The Effects of Static Frictions on the Drilling Process of Hammer-Drill System

2005 ◽  
Author(s):  
Y. Xu ◽  
K. L. Yung ◽  
S. M. Ko
Keyword(s):  
Dynamic Model ◽  
Cutting Process ◽  
Drilling Process ◽  
Normal Impact ◽  
New Model ◽  
Mars Mission ◽  
Dynamic Analyses ◽  
Drill System

Static frictions are neglected in many dynamic analyses mainly due to inappropriate modeling of them. A new dynamic model describing the nonlinear and discrete features of static frictions is proposed in this paper. Using the new model, the drilling process of the hammer-drill system utilized in the EAS’ Mars mission is analyzed. It is shown that most important functions of the hammer-drill system are realized by static frictions, which were not observed before the introduction of the new model of static frictions. Static frictions provide the torsional force on the drill and make the normal impact happen before the rotation, which is critical to the efficiency of the cutting process of the hammer-drill system.

Dynamic model of cutting process with modulated spindle speed

2012 ◽  
Author(s):  
R. Rusinek ◽  
K. Kecik ◽  
J. Warminski ◽  
A. Weremczuk
Keyword(s):  
Dynamic Model ◽  
Spindle Speed ◽  
Cutting Process

Study of a synchronizer mechanism through multibody dynamic analysis

2018 ◽  
Vol 233 (6) ◽  
pp. 1601-1613 ◽  
Author(s):  
Ali Farokhi Nejad ◽  
Giorgio Chiandussi ◽  
Vincenzo Solimine ◽  
Andrea Serra
Keyword(s):  
Dynamic Model ◽  
Three Dimensional ◽  
Time Estimation ◽  
Test Rig ◽  
Operational Conditions ◽  
Multibody Dynamic ◽  
Dynamic Analyses ◽  
Single Cone ◽  
Good Agreement ◽  
Numerical Approaches

The synchronizer mechanism represents the essential component in manual, automatic manual, and dual-clutch transmissions. This paper describes a multibody dynamic model for analysis of a synchronizer mechanism subjected to different operational conditions. The three-dimensional multi-dynamic model is developed to predict the dynamic response of synchronizer, especially for calculation of synchronization time. For the purpose of validation, three different synchronizers (single-cone, double-cone, and triple-cone synchronizers) were used on the test rig machine. For the purpose of synchronizing time estimation, an analytical formulation is proposed. The results of the analytical and multibody dynamic analyses were compared with the experimental data, showing a good agreement. The results of analytical and numerical approaches show that the predicted time of synchronization is more precise than previous works. A sensitivity analysis was performed on the single-cone synchronizer, and the effect of tolerance dimension on the dynamic behavior of the synchronizer was reported.

A Novel Backstepping Approach for the Attenuation of Torsional Oscillations in Drill Strings

2016 ◽  
Vol 248 ◽  
pp. 85-92 ◽  
Author(s):  
Farooq Kifayat Ullah ◽  
Franklyn Duarte ◽  
Christian Bohn
Keyword(s):  
Torsional Oscillation ◽  
Friction Model ◽  
Drill String ◽  
Cutting Process ◽  
Underactuated System ◽  
Drilling Process ◽  
Control Input ◽  
Nonlinear Phenomenon ◽  
Stick Slip ◽  
Torsional Oscillations

