The influence of the links lengths of the four-bar linkage on the dwell angle, the reverse rotation angle and relative displacement of the links associated by the elastic element in the dwell period of the output link

2021 ◽  
Author(s):  
T. A. Balabina ◽  
M. Yu. Karelina ◽  
A. N. Mamaev
Keyword(s):  
Elastic Element ◽  
Rotation Angle ◽  
Relative Displacement ◽  
Output Link ◽  
Four Bar Linkage ◽  
Dwell Period

THE INFLUENCE OF THE LENGTHS OF THE LINKS OF THE HINGED FOUR-LINK ON THE ANGLE OF HEIGHT, RETURN ANGLE AND RELATIVE DISPLACEMENT OF LINKS CONNECTED BY THE ELASTIC ELEMENT DURING THE OUTPUT LINK STABILITY

2020 ◽  
Author(s):  
Tat'yana Balabina ◽  
Mariya Karelina ◽  
Aleksey Mamaev
Keyword(s):  
Elastic Element ◽  
Variable Structure ◽  
Relative Displacement ◽  
Technological Equipment ◽  
Output Link ◽  
Periodic Rotation ◽  
Link Stability ◽  
Wide Possibility ◽  
The One ◽  
Automatic Action

Toothed-lever and cam-toothed-lever mechanisms are widely used in technological equipment of automatic and semi-automatic action to convert the one-way rotational motion of the input link into one-way rotary motion of the output link with periodic stops. To ensure periodic rotation with a precise fixed length, an elastic element with a preload of two-sided action is introduced into the mechanism, as a result of which the mechanism has a variable structure. Compared to other mechanisms of periodic rotation, in gear-link mechanisms there is a wide possibility of influencing the function of the position of the output link, the angle of reverse rotation and the relative displacements of the links connected to each other by an elastic element by changing the lengths of the links of the basic hinged four-link

scholarly journals About the weight and size parameters of electromagnetic stiffness correctors

2021 ◽  
Vol 2131 (5) ◽  
pp. 052003
Author(s):  
V Y Gross ◽  
A V Zharov ◽  
A M Baranovskiy ◽  
S N Reutov
Keyword(s):  
Relative Position ◽  
Elastic Element ◽  
Relative Displacement ◽  
Negative Stiffness ◽  
Stiffness Coefficient ◽  
Power Characteristic ◽  
Negative Coefficient ◽  
Static Stiffness ◽  
Vibration Isolators ◽  
Mathematical Expressions

Abstract A significant reduction in the levels of general ship vibrations can be achieved by using vibration isolators with a “floating” section of zero stiffness in vibration protection suspensions. In such devices, in parallel to the main elastic element, the so-called stiffness corrector (compensator) is switched on - a device with a negative coefficient of static stiffness, equipped with a restructuring system that ensures the retention of the corrector elements when the relative position of the vibrating and protected objects, caused by a change in static forces acting on these objects. One of the variants of the corrector is an electromagnetic stiffness corrector, in which the power characteristic with a negative stiffness coefficient is provided by two electromagnets with a common armature turned on in opposite directions. The disadvantage of such correctors is the dependence of their overall dimensions on the value of the permissible relative displacement of the vibrating and protected objects. The article deduced mathematical expressions that approximately determine the dependence of the overall dimensions of the stiffness corrector electromagnets on the value of the calculated relative displacement of the vibrating and protected objects, the possible field of application of vibration isolators Xwith electromagnetic stiffness correctors is determined.

Approximate Kinematic Equations for Multiple-Input Small-Crank Mechanisms: Four-Bar Based Mechanisms

1994 ◽  
Author(s):  
Kambiz Farhang ◽  
Partha S. Basu
Keyword(s):  
Output Link ◽  
Recursive Procedure ◽  
Recursive Formulation ◽  
Constraint Equations ◽  
Multiple Input ◽  
N Input ◽  
The Mean ◽  
Recursive Equations ◽  
Four Bar Linkage ◽  
Input Mechanism

Abstract Approximate kinematic equations are developed for multiple-input small-crank mechanisms derived from a basic planar four-bar linkage. Application of a method in which an output link is presumed to comprise a mean and a perturbational motions, the vector loop approach, and a recursive formulation facilitates derivation of the approximate kinematic equations. For a general n-input mechanism, two sets of constraint equations are established: a set of nonlinear recursive equations relating the mean link orientations and a set of linear recursive equations for the purturbational motions. The recursive procedure is demonstrated by developing approximate kinematic equations for four-bar based two-, three- and four-input small-crank mechanisms.

