An Energy-Based Approach to the Dynamics of Impacts in Unilaterally-Constrained Multibody Systems

2007 ◽  
Author(s):  
Seyed Ali Modarres Najafabadi ◽  
Jo´zsef Ko¨vecses ◽  
Jorge Angeles
Keyword(s):  
Multibody Systems ◽  
Point Contact ◽  
Coefficient Of Restitution ◽  
Multiple Point ◽  
Dynamics Analysis ◽  
Constrained Multibody Systems ◽  
Novel Approach ◽  
Potential Applications ◽  
Definition Of ◽  
Tangential Directions

This paper introduces a novel approach to dynamics analysis of contacts involving multibody systems, and particularly the case of simultaneous multiple-point impact. This approach is based on an analysis of energy absorption and restitution during impact, using a decomposition technique, which exactly decouples the kinetic energy associated with the normal and tangential directions of the contact pairs. Such decomposition leads to a generalized definition of the energetic coefficient of restitution, which allows for consideration of simultaneous multiple-point contact scenarios. The main advantages of this new definition and the potential applications of the said technique are highlighted.

Generalization of the Energetic Coefficient of Restitution for Contacts in Multibody Systems

2008 ◽  
Vol 3 (4) ◽  
Author(s):  
Seyed Ali Modarres Najafabadi ◽  
József Kövecses ◽  
Jorge Angeles
Keyword(s):  
Kinetic Energy ◽  
Energy Absorption ◽  
Multibody Systems ◽  
Point Contact ◽  
Coefficient Of Restitution ◽  
Multiple Point ◽  
Decomposition Technique ◽  
Potential Applications ◽  
New Interpretation ◽  
Tangential Directions

This paper introduces a new interpretation of the energetic coefficient of restitution, especially applicable to contact involving multibody systems. This interpretation generalizes the concept of the energetic coefficient of restitution and allows for consideration of simultaneous multiple-point contact scenarios. Such a generalization is obtained by an analysis of energy absorption and restitution during impact, using a decomposition technique, which exactly decouples the kinetic energy associated with the normal and tangential directions of the contact pairs. The main advantages of the new definition and its potential applications are highlighted.

A Comparative Study of Approaches to Dynamics Modeling of Contact Transitions in Multibody Systems

2005 ◽  
Author(s):  
Seyed Ali Modarres Najafabadi ◽  
Jo´zsef Ko¨vecses ◽  
Jorge Angeles
Keyword(s):  
Comparative Study ◽  
Dynamic Analysis ◽  
Multibody Systems ◽  
Multibody System ◽  
Point Contact ◽  
Transition Phase ◽  
Multiple Point ◽  
Dynamics Modeling ◽  
Modeling Techniques ◽  
Two Bodies

This paper presents detailed discussions and a potential grouping of various approaches to the dynamic analysis of the transition phase in multibody contacts. The methods considered are able to address the general case of multiple-point contact. The main grouping principle relies on the fundamental unilateral nature of the contact between two bodies in a multibody system. Based on this, three main classes of modeling techniques are considered.

On modeling and dynamics of a multiple launch rocket system

2021 ◽  
pp. 095441002098224
Author(s):  
Bo Li ◽  
Xiaoting Rui ◽  
Guoping Wang ◽  
Jianshu Zhang ◽  
Qinbo Zhou
Keyword(s):  
Monte Carlo ◽  
Multibody Systems ◽  
Euler Method ◽  
Dynamics Analysis ◽  
Analysis Problem ◽  
Dynamic Design ◽  
Proposed Model ◽  
And Control ◽  
Rocket System ◽  
Complete Process

