scholarly journals The stability of rotating rods under the action of vibro-impact load

2021 ◽  
pp. 113-121
Author(s):  
Petro Lizunov ◽  
Valentyn Nedin
Keyword(s):  
Impact Load ◽  
Stability Loss ◽  
Drilling Process ◽  
Rotary Drilling ◽  
Impact Action ◽  
Modes Of Vibration ◽  
Considerable Length ◽  
The Stability ◽  
Oscillating Motion ◽  
Rotating Rods

The paper presents the investigation results of the vibro-impact loads’ influence on the stability of vibro-drilling machine’ drill-rod in the process of well in hard rock. The drilling process of such wells is significantly facilitated in case of vibro-impact action. The destroying of the rocks during the vibro-rotary drilling occurs via the complex effect of the vibration impulses and rotational motion. In this way, the task of such drill-rod study stability has actuality. In this case, the various modes of vibration and stability loss are possible. In this regard, the study was done by developed software, in which a technique of computer simulation of the oscillating motion of considerable length rotating rods under the action of axial periodic loads is implemented. Such software gives the possibility to model the oscillatory motion of rotating rods and determine the parameters by witch the dynamic stability loss of the studied system can occur. Using this software the diagrams with regions of stable and unstable motion of the rotating rod were drawn for different parameters of the considered system. The process of oscillation is considered in space with account of inertia forces and geometric nonlinearity of the rod. It is shown, that on certain rotational speeds and frequencies of vibro-impact load there are ranges of unstable motion where the run of equipment can inevitably lead to destruction. The obtained results have been analyzed. The conclusion about the possibility of running the equipment in certain frequency ranges is made.

scholarly journals Analysis and Testing of Load Characteristics for Rotary-Percussive Drilling of Lunar Rock Simulant with a Lunar Regolith Coring Bit

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Peng Li ◽  
Hui Zhang ◽  
Shengyuan Jiang ◽  
Weiwei Zhang
Keyword(s):  
Impact Load ◽  
Rotational Velocity ◽  
Lunar Regolith ◽  
Drilling Process ◽  
Percussive Drilling ◽  
Analytic Equation ◽  
Lunar Rock ◽  
Rotary Drilling ◽  
Drilling Parameters ◽  
Load Characteristics

Based on an optimized lunar regolith coring bit (LRCB) configuration, the load characteristics of rotary-percussive drilling of lunar rock simulant in a laboratory environment are analyzed to determine the effects of the drilling parameters (the rotational velocity, the penetration rate, and the percussion frequency) on the drilling load. The process of rotary drilling into lunar rock using an LRCB is modeled as an interaction between an elemental blade and the rock. The rock’s fracture mechanism during different stages of the percussive mechanism is analyzed to create a load forecasting model for the cutting and percussive fracturing of rock using an elemental blade. Finally, a model of the load on the LRCB is obtained from the analytic equation for the bit’s cutting blade distribution; experimental verification of the rotary-impact load characteristics for lunar rock simulant with different parameters is performed. The results show that the penetrations per revolution (PPR) are the primary parameter influencing the drilling load. When the PPR are fixed, increasing the percussion frequency reduces the drilling load on the rock. Additionally, the variation pattern of the drilling load of the bit is in agreement with that predicted by the theoretical model. This provides a research basis for subsequent optimization of the drilling procedure and online recognition of the drilling process.

Study on the bearing resistance of axially compressed L-shaped stainless steel core plate wall based on the stability loss

2021 ◽  
Vol 249 ◽  
pp. 113264
Author(s):  
Xing-Ping Shu ◽  
Huai-Bing Wang ◽  
Yi Li ◽  
Zhi-Shen Yuan ◽  
Ke Li
Keyword(s):  
Stainless Steel ◽  
Stability Loss ◽  
Steel Core ◽  
The Stability

scholarly journals Stability Evaluation Method of Hole Wall for Bored Pile under Blasting Impact

Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 79
Author(s):  
Qiuwei Yang ◽  
Zhikun Ba ◽  
Zhuo Zhao ◽  
Xi Peng ◽  
Yun Sun
Keyword(s):  
Pile Foundation ◽  
Evaluation Method ◽  
Impact Load ◽  
Stability Evaluation ◽  
Foundation Construction ◽  
Concentration Problem ◽  
Hole Wall ◽  
Failure Theory ◽  
Collapse Failure ◽  
The Stability

Blasting impact load may be encountered during the construction of some pile foundation projects. Due to the effect of blasting impact, hole collapse can easily occur in the hole-forming stage of pile foundation construction. In order to prevent hole collapse, it is very necessary to evaluate the stability of a pile hole wall before pile foundation construction. The calculation of hole collapse can usually be attributed to an axisymmetric circular hole stress concentration problem. However, the existing collapse failure theory of pile hole hardly considers the effect of blasting impact load. In view of this, this paper proposes the stability evaluation method of a pile hole wall under blasting impact. Compared with the existing collapse failure theory, the proposed method fully considers the effect of blasting impact stress. Using Mohr–Coulomb strength theory and symmetry analysis, the strength condition of collapse failure is established in this work for accurate evaluation of the stability of a hole wall. The proposed stability evaluation method is demonstrated by a pile foundation construction project of a bridge. Moreover, a shaking table test on the pile hole model was performed to verify the proposed method by experimental data. The results indicate the effectiveness and usability of the proposed method. The proposed method provides a feasible way for the stability analysis of a pile hole wall under blasting impact.

scholarly journals ALGORITHM AND SOFTWARE FOR CALCULATING THE STABILITY OF THE FORM OF EQUILIBRIUM OF DISCRETE SYSTEMS

2019 ◽  
Vol 13 (3) ◽  
pp. 44-49
Author(s):  
A.A. SHKURUPIY ◽  
A.N. PASCHENKO ◽  
P.B. MYTROFANOV
Keyword(s):  
Discrete Systems ◽  
Stability Loss ◽  
Transcendental Equation ◽  
Loss Of Stability ◽  
Displacement Method ◽  
Software Complex ◽  
Complex Functions ◽  
Transcendental Functions ◽  
The Stability ◽  
Theoretical Mechanics

The paper presents an algorithm for calculating the stability of the form of equilibrium of the first kind of compressed discrete systems by the method of displacements in combination with themethods of iterations and bisection. The use of the displacement method in combination with the iteration and bisection methods makes it possible to effectively determine the minimum critical stress or strain at the first bifurcation and their corresponding form of loss of stability, both for statically determined and statically undetectable systems. This approach, using matrixforms, makes it possible to significantly simplify the calculations of the analytical condition for the loss of stability of compressed discrete systems (the stability loss equation), which has high orders, as well as to construct the form of loss of stability corresponding to a critical load, that is, to solve the problem of loss of stability of equilibrium. The calculation of the compressed discrete system on the stability of the form of equilibrium actually reduces to the solution of the difficultly described nonlinear transcendental equation, which is the equation of loss of stability. The difficulty lies in the absence of an analytical solution of such an equation due to the presence of complex functions of Zhukovsky, which have transcendental functions in their structure. Such solution can be performed only with the use of numerical methods. This algorithm for calculating the loss of equilibrium of the first kind of compressed discrete systems by displacement in combination with the methods of iteration and bisection is implemented in the software complex "Persist" for a PC in Windows OS. The program was approbated and implemented in theeducational process at the Department of Structural and Theoretical Mechanics of the Poltava National Technical Yuri Kondratyuk University during the training of specialists in engineering specialties.