A Systematic Method for Kinematics Synthesis of High-Speed Mechanisms With Optimally Integrated Smart Materials

2000 ◽  
Author(s):  
J. Rastegar ◽  
L. Yuan
Keyword(s):  
Smart Materials ◽  
High Speed ◽  
Vibrational Excitation ◽  
High Harmonic ◽  
Harmonic Component ◽  
Linkage Mechanism ◽  
Output Link ◽  
Mechanism Synthesis ◽  
Systematic Method ◽  
Four Bar Linkage

Abstract A systematic method is presented for kinematics synthesis of high-speed mechanisms with optimally integrated smart materials based actuators for the purpose of modifying the output link motion. As an example, the method is applied to a four-bar linkage mechanism that is synthesized for function generation to eliminate the high harmonic component of the output link motion. For mechanisms with rigid links, the high harmonic motions are generated due to the nonlinearity of the kinematics of their closed-loop chains. By eliminating the high harmonic component of the output motion, the potential vibrational excitation that the mechanism can impart on the overall system and its own structure is greatly reduced. The resulting system should therefore be capable of operating at higher speeds with increased precision. A numerical example is provided together with a discussion of the application of the method to other mechanism synthesis problems and some related topics of interest.

A Systematic Method for Kinematics Synthesis of High-Speed Mechanisms With Optimally Integrated Smart Materials

2000 ◽  
Vol 124 (1) ◽  
pp. 14-20 ◽  
Author(s):  
J. Rastegar ◽  
L. Yuan
Keyword(s):  
Smart Materials ◽  
High Speed ◽  
Vibrational Excitation ◽  
High Harmonic ◽  
Harmonic Component ◽  
Linkage Mechanism ◽  
Output Link ◽  
Mechanism Synthesis ◽  
Systematic Method ◽  
Four Bar Linkage

A systematic method is presented for kinematics synthesis of high-speed mechanisms with optimally integrated smart materials based actuators for the purpose of modifying the output link motion. As an example, the method is applied to a four-bar linkage mechanism that is synthesized for function generation to eliminate the high harmonic component of the output link motion. For mechanisms with rigid links, the high harmonic motions are generated due to the nonlinearity of the kinematics of their closed-loop chains. By eliminating the high harmonic component of the output motion, the potential vibrational excitation that the mechanism can impart on the overall system and its own structure is greatly reduced. The resulting system should therefore be capable of operating at higher speeds and with greater precision. A numerical example is provided together with a discussion of the application of the method to other mechanism synthesis problems and some related topics of interest.

Numerical Analysis on Anti-Seismic Dynamic Response of Rectangular Caisson Foundation

2014 ◽  
Vol 1030-1032 ◽  
pp. 811-814
Author(s):  
Lin Wang ◽  
Guo Jian Shao ◽  
Feng Hu
Keyword(s):  
Dynamic Response ◽  
Seismic Waves ◽  
Rotation Angle ◽  
Soil Layer ◽  
Time History ◽  
Relative Displacement ◽  
Calculation Model ◽  
Future Research ◽  
Key Points ◽  
Set Up

Based on the software FLAC3D, we set up the dynamic calculation model. By applying the horizontal (x direction) seismic waves at the bottom of the model, we simulate the earthquake action to the caisson foundation and the soil body around it and obtain the time-history curves of the acceleration, the velocity and the displacement of the key points in the model in x direction. We also obtain the rotation angle time-history curve and the relative displacement time-history curve of two key points at the bottom of the caisson foundation. Through the analysis on these curves, we know the maximum values of the acceleration, the velocity and the displacement of the top portion of the caisson foundation are 393.6 cm/s2, 75.9 cm/s, 28.5 cm, and the maximum rotation angle of the caisson foundation is 0.08°. We sure the bond of the caisson foundation bottom and the below soil layer is firm and the relative displacement is only 1.3 mm. Looked from the overall,the anti-seismic property of the caisson foundation is good. The above results provide a reliable basis for the future research on the dynamic response of caisson foundation.