Dynamics analysis is currently a key technique to fully understand the dynamic characteristics of sophisticated mechanical systems because it is a prerequisite for dynamic design and control studies. In this study, a dynamics analysis problem for a multiple launch rocket system (MLRS) is developed. We particularly focus on the deductions of equations governing the motion of the MLRS without rockets by using a transfer matrix method for multibody systems and the motion of rockets via the Newton–Euler method. By combining the two equations, the differential equations of the MLRS are obtained. The complete process of the rockets’ ignition, movement in the barrels, airborne flight, and landing is numerically simulated via the Monte Carlo stochastic method. An experiment is implemented to validate the proposed model and the corresponding numerical results.

scholarly journals Learning Curves: A Novel Approach for Robustness Improvement of Load Forecasting

2021 ◽  
Vol 5 (1) ◽  
pp. 38
Author(s):  
Chiara Giola ◽  
Piero Danti ◽  
Sandro Magnani
Keyword(s):  
Load Forecasting ◽  
Learning Curves ◽  
Machine Learning Techniques ◽  
Essential Information ◽  
Set Size ◽  
Novel Approach ◽  
Learning Techniques ◽  
Energy Plant ◽  
Definition Of ◽  
The Right

In the age of AI, companies strive to extract benefits from data. In the first steps of data analysis, an arduous dilemma scientists have to cope with is the definition of the ’right’ quantity of data needed for a certain task. In particular, when dealing with energy management, one of the most thriving application of AI is the consumption’s optimization of energy plant generators. When designing a strategy to improve the generators’ schedule, a piece of essential information is the future energy load requested by the plant. This topic, in the literature it is referred to as load forecasting, has lately gained great popularity; in this paper authors underline the problem of estimating the correct size of data to train prediction algorithms and propose a suitable methodology. The main characters of this methodology are the Learning Curves, a powerful tool to track algorithms performance whilst data training-set size varies. At first, a brief review of the state of the art and a shallow analysis of eligible machine learning techniques are offered. Furthermore, the hypothesis and constraints of the work are explained, presenting the dataset and the goal of the analysis. Finally, the methodology is elucidated and the results are discussed.

scholarly journals Multiple point contact wear prediction and source identification scheme using a single channel blended airborne acoustic signature

2020 ◽  
Vol 53 (3) ◽  
pp. 283-288
Author(s):  
Muhammad Atayyab Shahid ◽  
Tariq Mairaj Khan ◽  
Kevin Lontin ◽  
Kanza Basit ◽  
Muhammad Khan
Keyword(s):  
Source Identification ◽  
Single Channel ◽  
Point Contact ◽  
Multiple Point ◽  
Wear Prediction ◽  
Identification Scheme ◽  
Contact Wear ◽  
Acoustic Signature

An Improved Mathematical Model of Galton Board With Velocity-Dependent Restitution

2017 ◽  
Vol 12 (6) ◽  
Author(s):  
Auni Aslah Mat Daud
Keyword(s):  
Mathematical Model ◽  
Random Walk ◽  
Symbolic Dynamics ◽  
Coefficient Of Restitution ◽  
Dynamics Analysis ◽  
The Novel ◽  
Francis Galton ◽  
The Way

A Galton board is an instrument invented in 1873 by Francis Galton (1822–1911). It is a box with a glass front and many horizontal nails or pins embedded in the back and a funnel. Galton and many modern statisticians claimed that a lead ball descending to the bottom of the Galton board would display random walk. In this study, a new mathematical model of Galton board is developed, to further improve three very recently proposed models. The novel contribution of this paper is the introduction of the velocity-dependent coefficient of restitution. The developed model is then analyzed using symbolic dynamics. The results of the symbolic dynamics analysis prove that the developed Galton board model does not behave the way Galton envisaged.

scholarly journals Generalized Wavelet Fisher’s Information of1/fαSignals

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Julio Ramírez-Pacheco ◽  
Homero Toral-Cruz ◽  
Luis Rizo-Domínguez ◽  
Joaquin Cortez-Gonzalez
Keyword(s):  
Fisher Information ◽  
Gaussian Noise ◽  
Structural Breaks ◽  
Wavelet Domain ◽  
Fractional Gaussian Noise ◽  
Domain Definition ◽  
Potential Applications ◽  
Definition Of ◽  
The Time Domain ◽  
Fisher's Information

