Investigation on the multiscale stick-slip phenomenon of cotton fabric

Stick-slip is a major problem in offshore drilling because it may cause damage to the drill bit as well as crushing or grinding the sediment layer, which is crucial problem in scientific drilling because the purpose of the scientific drilling is to recover core samples from the layers. To mitigate stick-slip, first of all it is necessary to establish a model of the torsional motion of the drill bit and express the stick-slip phenomenon. Toward this end, the present study proposes a model of torsional waves propagating in a drillstring. An analytical model is developed and used to derive a neutral delay differential equation (NDDE), a special type of equation that requires time history, and an analytical model of stick-slip is derived for friction models between the drill bit and the layer as well as the rotation speed applied to the uppermost part of the drill string. In this study, the stick-slip model is numerically analyzed for several conditions and a time series of the bit motions is obtained. Based on the analytical results, the appearance of stick-slip and its severity are discussed. A small-scale model experiment was conducted in a water tank to observe the stick-slip phenomenon, and the result is discussed with numerical analysis. In addition, utilizing surface drilling data acquired from the actual drilling operations of the scientific drillship Chikyu, occurrence of stick-slip phenomenon is discussed.

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Normal load, slip rate and roughness influence on the PMMA dynamics of sliding. 2. Characterization of the stick-slip phenomenon

Computer Standards & Interfaces ◽

10.1016/s0920-5489(99)92034-2 ◽

1999 ◽

Vol 21 (2) ◽

pp. 128

Author(s):

S. Bouissou ◽

J.P. Petit ◽

M. Barquins

Keyword(s):

Normal Load ◽

Slip Rate ◽

Stick Slip ◽

Slip Phenomenon

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Effect of laser-textured micro dimples on inhibition of stick-slip phenomenon of sliding guideway

Industrial Lubrication and Tribology ◽

10.1108/ilt-08-2021-0339 ◽

2022 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Yonghong Fu ◽

Jie Yang ◽

Hao Wang ◽

Yuyang He

Keyword(s):

Hydrodynamic Lubrication ◽

Textured Surface ◽

Stick Slip ◽

Content Type ◽

Speed Range ◽

Lubrication Condition ◽

Micro Dimples ◽

Pin On Disk ◽

Micro Dimple ◽

Slip Phenomenon

Purpose This study aims to investigate the efficacy of micro dimple in inhibiting stick-slip phenomenon on the sliding guideway. Design/methodology/approach In this study, micro-dimples were fabricated by laser on surfaces of steel disk and guideway. The disks and guideways were respectively performed pin-on-disk tribological tests and working condition experiments to study differences in lubrication condition and friction stability between textured and untextured surfaces. Findings Micro-dimples help reduce critical sliding speed that allows contact surfaces to enter in hydrodynamic lubrication regime. This increases hydrodynamic lubrication range and narrows speed range where stick-slip phenomenon can occur, enhancing sliding guideway’s adaptability for broader working conditions. Furthermore, friction stability on the textured surface improved, lowering the occurrence possibility of stick-slip phenomenon. Finally, difference between static and kinetic frictions on the textured surface is lower relative to the untextured surface, which decreases the critical velocity when the stick-slip phenomenon occurs. Originality/value The results indicate that laser-textured micro-dimples are significantly conducive to inhibit stick-slip phenomenon, thus providing smoother movement for the guideway and eventually increasing precision of the machine.

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FRICTION ANALYSIS IN CASE OF THE CARRIAGE- FEED SHAFT CINEMATIC COUPLING AT CNC LATHE

International Journal of Engineering Technologies and Management Research ◽

10.29121/ijetmr.v7.i5.2020.671 ◽

2020 ◽

Vol 7 (5) ◽

pp. 30-37

Author(s):

Daniel Popescu

Keyword(s):

Mathematical Model ◽

Rational Design ◽

Normal Force ◽

Stick Slip ◽

Disturbing Force ◽

Dimensional Precision ◽

Cnc Lathe ◽

Elastic Systems ◽

Friction Analysis ◽

Slip Phenomenon

The paper presents a mathematical model for analysis of friction between the tool bearing saddle and conductor at CNC lathe. The analysis of longitudinal advance movement laws is performed taking into account the appearance and development of disturbing harmonic forces created by auto-vibrations determined by the interaction between the partial elastic systems of tool and workpiece. The friction force is emphasized as product of two components depending on the sliding speed and on the normal disturbing force. By establishing the dynamic response of the system, when the normal force depends linearly on speed, acceleration and mobile ensemble position, the premises are created for stability analysis of the friction movement, obtaining the limit speeds under which the stick-slip phenomenon occurs. Thus, it is provided for a rational design of CNC lathe elastic structure, in order to improve the surface quality and the dimensional precision.

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Development of Artificial Skin Using Keratin Film for Evaluation of Puncture Performance of Microneedle

Journal of Robotics and Mechatronics ◽

10.20965/jrm.2020.p0351 ◽

2020 ◽

Vol 32 (2) ◽

pp. 351-361

Author(s):

Ryo Nishino ◽

Seiji Aoyagi ◽

Masato Suzuki ◽

Atsushi Ueda ◽

Yuki Okumura ◽

...

