Experimental investigation of the effect of in-plane vibrations on friction for different materials

Drill string torsional and longitudinal oscillation can significantly reduce axial drag in horizontal drilling. An improved theoretical model for the analysis of the frictional force was proposed based on microscopic contact deformation theory and a bristle model. The established model, an improved dynamic friction model established for drill strings in a wellbore, was used to determine the relationship of friction force changes and the drill string torsional vibration. The model results were in good agreement with the experimental data, verifying the accuracy of the established model. The analysis of the influence of drilling mud properties indicated that there is an approximately linear relationship between the axial friction force and dynamic shear and viscosity. The influence of drill string torsional oscillation on the axial friction force is discussed. The results indicated that the drill string transverse velocity is a prerequisite for reducing axial friction. In addition, low amplitude of torsional vibration speed can significantly reduce axial friction. Then, increasing the amplitude of transverse vibration speed, the effect of axial reduction is not significant. In addition, by involving general field drilling parameters, this model can accurately describe the friction behavior and quantitatively predict the frictional resistance in horizontal drilling.

Section: Simulation Parametersmentioning

confidence: 99%

Modeling Friction Performance of Drill String Torsional Oscillation Using Dynamic Friction Model

Wang

Chen

Rui

et al. 2017

“…The test units built by Leus and Gutowski [23] and Wang et al [25] have a common point that the sliding specimen (upper specimen) was not constrained in the normal direction and relied only on gravity to maintain effective contact with the vibration specimen (bottom specimen). But as mentioned above, axial vibration can inevitably cause normal vibration, resulting in unstable normal force.…”

Section: Comparison Of Experimental Setupmentioning

confidence: 99%

“…Both Leus and Gutowski [23] and Wang et al [25] carried out friction experiments in the indoor environment. However, this experimental scheme takes into account not only ambient temperature and relative humidity, but also the effect of fluid lubrication.…”

Section: Comparison Of Experimental Setupmentioning

confidence: 99%

“…Obviously, it has great difference with the actual operating situation of hydraulic oscillator. Wang et al [25] studied the effect of axial vibration and transverse vibration on steel-rock plane sliding friction pairs, however, with a wide distribution of vibration frequencies and without consideration of the drilling fluids' lubrication effect.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Axial Vibration on Sliding Frictional Force between Shale and 45 Steel

Hao

Chen

Liu

et al. 2018

Activating drill string vibration is an effective means to mitigate the excessive drag encountered during drilling complexstructure wells. However, the Coulomb model cannot describe the sliding friction behavior between drill string and borehole rock with imposed axial vibrations. To solve this problem, a specially designed experimental setup was utilized to investigate the characteristics of axial vibrating-sliding coupling friction. The results indicate that when vibration velocity is greater than sliding velocity, axial vibration can significantly reduce friction force between contact surfaces. Its friction reduction mechanism embodies not only the changes of instantaneous friction force, but also friction coefficient. Meanwhile, a friction coupling model was established based on the Hertz contact theory and Dahl model. The corresponding computational program was developed in Matlab/Simulink environment. The calculation results are in good agreement with the experimental results, verifying the validity of the present method. Furthermore, to overcome the shortcoming of Dahl model, a dynamic friction coefficient model was proposed to evaluate the friction-reducing effect of axial vibration using dimensional analysis method. The model parameters under different lubrication conditions were retrieved through inverse calculation with experimental data. This method provides a new solution for evaluating the friction-reducing effect of hydraulic oscillator and optimizing its placement.

“…This phenomenon could result in malfunctions in application and machining process. Vibration, a classical phenomenon, indicates operating accuracy and stability of the structures, and long-term vibration may cause fatigue damage to the structures and reduce their service life [5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Simulations and Experiments on Vibration Control of Aerospace Thin-Walled Parts via Preload

Zhang

2017

Thin-walled parts primarily comprise the entire piece of rough machining, and the material removal rate can surpass 95%. Numerous components with thin-walled structures are preferred in the aerospace industry for their light weight, high strength, and other advantages. In aerospace thin-walled workpiece machining processes and practical applications, they are excited by the vibration. The preload changing the modal stiffness of the part is found and this change causes continuous changes in the natural frequency. Researching on the influence of pretightening force on dynamic characteristics of thin-walled components is highly significant for controlling vibration. In this study, the typical aviation thin-walled part is the research object. Finite element numerical simulation and experimental verification are employed to analyze the dynamic characteristics of 7075 aluminum alloy thin-walled plates under different preloads for exploring the relationship between natural frequency and preload. The relationship is validated by comparative results. Both the simulation and experimental results show that the natural frequencies of plates increase following the augmentation of the preload. Thus, this research introduces the method where vibration of aerospace thin-walled parts is reduced by preload. For practical engineering application, a program showing the relationship between natural frequency and preload is written using Visual Basic language.