This paper defines the generalized wavelet Fisher information of parameterq. This information measure is obtained by generalizing the time-domain definition of Fisher’s information of Furuichi to the wavelet domain and allows to quantify smoothness and correlation, among other signals characteristics. Closed-form expressions of generalized wavelet Fisher information for1/fαsignals are determined and a detailed discussion of their properties, characteristics and their relationship with waveletq-Fisher information are given. Information planes of1/fsignals Fisher information are obtained and, based on these, potential applications are highlighted. Finally, generalized wavelet Fisher information is applied to the problem of detecting and locating weak structural breaks in stationary1/fsignals, particularly for fractional Gaussian noise series. It is shown that by using a joint Fisher/F-Statistic procedure, significant improvements in time and accuracy are achieved in comparison with the sole application of theF-statistic.

Synthesis of Planar, Compliant Four-Bar Mechanisms for Compliant-Segment Motion Generation

1999 ◽  
Vol 123 (4) ◽  
pp. 535-541 ◽  
Author(s):  
L. Saggere ◽  
S. Kota
Keyword(s):  
Compliant Mechanisms ◽  
Shape Change ◽  
Synthesis Method ◽  
Elastic Equilibrium ◽  
Body Motion ◽  
Motion Generation ◽  
Generation Task ◽  
Potential Applications ◽  
Flexible Segment ◽  
Definition Of

Compliant four-bar mechanisms treated in previous works consisted of at least one rigid moving link, and such mechanisms synthesized for motion generation tasks have always comprised a rigid coupler link, bearing with the conventional definition of motion generation for rigid-link mechanisms. This paper introduces a new task called compliant-segment motion generation where the coupler is a flexible segment and requires a prescribed shape change along with a rigid-body motion. The paper presents a systematic procedure for synthesis of single-loop compliant mechanisms with no moving rigid-links for compliant-segment motion generation task. Such compliant mechanisms have potential applications in adaptive structures. The synthesis method presented involves an atypical inverse elastica problem that is not reported in the literature. This inverse problem is solved by extending the loop-closure equation used in the synthesis of rigid-links to the flexible segments, and then combining it with elastic equilibrium equation in an optimization scheme. The method is illustrated by a numerical example.

The Optimum Power Load: A Simple and Powerful Tool for Testing and Training

2021 ◽  
pp. 1-9
Author(s):  
Irineu Loturco ◽  
Antonio Dello Iacono ◽  
Fábio Y. Nakamura ◽  
Tomás T. Freitas ◽  
Daniel Boullosa ◽  
...  
Keyword(s):  
Strong Support ◽  
Current Evidence ◽  
Novel Approach ◽  
Power Load ◽  
Velocity Relationship ◽  
Potential Applications ◽  
Bar Velocity ◽  
Acute And Chronic Effects ◽  
Testing Protocols ◽  
And Training

Purpose: The optimal power load is defined as the load that maximizes power output in a given exercise. This load can be determined through the use of various instruments, under different testing protocols. Specifically, the “optimum power load” (OPL) is derived from the load–velocity relationship, using only bar force and bar velocity in the power computation. The OPL is easily assessed using a simple incremental testing protocol, based on relative percentages of body mass. To date, several studies have examined the associations between the OPL and different sport-specific measures, as well as its acute and chronic effects on athletic performance. The aim of this brief review is to present and summarize the current evidence regarding the OPL, highlighting the main lines of research on this topic and discussing the potential applications of this novel approach for testing and training. Conclusions: The validity and simplicity of OPL-based schemes provide strong support for their use as an alternative to more traditional strength–power training strategies. The OPL method can be effectively used by coaches and sport scientists in different sports and populations, with different purposes and configurations.

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