A common problem in the petroleum drilling process is the torsional oscillation generated by the friction present during the cutting process. Torsional oscillations in drill string are particularly difficult to control because the drill string is an underactuated system, it has a very small diameter to length ratio and it is driven at top end with the cutting process at the other end. These factors make the drill string prone to self-excited torsional vibrations caused by the stick-slip of the cutting bit. The system is modeled as a torsional pendulum with two degrees of freedom, where the upper inertia models the top drive and also part of the drilling pipes. The bottom inertia models the bottom hole assembly (BHA). The drill is considered to be a massless torsional spring-damper. The drill string is subjected to friction, which is formulated using a dry friction model. The friction model takes into account Coulomb friction, stiction and Stribeck effect. The latter friction component is the main nonlinear phenomenon that introduces negative damping at the bit; it leads to self-enforcing stick-slip torsional oscillations.In the approach of this work, for the attenuation of these self-excited oscillations a recursive backstepping control strategy is used and it is carried out in continuous time. The main contribution of this work, which is different from the backstepping approaches reported in the literature, is to use a nonlinear/artificial damping as virtual control input. The stability of the system has been proven in the sense of Lyapunov. The goal of the proposed algorithm is to deal the underactuation of the system and to provide a good response for different operating points. The effectiveness and robustness of the controller has been tested in simulations.

Some Applications of State and Parameter Estimation to Machine Tool Problems: I—Applications of Nonsequential Estimation

1970 ◽  
Vol 92 (3) ◽  
pp. 633-646 ◽  
Author(s):  
Russell F. Henke
Keyword(s):  
Machine Tool ◽  
Dynamic Model ◽  
High Speed ◽  
Metal Cutting ◽  
Sequential Estimation ◽  
Cutting Process ◽  
Damping Factor ◽  
Process Data ◽  
Identification Schemes ◽  
On Line

A general introduction to the area of off-line and on-line identification of systems is given, and applications of these techniques to machine tool problems, especially adaptive or optimal control, are discussed. The problem of identifying the dynamic model of the metal cutting process is given special emphasis. A general formulation of the nonsequential or off-line estimation problem is presented using state variable notation, so that nonlinearities and time varying parameters may be present. Two techniques tailored to the use of the high-speed digital computer are developed to solve this general problem. The first utilizes a direct multivariable search to match the output, of an assumed dynamic model to actual experimental observations in a least squares sense. The second method uses a modified quasilinearization procedure. Controlled digital experiments are used to refine and test the proposed techniques. The two algorithms are then applied to actual experimental cutting process data. Estimates of the cutting stiffness and damping factor in the dynamic model of the cutting process are obtained, thus demonstrating the effectiveness of the developed nonsequential identification schemes, and showing that the assumed linear dynamic model adequately represents the cutting process. A later paper will consider sequential estimation applications.

Determining the Position of Cutting Tool in Drilling for Analysis of Mechanical Actions

2013 ◽  
Vol 325-326 ◽  
pp. 1382-1386
Author(s):  
Elena Luminiţa Olteanu ◽  
Raynald Laheurte ◽  
Philippe Darnis ◽  
Claudiu Florinel Bîşu
Keyword(s):  
Cutting Tool ◽  
Cutting Process ◽  
Drilling Process ◽  
Tool Position ◽  
Mechanical Phenomena

The mechanical actions measurement can highlight a series of mechanical phenomena occurring in the cutting process. During the experiments, we use a six-component dynamometer to measured the forces and the moments applied by the tool to the workpiece. In this paper, the authors present a method for determining the cutting tool position in drilling process, with purpose to transport of the moments (calculation of the torsor in each of the holes). Then can be achieved analyze of the forces and moments for every hole.

New Model with Spring and Simulation of Flexible Manipulator

2014 ◽  
Vol 513-517 ◽  
pp. 3840-3843
Author(s):  
Ying Tian ◽  
Jian Hua Qian ◽  
Qing Song Liu ◽  
Jie Yuan
Keyword(s):  
Computer Simulation ◽  
Dynamic Model ◽  
Elastic Energy ◽  
Lagrange Equation ◽  
Rigid Bodies ◽  
Flexible Manipulator ◽  
Dynamic Parameters ◽  
New Model ◽  
Real Model ◽  
Model Computer

For easily calculated and more accurate dynamic model of single flexible manipulator, a new model was built through connection of spring and two rigid bodies. It is approximate to the real model of single manipulator in trajectory of end point. With simplifying manipulator and introducing simplified and Predetermined elastic energy of manipulator, Lagrange equation was used to built dynamic model based on the new model. And based on dynamic model, computer simulation result of dynamic parameters with Matlab software proved that the new model is available simple and easily-adjusted.

