significantly simplified. Mathematical modeling followed by digital 3D visualization allows optimizing most of the design solutions, technical and economic indicators, and operating modes based on multivariate calculations and simulations that constitute the essence of a computer experiment, which repeatedly speeds up and reduces the cost of creating new, innovative, competitive equipment. Intense competition in the market forces manufacturers not only to look for new design solutions, but also to optimize the existing life cycle of equipment, thus the relevance of this work is due to the improvement of the design stage in the life cycle of the machine, through the use of a new concept of information support using CAD SolidWorks.

Tooth Flank Corrections of Wide Face Width Helical Gears That Account for Shaft Deflections

2003 ◽  
Author(s):  
Shan Chang ◽  
Donald R. Houser ◽  
Jonny Harianto
Keyword(s):  
Power Transmission ◽  
Design Stage ◽  
Distribution Analysis ◽  
Wide Face ◽  
Helical Gears ◽  
Transmission Errors ◽  
Face Width ◽  
Load Distributions ◽  
Deflection Analysis ◽  
Tooth Flank

The tooth flank correction of power transmission helical gears with wide face width is studied by using a finite element based shaft deflection analysis program in conjunction with a numerical load distribution analysis procedure. The load distributions along the line of action, the elastic deflections and transmission errors of gear pairs are obtained by solving the equations of compatibility of displacement and equilibrium of forces. This paper discusses the influences of tooth flank corrections (tip relief, root relief, lead modification, end relief and their combinations) on gear stresses and transmission errors due to shaft deflections. The technique used in the paper has the capability of modeling all significant geometric and elastic contributions due to tooth contact of the pair being analyzed as well as other gears mounted on the same shafts. The results show that it is possible to optimize at the design stage the gear micro-geometry for minimum stresses and transmission errors without changing the gear macro-geometry.

The Major Transitions in Evolution

1997 ◽  
Author(s):  
John Maynard Smith ◽  
Eors Szathmary
Keyword(s):  
Full Range ◽  
Evolution Of Cooperation ◽  
Major Transitions ◽  
Insect Societies ◽  
Wide Range ◽  
Major Transition ◽  
Life Itself ◽  
History Of ◽  
Emergence Of Cooperation ◽  
Multicellular Organisms

Over the history of life there have been several major changes in the way genetic information is organized and transmitted from one generation to the next. These transitions include the origin of life itself, the first eukaryotic cells, reproduction by sexual means, the appearance of multicellular plants and animals, the emergence of cooperation and of animal societies, and the unique language ability of humans. This ambitious book provides the first unified discussion of the full range of these transitions. The authors highlight the similarities between different transitions--between the union of replicating molecules to form chromosomes and of cells to form multicellular organisms, for example--and show how understanding one transition sheds light on others. They trace a common theme throughout the history of evolution: after a major transition some entities lose the ability to replicate independently, becoming able to reproduce only as part of a larger whole. The authors investigate this pattern and why selection between entities at a lower level does not disrupt selection at more complex levels. Their explanation encompasses a compelling theory of the evolution of cooperation at all levels of complexity. Engagingly written and filled with numerous illustrations, this book can be read with enjoyment by anyone with an undergraduate training in biology. It is ideal for advanced discussion groups on evolution and includes accessible discussions of a wide range of topics, from molecular biology and linguistics to insect societies.

Oxford Studies in Medieval Philosophy Volume 7

2019 ◽  
Keyword(s):  
Late Antiquity ◽  
Full Range ◽  
Current Work ◽  
Medieval Philosophy ◽  
Original Essays ◽  
Wide Range ◽  
Extended Review

Oxford Studies in Medieval Philosophy annually collects the best current work in the field of medieval philosophy. The various volumes print original essays, reviews, critical discussions, and editions of texts. The aim is to contribute to an understanding of the full range of themes and problems in all aspects of the field, from late antiquity into the Renaissance, and extending over the Jewish, Islamic, and Christian traditions. Volume 6 includes work on a wide range of topics, including Davlat Dadikhuda on Avicenna, Christopher Martin on Abelard’s ontology, Jeremy Skrzypek and Gloria Frost on Aquinas’s ontology, Jean‐Luc Solère on instrumental causality, Peter John Hartman on Durand of St.‐Pourçain, and Kamil Majcherek on Chatton’s rejection of final causality. The volume also includes an extended review of Thomas Williams of a new book on Aquinas’s ethics by Colleen McCluskey.

scholarly journals A broadbanded pressure differential wave energy converter based on dielectric elastomer generators

2021 ◽  
Author(s):  
Michele Righi ◽  
Giacomo Moretti ◽  
David Forehand ◽  
Lorenzo Agostini ◽  
Rocco Vertechy ◽  
...  
Keyword(s):  
Wave Energy ◽  
Large Deformations ◽  
Dielectric Elastomer ◽  
Wave Energy Converter ◽  
Pressure Differential ◽  
Design Stage ◽  
Small Scale ◽  
Energy Converter ◽  
Wide Range ◽  
The Waves

AbstractDielectric elastomer generators (DEGs) are a promising option for the implementation of affordable and reliable sea wave energy converters (WECs), as they show considerable promise in replacing expensive and inefficient power take-off systems with cheap direct-drive generators. This paper introduces a concept of a pressure differential wave energy converter, equipped with a DEG power take-off operating in direct contact with sea water. The device consists of a closed submerged air chamber, with a fluid-directing duct and a deformable DEG power take-off mounted on its top surface. The DEG is cyclically deformed by wave-induced pressure, thus acting both as the power take-off and as a deformable interface with the waves. This layout allows the partial balancing of the stiffness due to the DEG’s elasticity with the negative hydrostatic stiffness contribution associated with the displacement of the water column on top of the DEG. This feature makes it possible to design devices in which the DEG exhibits large deformations over a wide range of excitation frequencies, potentially achieving large power capture in a wide range of sea states. We propose a modelling approach for the system that relies on potential-flow theory and electroelasticity theory. This model makes it possible to predict the system dynamic response in different operational conditions and it is computationally efficient to perform iterative and repeated simulations, which are required at the design stage of a new WEC. We performed tests on a small-scale prototype in a wave tank with the aim of investigating the fluid–structure interaction between the DEG membrane and the waves in dynamical conditions and validating the numerical model. The experimental results proved that the device exhibits large deformations of the DEG power take-off over a broad range of monochromatic and panchromatic sea states. The proposed model demonstrates good agreement with the experimental data, hence proving its suitability and effectiveness as a design and prediction tool.

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