Kinematic Synthesis of Spherical Two-Gear Drives With Prescribed Entire-Motion Characteristics: Unlimited Crank Rotations and Optimum Transmission. Part 2: Applications

1986 ◽  
Vol 108 (1) ◽  
pp. 53-59 ◽  
Author(s):  
T. W. Lee ◽  
E. Akbil
Keyword(s):  
Design Procedure ◽  
Companion Paper ◽  
Analytical Investigation ◽  
Design Guidelines ◽  
Kinematic Synthesis ◽  
Computer Aided Analysis ◽  
Transmission Part ◽  
Motion Characteristics ◽  
Gear Drives ◽  
Insight Into

The theory developed in Part 1 [1] as well as in a companion paper [2] has been applied to the kinematic synthesis of a special class of spherical two-gear drives, including the Rotary Step Mechanism, with prescribed entire-motion characteristics. Insight into the behavior of such mechanisms can be interpreted through the results of an analytical investigation of mechanism characteristics. A useful design procedure, a design table, and a set of design guidelines are presented. Examples are given to illustrate both the analytical synthesis and the computer-aided analysis procedures.

Kinematic Synthesis of Spherical Two-Gear Drives With Prescribed Entire-Motion Characteristics: Unlimited Crank Rotations and Optimum Transmission. Part 1: Theory

1986 ◽  
Vol 108 (1) ◽  
pp. 46-52 ◽  
Author(s):  
T. W. Lee ◽  
E. Akbil
Keyword(s):  
Rational Design ◽  
Transmission Characteristics ◽  
Kinematic Synthesis ◽  
Input And Output ◽  
Special Cases ◽  
Transmission Part ◽  
Motion Characteristics ◽  
Gear Drives ◽  
Algebraic Solutions

This investigation is concerned with the determination of the rotatability of the input and output cranks and the optimization of transmission characteristics of spherical two-gear drives. Algebraic solutions are shown to be feasible only in a few special cases. In general, numerical synthesis procedures, involving either optimization or parameter scanning processes, are essential and they are developed from the general theory presented in this paper. The results, including conditions that can be regarded as an extension of the Grashof’s rule to the class of spherical geared mechanisms, are useful for the rational design of mechanisms. Applications of the theory to practical mechanisms design are given in Part 2.

Kinematic Synthesis of Spherical Two-Gear Drives With Prescribed Entire-Motion Characteristics: Displacement Analysis and Dwell Characteristics

1983 ◽  
Vol 105 (4) ◽  
pp. 663-671 ◽  
Author(s):  
T. W. Lee ◽  
E. Akbil
Keyword(s):  
Kinematic Synthesis ◽  
Displacement Analysis ◽  
Gear Drive ◽  
Transmission Angle ◽  
Computer Aided ◽  
Displacement Equation ◽  
Synthesis Procedure ◽  
Motion Characteristics ◽  
Joint Consideration ◽  
Gear Drives

This paper presents an analytical and computer-aided procedure on the kinematic synthesis of the spherical two-gear drive with prescribed dwell characteristics. The first part gives a displacement analysis which includes an investigation of the general case of spherical five-link, 5R mechanisms and the spherical geared five-link case. Two approaches, one making use of the spherical trigonometric relations and the other involving sequential coordinate transformations by real and orthogonal [3 × 3] matrices, yield identical input-output expressions. The remainder of the paper focuses on the dwell characteristics of the spherical two-gear drive using algebraic methods based on the displacement equation. Dwell criteria for the general mth-order dwell are derived. A specific example which involves a joint consideration of other entire-motion characteristics, such as limit positions and transmission-angle variations, is given to illustrate both the theory as well as the computer-aided synthesis procedure.

Kinematic Synthesis of Planar Two-Gear Drives With Prescribed Dwell Characteristics

1982 ◽  
Vol 104 (4) ◽  
pp. 687-697
Author(s):  
T. W. Lee ◽  
Y. Shereshevsky
Keyword(s):  
Velocity Fluctuation ◽  
Kinematic Synthesis ◽  
Numerical Examples ◽  
Design Chart ◽  
Gear Drive ◽  
Computer Aided ◽  
Motion Characteristics ◽  
Gear Drives ◽  
Four Bar Linkage ◽  
Analysis Of Motion

This paper presents an analytical and computer-aided procedure on the kinematic synthesis of the planar two-gear drive. The drive is designed as a reversing mechanism and as a nonreversing mechanism either with or without dwell. Dwell characteristics of the mechanism are investigated using algebraic methods. It is found that the problem relates closely to the velocity-fluctuation of the four-bar linkage. Both general and specific dwell criteria are derived. An efficient computer-aided procedure can be used for the analysis of motion characteristics and for the development of a design chart. Numerical examples illustrate both analytical as well as graphical synthesis procedures.

