scholarly journals The Synthesis of Function Generating Mechanisms for Periodic Curves Using Large Numbers of Double-Crank Linkages

2017 ◽  
Vol 9 (3) ◽  
Author(s):  
Hessein Ali ◽  
Andrew P. Murray ◽  
David H. Myszka
Keyword(s):  
Periodic Function ◽  
Synthesis Process ◽  
Connecting Rod ◽  
Large Numbers ◽  
Structural Error ◽  
Rigid Connection ◽  
Multiple Maxima ◽  
Planar Linkages ◽  
Drag Link ◽  
Crank Mechanism

This paper presents a methodology for synthesizing planar linkages to approximate any prescribed periodic function. The mechanisms selected for this task are the slider-crank and the geared five-bar with connecting rod and sliding output (GFBS), where any number of double-crank (or drag-link) four-bars are used as drivers. A slider-crank mechanism, when comparing the input crank rotation to the output slider displacement, produces a sinusoid-like function. Instead of directly driving the input crank, a drag-link four-bar may be added to drive the crank from its output via a rigid connection between the two. Driving the input of the added four-bar results in a function that modifies the sinusoid-like curve. This process can be continued through the addition of more drag-link mechanisms to the device, progressively altering the curve toward any periodic function with a single maximum. For periodic functions with multiple maxima, a GFBS is used as the terminal linkage added to the chain of drag-link mechanisms. The synthesis process starts by analyzing one period of the function to design either the terminal slider-crank or terminal GFBS. matlab's fmincon command is then utilized as the four-bars are added to reduce the structural error between the desired function and the input–output function of the mechanism. Mechanisms have been synthesized in this fashion to include a large number of links that are capable of closely producing functions with a variety of intriguing features.

Reducing Structural Error in Function Generating Mechanisms via the Addition of Large Numbers of Four-Bar Mechanisms

2015 ◽  
Author(s):  
Hessein Ali ◽  
Andrew P. Murray ◽  
David H. Myszka
Keyword(s):  
Periodic Function ◽  
Synthesis Process ◽  
Connecting Rod ◽  
Large Numbers ◽  
Structural Error ◽  
Rigid Connection ◽  
Multiple Maxima ◽  
Planar Linkages ◽  
Drag Link ◽  
Crank Mechanism

This paper presents a methodology for synthesizing planar linkages to approximate any prescribed periodic function. The mechanisms selected for this task are the slider-crank and the geared five-bar with connecting rod and sliding output (GFBS), where any number of drag-link (or double crank) four-bars are used as drivers. A slider-crank mechanism, when comparing the input crank rotation to the output slider displacement, produces a sinusoid-like function. Instead of directly driving the input crank, a drag-link four-bar may be added that drives the crank from its output via a rigid connection between the two. Driving the input of the added four-bar results in a function that is less sinusoid-like. This process can be continued through the addition of more drag-link mechanisms to the device, slowly altering the curve toward any periodic function with a single maximum. For periodic functions with multiple maxima, a GFBS is used as the terminal linkage added to the chain of drag-link mechanisms. The synthesis process starts by analyzing one period of the function to design either the terminal slider-crank or terminal GFBS. A randomized local search is then conducted as the four-bars are added to minimize the structural error between the desired function and the input-output function of the mechanism. Mechanisms have been “grown” in this fashion to dozens of links that are capable of closely producing functions with a variety of intriguing features.

scholarly journals REDUCING STRUCTURAL ERROR IN FUNCTION GENERATING MECHANISMS VIA THE ADDITION OF LARGE NUMBERS OF FOUR-BAR MECHANISMS

2017 ◽  
Author(s):  
Hessein
Keyword(s):  
Periodic Function ◽  
Synthesis Process ◽  
Periodic Functions ◽  
Connecting Rod ◽  
Large Numbers ◽  
Structural Error ◽  
Rigid Connection ◽  
Multiple Maxima ◽  
Drag Link ◽  
Crank Mechanism

