The effect of cross-sectional parameters on the dynamics of elastic mechanisms

1996 ◽  
Vol 31 (7) ◽  
pp. 947-955 ◽  
Author(s):  
Yue-Qing Yu ◽  
M.R. Smith
Keyword(s):  
Cross Sectional ◽  
Sectional Parameters

Modelling of Rotating Twisted Blades as 1D Continuum

2016 ◽  
Vol 821 ◽  
pp. 183-190
Author(s):  
Jan Brůha ◽  
Drahomír Rychecký
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Beam Theory ◽  
Parameter Tuning ◽  
Finite Element Models ◽  
Cross Sectional ◽  
One Dimensional ◽  
Rayleigh Beam ◽  
Twisted Blade ◽  
Sectional Parameters

Presented paper deals with modelling of a twisted blade with rhombic shroud as one-dimensional continuum by means of Rayleigh beam finite elements with varying cross-sectional parameters along the finite elements. The blade is clamped into a rotating rigid disk and the shroud is considered to be a rigid body. Since the finite element models based on the Rayleigh beam theory tend to slightly overestimate natural frequencies and underestimate deflections in comparison with finite element models including shear deformation effects, parameter tuning of the blade is performed.

Characterization of drag reduction performance over rotating microgrooves with different cross-sections

2019 ◽  
Vol 234 (6) ◽  
pp. 1746-1758
Author(s):  
Suping Wen ◽  
Wenbo Wang ◽  
Zhixuan Zhang
Keyword(s):  
Drag Reduction ◽  
Cross Sections ◽  
Turbulence Intensity ◽  
Reynolds Numbers ◽  
Cross Sectional ◽  
Dimensionless Velocity ◽  
Velocity Shift ◽  
Maximum Drag Reduction ◽  
Sectional Parameters

This paper presents a study of cross-sectional parameters and optimal drag reduction performance specifically for drag reduction in rotating microgroove applications. Rotating triangular microgrooves with nine asymmetrical and symmetrical cross-sections were numerically studied. In addition, a representative symmetrical rotating microgroove was experimentally tested. Positive asymmetrical microgrooves (including symmetrical microgrooves) were found to be sensitive to rotating Reynolds numbers and produced more significant drag reduction. Compared with a dimensioned asymmetry variable and other dimensionless parameters, the dimensionless asymmetry variable i+ could be used to describe drag reduction performance, which captured both the influence of microgroove cross-sectional asymmetry and turbulence intensity. A maximum drag reduction of up to 8.9% was obtained at 9.2 i+. With the exception of the torque, the velocity shift obtained from dimensionless velocity profiles could also be used to predict drag reduction performance, which has the potential for wider and more comprehensive application for any drag reduction technology.

Cross-Sectional Parameters of Cotton Fibers

1979 ◽  
Vol 49 (9) ◽  
pp. 540-542 ◽  
Author(s):  
J.J. Hebert ◽  
E.K. Boylston ◽  
J.I. Wadsworth
Keyword(s):  
Cotton Fibers ◽  
Cross Sectional ◽  
Sectional Parameters

Simultaneous Optimization of Structure and Control for Vibration Suppression

1999 ◽  
Vol 121 (2) ◽  
pp. 237-243 ◽  
Author(s):  
Ye Zhu ◽  
Jinhao Qiu ◽  
Junji Tani ◽  
Yuta Urushiyama ◽  
Yasuharu Hontani
Keyword(s):  
Structural Optimization ◽  
Vibration Suppression ◽  
Optimization Problems ◽  
Simultaneous Optimization ◽  
Control Input ◽  
Cross Sectional ◽  
Traditional Design ◽  
Simulation Results ◽  
Sectional Parameters ◽  
And Control

A method of simultaneous optimization of structure and control using mixed H2 and H∞ norms of the transfer function as the objective function is proposed and the modeling and formulation of simultaneous optimization problems associated with this approach are discussed in this paper. Simultaneous optimization is realized by iteratively executing structural optimization and controller optimization. Both serial and parallel approaches to combine structural optimization and controller optimization are investigated. They are applied to the simultaneous optimization of the cross-sectional parameters of a spring-supported beam and the parameters of the controller used to actively suppress the vibration of the beam. The performance of both displacement output and control input is improved significantly after simultaneous optimization. The simulation results show the great potential advantages of simultaneous optimization over traditional design methods and the effectiveness of the proposed approach.

