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Step-response of discontinuous non-linear torsional systems : = Experimental and parameter estimation studies.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Step-response of discontinuous non-linear torsional systems :/
Reminder of title:	Experimental and parameter estimation studies.
Author:	Krak, Michael David.
Description:	1 online resource (185 pages)
Notes:	Source: Dissertation Abstracts International, Volume: 78-04(E), Section: B.
Contained By:	Dissertation Abstracts International78-04B(E).
Subject:	Mechanical engineering. -
Online resource:	click for full text (PQDT)
ISBN:	9781369370492

Step-response of discontinuous non-linear torsional systems : = Experimental and parameter estimation studies.
Krak, Michael David.

Step-response of discontinuous non-linear torsional systems :Experimental and parameter estimation studies. - 1 online resource (185 pages)

Source: Dissertation Abstracts International, Volume: 78-04(E), Section: B.

Thesis (Ph.D.)

Includes bibliographical references

This study examines the step-response of discontinuous non-linear torsional systems that contain clearances, multi-staged torsional springs, stopper or pre-load features, and multi-staged dry friction elements. The primary goal of this work is to develop two new laboratory experiments to provide benchmark data and to propose time domain estimation methods for elastic and dissipative parameters as well as for time-varying oscillatory periods. First, a new laboratory experiment, incorporating a multi-staged clutch damper, is designed, built, and instrumented. Typical measured responses under a step-like torque loading exhibit rich non-linear behavior, such as vibro-impact phenomena with distinct regimes (i.e. single and double-sided impacts) and time-varying oscillatory periods. Predictions from a minimal order non-linear model verify that the experiment performs well and as designed. Second, an original laboratory experiment is developed as a more scientific version of the first (component driven) experiment, with focus on stiffness non-linearity. It is excited by a step-like torque in no-clearance, single-clearance, and dual-clearance configurations, each described by minimal order positive-definite non-linear models. The feasibility of this experiment is verified by comparing measurements with predictions from analogous models. Both hardening and softening trends in the time-varying oscillatory periods are found in the experiments and are discussed in the context of double and single-sided impact regimes.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9781369370492Subjects--Topical Terms:

557493
Mechanical engineering.
Index Terms--Genre/Form:

554714
Electronic books.

Step-response of discontinuous non-linear torsional systems : = Experimental and parameter estimation studies.
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245 1 0 $a Step-response of discontinuous non-linear torsional systems : $b Experimental and parameter estimation studies.
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500 $a Source: Dissertation Abstracts International, Volume: 78-04(E), Section: B.
500 $a Adviser: Rajendra Singh.
502 $a Thesis (Ph.D.) $c The Ohio State University $d 2016.
504 $a Includes bibliographical references
520 $a This study examines the step-response of discontinuous non-linear torsional systems that contain clearances, multi-staged torsional springs, stopper or pre-load features, and multi-staged dry friction elements. The primary goal of this work is to develop two new laboratory experiments to provide benchmark data and to propose time domain estimation methods for elastic and dissipative parameters as well as for time-varying oscillatory periods. First, a new laboratory experiment, incorporating a multi-staged clutch damper, is designed, built, and instrumented. Typical measured responses under a step-like torque loading exhibit rich non-linear behavior, such as vibro-impact phenomena with distinct regimes (i.e. single and double-sided impacts) and time-varying oscillatory periods. Predictions from a minimal order non-linear model verify that the experiment performs well and as designed. Second, an original laboratory experiment is developed as a more scientific version of the first (component driven) experiment, with focus on stiffness non-linearity. It is excited by a step-like torque in no-clearance, single-clearance, and dual-clearance configurations, each described by minimal order positive-definite non-linear models. The feasibility of this experiment is verified by comparing measurements with predictions from analogous models. Both hardening and softening trends in the time-varying oscillatory periods are found in the experiments and are discussed in the context of double and single-sided impact regimes.
520 $a Next, a refined method to estimate the time-varying oscillatory periods of the step-response of a non-linear torsional device is developed by extending the prior work on the stochastic linearization techniques. Subsequently, an instantaneous expected value operator and the concept of instantaneous effective stiffness are formulated. The proposed method is rigorously illustrated via two computational example cases and the necessary digital signal processing parameters for time domain analysis are investigated. The feasibility of the proposed method is demonstrated by estimating trends in measured time-varying oscillatory periods. Finally, a refined time domain method to estimate elastic and dissipative parameters of a practical non-linear component is formulated. Since prior estimation methods have utilized either linearization or assumed that non-linearities are differentiable, the proposed method is developed specifically for devices that contain discontinuous non-linear features. Elastic parameters are first estimated through an instantaneous stochastic linearization technique. Then, the energy balance principle is employed to estimate a combination of viscous and Coulomb damping parameters for seven local (stage-dependent) and global (single-staged) damping formulations. The proposed method is validated by comparing time domain predictions from non-linear models to measurements. Non-linear models that utilize the proposed stage-dependent damping formulations are found to be superior to those that solely rely only on parameters from a quasi-static experiment. On a more fundamental note, both experiments overcome the general void in the field of experimental non-linear dynamics. The proposed experimental methods, benchmark data, and parameter estimation techniques should be equally valuable to the scientific literature and engineering practice.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Mechanical engineering. $3 557493
655 7 $a Electronic books. $2 local $3 554714
690 $a 0548
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710 2 $a The Ohio State University. $b Mechanical Engineering. $3 1148711
773 0 $t Dissertation Abstracts International $g 78-04B(E).
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10294644 $z click for full text (PQDT)