This paper presents a methodology for synthesizing planarlinkages to approximate any prescribed periodic function. Themechanisms selected for this task are the slider-crank and thegeared five-bar with connecting rod and sliding output (GFBS),where any number of drag-link (or double crank) four-bars areused as drivers. A slider-crank mechanism, when comparing theinput crank rotation to the output slider displacement, producesa sinusoid-like function. Instead of directly driving the inputcrank, a drag-link four-bar may be added that drives the crankfrom its output via a rigid connection between the two. Drivingthe input of the added four-bar results in a function that is lesssinusoid-like. This process can be continued through the additionof more drag-link mechanisms to the device, slowly alteringthe curve toward any periodic function with a single maximum.For periodic functions with multiple maxima, a GFBS is usedas the terminal linkage added to the chain of drag-link mechanisms.The synthesis process starts by analyzing one period ofthe function to design either the terminal slider-crank or terminalGFBS. A randomized local search is then conducted as thefour-bars are added to minimize the structural error between thedesired function and the input-output function of the mechanism.Mechanisms have been “grown” in this fashion to dozens of linksthat are capable of closely producing functions with a variety ofintriguing features.

scholarly journals The Synthesis of Function Generating Mechanisms for Periodic Curves Using Large Numbers of Double-Crank Linkages

2017 ◽  
Author(s):  
Hessein
Keyword(s):  
Periodic Function ◽  
Periodic Functions ◽  
Connecting Rod ◽  
Large Numbers ◽  
Structural Error ◽  
Rigid Connection ◽  
Multiple Maxima ◽  
Planar Linkages ◽  
Drag Link ◽  
Crank Mechanism

This paper presents a methodology for synthesizing planar linkages to approximate anyprescribed periodic function. The mechanisms selected for this task are the slider-crankand the geared five-bar with connecting rod and sliding output (GFBS), where any numberof double-crank (or drag-link) four-bars are used as drivers. A slider-crank mechanism,when comparing the input crank rotation to the output slider displacement,produces a sinusoid-like function. Instead of directly driving the input crank, a drag-linkfour-bar may be added to drive the crank from its output via a rigid connection betweenthe two. Driving the input of the added four-bar results in a function that modifies thesinusoid-like curve. This process can be continued through the addition of moredrag-link mechanisms to the device, progressively altering the curve toward any periodicfunction with a single maximum. For periodic functions with multiple maxima, a GFBS isused as the terminal linkage added to the chain of drag-link mechanisms. The synthesisprocess starts by analyzing one period of the function to design either the terminal slidercrankor terminal GFBS. MATLAB’s fmincon command is then utilized as the four-bars areadded to reduce the structural error between the desired function and the input–outputfunction of the mechanism. Mechanisms have been synthesized in this fashion to includea large number of links that are capable of closely producing functions with a variety ofintriguing features

Dynamic stability analysis of linkages with elastic members via analog simulation

SIMULATION ◽  
1972 ◽  
Vol 18 (2) ◽  
pp. 67-74
Author(s):  
J.A. Seevers ◽  
A.T. Yang
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Flexural Vibration ◽  
Parabolic Partial Differential Equation ◽  
Speed Ratio ◽  
Connecting Rod ◽  
Analog Simulation ◽  
Modal Equation ◽  
Planar Linkages ◽  
Crank Mechanism

Small-amplitude flexural vibration of a slightly deformable binary link in a planar linkage is governed by a fourth-order parabolic partial differential equation. Specifically, for a slider- crank mechanism with an elastic connecting rod, stability charts are obtained via analog simulation on the basis of the principal modal equation of vibration. It is found that stability of the mechanism depends on three nondimensional parameters - length ratio, mass ratio, and rigidity-speed ratio. The procedure of dynamic stability analysis via analog simulation for the slider-crank may be applied to other planar linkages with elastic binary links.

Vibration Analysis of the Flexible Connecting Rod With the Breathing Crack in a Slider-Crank Mechanism

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Yan-Shin Shih ◽  
Chen-Yuan Chung
Keyword(s):  
Governing Equation ◽  
Moving Boundary ◽  
Beam Theory ◽  
Crack Model ◽  
Breathing Crack ◽  
Connecting Rod ◽  
Bernoulli Beam ◽  
The Galerkin Method ◽  
Euler Bernoulli Beam ◽  
Crank Mechanism

This paper investigates the dynamic response of the cracked and flexible connecting rod in a slider-crank mechanism. Using Euler–Bernoulli beam theory to model the connecting rod without a crack, the governing equation and boundary conditions of the rod's transverse vibration are derived through Hamilton's principle. The moving boundary constraint of the joint between the connecting rod and the slider is considered. After transforming variables and applying the Galerkin method, the governing equation without a crack is reduced to a time-dependent differential equation. After this, the stiffness without a crack is replaced by the stiffness with a crack in the equation. Then, the Runge–Kutta numerical method is applied to solve the transient amplitude of the cracked connecting rod. In addition, the breathing crack model is applied to discuss the behavior of vibration. The influence of cracks with different crack depths on natural frequencies and amplitudes is also discussed. The results of the proposed method agree with the experimental and numerical results available in the literature.