Kinematic Geometry of Wheeled Vehicle Systems

1996 ◽  
Author(s):  
S. V. Sreenivasan ◽  
P. Nanua
Keyword(s):  
Geometric Approach ◽  
Companion Paper ◽  
Kinematic Chains ◽  
Uneven Terrain ◽  
Geometric Conditions ◽  
Kinematic Study ◽  
Vehicle Systems ◽  
Motion Characteristics ◽  
The One ◽  
Wheeled Vehicles

Abstract This paper addresses instantaneous motion characteristics of wheeled vehicles systems on even and uneven terrain. A thorough kinematic geometric approach which utilizes screw system theory is used to investigate vehicle-terrain combinations as spatial mechanisms that possess multiple closed kinematic chains. It is shown that if the vehicle-terrain combination satisfies certain geometric conditions, for instance when the vehicle operates on even terrain, the system becomes singular or non-Kutzbachian — it possesses finite range mobility that is different from the one obtained using Kutzbach criterion. An application of this geometric approach to the study of rate kinematics of various classes of wheeled vehicles is also included. This approach provides an integrated framework to study the kinematic effects of varying the vehicle and/or terrain geometric parameters from their nominal values. In addition, design enhancements of existing vehicles are suggested using this approach. This kinematic study is closely related to the force distribution characteristics of wheeled vehicles which is the subject of the companion paper [SN96].

scholarly journals Some Extended Results on the Design of Punctured Serially Concatenated Convolutional Codes

2017 ◽  
Vol 2 (3) ◽  
pp. 235
Author(s):  
Massimiliano Laddomada ◽  
Bartolo Scanavino
Keyword(s):  
Error Probability ◽  
Selection Criteria ◽  
Convolutional Codes ◽  
Companion Paper ◽  
Design Guidelines ◽  
Effective Algorithm ◽  
Signal To Noise ◽  
Convolutional Encoders ◽  
Simulation Results ◽  
Serially Concatenated

The aim of this paper is twofold. On one hand, it presents the results of the search for good punctured systematicrecursive convolutional encoders suitable for application in serially concatenated convolutional codes (SCCCs) operating in two different target regions: at low-to moderate signal-to-noise ratios (SNRs), i.e., in the so called waterfall region, and at high SNRs. On the other hand, it provides some useful design guidelines for choosing the constituent encoders in an SCCC. The results of the search for good SCCCs operating in the waterfall region rely upon an effective algorithm, based on density evolution technique, first proposed in a companion paper. Good punctured SCCCs were obtained through considerationsdeduced by the behaviour of the bit error probability of an SCCC for high values of both SNR and interleaver length, i.e., through asymptotic considerations. The mother codes in the serial concatenation are rate 1/2 recursive convolutional encoders (RCC) found by an exhaustive search for encoders tailored to SCCC schemes, using two different selection criteria. Extensive tables of optimized puncturing patterns for various mother codes and SCCCs are presented along with sample simulation results.

On the Motion Characteristics of Tripode Joints. Part 1: General Case

1984 ◽  
Vol 106 (2) ◽  
pp. 228-234 ◽  
Author(s):  
E. Akbil ◽  
T. W. Lee
Keyword(s):  
Constant Velocity ◽  
Analytical Study ◽  
Orbital Motion ◽  
Analytical Investigation ◽  
Rigorous Proof ◽  
Input Output ◽  
Arbitrary Position ◽  
Motion Parameters ◽  
Motion Characteristics ◽  
Output Equation

This paper is concerned with the analytical investigation of the motion characteristics of tripode joints with general proportions and arbitrary position of shafts. It provides a rigorous proof that the tripode joint is not a true constant velocity joint except in ideal cases, and this is due to the inherent orbital motion of the output spider shaft. Algebraic derivations of the input-output equation and explicit relations for motion parameters are presented. From this general analytical study, some insights into the behavior of the tripode joint are observed and interpreted.

