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Ch. S. N. Murthy - One of the best experts on this subject based on the ideXlab platform.
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Temperature Measurement During Rotary Drilling of Rocks - A Statistical Approach
International Conference on Emerging Trends in Engineering (ICETE), 2020Co-Authors: Vijay Kumar Shankar, B. M. Kunar, Ch. S. N. MurthyAbstract:This paper discusses a statistical analysis to measure the temperature during Rotary Drilling of fine-grained sandstone (pink) using embedded thermocouple method. The regression models consist of three input variables such as diameter of the bit, rpm and rate of penetration for different depth of thermocouples. Experimental test were conducted in computer numerical control (CNC) vertical machining centre. The measured temperature has been applied to study the influencing parameter using statistical technique. Analysis of variance (ANOVA) shows that the percentage contribution ratio of each operational parameters on temperature (output response). The most influencing parameter for temperature is rate of penetration with a percentage contribution of 71.32%, followed by drill bit diameter and spindle speed which contribute 19.27% and 2.99% respectively. The ANOVA and regression models for temperature give p-values of less than 0.05. Hence the predicted regression models are statistically significant and good predictive capabilities with acceptable accuracy.
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ANN model for prediction of bit–rock interface temperature during Rotary Drilling of limestone using embedded thermocouple technique
Journal of Thermal Analysis and Calorimetry, 2019Co-Authors: Vijay Kumar Shankar, B. M. Kunar, Ch. S. N. MurthyAbstract:In the present work, an artificial neural network (ANN) model has been developed to predict the bit–rock interface temperature using a newly fabricated grounded K-type thermocouple (range 0–1250 °C) during Rotary Drilling in a CNC vertical machining center. The data have been taken from experimental observation using an embedded thermocouple technique in the laboratory at room temperature (28 °C) using a masonry drill bit. The observations were made using four different operational conditions, namely drill bit diameter (6, 8, 10, 12 and 16 mm), spindle speed (250, 300, 350, 400 and 450 rpm), rate of penetration (2, 4, 6, 8 and 10 mm min^−1) and depth (6, 14, 22 and 30 mm). The ANN has been developed based on the multi layer perceptron neural network (MLPNN) with four different input parameters. A Levenberg–Marquardt (LM) algorithm with feed-forward and backward propagation has been used in this model. The predicted value of the bit–rock interface temperature with the highest R ^2 value provides a satisfactory result with the experimental data. The training value of RMSE is 1.2127, MAPE is 0.0196 and R ^2 is 0.9960, while the testing value of RMSE is 1.2770, MAPE is 0.0170 and R ^2 is 0.9978. The ANN model shows that the proposed MLPNN model successfully predicts the bit–rock interface temperature during the Rotary Drilling of limestone.
Vijay Kumar Shankar - One of the best experts on this subject based on the ideXlab platform.
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Measurement of bit-rock interface temperature and wear rate of the tungsten carbide drill bit during Rotary Drilling
Friction, 2020Co-Authors: Vijay Kumar Shankar, B. M. Kunar, Chivukula Suryanarayana Murthy, M R RameshAbstract:Rock Drilling is an essential operation in mining industries. Temperature at the bit-rock interface plays a major role in the wear rate of the drill bit. This paper primarily focuses on the wear rate of tungsten carbide (WC) drill bit and the interrelationship between temperature and wear rate during Rotary Drilling operations conducted using a computer numerical control (CNC) machine. The interrelationship between the temperature and wear rate was studied with regard to three types of rock samples, i.e., fine-grained sandstone (FG) of uniaxial compressive strength (UCS) that is 17.83 MPa, medium-grained sandstone (MG) of UCS that is 13.70 MPa, and fine-grained sandstone pink (FGP) of UCS that is 51.67 MPa. Wear rate of the drill bit has been measured using controlled parameters, i.e., drill bit diameter (6, 8, 10, 12, and 16 mm), spindle speed (250, 300, 350, 400, and 450 rpm), and penetration rate (2, 4, 6, 8, and 10 mm/min), respectively. Further, a fully instrumented laboratory Drilling set-up was utilized. The weight of each bit was measured after the bit reached 30 mm depth in each type of the rock sample. Furthermore, effects of the bit-rock interface temperature and operational parameters on wear rate of the drill bits were examined. The results show that the wear rate of drill bits increased with an increase in temperature for all the bit-rock combinations considered. This is due to the silica content of the rock sample, which leads to an increase in the frictional heat between the bit-rock interfaces. However, in case of medium-grained sandstone, the weight percentage (wt%) of SiO_2 is around 7.23 wt%, which presents a very low wear rate coefficient of 6.33×10^−2 mg/(N·m). Moreover, the temperature rise during Drilling is also minimum, i.e., around 74 °C, in comparison to that of fine-grained sandstone and fine-grained sandstone pink. In addition, this paper develops the relationship between temperature and wear rate characteristics by employing simple linear regression analysis.