Modeling the Vibratory Drilling Process

1999 ◽  
Author(s):  
Stephen A. Batzer ◽  
Alexander M. Gouskov ◽  
Sergey A. Voronov
Keyword(s):  
Rotational Velocity ◽  
Time Lag ◽  
Chip Thickness ◽  
Cutting Conditions ◽  
Model Parameters ◽  
Drilling Process ◽  
Workpiece Material ◽  
Velocity Amplitude ◽  
The Stability

Abstract The dynamic behavior of deep-hole vibratory drilling is analyzed. The mathematical model presented allows the determination of axial tool and workpiece displacements and cutting forces for significant dynamic system behavior such as the entrance of the cutting tool into workpiece material and exit. Model parameters include the actual rigidity of the tool and workpiece, time-varying chip thickness, time lag for chip formation due to tool rotation and possible disengagement of drill cutting edges from the workpiece due to tool and/or workpiece axial vibrations. The main features of this model are its nonlinearity and inclusion of time lag differential equations which require numeric solutions. The specific cutting conditions (feed, tool rotational velocity, amplitude and frequency of forced vibrations) necessary to obtain discontinuous chips and reliable removal are determined. The stability conditions of excited vibrations are also investigated. Calculated bifurcation diagrams make it possible to derive the domain of system parameters along with the determination of optimal cutting conditions.

scholarly journals Assessment of parting rock weak zones under the joint and downward mining of coal seams

2018 ◽  
Vol 66 ◽  
pp. 03001 ◽  
Author(s):  
Volodymyr Bondarenko ◽  
Iryna Kovalevska ◽  
Hennadii Symanovych ◽  
Mykhailo Barabash ◽  
Vasyl Snihur
Keyword(s):  
Stress Component ◽  
Stability Loss ◽  
Coal Seams ◽  
Security Systems ◽  
Relationship Patterns ◽  
Instrumental Observations ◽  
Set Up ◽  
The Stability ◽  
The Relationship ◽  
Weak Zones

The aim of the forecasting effort is to identify troublesome zones of stability loss by a parting lengthwise of the extraction panel under the joint and downward mining of coal seams. Analyses have been carried out of active stress component curves for a 3-D model computational experiment compared with the strength characteristic of each lithotype of a parting. An algorithm has been developed for the stability assessment of a parting lengthwise along the extraction panel. The relationship patterns have been estimated between the sizes of the parting rocks discontinuity zones and the main geomechanical parameters. A scientifically grounded basis has been created for the detection of the parting rock weak zones lengthwise along the extraction panel for the calculation of the mounting and security systems of the development works. A complex of underground instrumental observations was made, which was used to set up a correspondence of patterns to indicate the variation in rock pressure manifestation intensity and the tendencies for changes in the parting structure. All of this confirms the adequacy of the techniques for parting state forecasting, which is recommended for use in the engineering documentation for the joint and downward mining of coal seams.

Dynamical properties about ultrasonic vibration assisted drilling of TiBw/TC4 composite

2020 ◽  
pp. 095440542096843
Author(s):  
Yong Feng ◽  
Haoxiang Wang ◽  
Min Zhang ◽  
Zihao Zhu ◽  
Xiaoyu Wang ◽  
...  
Keyword(s):  
Ultrasonic Vibration ◽  
Cutting Tools ◽  
System Model ◽  
Force Model ◽  
Drilling Process ◽  
Drilling Force ◽  
Dry Cutting ◽  
Analysis System ◽  
The Stability ◽  
Three Degree Of Freedom

TiBw / TC4 composite material was used as the machining object of Ultrasonic vibration assisted drilling (UVAD), the single directional three-degree-of-freedom dynamical system model was established. The dynamic signal test and analysis system was used for modal experiment to identify the parameters in the model. Under the condition of dry cutting, the drilling axial force and tool vibration in the drilling process are studied. The results showed that the maximum values of the predicted and measured axial drilling force were 412.5N and 439.6N respectively, and the error rate was 6.165%, which verified the reliability of the predicted axial drilling force model. For cutting tools, the average amplitudes of simulated vibration and measured vibration were 0.1124mm and 0.1151mm respectively, with a difference of 2.402%, and the overall trends were the same, which verifies the reliability of the dynamical model. Finally, the stability of drilling process was analyzed, and the frequency and amplitude of ultrasonic vibration were analyzed. The results show that in order to expand the unconditional stability region, it is more efficient to increase the amplitude than to increase the frequency.

