scholarly journals Prediction Model of Drilling Performance for Percussive Rock Drilling Tool

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Dae-Ji Kim ◽  
Jaewon Kim ◽  
Booyeong Lee ◽  
Min-Seok Shin ◽  
Joo-Young Oh ◽  
...  
Keyword(s):  
Prediction Model ◽  
Dynamic Effect ◽  
Drill Bit ◽  
Motion Model ◽  
Percussive Drilling ◽  
Drilling Tool ◽  
Rock Types ◽  
Drilling Performance ◽  
The Impact

This study suggests a method for quantitatively estimating the drilling performance of the down-the-hole (DTH) hammer during percussive drilling of rock surfaces. A pneumatic dynamic model of the DTH hammer was developed that considers the mass flow rate relations representing the orifice opening areas of the air tube, the piston, and bit flushing channels. A drill bit motion model was developed to represent the dynamics of a drill bit impacted by a dropped piston and explain the impact stress propagation and rock-crushing mechanism. The rock-crushing effect of the drill button bit was measured through a piston drop test. The pneumatic hammer model and drill bit motion model were then combined in a prediction model to determine the impact efficiency according to different rock types (i.e., soft, medium-hard, and very hard). The drilling efficiency was defined as the input value of the prediction model, which was used to simulate the drilling performance of DTH hammers considering the rock type and dynamic effect of the drill bit. Finally, the simulation results were compared with the results of in situ drilling tests for verification.

scholarly journals Research on Impact Stress Transfer Characteristics of Lunar Rock Coring Drill

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Peng Li ◽  
Yizhuo Wang ◽  
Bo Xu ◽  
Junwei Liu ◽  
Weiwei Zhang
Keyword(s):  
Impact Energy ◽  
Lunar Surface ◽  
Cutting Edge ◽  
Design Parameters ◽  
Drill Bit ◽  
Drilling Tool ◽  
Drill Stem ◽  
Impact Stress ◽  
Transfer Characteristics ◽  
The Impact

In the whole lunar surface drilling and sampling task, it is critical to make the operation of the drilling and sampling impact system efficient and reliable. This paper focuses on how to improve the impact stress obtained at the cutting edge of the drill bit. Firstly, with the objective of maximizing the output impact energy, the design parameters of the percussive mechanism are optimally selected; based on the one-dimensional stress wave transfer theory, the collision input model and transfer models of impact stress in the drilling tool are established. Secondly, in order to verify the above design parameters and theoretical models, the percussive drive characteristics’ test and the transfer characteristics’ tests of impact stress in the drill stem and drilling tool joints are carried out in turn. The experimental results are consistent with the theoretical analysis, which clarifies the transfer characteristics of the impact stress at the various stages of generation, incidence, and transfer to the cutting edge. It was finally found that increasing the percussive frequency and impact energy of the percussive mechanism as well as the contact stiffness of the collision surface can increase the incident impact stress of the drilling tool, while reducing the length of the screw connection between the drill bit and the drill stem can reduce the impact stress loss. This provides a theoretical reference for the design of the percussive mechanism and drilling tools in lunar surface drilling and sampling tasks.

scholarly journals Measurement of Stress Waves Propagation in Percussive Drilling

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3677
Author(s):  
Diego Scaccabarozzi ◽  
Bortolino Saggin
Keyword(s):  
Stress Wave ◽  
Axial Stress ◽  
Element Model ◽  
Stress Waves ◽  
Stress Wave Propagation ◽  
Drill Bit ◽  
Torsional Vibrations ◽  
Flexural Stress ◽  
Percussive Drilling ◽  
The Impact

This work describes the results of a test campaign aimed to measure the propagation of longitudinal, torsional, and flexural stress waves on a drill bit during percussive rock drilling. Although the stress wave propagation during percussive drilling has been extensively modeled and studied in the literature, its experimental characterization is poorly documented and generally limited to the detection of the longitudinal stress waves. The activity was performed under continuous drilling while varying three parameters, the type of concrete, the operator feeding force, and the drilling hammer rotational speed. It was found that axial stress wave frequencies and spectral amplitudes depend on the investigated parameters. Moreover, a relevant coupling between axial and torsional vibrations was evidenced, while negligible contribution was found from the bending modes. A finite element model of the drill bit and percussive element was developed to simulate the impact and the coupling between axial and torsional vibrations. A strong correlation was found between computed and measured axial stress spectra, but additional studies are required to achieve a satisfactory agreement between the measured and the simulated torque vibrations.