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Temperature Measurement During Rotary Drilling of Rocks - A Statistical Approach
International Conference on Emerging Trends in Engineering (ICETE), 2020Co-Authors: Vijay Kumar Shankar, B. M. Kunar, Ch. S. N. MurthyAbstract:This paper discusses a statistical analysis to measure the temperature during Rotary Drilling of fine-grained sandstone (pink) using embedded thermocouple method. The regression models consist of three input variables such as diameter of the bit, rpm and rate of penetration for different depth of thermocouples. Experimental test were conducted in computer numerical control (CNC) vertical machining centre. The measured temperature has been applied to study the influencing parameter using statistical technique. Analysis of variance (ANOVA) shows that the percentage contribution ratio of each operational parameters on temperature (output response). The most influencing parameter for temperature is rate of penetration with a percentage contribution of 71.32%, followed by drill bit diameter and spindle speed which contribute 19.27% and 2.99% respectively. The ANOVA and regression models for temperature give p-values of less than 0.05. Hence the predicted regression models are statistically significant and good predictive capabilities with acceptable accuracy.
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ANN model for prediction of bit–rock interface temperature during Rotary Drilling of limestone using embedded thermocouple technique
Journal of Thermal Analysis and Calorimetry, 2019Co-Authors: Vijay Kumar Shankar, B. M. Kunar, Ch. S. N. MurthyAbstract:In the present work, an artificial neural network (ANN) model has been developed to predict the bit–rock interface temperature using a newly fabricated grounded K-type thermocouple (range 0–1250 °C) during Rotary Drilling in a CNC vertical machining center. The data have been taken from experimental observation using an embedded thermocouple technique in the laboratory at room temperature (28 °C) using a masonry drill bit. The observations were made using four different operational conditions, namely drill bit diameter (6, 8, 10, 12 and 16 mm), spindle speed (250, 300, 350, 400 and 450 rpm), rate of penetration (2, 4, 6, 8 and 10 mm min^−1) and depth (6, 14, 22 and 30 mm). The ANN has been developed based on the multi layer perceptron neural network (MLPNN) with four different input parameters. A Levenberg–Marquardt (LM) algorithm with feed-forward and backward propagation has been used in this model. The predicted value of the bit–rock interface temperature with the highest R ^2 value provides a satisfactory result with the experimental data. The training value of RMSE is 1.2127, MAPE is 0.0196 and R ^2 is 0.9960, while the testing value of RMSE is 1.2770, MAPE is 0.0170 and R ^2 is 0.9978. The ANN model shows that the proposed MLPNN model successfully predicts the bit–rock interface temperature during the Rotary Drilling of limestone.
