scholarly journals Numerical Simulation Research on Cutting Rock with a PDC Cutter Assisted by an Impact Force

2022 ◽  
Vol 2022 ◽  
pp. 1-9
Author(s):  
Yong Wang ◽  
Hongjian Ni ◽  
Ruihe Wang ◽  
Bin Huang ◽  
Shubin Liu ◽  
...  
Keyword(s):  
Frequency Spectrum ◽  
Impact Force ◽  
Low Frequency ◽  
Dominant Frequency ◽  
Impact Frequency ◽  
Cutting Depth ◽  
Threshold Frequency ◽  
Weight On Bit ◽  
Threshold Amplitude ◽  
The Impact

Extensive studies have been carried out on cutting rock with a PDC cutter, but cutting rock assisted by impact force is rarely studied. In this paper, cutting rock using conical and cylindrical PDC cutters assisted by impact force were researched with the explicit dynamic model. The laws of cutting rock using a cylindrical cutter assisted by impact force are the same as those of a conical cutter. There are thresholds of impact frequency and amplitude when they are single variables. When impact frequency is lower than the threshold frequency, the impact frequency is the dominant frequency in the frequency spectrum of weight on bit (WOB), and the amplitude of dominant frequency and removal volume decreases with the increase of impact frequency. When the impact frequency is higher than the threshold frequency, there is no dominant frequency in the frequency spectrum of WOB, and the removal volume behaves the same. When the impact force is lower than the threshold amplitude, there is no dominant frequency in the frequency spectrum of WOB, and it does not affect the removal volume but the removal volume is positively correlated with the impact amplitude. When the impact amplitude is higher than the threshold amplitude, the removal volume is also positively correlated with the impact amplitude, and the removal volume assisted by low-frequency (20 Hz and 40 Hz) impact force is higher. The frequency threshold and amplitude threshold of the conical cutter are smaller than those of the cylindrical cutter. Although the cutting depth and removal volume of the conical cutter are lower than those of the cylindrical cutter, the amplifications of cutting depth and removal volume of the conical cutter are higher than those of the cylindrical cutter when assisted by impact force.

scholarly journals Experimental Study on Axial Impact Mitigating Stick-Slip Vibration with a PDC Bit

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Yong Wang ◽  
Hongjian Ni ◽  
Yiliu (Paul) Tu ◽  
Ruihe Wang ◽  
Xueying Wang ◽  
...  
Keyword(s):  
Impact Force ◽  
Impact Load ◽  
Similarity Theory ◽  
Impact Frequency ◽  
Stick Slip ◽  
Axial Impact ◽  
Pdc Bit ◽  
Fluctuation Amplitude ◽  
Rotary Speed ◽  
The Impact

Stick-slip vibration reduces the drilling rate of penetration, causes early wear of bits, and threatens the safety of downhole tools. Therefore, it is necessary to study suppression methods of stick-slip vibration to achieve efficient and safe drilling. Field tests show that the use of downhole axial impactors is helpful to mitigate stick-slip vibration and improve rock-breaking efficiency. However, there are many deficiencies in the study of how axial impact load affects stick-slip vibration of a PDC bit. In this paper, based on the two-degrees-of-freedom spring-mass-damper model and similarity theory, a laboratory experiment device for suppressing stick-slip vibration of a PDC bit under axial impact load has been developed, and systematic experimental research has been carried out. The results show that the axial impact force can suppress the stick-slip vibration by reducing the amplitude of weight on bit and torque fluctuations and by increasing the main frequency of torque. The amplitude of impact force affects the choice of the optimal back-rake angle. The impact frequency is negatively correlated with the fluctuation amplitude of the rotary speed. When the impact frequency is greater than 100 Hz, the fluctuation amplitude of the rotary speed will not decrease.