Keyword(s):

Stratum Corneum ◽

Human Skin ◽

Human Hair ◽

Subcutaneous Tissue ◽

Artificial Skin ◽

Resistance Force ◽

Stick Slip ◽

Silicon Rubber ◽

Animal Skin ◽

Slip Phenomenon

Humans do not feel pain when bitten by mosquitos; therefore, we have attempted to develop a microneedle that mimics the puncturing mechanism of mosquitos. We have quantitatively evaluated the puncturing performance of the developed microneedle by puncturing an artificial skin made from polydimethylsiloxane (PDMS), a kind of silicon rubber. Unlike the mono-layered PDMS, however, animal skin including human skin is structured to have a hard stratum corneum, epidermis and dermis over soft subcutaneous tissue. In this paper, we propose an artificial skin having a two-layered hard/soft structure, constructed from PDMS with a human-hair-derived keratin film adhered onto the top surface. We evaluated the hardness of the keratin film (Young’s modulus) and found that it could qualitatively simulate the hard layers of the skin including the stratum corneum. The artificial skin we developed reproduced the following phenomena: the decrease in resistance force of animal skin at the point when the needle penetrates the surface followed by variation in resistance due to the stick-slip phenomenon as the needle penetrates more deeply.

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Simulacija i odstranjivanje stick-slip efekta servosistema sprovodnog aparata hidraulične turbine

Energija, Ekonomija, Ekologija ◽

10.46793/eee21-1.37b ◽

2021 ◽

Vol 23 (1) ◽

pp. 37-41

Author(s):

Darko Babunski ◽

◽

Emil Zaev ◽

Atanasko Tuneski ◽

Laze Trajkovski ◽

...

Keyword(s):

Hydraulic Cylinder ◽

Friction Model ◽

Slip Effect ◽

Hydraulic Systems ◽

Hydraulic Actuator ◽

Stick Slip ◽

Hydro Turbine ◽

Servo Mechanism ◽

The Mathematical Model ◽

Slip Phenomenon

Friction is a repeatable and undesirable problem in hydraulic systems where always has to be a tendency for its removal. In this paper, the friction model is presented through which the most accurate results are achieved and the way of friction compensation, approached trough technique presented with the mathematical model of a hydraulic cylinder of a hydro turbine wicket gate controlled by a servomechanism. Mathematical modelling of a servo mechanism and hydraulic actuator, and also the simulation of hydraulic cylinder as a part of a hydro turbine wicket gate hydraulic system where the stick-slip phenomenon is present between the system components that are in contact is presented. Applied results in this paper and the theory behind them precisely demonstrate under what circumstances the stick-slip phenomenon appears in such a system. The stick-slip effect is simulated using Simulink and Hopsan software and the analysis of the results are given in this paper. Removal of the stick-slip effect is presented with the design of a cascade control implemented to control the behaviour of the system and remove the appearance of a jerking motion.

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Tribological functionalization of titanium alloys by Micro-Arc Oxidation for marine applications

MATEC Web of Conferences ◽

10.1051/matecconf/202032109001 ◽

2020 ◽

Vol 321 ◽

pp. 09001

Author(s):

Aude MATHIS ◽

Thierry MILLOT ◽

Vincent BRANGER ◽

Remy MULLER ◽

Jean-Yves GUENEHEUX

Keyword(s):

Friction Coefficient ◽

Titanium Alloys ◽

Pure Titanium ◽

Dynamic Contact ◽

Electrochemical Process ◽

Commercially Pure Titanium ◽

Tribological Behaviour ◽

Stick Slip ◽

Micro Arc Oxidation ◽

Slip Phenomenon

Micro-arc Oxidation (MAO) process is a plasma assisted electrochemical process, which allows formation of ceramic-like dry oxides on top of light alloys surfaces. The good corrosion resistance as well as the low density of titanium alloys are recognized and so required for conception of structural parts in marine environment. However, their tribological behaviour reveals an important tendency to stick-slip phenomenon, which makes use of these alloys for dynamic contact mechanisms difficult. Through the MAO project from IRT M2P, formation of a MAO coating composed of aluminium titanate has been investigated to improve tribological behaviour of a commercially pure titanium (Grade 2) and an α+β alloy (TA6V, Grade 5). Pin-on-disc testing has been carried out to evaluate friction coefficient and the presence or not of stick-slip phenomenon in various contact configurations (involving non-treated titanium surfaces, MAO treated surfaces, with steel or titanium balls …) in dry or artificial seawater media. Those test campaigns are completed by evaluation of fatigue behaviour, and tribological testing on a demonstrator. Finally, this study highlights influence of MAO coating on diminishing (to removed) stick-slip phenomenon, accompanied by a reduction of friction coefficient, whatever the kind of contact (single treated surface or both ones) and the medium.

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