B. M. Kunar - One of the best experts on this subject based on the ideXlab platform.
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Measurement of bit-rock interface temperature and wear rate of the tungsten carbide drill bit during Rotary Drilling
Friction, 2020Co-Authors: Vijay Kumar Shankar, B. M. Kunar, Chivukula Suryanarayana Murthy, M R RameshAbstract:Rock Drilling is an essential operation in mining industries. Temperature at the bit-rock interface plays a major role in the wear rate of the drill bit. This paper primarily focuses on the wear rate of tungsten carbide (WC) drill bit and the interrelationship between temperature and wear rate during Rotary Drilling operations conducted using a computer numerical control (CNC) machine. The interrelationship between the temperature and wear rate was studied with regard to three types of rock samples, i.e., fine-grained sandstone (FG) of uniaxial compressive strength (UCS) that is 17.83 MPa, medium-grained sandstone (MG) of UCS that is 13.70 MPa, and fine-grained sandstone pink (FGP) of UCS that is 51.67 MPa. Wear rate of the drill bit has been measured using controlled parameters, i.e., drill bit diameter (6, 8, 10, 12, and 16 mm), spindle speed (250, 300, 350, 400, and 450 rpm), and penetration rate (2, 4, 6, 8, and 10 mm/min), respectively. Further, a fully instrumented laboratory Drilling set-up was utilized. The weight of each bit was measured after the bit reached 30 mm depth in each type of the rock sample. Furthermore, effects of the bit-rock interface temperature and operational parameters on wear rate of the drill bits were examined. The results show that the wear rate of drill bits increased with an increase in temperature for all the bit-rock combinations considered. This is due to the silica content of the rock sample, which leads to an increase in the frictional heat between the bit-rock interfaces. However, in case of medium-grained sandstone, the weight percentage (wt%) of SiO_2 is around 7.23 wt%, which presents a very low wear rate coefficient of 6.33×10^−2 mg/(N·m). Moreover, the temperature rise during Drilling is also minimum, i.e., around 74 °C, in comparison to that of fine-grained sandstone and fine-grained sandstone pink. In addition, this paper develops the relationship between temperature and wear rate characteristics by employing simple linear regression analysis.
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Temperature Measurement During Rotary Drilling of Rocks - A Statistical Approach
International Conference on Emerging Trends in Engineering (ICETE), 2020Co-Authors: Vijay Kumar Shankar, B. M. Kunar, Ch. S. N. MurthyAbstract:This paper discusses a statistical analysis to measure the temperature during Rotary Drilling of fine-grained sandstone (pink) using embedded thermocouple method. The regression models consist of three input variables such as diameter of the bit, rpm and rate of penetration for different depth of thermocouples. Experimental test were conducted in computer numerical control (CNC) vertical machining centre. The measured temperature has been applied to study the influencing parameter using statistical technique. Analysis of variance (ANOVA) shows that the percentage contribution ratio of each operational parameters on temperature (output response). The most influencing parameter for temperature is rate of penetration with a percentage contribution of 71.32%, followed by drill bit diameter and spindle speed which contribute 19.27% and 2.99% respectively. The ANOVA and regression models for temperature give p-values of less than 0.05. Hence the predicted regression models are statistically significant and good predictive capabilities with acceptable accuracy.
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ANN model for prediction of bit–rock interface temperature during Rotary Drilling of limestone using embedded thermocouple technique
Journal of Thermal Analysis and Calorimetry, 2019Co-Authors: Vijay Kumar Shankar, B. M. Kunar, Ch. S. N. MurthyAbstract:In the present work, an artificial neural network (ANN) model has been developed to predict the bit–rock interface temperature using a newly fabricated grounded K-type thermocouple (range 0–1250 °C) during Rotary Drilling in a CNC vertical machining center. The data have been taken from experimental observation using an embedded thermocouple technique in the laboratory at room temperature (28 °C) using a masonry drill bit. The observations were made using four different operational conditions, namely drill bit diameter (6, 8, 10, 12 and 16 mm), spindle speed (250, 300, 350, 400 and 450 rpm), rate of penetration (2, 4, 6, 8 and 10 mm min^−1) and depth (6, 14, 22 and 30 mm). The ANN has been developed based on the multi layer perceptron neural network (MLPNN) with four different input parameters. A Levenberg–Marquardt (LM) algorithm with feed-forward and backward propagation has been used in this model. The predicted value of the bit–rock interface temperature with the highest R ^2 value provides a satisfactory result with the experimental data. The training value of RMSE is 1.2127, MAPE is 0.0196 and R ^2 is 0.9960, while the testing value of RMSE is 1.2770, MAPE is 0.0170 and R ^2 is 0.9978. The ANN model shows that the proposed MLPNN model successfully predicts the bit–rock interface temperature during the Rotary Drilling of limestone.
