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.

Stability and Steady-State Vibrations in a High-Speed Slider-Crank Mechanism

1970 ◽  
Vol 37 (4) ◽  
pp. 1069-1076 ◽  
Author(s):  
P. W. Jasinski ◽  
H. C. Lee ◽  
G. N. Sandor
Keyword(s):  
Steady State ◽  
Small Parameter ◽  
High Speed ◽  
Analytical Study ◽  
Elastic Stability ◽  
Connecting Rod ◽  
Concentrated Mass ◽  
Transverse Vibrations ◽  
Steady State Solutions ◽  
Crank Mechanism

The research presented in this paper is an analytical study of the vibrations associated with planar mechanical linkages. Specifically, the vibrations of a high-speed slider-crank mechanism with a uniform elastic connecting rod and a rigid crank are studied. The elastic connecting rod, with distributed mass, is taken to be externally, viscously damped with a concentrated mass present at its sliding end. The equations governing the longitudinal and transverse vibrations of the elastic connecting rod 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 of the connecting rod are obtained.

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.

A Variational Principle for the Hygrothermoelastodynamic Analysis of Mechanism Systems

1987 ◽  
Vol 109 (3) ◽  
pp. 294-300 ◽  
Author(s):  
C. K. Sung ◽  
B. S. Thompson
Keyword(s):  
High Speed ◽  
High Performance ◽  
Fibrous Composite ◽  
Equations Of Motion ◽  
Problem Definition ◽  
Theoretical Development ◽  
Connecting Rod ◽  
Rigid Body Motions ◽  
Crank Mechanism ◽  
Approximate Equations

A variational theorem is presented that may be employed for systematically establishing the equations governing the dynamic response of flexible planar linkage mechanisms simultaneously subjected to both mechanical and hygrothermal loadings. This theoretical development is motivated by recent research advocating that high-speed mechanisms should be fabricated in polymeric fibrous composite materials in order to achieve high-performance characteristics. The constitutive behavior of some of these materials is, however, dependent upon the ambient environmental conditions, and hence mathematical models must be developed in order to predict the response of mechanism systems fabricated with these materials. This class of mechanism systems is modeled herein as a set of continua in which elastic deformations are superimposed upon gross rigid-body motions. By permitting arbitrary independent variations of the system parameters for each link, approximate equations of motion, energy balance, mass balance, and boundary conditions may be systematically constructed. As an illustrative example, the derivation of a problem definition for the flexible connecting-rod of a slider-crank mechanism subjected to hygrothermal loading is presented.

Dynamic Response of a High-Speed Slider-Crank Mechanism With an Elastic Connecting Rod

1975 ◽  
Vol 97 (2) ◽  
pp. 542-550 ◽  
Author(s):  
S.-C. Chu ◽  
K. C. Pan
Keyword(s):  
Partial Differential Equations ◽  
Differential Equations ◽  
Dynamic Response ◽  
Ordinary Differential Equations ◽  
High Speed ◽  
Polynomial Method ◽  
Connecting Rod ◽  
Partial Differential ◽  
Weighted Residuals ◽  
Crank Mechanism

To achieve the performance of a mechanism to a higher degree of accuracy requires that the elastic deformations of a member in a mechanism under dynamic loading conditions be taken into account. Coupled nonlinear governing partial differential equations have been derived for transverse and longitudinal vibrations of an elastic connecting rod in a slider-crank mechanism operating at high speed conditions. The derived coupled governing nonlinear partial differential equations of motion were transformed into ordinary differential equations by use of the Kantorovich method and the method of weighted residuals. The resulting coupled ordinary differential equations were solved numerically by use of the piecewise polynomial method and the fourth-order Runge-Kutta method. The dynamic response of the system has been investigated on the basis of natural frequencies of the first mode free vibrations, the ratios of the length of crank to the length of connecting rod, viscous damping, and rotating speeds of crank. These parameters can be used by the designer to predict the vibrations of an elastic mechanism under high-speed conditions.

Aspects Concerning the Dynamics of the Mechanisms with Clearances

2013 ◽  
Vol 837 ◽  
pp. 411-415
Author(s):  
Jan Cristian Grigore
Keyword(s):  
Reaction Force ◽  
Recovery Phase ◽  
Initial Position ◽  
Normal Reaction ◽  
Connecting Rod ◽  
Flight Phase ◽  
Clearance Mechanism ◽  
Distance Difference ◽  
The Moment ◽  
Crank Mechanism

The clearances in the cinematic links appear due to the long functioning. In the paper we shall make a few considerations of geometric and mechanic type about the clearances in the linkages, linkages planes with rotation joint links. We shall elaborate methods to study the influence of the clearances. Consider a rotational kinematic coupling clearance, the clearance being defined by the distance, difference between the radius of the bearing and the radius of the journal. This relationship between elements is unilateral. Journal's behaviour inside the bearing can be highlighted the value normal reaction force. The journal can have the following phases, phase contact (when there is contact between the bearing and journal, the normal reaction force is zero) flight phase (no contact between end journal bearing at this stage is normal reaction force 0). It is considered the most dangerous phase, recovery phase of flight phase where the contact is restored. In this phase occurs shocks, shocks in turn produce vibration in the mechanism leading to the destruction of the system. The clearance size is directly proportional to magnitude impact and vibration level especially high. To be reduced or even eliminated these shocks, the paper presents a solution. Crank Mechanism with clearance, mechanism considered in this paper applies a force so that maintain contact between the bearing and journal, is considered the center of gravity of the connecting rod the forces and the moment. Based on the relations obtained from equation echililibru and vector equation of the contour goes to the numerical calculation for the engine element is inserted angle value (which defines the initial position of the mechanism), one deduces the angles, which define the position of the mechanism. Any would be their source of appearance, they usually produce unwished effects during the mechanisms functioning.