Investigation of Heat Pipe Cooling in Drilling Applications: Part 2—Thermal, Structural Static, and Dynamic Analyses

2009 ◽  
Author(s):  
Lin Zhu ◽  
Tien-Chien Jen ◽  
Chen-Long Yin ◽  
Yi-Hsin Yen ◽  
Mei Zhu ◽  
...  
Keyword(s):  
Heat Pipe ◽  
Tool Life ◽  
Cutting Temperature ◽  
Dimensional Accuracy ◽  
Mechanical Effect ◽  
Machining Process ◽  
Drilling Process ◽  
Dynamic Analyses ◽  
Thermal Wear ◽  
3D Finite Element Method

Drilling is a highly complex machining process coupled with thermo-mechanical effect. Both the rapid plastic deformation of the workpiece and the friction along the drill-chip interface can contribute to localized heating and increasing temperature in the workpiece and tool. The cutting temperature at the tool-chip interface plays an important role in determining the tool thermal wear. This in turn affects the dimensional accuracy of the workpiece and the tool life of drill. A new embedded heat pipe technology has been proven to be able to effectively not only remove the heat generated at the tool-chip interface in drilling, but also minimize pollution and contamination of the environment caused by cutting fluids. Less tool wear can then be achieved, thus prolonging the tool life. 3D Finite Element method using COSMOS/works is employed to study coupled effects of thermal, structural static and dynamic analyses in a drilling process to check the feasibility and effectiveness of the heat pipe drill. Four different cases, solid drill without coolant, solid drill with coolant, heat pipe drill, and heat pipe drill with coolant, are explored, respectively. The results from this study can be used to define geometric parameters for optimal designs.

A Robust Rate of Penetration Model for Carbonate Formation

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Ahmad Al-AbdulJabbar ◽  
Salaheldin Elkatatny ◽  
Mohamed Mahmoud ◽  
Khaled Abdelgawad ◽  
Abdulaziz Al-Majed
Keyword(s):  
Compressive Strength ◽  
Drilling Fluid ◽  
Coefficient Of Determination ◽  
Percentage Error ◽  
Drilling Process ◽  
Rate Of Penetration ◽  
New Model ◽  
Carbonate Formation ◽  
Drilling Parameters ◽  
Fluid Properties

During the drilling operations, optimizing the rate of penetration (ROP) is very crucial, because it can significantly reduce the overall cost of the drilling process. ROP is defined as the speed at which the drill bit breaks the rock to deepen the hole, and it is measured in units of feet per hour or meters per hour. ROP prediction is very challenging before drilling, because it depends on many parameters that should be optimized. Several models have been developed in the literature to predict ROP. Most of the developed models used drilling parameters such as weight on bit (WOB), pumping rate (Q), and string revolutions per minute (RPM). Few researchers considered the effect of mud properties on ROP by including a small number of actual field measurements. This paper introduces a new robust model to predict the ROP using both drilling parameters (WOB, Q, ROP, torque (T), standpipe pressure (SPP), uniaxial compressive strength (UCS), and mud properties (density and viscosity) using 7000 real-time data measurements. In addition, the relative importance of drilling fluid properties, rock strength, and drilling parameters to ROP is determined. The obtained results showed that the ROP is highly affected by WOB, RPM, T, and horsepower (HP), where the coefficient of determination (T2) was 0.71, 0.87, 0.70, and 0.92 for WOB, RPM, T, and HP, respectively. ROP also showed a strong function of mud fluid properties, where R2 was 0.70 and 0.70 for plastic viscosity (PV) and mud density, respectively. No clear relationship was observed between ROP and yield point (YP) for more than 500 field data points. The new model predicts the ROP with average absolute percentage error (AAPE) of 5% and correlation coefficient (R) of 0.93. In addition, the new model outperformed three existing ROP models. The novelty in this paper is the application of the clustering technique in which the formations are clustered based on their compressive strength range to predict the ROP. Clustering yielded accurate ROP prediction compared to the field ROP.