scholarly journals Study on the stability of a shear-thinning suspension used in oil well drilling

2018 ◽  
Vol 73 ◽  
pp. 10 ◽  
Author(s):  
Flávia M. Fagundes ◽  
Nara B.C. Santos ◽  
João Jorge R. Damasceno ◽  
Fábio O. Arouca
Keyword(s):  
Gamma Ray ◽  
Drilling Fluid ◽  
Shear Thinning ◽  
Drilling Fluids ◽  
Oil Well ◽  
Drilling Process ◽  
Well Drilling ◽  
Constant Rate ◽  
The Stability ◽  
Solid Liquid

In order to avoid solid-liquid gravitational separation of particles in the drilling fluid and cuttings generated in this process, the oil industry has been developing drilling fluids with shear-thinning and thixotropic characteristics. In case of operational stops in the drilling process, the intense sedimentation of these particles can damage the equipment used and the well. In this context, this study simulated an operational stop to obtain information about stability of solids in a paraffin-based suspension with time-dependent shear-thinning behavior, which has already been used in current drilling processes. A long-term test using gamma-ray attenuation technique identified the separation dynamics of a set of micrometric particles belonging to and incorporated into the drilling fluid during operation. This test verified the typical regions of gravitational sedimentation and, through constant concentration curves, indicated that the sedimentation process did not occur at a constant rate. This study also proposed a constitutive equation for pressure on solids.

Relationships Between Wheel/Rail Surface Impact Loadings and Correspondingly Transmitted Tie/Ballast Impact Pressures for Revenue Train Operations

2018 ◽  
Author(s):  
Travis J. Watts ◽  
Jerry G. Rose ◽  
Ethan J. Russell
Keyword(s):  
Test Section ◽  
Impact Load ◽  
Peak Force ◽  
Pressure Measurements ◽  
Track Geometry ◽  
Impact Forces ◽  
Interfacial Pressure ◽  
Degradation Rates ◽  
The Stability ◽  
The Impact

A series of specially designed granular material pressure cells were precisely positioned directly below the rail at the tie/ballast interface to measure typical interfacial pressures exerted by revenue freight trains. These vertical pressures were compared to the recorded wheel/rail nominal and peak forces for the same trains traversing nearby mainline wheel impact load detectors (WILDs). The cells were imbedded within the bottom of new wood ties so that the surfaces of the pressure cells were even with the bottoms of the ties and the underlying ballast. The cells were inserted below consecutive rail seats of one rail to record pressures for a complete wheel rotation. The stability and tightness of the ballast support influenced the magnitudes and consistencies of the recorded ballast pressures. Considerable effort was required to provide consistent ballast conditions for the instrumented ties and adjacent undisturbed transition ties. Norfolk Southern (NS) crews surfaced and tamped through the test section and adjacent approach ties. This effort along with normal accruing train traffic subsequently resulted in reasonably consistent pressure measurements throughout the test section. The impact ratio (impact factor) and peak force values recorded by the WILDs compared favorably with the resulting magnitudes of the transferred pressures at the tie/ballast interface. High peak force and high impact ratio WILD readings indicate the presence of wheel imperfections that increase nominal forces at the rail/wheel interface. The resulting increased dynamic impact forces can contribute to higher degradation rates for the track component materials and more rapid degradation rates of the track geometry. The paper contains comparative WILD force measurements and tie/ballast interfacial pressure measurements for loaded and empty trains. Typical tie/ballast pressures for locomotives and loaded freight cars ranges from 20 to 30 psi (140 to 210 kPa) for smooth wheels producing negligible impacts. The effect of increased wheel/rail impacts and peak force values on the correspondingly transmitted pressures at the tie/ballast interface is significant, with increased pressures of several orders of magnitude compared to nominal impact forces from wheels.

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