Stochastic dynamics of a drill-string with uncertain weight-on-hook

Ritto, T.G.; Soize, Christian; Sampaio, Rubens

doi:10.1590/s1678-58782010000300008

Cited by 15 publications

(10 citation statements)

References 19 publications

(19 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An appropriate probabilistic model for each random variable, denoted as X, is constructed accounting for the available information only, which is the following: (1) the support of the probability density function is ]0, +∞[; (2) the mean values are such that E[X] =X; and (3) zero is a repulsive value for the positive-valued random variables, which is accounted for by the condition E[ln(X)] = c X with |c X | < +∞. The Maximum Entropy Principle yields a Gamma probability density function for each stochastic variable X (Jaynes, 1957;Kapur, 1993;Soize, 2001;Ritto et al, 2010)…”

Section: Stochastic Modeling For Uncertainty Quantificationmentioning

confidence: 99%

Effect of parametric uncertainties on the performance of a piezoelectric energy harvesting device

Godoy

Trindade

2012

J. Braz. Soc. Mech. Sci. & Eng.

View full text Add to dashboard Cite

The use of piezoelectric materials for the development of electromechanical devices for the harvesting or scavenging of ambient vibrations has been extensively studied over the last decade. The energy conversion from mechanical (vibratory) to electrical energy is provided by the electromechanical coupling between mechanical strains/stresses and electric charges/voltages in the piezoelectric material. The majority of the studies found in the open literature present a tip-mass cantilever piezoelectric device tuned on the operating frequency. Although recent results show that these devices can be quite effective for harvesting small amounts of electrical energy, little has been published on the robustness of these devices or on the effect of parametric uncertainties on the energy harvested. This work focuses on a cantilever plate with bonded piezoelectric patches and a tip-mass serving as an energy harvesting device. The rectifier and storage electric circuit was replaced by a resistive circuit (R). In addition, an alternative to improve the harvesting performance by adding an inductance in series to the harvesting circuit, thus leading to a resonant circuit (RL), is considered. A coupled finite element model leading to mechanical (displacements) and electrical (charges at electrodes) degrees of freedom is considered. An analysis of the effect of parametric uncertainties of the device on the electric output is performed. Piezoelectric and dielectric constants of the piezoelectric active layers and electric circuit equivalent inductance are considered as stochastic parameters. Mean and confidence intervals of the electric output are evaluated.

show abstract

Section: Stochastic Modeling For Uncertainty Quantificationmentioning

confidence: 99%

Effect of parametric uncertainties on the performance of a piezoelectric energy harvesting device

Godoy

Trindade

2012

J. Braz. Soc. Mech. Sci. & Eng.

View full text Add to dashboard Cite

show abstract

“…The authors' focus was placed on the bitrock interaction and the drilling fluid effect on dynamics. In some other papers, [20,21] also studied the uncertainties in the weight-on-hook.…”

Section: Introductionmentioning

confidence: 99%

Stick-Slip Analysis of a Drill String Subjected to Deterministic Excitation and Stochastic Excitation

Qiu

Yang²,

Butt³

2016

Shock and Vibration

View full text Add to dashboard Cite

Using a finite element model, this paper investigates the torsional vibration of a drill string under combined deterministic excitation and random excitation. The random excitation is caused by the random friction coefficients between the drill bit and the bottom of the hole and assumed as white noise. Simulation shows that the responses under random excitation become random too, and the probabilistic distribution of the responses at each discretized time instant is obtained. The two points, entering and leaving the stick stage, are examined with special attention. The results indicate that the two points become random under random excitation, and the distributions are not normal even when the excitation is assumed as Gaussian white noise.

show abstract

“…There are few articles concerned with uncertainty quantification and stochastic analysis of the drill-string dynamics; in particular, we may cite [3][4][5][6][7][8]. Spanos et al [3] analyzed stochastic lateral forces at the bit.…”

Section: Introductionmentioning

confidence: 99%

“…Later, they proposed a robust optimization problem to maximize the rate of penetration of the system without damaging it [7]. Finally, they analyzed a random weight-on-hook [8].…”

Section: Introductionmentioning

confidence: 99%

Stochastic Drill-String Dynamics With Uncertainty on the Imposed Speed and on the Bit-Rock Parameters

Ritto

Sampaio

2012

Int J Uncertainty Quantification

View full text Add to dashboard Cite

A drill string is a slender structure with nonlinear dynamics; it is an equipment used in the oil industry to drill rock in the search of oil and gas. The aim of this paper is to model the uncertainties related to the speed imposed at the top and uncertainties related to the bit-rock parameters, and to investigate how these uncertainties propagate throughout the system. The continuum system is linearized about the prestressed configuration, the finite-element model is applied to discretize the system, and then a reduced-order model is constructed using normal modes of the linearized system; only torsional and axial vibrations are considered in the analysis. A constant rotational speed is imposed at the top and a nonlinear bit-rock interaction acts at the bottom. A probabilistic approach is used to model the uncertainties and the Monte Carlo method is used to approximate the stochastic differential equations.

show abstract

Stochastic dynamics of a drill-string with uncertain weight-on-hook

Cited by 15 publications

References 19 publications

Effect of parametric uncertainties on the performance of a piezoelectric energy harvesting device

Effect of parametric uncertainties on the performance of a piezoelectric energy harvesting device

Stick-Slip Analysis of a Drill String Subjected to Deterministic Excitation and Stochastic Excitation

Stochastic Drill-String Dynamics With Uncertainty on the Imposed Speed and on the Bit-Rock Parameters

Contact Info

Product

Resources

About