Research and Field Application of the Axial-Torsional Coupled Percussion Drilling Technology

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Zongjie Mu ◽  
Gensheng Li ◽  
Zhongwei Huang ◽  
Jingbin Li ◽  
Hengyu Song
Keyword(s):  
Impact Force ◽  
Field Application ◽  
Fluid Density ◽  
Direct Proportion ◽  
Impact Frequency ◽  
Axial Impact ◽  
Pump Rate ◽  
Drilling Technology ◽  
The Impact ◽  
Percussion Drilling

Abstract Enhancing the rate of penetration (ROP) is one of the goals pursued by the oil and gas drilling industry. It has been proved that percussion drilling is a feasible method to increase drilling efficiency. However, single percussion drilling technology (axial percussion or torsional percussion) cannot cater to the current needs. This paper proposed a new technology/tool called the axial-torsional coupled percussion drilling, which can use the advantages of the percussion drilling in a better way. Mechanical structure and working principle of this tool were first introduced in detail and the theoretical analysis of the impact force and the impact frequency were then conducted. It was found that both the axial impact force and the torsional impact force are in direct proportion to the fluid density and are in direct proportion to the square of the pump rate. Both the axial impact frequency and the torsional impact frequency are in direct proportion to the pump rate and are in direct proportion to the square root of the fluid density. Subsequently, a laboratory experiment was conducted to verify the above theoretical results. The tools were applied to the oil field in Xin Jiang province, China. Field application results indicate that the penetration rate of the test well is averagely 1.6–3.3 times as fast as that of the adjacent well.

On the Vibration of Rotor With Rotor/Stopper Rubbing

1999 ◽  
Author(s):  
Xingjian Dai ◽  
Xiaozhang Zhang ◽  
Zhaoxiong Jin
Keyword(s):  
Impact Force ◽  
Low Frequency ◽  
Experimental Methods ◽  
Harmonic Excitation ◽  
Rotor Vibration ◽  
Rotating Speed ◽  
Subharmonic Response ◽  
The Impact ◽  
Bearing System ◽  
Flywheel Rotor

Abstract The vibration of a flywheel rotor with rotor/stopper rubbing is investigated by experimental methods. In the experiments, the large amplitude of the rotor vibration is excited by the electromagnetic harmonic excitation force and thus causes the rubbing between the rotor and the stopper. The stable rubbing rotor vibration shows that the stopper can limit the amplitude of low frequency precession effectively. The rotor to stopper collision and rub appears occasionally. The rubbing has little effect on the rotating speed of the rotor. The forced vibration becomes complex and nonlinear in the time and frequency domain when the collision and rubbing occurs. The observed high order harmonics are sub-synchronous but not subharmonic response. The second modal forward whirl of the rotor-bearing system is excited by the impact force and decays quickly.

scholarly journals Vibration responses characteristics of a Ginkgo biloba tree excited under harmonic excitation

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256492
Author(s):  
Huan Lin ◽  
Leihou Sun
Keyword(s):  
Frequency Spectrum ◽  
Ginkgo Biloba ◽  
Low Frequency ◽  
Harmonic Excitation ◽  
Dynamic Responses ◽  
Impact Excitation ◽  
Single Frequency ◽  
Vibration Responses ◽  
Different Characteristics ◽  
The Impact

The most effective method of the fruit harvesting is the mechanical harvest. The frequency spectrum of different testing positions on a Ginkgo biloba tree under the impact excitation was tested in the laboratory. The acceleration responses under the harmonic excitation were measured at the frequency of the peak and trough points in the frequency spectrum curves. Results of this research indicate that the frequency spectrum presented the consistency on the same branch but distinction among different branches. There was a correspondence between the frequency spectrum characteristics and the vibration responses. The vibration responses could be strengthened at the resonant frequency. Merely, the acceleration responses at low frequency were very weak. At higher frequency, the vibration responses were strong but presented different characteristics among different branches. The acceleration response on the trunk was always the weakest. On the same branch, the dynamic responses presented the similar characteristics and the acceleration amplitude increased gradually as the testing position was located away from the excitation point on the trunk. Among different branches, the strongest dynamic response appeared at different frequencies. Our results indicate that it was difficult to induce the strong vibration response of all the branches at the single frequency during the practical mechanical harvesting of fruits.