Analysis of the Lubrication Regimes at the Small End and Big End of a Connecting Rod of a High Performance Motorbike Engine

2012 ◽  
Author(s):  
Luca Bertocchi ◽  
Matteo Giacopini ◽  
Daniele Dini
Keyword(s):  
Rotational Speed ◽  
High Speed ◽  
High Performance ◽  
Hydrodynamic Lubrication ◽  
Vertical Axis ◽  
Connecting Rod ◽  
Lubrication Regimes ◽  
High Speed Rotation ◽  
Speed Rotation ◽  
Squeeze Effect

In the present paper, the algorithm proposed by Giacopini et. al. [1], based on a mass-conserving formulation of the Reynolds equation using the concept of complementarity is suitably extended to include the effects of compressibility, piezoviscosity and shear-thinning on the lubricant properties. This improved algorithm is employed to analyse the performance of the lubricated small end and big end bearings of a connecting rod of a high performance motorbike engine. The application of the algorithm proposed to both the small end and the big end of a con-rod is challenging because of the different causes that sustain the hydrodynamic lubrication in the two cases. In the con-rod big end, the fluid film is mainly generated by the relative high speed rotation between the rod and the crankshaft. The relative speed between the two races forms a wedge of fluid that assures appropriate lubrication and avoids undesired direct contacts. On the contrary, at the con-rod small end the relative rotational speed is low and a complete rotation between the mating surfaces does not occurs since the con-rod only oscillates around its vertical axis. Thus, at every revolution of the crankshaft, there are two different moments in which the relative rotational speed between the con-rod and the piston pin is null. Therefore, the dominant effect in the lubrication is the squeeze caused by the high loads transmitted through the piston pin. In particular both combustion forces and inertial forces contribute to the squeeze effect. This work shows how the formulation developed by the authors is capable of predicting the performance of journal bearings in the unsteady regime, where cavitation and reformation occur several times. Moreover, the effects of the pressure and the shear rate on the density and on the viscosity of the lubricant are taken into account.

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 Damping of vertical and horizontal transverse vibrations in the bridge span structures

2018 ◽  
Vol 216 ◽  
pp. 01015
Author(s):  
Darya Provornaya ◽  
Sergey Glushkov ◽  
Leonid Solovyev
Keyword(s):  
High Speed ◽  
Vibration Isolation ◽  
Seismic Protection ◽  
Rolling Stock ◽  
Railway Bridge ◽  
Vibration Damper ◽  
Dynamic Vibration ◽  
Bridge Span ◽  
Transverse Vibrations ◽  
Dynamic Damping

The paper considers the issues of vibration isolation of railway bridge units on high-speed lines and seismic protection using dynamic vibration dampers. The purpose of the research is to justify the efficiency of damping the dynamic vibrations of the bridge supports with seismic insulating support parts. The research methodology involves building mathematical models of the systems under consideration and their numerical analysis. The methods of structural mechanics and dynamics of structures were used for solving the assigned tasks. The basic mathematical dependences of the vibration system with two seismic masses were developed. The rolling stock was represented by concentrated forces moving along the span structure. As a result, a new scheme for dynamic damping of vibration of the bridge supports was proposed according to which the span structure used as the dynamic vibration damper has an additional fastening on a rigid abutment.

Circuit Breaker Mechanical Characteristic Parameters Measurement Based on Machine Vision

2014 ◽  
Vol 687-691 ◽  
pp. 934-937
Author(s):  
Shu Tao Zhao ◽  
Yu Tao Xu ◽  
Zhi Wan Cheng ◽  
Jian Feng Ren ◽  
Dan Jiang
Keyword(s):  
Mechanical Characteristic ◽  
Template Matching ◽  
High Speed ◽  
Circuit Breaker ◽  
Motion Pictures ◽  
Time Interval ◽  
Connecting Rod ◽  
Characteristic Parameters ◽  
Coordinate Changes ◽  
Parameters Measurement

Aim at the disadvantages of traditional circuit breaker mechanical characteristic parameters test. Get the motion pictures of insulation connecting rod through high-speed camera, using the finite difference method to quickly screen out the motion pictures, and selecting punctuation area as a template for learning, using non-uniform sampling have a template matching, obtain the center coordinates of matching results, time interval is known every frame. Through coordinate changes over time we can obtain mechanical parameters of the circuit breaker accurately, fast, conveniently. Lab VIEW programs achieve the above process automatically.

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