Experimental Verification of Machining Process of Ultrasonic Drilling

2012 ◽  
Vol 516 ◽  
pp. 275-280 ◽  
Author(s):  
Hiromi Isobe ◽  
Yusuke Uehara ◽  
Keisuke Hara ◽  
Takashi Onuma ◽  
Arata Mihara
Keyword(s):  
Stress Distribution ◽  
High Speed ◽  
Cutting Process ◽  
Machining Process ◽  
Drilling Process ◽  
Distribution Diagram ◽  
Heat Resistant Steel ◽  
Ultrasonic Drilling ◽  
Photoelastic Analysis ◽  
Stress Boundary

Drill processing of difficult-to-cut materials such as ceramics, hardened steel, glass and heat-resistant steel is widely required in the industrial world. Furthermore the drilling process becomes more and more difficult in the case of hole diameters less than one millimetre. In order to achieve the requirements for the drilling process, ultrasonically assisted machining is applicable. Ultrasonic vibration assisted machining techniques are suitable for machining difficult-to-cut materials precisely. However, the cutting process of ultrasonic drilling has not been clarified. It is difficult to observe directly the effect of vibration. The aim of this study is to observe the dynamic, instantaneous and micro cutting process. In this report, a high-speed camera with a polarized device, which is appropriately arranged, realized the visualization of the process of ultrasonic drilling based on photoelastic analysis. For conventional drilling, the stress distribution diagram showed that the intensive stress occurred in limited areas under the chisel because the chisel edge of the drill produces large plastic deformation. On the other hand, the ultrasonic drilling produced spread stress distribution and a stress boundary far away from the chisel. The photoelastic analysis showed the explicit difference of drilling processes.

Rapid calculation method for estimating static and dynamic performances of closed hydrostatic guideways

2017 ◽  
Vol 69 (6) ◽  
pp. 1040-1048 ◽  
Author(s):  
Zhiwei Wang ◽  
Yi Liu ◽  
Feng Wang
Keyword(s):  
Dynamic Model ◽  
Lagrange Equation ◽  
Dynamic Stiffness ◽  
Step Response ◽  
Nonlinear Spring ◽  
Content Type ◽  
New Model ◽  
Linear Spring ◽  
Spring Coefficient ◽  
Better Than

Purpose The purpose of this paper is to establish a simplified model of the closed hydrostatic guideway for the rapid analysis of static and dynamic characteristics. Further, the influence of compressibility and dynamic frequency are taken into consideration in the new dynamic model. Design/methodology/approach The new model is based on the second kind of Lagrange equation. In this model, the closed hydrostatic guideway is supported by 12 pads, and each oil pad is equivalent to a nonlinear spring-damper system. The equivalent spring coefficient and damper coefficient of the oil pad are extracted by the three different equivalent methods. Finally, the validation experiments of step load response and dynamic stiffness are conducted on a hydrostatic guideway. Findings For solving the step response, the linear spring-damper model and the nonlinear spring-damper Model 1 are better than the nonlinear spring-damper Model 2. The accuracy of the three methods are very high for static stiffness calculation. For the calculation of dynamic stiffness, the nonlinear spring-damper Model 2 is better than the nonlinear spring-damper Model 1. The linear spring-damper model has low precision for dynamic stiffness calculation, especially at high frequency. The accuracy of the new model is validated by experiments. Originality/value The equivalent method of nonlinear spring-damper system has higher accuracy. Different equivalent methods should be adopted for different load types. The computational speeds of the new dynamic model with the three methods are much better than finite element method (about ten times).

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