scholarly journals Design of a New Type of Torsional Impactor and Analysis of Its Impact Performance

2021 ◽  
Vol 11 (22) ◽  
pp. 11037
Author(s):  
Xianfeng Tan ◽  
Zongtao Chen ◽  
Songcheng Tan ◽  
Longchen Duan ◽  
Chao Xu ◽  
...  
Keyword(s):  
Rotation Speed ◽  
Impact Force ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Impact Angle ◽  
Impact Frequency ◽  
Stick Slip ◽  
Transmission Shaft ◽  
New Type ◽  
The Impact

In view of the stick-slip phenomenon in deep and hard rock drilling, a new type of torsional impactor that can provide torsional impact vibration was designed. According to the working principle and structural characteristics of the designed torsional impactor, this paper theoretically analyzes the influences of different structural parameters and motion parameters on the impact frequency, impact force, and impact torque of the torsional impactor. The results show that the impact frequency f is directly proportional to the rotational speed VZ of the transmission shaft and the installed number n of torsional impact generating devices. Additionally, the impact force F is directly proportional to sine value of the impact angle α (i.e., sinα), impact hammer mass m, impact hammer rotation speed VZ (i.e., transmission shaft rotation speed), and impact hammer rotation radius r and is inversely proportional to action time Δt of the impact hammer and impact anvil. Furthermore, the impact torque M is directly proportional to the impact force F and rotary radius r of the impact hammer. This article lays a foundation for further theoretical and experimental research of torsional impactors and provides a reference for the design and testing of torsional impactors.

Energy Analysis for Energy Dissipation Shed-Tunnel’s Rockfall Impact Signal

2011 ◽  
Vol 261-263 ◽  
pp. 1054-1057 ◽  
Author(s):  
Lin Feng Wang ◽  
Hong Mei Tang ◽  
Hong Kai Chen
Keyword(s):  
Energy Dissipation ◽  
Impact Energy ◽  
High Frequency ◽  
Energy Analysis ◽  
Low Frequency ◽  
Prevention Measures ◽  
Impact Frequency ◽  
Wavelet Theory ◽  
Frequency Increase ◽  
The Impact

Shed-tunnel is one of common prevention measures along the highway. First, denoised the rockfall impact signal when the rock impact the ordinary shed-tunnel and the energy dissipation shed-tunnel by the wavelet theory. The calculation result indicated that the wavelet theory’s denoise effect is very good. Then, pick-up each frequency band’s the rockfall impact signal, and analysed the energy for each frequency band’s impact signal. The result indicated that the energy dissipation shed-tunnel’s impact energy concentrate in the low frequency part. There are only 0.4% impact energy in the high frequency part. Besides, the energy dissipation shed-tunnel’s impact energy in the low frequency part is higher than the the ordinary shed-tunnel, and the energy dissipation shed-tunnel’s impact energy depressed velocity when the impact frequency increase is fast than the ordinary shed-tunnel. So the energy dissipation shed-tunnel’s design must consider the low frequency impact,and could ignore the high frequency impact.