scholarly journals Design of a prototype of an engine mechanism with rotating cylinders

2020 ◽  
Vol 318 ◽  
pp. 01004
Author(s):  
Miroslav Blatnický ◽  
Ján Dižo
Keyword(s):  
High Speed ◽  
Cooling System ◽  
Ambient Air ◽  
Combustion Engines ◽  
Connecting Rod ◽  
Rotating Cylinders ◽  
Liquid Cooling ◽  
Working Cycle ◽  
Liquid Cooling System ◽  
Crank Mechanism

In this article, authors focus on the design and construction of a real prototype of an engine mechanism with rotating cylinders and its using mainly in piston combustion engines. It is assumed, that the normal force of a piston will be completely eliminated, because the swing angle of a connecting rod will equal to zero during the whole working cycle, since the connecting arm of the piston moves just the cylinder axis. It will by allowed by the conceptual design of the mechanism presented in this article. As rotating blocks of cylinders concurrently act as a flywheel, it is proposed, that in this way there is possible to save the mass of additional flywheels. Moreover, liquid cooling system is not necessary, because the rotating cylinders sufficiently transfer heat to ambient air. In addition, the output of torque will be reached without necessity of gear transmission, which results to decreasing of needs of mechanism lubrication. Other advance of the designed mechanism are two outputs. The first output is low-speed and it goes out from rotating cylinders, i. e. from the slider-crank mechanism with revolutions n1. The other output is high-speed, from the crankshaft with revolutions n2. Because of more favourable properties of the mechanism, authors have decided to create a real device to confirm all mentioned advantages of the mechanism by the suitable way.

Vibrations of Elastic Connecting Rod of a High-Speed Slider-Crank Mechanism

1971 ◽  
Vol 93 (2) ◽  
pp. 636-644 ◽  
Author(s):  
Peter W. Jasinski ◽  
Ho Chong Lee ◽  
George N. Sandor
Keyword(s):  
Small Parameter ◽  
High Speed ◽  
Elastic Stability ◽  
Method Of Averaging ◽  
Connecting Rod ◽  
Transverse Vibrations ◽  
Elastic Bar ◽  
The Moment ◽  
Steady State Solutions ◽  
Crank Mechanism

The research involved in this paper falls into the area of analytical vibrations applied to planar mechanical linkages. Specifically, a study of the vibrations, associated with an elastic connecting-bar for a high-speed slider-crank mechanism, is made. To simplify the mathematical analysis, the vibrations of an externally viscously damped uniform elastic connecting bar is taken to be hinged at each end (i.e., the moment and displacement are assumed to vanish at each end). The equations governing the vibrations of the elastic bar are derived, a small parameter is found, and the solution is developed as an asymptotic expansion in terms of this small parameter with the aid of the Krylov-Bogoliubov method of averaging. The elastic stability is studied and the steady-state solutions for both the longitudinal and transverse vibrations are found.

Balancing the Moments of a VR5 Engine Taking into Account a Desaxial Crank Mechanism and Cylinder Camber Angle

2020 ◽  
pp. 41-49
Author(s):  
N.D. Chainov ◽  
P.R. Vallejo Maldonado
Keyword(s):  
Relative Displacement ◽  
Working Fluid ◽  
Inertial Forces ◽  
Structural Elements ◽  
Connecting Rod ◽  
Cylinder Axis ◽  
Acoustic Characteristics ◽  
Camber Angle ◽  
Inertia Forces ◽  
Crank Mechanism

Automobile piston engines with a desaxial crank mechanism are characterized by increased vibration activity associated with a cyclic change in the pressure of the working fluid in the cylinders and inertial forces associated with the reciprocating and rotational movement of the crank mechanism moving masses. Properties reflecting the consumer properties of the engine, including acoustic characteristics, are largely determined by the level of vibration of the structural elements of the desaxial crank mechanism and, first of all, by the balance of inertial forces during operation. The article discusses balancing of five-cylinder four-stroke VR type engines with a desaxial crank mechanism and uniform flash alternation. The authors introduce formulas that can be used to determine and analyze moments of the inertia forces of the reciprocating and rotating masses arising in VR5 engines at the set values of the cylinder camber angle, the ratio of the crank radius to the connecting rod length and the relative displacement of the cylinder axis. A method of balancing the moments of inertia forces of the reciprocating and rotating masses is proposed.

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