Development of Structural Design Guidelines for Porous Asphalt Pavement

2018 ◽  
Vol 2672 (40) ◽  
pp. 197-206 ◽  
Author(s):  
Kevin D. Hall ◽  
Charles W. Schwartz
Keyword(s):  
Structural Design ◽  
Design Procedure ◽  
Field Performance ◽  
Design Guidelines ◽  
Empirical Approach ◽  
Asphalt Pavements ◽  
Design Parameters ◽  
Extensive Literature ◽  
Porous Asphalt ◽  
Design Procedures

Porous asphalt pavements allow designers to introduce more sustainability into projects and lessen their environmental impact. Current design procedures are based primarily on hydrologic considerations; comparatively little attention has been paid to their structural design aspects. As their use grows, a design procedure and representative material structural properties are needed to ensure that porous pavements do not deteriorate excessively under traffic loads. The objective of this project was to develop a simple, easy to apply design procedure for the structural design of porous asphalt pavements. Two methodologies were considered for such a structural design procedure: ( a) the 1993 AASHTO Pavement Design Guide empirical approach, and ( b) the mechanistic–empirical approach employed by the AASHTOWare Pavement ME Design software. A multifactor evaluation indicated the empirical 1993 AASHTO design procedure to be the most appropriate platform at this time. It is noted, however, that both design procedures lack validation of porous asphalt pavements against field performance. AASHTO design parameters and associated material characteristics are recommended, based on an extensive literature review. For “thin” open-graded base structures (12 in. or less), the AASHTO procedure is performed as published in the 1993 Guide. For “thick” base structures (>12 in.), the base/subgrade combination is considered a composite system which supports the porous asphalt layer; an equivalent deflection-based approach is described to estimate the composite resilient modulus of the foundation system, prior to applying the 1993 AASHTO design procedure.

Frequency Window Method for Strongly Coupled and Multiply Connected Structural Systems: Multiple-Mode Windows

1992 ◽  
Vol 59 (2S) ◽  
pp. S244-S252 ◽  
Author(s):  
K.-W. Min ◽  
T. Igusa ◽  
J. D. Achenbach
Keyword(s):  
Companion Paper ◽  
Structural System ◽  
Strongly Coupled ◽  
Multiply Connected ◽  
Multiple Mode ◽  
Window Method ◽  
Frequency Window ◽  
Rational Expressions ◽  
Insight Into ◽  
Reduced Problem

In a companion paper, a method is presented to analyze the dynamic behavior of a structural system consisting of a main structure and strongly coupled, multiply connected substructures. Lagrange’s equations are used to develop a characteristic equation for connected substructures in terms of substructure impedances and mobilities. A frequency window method is used to reduce the complexity of the problem by a decomposition of the impedance and mobility functions into dominant and higher-order rational expressions. From the reduced problem, simple expressions for the modal properties are developed using matrix algebraic methods, which provide insight into the resonance characteristics of the connected substructures. Onemode windows were discussed in detail and examples were presented. In the present paper the theory is extended to multiple-mode windows.

Simplified Design of Combustion Chamber for Small Gas Turbine Applications

2005 ◽  
Author(s):  
Digvijay B. Kulshreshtha ◽  
S. A. Channiwala
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Design Procedure ◽  
Design Guidelines ◽  
Radial Temperature ◽  
Turbine Engine ◽  
Design Methodologies ◽  
Critical Components ◽  
Discrete Manner ◽  
Centerline Temperature

The combustion chamber of gas turbine unit is one of the most critical components to be designed. Scanning through literature reveals that the design methodologies for combustion chamber are available in a discrete manner and there exist a need to compile this information and evolve a systematic design procedure for combustion chamber. The present paper is an attempt towards presenting such a complete design methodology of combustion chamber for small gas turbine applications. The combustion chamber for the 20 kW gas turbine engine has been designed and fabricated as per these summarized design guidelines then checked for the axial and radial temperature profiles as well as liner wall temperatures, experimentally. The liner wall temperatures achieved is in the vicinity of 300°C when centerline temperature is of the order of 1300°C. This adequately validates the design methodologies proposed in this paper.

The Use of TPMC for Designing MRFs Equipped with FREEDAM Connections: Performance Evaluation

2018 ◽  
Vol 763 ◽  
pp. 983-991 ◽  
Author(s):  
Rosario Montuori ◽  
Elide Nastri ◽  
Vincenzo Piluso ◽  
Simona Streppone
Keyword(s):  
Performance Evaluation ◽  
Dynamic Analysis ◽  
Design Procedure ◽  
Incremental Dynamic Analysis ◽  
Companion Paper ◽  
Collapse Mechanism ◽  
The Real ◽  
Interstorey Drift ◽  
Global Type ◽  
Steel Mrfs

The work herein presented is devoted to the validation of TPMC design procedure applied to steel MRFs equipped with FREEDAM dampers located at beam-to-column joints. The seismic performances evaluations of the designed structure have been carried out by means of both Push-over analysis and Incremental Dynamic Analysis. In particular, the Push-over analysis aims to confirm the real development of a collapse mechanism of global type, while, through IDA analysis, Maximum Interstorey Drift and Top Residual Displacement performed by the designed structures have been pointed out. For this reason, a MRF whose design procedure by TPMC is detailed in a companion paper has been subjected to both push-over and IDA analysis.

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