Pankaj Wahi - One of the best experts on this subject based on the ideXlab platform.
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Criticality of bifurcation in the tuned axial–torsional Rotary Drilling model
Nonlinear Dynamics, 2017Co-Authors: Sunit K. Gupta, Pankaj WahiAbstract:We study the bifurcation characteristics of a lumped-parameter model of Rotary Drilling with 1:1 internal resonance between the axial and the torsional modes which leads to the largest stability thresholds. For this special case, the two-degree-of-freedom model for the drill-string reduces to an effectively single-degree-of-freedom system facilitating further analysis. The regenerative effect of the cutting action due to the axial vibrations is incorporated through a delayed term in the cutting force with the delay depending on the torsional oscillations. This state dependency of the delay introduces nonlinearity in the current model. Steady Drilling loses stability via a Hopf bifurcation, and the nature of the bifurcation is determined by an analytical study using the method of multiple scales. We find that both subcritical and supercritical Hopf bifurcations are present in this system depending on the choice of operating parameters. Hence, the nonlinearity due to the state-dependent delay term could both be stabilizing or destabilizing in nature, and the self-interruption nonlinearity is essential to capture the global behavior. Numerical bifurcation analysis of a global axial–torsional model of Rotary Drilling further confirms the analytical results from the method of multiple scales. Further exploration of the Rotary Drilling dynamics unravels more complex phenomena including grazing bifurcations and possibly chaotic solutions.
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global axial torsional dynamics during Rotary Drilling
Journal of Sound and Vibration, 2016Co-Authors: Sunit K. Gupta, Pankaj WahiAbstract:Abstract We have studied the global dynamics of the bottom hole assembly (BHA) during Rotary Drilling with a lumped parameter axial–torsional model for the drill-string and a linear cutting force model. Our approach accounts for bit-bounce and stick-slip along with the regenerative effect and is independent of the drill-string and the bit–rock interaction model. Regenerative axial dynamics due to variable depth of cut is incorporated through a functional description of the cut surface profile instead of a delay differential equation with a state-dependent delay. The evolution of the cut surface is governed by a nonlinear partial differential equation (PDE) which is coupled with the ordinary differential equations (ODEs) governing the longitudinal and angular dynamics of the BHA. The boundary condition for the PDE captures multiple regeneration in the event of bit-bounce. Interruption in the torsional dynamics is included by considering separate evolution equations for the various states during the stick period. Finite-dimensional approximation for our coupled PDE-ODE model has been obtained and validated by comparing our results against existing results. Bifurcation analysis of our system reveals a supercritical Hopf bifurcation leading to periodic vibrations without bit-bounce and stick-slip which is followed by solutions involving bit-bounce or stick-slip depending on the operating parameters. Further inroads into the unstable regime leads to a variety of complex behavior including co-existence of periodic and chaotic solutions involving both bit-bounce and stick-slip.
Wu Jin-wen - One of the best experts on this subject based on the ideXlab platform.
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Percussive Rotary Drilling law of granite under high temperature and high pressure
Chinese Journal of Geotechnical Engineering, 2010Co-Authors: Wu Jin-wenAbstract:The thermo-cracking of granite will happen under high temperature and high pressure.Its intensity and fracture toughness both decrease.Study on the percussive Rotary Drilling law under various temperatures is of great significance because it can provide a theoretical basis for new Drilling process designed for geothermal production.The law of impact grinding through experiments on a large-size(φ 200 mm × 400 mm) granite is studied by use of the 20 MN servo-controlled triaxial rock testing machine with high temperature and pressure.The conclusions are as follows:(1) under high pressure,the intensity of granite gradually decreases and the percussive Rotary Drilling speed increases gradually with the increase of temperature;(2) under high pressure,the unit energy consumption for percussive Rotary Drilling decreases and the Drilling efficiency is greatly improved with the increase of temperature;(3) under high temperature and high pressure and within some Drilling pressure and percussive power limit,the Drilling speed increases with the increase of pressure or power.The unit rock-crashing power consumption gradually decreases with the increase of pressure.