Technical note: The effect of midshaft location on the error ranges of femoral and tibial cross-sectional parameters

2009 ◽  
Vol 141 (2) ◽  
pp. 325-332 ◽  
Author(s):  
Vladimír Sládek ◽  
Margit Berner ◽  
Patrik Galeta ◽  
Lukáš Friedl ◽  
Šárka Kudrnová
Keyword(s):  
Technical Note ◽  
Cross Sectional ◽  
Sectional Parameters

scholarly journals Modeling and Experimentation of the Unidirectional Orthodontic Force of Second Sequential Loop Orthodontic Archwire

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Jin-Gang Jiang ◽  
Yi-Hao Chen ◽  
Lei Wang ◽  
Yong-De Zhang ◽  
Yi Liu ◽  
...  
Keyword(s):  
Structural Characteristics ◽  
Beam Deflection ◽  
Forecasting Model ◽  
Cross Sectional ◽  
Orthodontic Force ◽  
Inherent Error ◽  
Sectional Parameters ◽  
Deflection Theory ◽  
The Relationship ◽  
Theoretical Results

The abnormal tooth arrangement is one of the most common clinical features of malocclusion which is mainly caused by the tooth root compression malformation. The second sequential loop is mostly used for the adjusting of the abnormal tooth arrangement. Now, the shape devise of orthodontic archwire depends completely on the doctor’s experience and patients’ feedback, this practice is time-consuming, and the treatment effect is unstable. The orthodontic-force of the different parameters of the second sequence loop, including different cross-sectional parameters, material parameters, and characteristic parameters, was compared and simulated for the abnormal condition of root compression deformity. In this paper, the analysis and experimental study on the unidirectional orthodontic-force were carried out. The different parameters of the second sequential loop are analyzed, and the equivalent beam deflection theory is used to analyze the relationship between orthodontic-force and archwire parameters. Based on the structural analysis of the second sequential loop, the device for measuring orthodontic force has been designed. The orthodontic force with different structural characteristics of archwire was compared and was measured. Finally, the correction factor was developed in the unidirectional orthodontic-force forecasting model to eliminate the influence of inherent error. The average relative error rate of the theoretical results of the unidirectional orthodontic-force forecasting model is between 12.6% and 8.75%, which verifies the accuracy of the prediction model.

Optimum Design of Flexible Mechanisms

1983 ◽  
Vol 105 (2) ◽  
pp. 267-272 ◽  
Author(s):  
Ce Zhang ◽  
H. T. Grandin
Keyword(s):  
Mechanism Design ◽  
Optimum Design ◽  
Optimality Criterion ◽  
Geometrical Parameters ◽  
Cross Sectional ◽  
Design Variables ◽  
Recursion Formulas ◽  
Kinematic Performance ◽  
Sectional Parameters ◽  
Flexible Mechanisms

In this paper the optimality criterion technique transplanted by Khan and his coworkers into mechanism design and the kinematical refinement technique proposed by the authors are combined into a novel procedure of optimum design of flexible mechanisms. Cross-sectional parameters are taken as the first group of design variables; a fully-stressed mechanism is obtained by using previous researchers’ recursion formulas which contain some improvements introduced by the authors. Geometrical parameters are used as the second group of design variables; a mechanism with improved criterion of kinematic performance is obtained by means of the kinematic refinement technique. The method presented is effective and steady. An example problem in the design of a four-bar path-generating mechanism is given to illustrate the procedure.

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