scholarly journals Erratum: Linear and Nonlinear Dynamical Analysis of a Crane Model

2020 ◽  
Vol 15 (3) ◽  
pp. 243
Author(s):  
Hmoumen Maourane ◽  
Tamás Szabó
2020 ◽  
Vol 15 (2) ◽  
pp. 82-93
Author(s):  
Hmoumen Maourane ◽  
Tamás Szabó

Abstract:This paper deals with the dynamical analysis of a crane model. Truss finite elements are used to discretize the suspending chains with the so called updated Lagrangian description. This nonlinear model is regarded to be the best approximation to which linear models are compared. The inertia and independent degrees of freedom are also taken into consideration by linear models. The goal is to find a linear model, which can be used as an observer in antisway control of a crane.


2020 ◽  
Vol 22 (4) ◽  
Author(s):  
Michalina Błażkiewicz

Purpose: Yoga is known as a type of exercise that combines physical, mental and spiritual aspects. There has not been much research on the postural control in various yoga poses. The aim of this study was to examine CoP regularity in both yoga instructors and novices during the performance of four yoga poses, and to verify the sensitivity of linear and nonlinear methods for assessing postural stability. Methods: The dynamic characteristics of CoP fluctuations were examined using linear and nonlinear methods on a group of 22 yoga instructors (Y) and 18 age-matched non-practitioners of yoga (NY). The study involved maintaining a balance for 20 seconds while performing four yoga poses. Results: Conventional analysis of CoP trajectories showed that NY and Y exhibited similar control of postural sway, as indicated by similar CoP path-length and area values observed in both groups. These results suggest that the special balance yoga training received by Y may not have an impact on less challenging balance conditions, such as the poses used in this experiment. Interestingly, nonlinear dynamical analysis of CoP showed that Y exhibited less CoP regularity and more complex signal than NY, as evidenced by higher values of sample entropy and fractal dimension. Conclusions: The results shed light on the surplus values of CoP trajectories in the nonlinear dynamical analysis to gain further insight into the mechanisms involved in posture control.


2009 ◽  
Vol 30 (6) ◽  
pp. 859-867 ◽  
Author(s):  
Metin Akay ◽  
Kui Wang ◽  
Yasemin M Akay ◽  
Andrei Dragomir ◽  
Jie Wu

2014 ◽  
Vol 919-921 ◽  
pp. 1273-1281
Author(s):  
Jin Duan ◽  
Yun Gui Li

In this paper, a three-dimensional beam element is developed for geometric nonlinear dynamical analysis. This element is based on the co-rotational formulation, in which the displacements of beam element are subdivided into rigid body movements and elastic deformations. The formulations are derived from the continuum mechanics based Updated Lagrangian incremental equations. The element can undergo large deflections and rotations, but small strains are assumed in the deduction. The validity of this element is confirmed by comparing with the numerical results in other literatures.


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