High Resolution Time-Frequency Analysis Base on Ricker Atom Matching Pursuit Decomposition

2013 ◽  
Vol 284-287 ◽  
pp. 3115-3119
Author(s):  
Wei Song ◽  
Jia Hui Zuo ◽  
Peng Cheng Hu
Keyword(s):  
Frequency Analysis ◽  
Matching Pursuit ◽  
Low Frequency ◽  
Seismic Signal ◽  
Dominant Frequency ◽  
Frequency Resolution ◽  
Frequency Variation ◽  
Time Frequency Analysis ◽  
Time Frequency ◽  
The Impact

The high accuracy time-frequency representation of non-stationary signals is one of the key researches in seismic signal analysis. Low-frequency part of the seismic data often has a higher frequency resolution, on the contrary it tends to have lower frequency resolution in the high frequency part. It’s difficult to fine characterize the time-frequency variation of non-stationary seismic signals by conventional time-frequency analysis methods due to the limitation of the window function. Therefore based on the Ricker wavelet, we put forward the matching pursuit seismic trace decomposition method. It decomposes the seismic records into a series of single component atoms with different centre time, dominant frequency and energy, by making use of the Wigner-Ville distribution, has the time-frequency resolution of seismic signal reach the limiting resolution of the uncertainty principle and skillfully avoid the impact of interference terms in conventional Wigner-Ville distribution.

scholarly journals Response of Edam cheese to non-destructive impact

2009 ◽  
Vol 57 (4) ◽  
pp. 55-62 ◽  
Author(s):  
Šárka Nedomová
Keyword(s):  
Spectral Analysis ◽  
Impact Force ◽  
Surface Displacement ◽  
Dominant Frequency ◽  
Response Functions ◽  
Cheese Ripening ◽  
Surface Displacements ◽  
Frequency Domains ◽  
The Impact ◽  
Non Destructive

The behaviour of the Edam cheese during its maturation under dynamic loading has been studied. The block of tested cheese has been loaded by the impact of an aluminium bar. The force between bar and cheese has been recorded. The surface displacements as well as the surface velocities have been obtained at the different points from the point of the bar impact using of the laser vibrometers. Response functions have been evaluated both in the time and frequency domains. It has been found that the degree of the cheese maturity is well characterized by the attenuation of the surface displacement maximum. This maturation is also described by the maximum of the impact force. The spectral analysis of the response functions revealed that there was a dominant frequency, which depends only on the degree of the cheese maturity. The developed method represents a promising procedure for the continuous recording of the cheese ripening.

scholarly journals Experimental investigation of the low-frequency impact sound transfer function of lightweight wooden floors via heel drops

Acta Acustica ◽  
2020 ◽  
Vol 4 (6) ◽  
pp. 23
Author(s):  
Yi Qin ◽  
Jin Jack Tan ◽  
Maarten Hornikx
Keyword(s):  
Natural Frequencies ◽  
Impact Force ◽  
Signal To Noise Ratio ◽  
Force Plate ◽  
Low Frequency ◽  
Superior Performance ◽  
High Input ◽  
Low Frequencies ◽  
Transfer Measurement ◽  
The Impact

The lightweight floor is a popular construction choice in buildings despite its poor low-frequency impact sound performance. This is exacerbated by common human activities, such as walking and jumping, that have high input force levels at low frequencies. Therefore, experimental evaluations of the low-frequency impact sound performance of a wooden lightweight floor are of interest to designers and researchers. The aim of this paper is to explore the use of heel drop for impact sound transfer measurement. An impact force plate has been built to accurately measure the heel-drop forces up to 200 Hz and the performances on two types of floors are evaluated. The heel drop has a higher energy level at low frequencies, resulting in higher coherence and signal-to-noise ratio and hence superior performance in characterizing the floors in the frequency range of below 40 Hz when compared to the impact hammer. Interestingly, in the case of a heel-drop excitation, the first natural frequencies of the floor decrease. It is in contrast to when a human is simply standing on it, which resulted in an increase of the natural frequencies upon impact hammer excitation.

Some thought on the Estimating of the Impact Force by an Experiment

2019 ◽  
Vol 7 (2) ◽  
pp. 205-213
Author(s):  
Yong-Doo Kim ◽  
Seung-Jae Lim ◽  
Hyun-Ung Bae ◽  
Kyoung-Ju Kim ◽  
Chin-Ok Lee ◽  
...  
Keyword(s):  
Impact Force ◽  
The Impact
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