Design of Drag-Link Mechanisms With Optimum Transmission Angle

1983 ◽  
Vol 105 (2) ◽  
pp. 254-258 ◽  
Author(s):  
Lung-Wen Tsai
Keyword(s):  
Extreme Values ◽  
Angular Displacement ◽  
Output Link ◽  
Link Length ◽  
Design Charts ◽  
Link Mechanism ◽  
Transmission Angle ◽  
New Criterion ◽  
Four Bar Linkage ◽  
Drag Link

In this paper, a new criterion for the design of a drag-link mechanism with optimum transmission angle is established. The transmission angle, the angle between the coupler link and output link of a four-bar linkage, is considered to be optimized when its extreme values deviate equally from 90 deg. Based on this criterion, design equations and design charts are developed. It is shown that the optimum drag-link mechanism is a turning-block linkage. It is also shown that to displace the drag-link mechanism with optimum transmission angle from its minimum lag to its maximum lag position, the input link must always rotate 180 deg and the corresponding angular displacement of the output link depends only on the link-length ratio of the output link to the fixed-link.

scholarly journals Mechanical sensitivity and the dynamics of evolutionary rate shifts in biomechanical systems

2017 ◽  
Vol 284 (1847) ◽  
pp. 20162325 ◽  
Author(s):  
Martha M. Muñoz ◽  
Philip S. L. Anderson ◽  
S. N. Patek
Keyword(s):  
Evolutionary Dynamics ◽  
Evolutionary Rate ◽  
Morphological Evolution ◽  
Evolutionary Rates ◽  
Mechanical Sensitivity ◽  
Output Link ◽  
Rates Of Evolution ◽  
Highly Sensitive ◽  
Four Bar Linkage ◽  
Raptorial Appendage

The influence of biophysical relationships on rates of morphological evolution is a cornerstone of evolutionary theory. Mechanical sensitivity—the correlation strength between mechanical output and the system's underlying morphological components—is thought to impact the evolutionary dynamics of form–function relationships, yet has rarely been examined. Here, we compare the evolutionary rates of the mechanical components of the four-bar linkage system in the raptorial appendage of mantis shrimp (Order Stomatopoda). This system's mechanical output (kinematic transmission (KT)) is highly sensitive to variation in its output link, and less sensitive to its input and coupler links. We found that differential mechanical sensitivity is associated with variation in evolutionary rate: KT and the output link exhibit faster rates of evolution than the input and coupler links to which KT is less sensitive. Furthermore, for KT and, to a lesser extent, the output link, rates of evolution were faster in ‘spearing’ stomatopods than ‘smashers’, indicating that mechanical sensitivity may influence trait-dependent diversification. Our results suggest that mechanical sensitivity can impact morphological evolution and guide the process of phenotypic diversification. The connection between mechanical sensitivity and evolutionary rates provides a window into the interaction between physical rules and the evolutionary dynamics of morphological diversification.

Structure and migration of planar defects in crystals observed in atomic scale

1978 ◽  
Vol 36 (1) ◽  
pp. 284-285 ◽  
Author(s):  
H. Hashimoto ◽  
Y. Sugimoto ◽  
Y. Takai ◽  
H. Endoh
Keyword(s):  
Electron Microscope ◽  
Rotation Angle ◽  
Crystal Surface ◽  
Electron Gun ◽  
Atomic Scale ◽  
Present Observation ◽  
Twist Boundary ◽  
Optical Magnification ◽  
Zinc Crystal ◽  
And Migration

As was demonstrated by the present authors that atomic structure of simple crystal can be photographed by the conventional 100 kV electron microscope adjusted at “aberration free focus (AFF)” condition. In order to operate the microscope at AFF condition effectively, highly stabilized electron beams with small energy spread and small beam divergence are necessary. In the present observation, a 120 kV electron microscope with LaB6 electron gun was used. The most of the images were taken with the direct electron optical magnification of 1.3 million times and then magnified photographically.1. Twist boundary of ZnSFig. 1 is the image of wurtzite single crystal with twist boundary grown on the surface of zinc crystal by the reaction of sulphur vapour of 1540 Torr at 500°C. Crystal surface is parallel to (00.1) plane and electron beam is incident along the axis normal to the crystal surface. In the twist boundary there is a dislocation net work between two perfect crystals with a certain rotation angle.

Musculoskeletal disorder risk associated with auto rotation angle during an assembly task

2009 ◽  
Author(s):  
Sue A. Ferguson ◽  
William S. Marras ◽  
W. Gary Allread ◽  
Gregory G. Knapik ◽  
Kimberly A. Vandlen ◽  
...  
Keyword(s):  
Musculoskeletal Disorder ◽  
Rotation Angle ◽  
Assembly Task ◽  
Disorder Risk
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