Optimal button arrangement of a percussion drill bit and its operating condition for improving drilling efficiency

2017 ◽  
Vol 232 (16) ◽  
pp. 2887-2898 ◽  
Author(s):  
Hoon Kang ◽  
Jin-Young Park ◽  
Jung-Woo Cho ◽  
Jin-Seok Jang ◽  
Kun-Woo Kim ◽  
...  
Keyword(s):  
Evaluation Method ◽  
Optimal Solution ◽  
Operating Conditions ◽  
Rock Surface ◽  
Drill Bit ◽  
Operating Condition ◽  
Drilling Performance ◽  
Impact Area ◽  
Specific Operating Condition ◽  
The Impact

This paper proposes an optimal button arrangement of a percussion drill bit and its operating condition to improve drilling efficiency. A new evaluation method is introduced for the button arrangement that utilizes the superimposed impact area, blank area, and drilling deviation moment as the quantitative indices to evaluate the impact of buttons on the rock surface. To determine the optimal button arrangement and its operating conditions, a progressive metamodel-based design optimization was conducted using the new evaluation indices as the analysis response, and then the optimal solution was determined through iteration. Consequently, all the button evaluation indices were reduced significantly and the impact areas were distributed uniformly under a specific operating condition. Additionally, the drilling performances of the optimal button arrangement were investigated according to the operating conditions to obtain the maximum drilling performance in terms of the drilling machine operation.

Development of Alternative Drive Concepts for Down-the-Hole Hammer in Deep Drilling

2015 ◽  
Author(s):  
Franziska Lehmann ◽  
Matthias Reich
Keyword(s):  
Test Facility ◽  
Drilling Mud ◽  
Percussive Drilling ◽  
Drilling Tool ◽  
Alternative Drive ◽  
New Energy ◽  
Deep Boreholes ◽  
Drilling Muds ◽  
The Impact ◽  
Conventional Drilling

Hard rock drilling is facing increasing importance by using geothermal energy as a new energy source. Percussive drilling methods are generally well suited for drilling hard rocks. However, until now there is no drilling tool available on the market that uses percussive drilling methods and can be applied in deep boreholes in combination with common drilling muds. The aim of the DGMK project 733 is to develop a hammer drill which generates the impact energy downhole and works with conventional drilling mud. Seven different drive concepts were developed during the feasibility study. Demonstrators were manufactured for four of the seven drive concepts. The evaluation of the drive concepts showed that two of them have a high potential for the implementation in the field. These two concepts will be developed further to laboratory prototypes and were investigated at a test facility.

scholarly journals Assessment of Preservative-Treated Wooden Poles Using Drilling-Resistance Measurements

Forests ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 20 ◽  
Author(s):  
Evgenii Sharapov ◽  
Christian Brischke ◽  
Holger Militz
Keyword(s):  
Treated Wood ◽  
Untreated Wood ◽  
Wood Properties ◽  
Potential Method ◽  
Drilling Tool ◽  
Drill Bits ◽  
Drilling Resistance ◽  
The Impact

An IML-Resi PD-400 drilling tool with two types of spade drill bits (IML System GmbH, Wiesloch, Germany) was used to evaluate the internal conditions of 3 m wooden poles made from Scots pine (Pinus sylvestris L.). Drilling tests were performed on poles that were industrially vacuum-pressure-impregnated with a copper-based preservative (Korasit KS-M) and untreated reference poles. Both types of poles were subject to 10.5 years of in-ground exposure. Wood moisture content (MC) was measured using a resistance-type moisture meter. MC varied between 15% and 60% in the radial and axial directions in both treated and untreated poles. A higher MC was detected in the underground, top, and outer (sapwood) parts of the poles. Typical drilling-resistance (DR) profiles of poles with internal defects were analyzed. Preservative treatment had a significant influence on wood durability in the underground part of the poles. Based on DR measurements, we found that untreated wood that was in contact with soil was severely degraded by insects and wood-destroying fungi. Conversely, treated wood generally showed no reduction in DR or feeding resistance (FR). DR profiling is a potential method for the in-situ or in vitro assessment and quality monitoring of preservative treatments and wood durability. The technological benefits of using drill bits with one major cutting edge, instead of standard drill bits with center-spiked tips and two major cutting edges, were not evident. A new graphical method was applied to present DR data and their spatial distribution in the poles. Future studies should focus on the impact of preservative treatments, thermal modification, and chemical modification on the DR and FR of wood. This may further elucidate the predictive value of DR and FR for wood properties.

