Results 31 to 40 of about 6,935 (243)
State-Dependent Delay and Drill-String Dynamics
Procedia IUTAM, 2017 Abstract In this work, stability analysis carried out with a reduced-order model of a drill string is presented. This model, which is nonlinear in nature and contains a state-dependent delay, is used to study coupled axial and torsion dynamics of the system.
Xie Zheng, Balakumar Balachandran
openaire +1 more source
Axial and torsional self-excited vibrations of a distributed drill-string [PDF]
, 2019 We consider a distributed axial-torsional drill-string model with a rate-independent bit-rock interaction law to study the occurrence and non-local characteristics of axial and torsional self-excited vibrations as caused by the regenerative effect.
Aarsnes, Ulf Jakob F. +3 more
core +1 more source
Analysis on Casing Wear Induced by Drill String Whirling during Workover Drill Grinding
Shiyou jixie, 2021 When the drill string rotates in the wellbore, it will whirl, collide with and rub against casing inwall, resulting in casing wear and reducing wellbore safety.
Cao Yinping +3 more
doaj
A Model-Based Intelligent Adjustment Method of Toolface for Bent-Housing Motor
Applied Sciences, 2023 The traditional toolface adjustment of a bent-housing motor is time-consuming and laborious. For the goal of rapid and accurate toolface adjustment, this paper presents an intelligent toolface adjustment method based on the drill string dynamics model ...
Tiansheng Deng +3 more
doaj +1 more source
Stochastic dynamics of a drill-string with uncertain weight-on-hook [PDF]
Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2010 A drill-string is a slender structure that turns and drills into the rock in search of oil. There are many sources of uncertainties in this complex dynamical system. However, this article is concerned only with uncertainties in the weight-on-hook, which is the supporting force exerted by the hook at the top. A probabilistic model is constructed for the
Ritto, T.G. +2 more
openaire +3 more sources
Helical Buckling of Drill-Strings
MATEC Web of Conferences, 2018 This paper presents experimental and numerical investigations of the complex drill-string vibration, with particular attention to the helical buckling of drill-strings and its influence on the system dynamics.
Kapitaniak Marcin +2 more
doaj +1 more source
Mathematics, 2021 Friction-induced stick-slip vibrations are one of the major causes for down-hole drill-string failures. Consequently, several nonlinear models and control approaches have been proposed to solve this problem.
Jorge Pérez-Aracil +5 more
doaj +1 more source
Review of Thermally Activated Twisted Coiled Polymer Actuators: A Materials Science Perspective
Advanced Functional Materials, EarlyView.Thermally activated twisted and coiled polymer actuators (TCPAs) combine lightweight design, large deformation, and scalable fabrication for soft robotic and wearable applications. This review connects polymer structure, processing history, helix geometry, and thermomechanical characterization to actuator performance, highlighting current challenges in
Nadja Schenk +3 more
wiley +1 more source
Advanced Healthcare Materials, EarlyView.We develop a covalent organic framework‐loaded Traditional Chinese Medicine monomer nanodrug delivery system (ISL@bCOF) via boron‐oxygen bonds, a smart response to glucose for delivering AI‐driven isoliquiritigenin (ISL) targeting ZBP1. This dynamic release mechanism, combined with transdermal delivery technology via potent microneedles, can modulate ...
Menghan Zhou +9 more
wiley +1 more source
Advanced Materials, EarlyView.Metal‐free carbon catalysts enable the sustainable synthesis of hydrogen peroxide via two‐electron oxygen reduction; however, active site complexity continues to hinder reliable interpretation. This review critiques correlation‐based approaches and highlights the importance of orthogonal experimental designs, standardized catalyst passports ...
Dayu Zhu +3 more
wiley +1 more source