In situ Quantification of the Impact of Episodic Enhanced Turbulent Events in Large Phytoplankton

2011 ◽  
Author(s):  
Percy L. Donaghay ◽  
Jan Rines ◽  
James Sullivan
Keyword(s):  
The Impact

scholarly journals Kinematics and dynamics analysis of new rotary-percussive PDM drilling tool

2021 ◽  
pp. 146134842198915
Author(s):  
Jialin Tian ◽  
Xuehua Hu ◽  
Liming Dai ◽  
Lin Yang ◽  
Yi Yang ◽  
...  
Keyword(s):  
Drill String ◽  
Structure Design ◽  
Drilling Process ◽  
Analysis Model ◽  
Drilling Tool ◽  
Stick Slip ◽  
Rate Of Penetration ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
The Impact

This paper presents a new drilling tool with multidirectional and controllable vibrations for enhancing the drilling rate of penetration and reducing the wellbore friction in complex well structure. Based on the structure design, the working mechanism is analyzed in downhole conditions. Then, combined with the impact theory and the drilling process, the theoretical models including the various impact forces are established. Also, to study the downhole performance, the bottom hole assembly dynamics characteristics in new condition are discussed. Moreover, to study the influence of key parameters on the impact force, the parabolic effect of the tool and the rebound of the drill string were considered, and the kinematics and mechanical properties of the new tool under working conditions were calculated. For the importance of the roller as a vibration generator, the displacement trajectory of the roller under different rotating speed and weight on bit was compared and analyzed. The reliable and accuracy of the theoretical model were verified by comparing the calculation results and experimental test results. The results show that the new design can produce a continuous and stable periodic impact. By adjusting the design parameter matching to the working condition, the bottom hole assembly with the new tool can improve the rate of penetration and reduce the wellbore friction or drilling stick-slip with benign vibration. The analysis model can also be used for a similar method or design just by changing the relative parameters. The research and results can provide references for enhancing drilling efficiency and safe production.

Bayesian analysis reveals the impact of load partitioning on microstructural evolution in Ti-6Al-4V during in-situ tensile loading

Materialia ◽  
2021 ◽  
Vol 15 ◽  
pp. 100993
Author(s):  
N. Armstrong ◽  
P.A. Lynch ◽  
P. Cizek ◽  
S.R. Kada ◽  
S. Slater ◽  
...  
Keyword(s):  
Bayesian Analysis ◽  
Microstructural Evolution ◽  
Tensile Loading ◽  
The Impact

scholarly journals Solid-Phase Extraction Embedded Dialysis (SPEED), an Innovative Procedure for the Investigation of Microbial Specialized Metabolites

Marine Drugs ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. 371
Author(s):  
Phuong-Y Mai ◽  
Géraldine Le Goff ◽  
Erwan Poupon ◽  
Philippe Lopes ◽  
Xavier Moppert ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Chemical Space ◽  
Molecular Profile ◽  
Phase Extraction ◽  
Specialized Metabolites ◽  
Streptomyces Albidoflavus ◽  
Cultivation Process ◽  
The Impact

Solid-phase extraction embedded dialysis (SPEED technology) is an innovative procedure developed to physically separate in-situ, during the cultivation, the mycelium of filament forming microorganisms, such as actinomycetes and fungi, and the XAD-16 resin used to trap the secreted specialized metabolites. SPEED consists of an external nylon cloth and an internal dialysis tube containing the XAD resin. The dialysis barrier selects the molecular weight of the trapped compounds, and prevents the aggregation of biomass or macromolecules on the XAD beads. The external nylon promotes the formation of a microbial biofilm, making SPEED a biofilm supported cultivation process. SPEED technology was applied to the marine Streptomyces albidoflavus 19-S21, isolated from a core of a submerged Kopara sampled at 20 m from the border of a saltwater pond. The chemical space of this strain was investigated effectively using a dereplication strategy based on molecular networking and in-depth chemical analysis. The results highlight the impact of culture support on the molecular profile of Streptomyces albidoflavus 19-S21 secondary metabolites.

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