Investigation of displacement fields in an abrasive waterjet drilling process: Part 2. Numerical analysis

2001 ◽  
Vol 41 (4) ◽  
pp. 388-402 ◽  
Author(s):  
Z. Guo ◽  
M. Ramulu
Keyword(s):  
Numerical Analysis ◽  
Abrasive Waterjet ◽  
Drilling Process ◽  
Displacement Fields ◽  
Abrasive Waterjet Drilling

Effect of Periodic Drilling Force on Instability in a Drilling Process

2005 ◽  
Vol 219 (8) ◽  
pp. 733-742 ◽  
Author(s):  
B W Huang ◽  
H K Kung ◽  
A W L Yao
Keyword(s):  
Numerical Analysis ◽  
Thrust Force ◽  
Dynamic Instability ◽  
Drilling Process ◽  
Twist Drill ◽  
Unstable Condition ◽  
Drilling Force ◽  
Cutting Geometry ◽  
Drilling Quality ◽  
Spinning Speed

The periodic drilling force effect on the dynamic instability of a drill in a drilling process was investigated. This investigation involves the cutting geometry drilling force from the two active parts of a twist drill subjected to small fluctuations during the drilling process. Theoretically, at some drilling force, this small drilling force fluctuation may lead the system into a dynamically unstable condition. Most hole location errors, reaming, and drill fractures occur in this unstable drilling process phase. The dynamic instability in a drilling process is an important issue in increasing the drilling quality and production rate. In this article, a pretwisted beam with a moving Winkler-type elastic foundation is used to simulate the drill and drilling process. Numerical analysis indicates that the unstable regions are enlarged and shifted to a lower frequency suddenly as the drill bites into a workpiece. It is also observed that the thrust force, spinning speed, and pretwisted angle effects drastically change the dynamic instability of drilling.

Numerical analysis of gas-dynamic instabilities during the laser drilling process

2006 ◽  
Vol 44 (8) ◽  
pp. 826-841 ◽  
Author(s):  
A.H. Khan ◽  
W. O’Neill ◽  
L. Tunna ◽  
C.J. Sutcliffe
Keyword(s):  
Numerical Analysis ◽  
Laser Drilling ◽  
Drilling Process ◽  
Gas Dynamic

Numerical analysis of a time domain elastoacoustic problem

2019 ◽  
Vol 40 (2) ◽  
pp. 1122-1153
Author(s):  
Rodolfo Araya ◽  
Rodolfo Rodríguez ◽  
Pablo Venegas
Keyword(s):  
Numerical Analysis ◽  
Error Estimates ◽  
Elastic Solid ◽  
Coupled System ◽  
Optimal Error Estimates ◽  
Finite Difference Schemes ◽  
Displacement Fields ◽  
Weak Formulation ◽  
Fully Discrete ◽  
Optimal Rate Of Convergence

Abstract This paper deals with the numerical analysis of a system of second order in time partial differential equations modeling the vibrations of a coupled system that consists of an elastic solid in contact with an inviscid compressible fluid. We analyze a weak formulation with the unknowns in both media being the respective displacement fields. For its numerical approximation, we propose first a semidiscrete in space discretization based on standard Lagrangian elements in the solid and Raviart–Thomas elements in the fluid. We establish its well-posedness and derive error estimates in appropriate norms for the proposed scheme. In particular, we obtain an $\mathrm L^{\infty }(\mathrm L^2)$ optimal rate of convergence under minimal regularity assumptions of the solution, which are proved to hold for appropriate data of the problem. Then we consider a fully discrete approximation based on a family of implicit finite difference schemes in time, from which we obtain optimal error estimates for sufficiently smooth solutions. Finally, we report some numerical results, which allow us to assess the performance of the method. These results also show that the numerical solution is not polluted by spurious modes as is the case with other alternative approaches.

scholarly journals Experimental study on the hole quality during abrasive waterjet drilling of CFRP

2021 ◽  
Vol 13 (2) ◽  
pp. 103-108
Author(s):  
Panagiotis Karmiris-Obratański ◽  
◽  
Nikolaos E. Karkalos ◽  
Dimitrios Skondras-Giousios ◽  
Emmanouil-Lazaros Papazoglou ◽  
...  
Keyword(s):  
Design Method ◽  
Orthogonal Design ◽  
Optical Microscope ◽  
Hole Diameter ◽  
Standoff Distance ◽  
Abrasive Waterjet ◽  
Hole Quality ◽  
Machining Processes ◽  
The Impact ◽  
Abrasive Waterjet Drilling

Abrasive Waterjet (AWJ) machining is considered an excellent alternative to conventional machining processes due to its superb machining characteristics. More specifically, Abrasive Waterjet drilling is nowadays a promising non-conventional process for obtaining high quality holes. In the present study, drilling experiments based on Taguchi L9 orthogonal design method were conducted via AWJ on carbon fiber reinforced polymer (CFRP) plate at various waterjet parameters, namely, different pressure, abrasive mass flow rate and standoff distance values. The purpose of the experiments was to investigate the impact of these process parameters on the quality of holes. The hole quality was determined by measuring the hole diameter error as well as the hole taper. The optical evaluation was implemented with the use of optical microscope and special measuring software. The ANOVA analysis of the results showed a significant influence of standoff distance regarding the hole diameter error and a combined influence of waterjet pressure and standoff distance regarding the hole taper. Furthermore, the optimal process parameter values for the optimization of the hole diameter error and hole taper were determined. The hole quality in terms of defects appearance was also quantitatively inspected, through optical imaging.

3D numerical analysis of drilling process: heat, wear, and built-up edge

2018 ◽  
Vol 6 (2) ◽  
pp. 204-214 ◽  
Author(s):  
Mohammad Lotfi ◽  
Saeid Amini ◽  
Ihsan Yaseen Al-Awady
Keyword(s):  
Numerical Analysis ◽  
Drilling Process ◽  
Process Heat

Numerical Analysis of Drilling Process of Bored Pile in Seasonal Frozen Ground in the West of China

2012 ◽  
Vol 256-259 ◽  
pp. 503-506
Author(s):  
Zhi Dong Duan ◽  
Ya Ping Wu ◽  
Pei Wu Yan
Keyword(s):  
Numerical Analysis ◽  
Plastic Region ◽  
Drilling Process ◽  
Analysis Model ◽  
Frozen Ground ◽  
The West ◽  
Bored Pile ◽  
Hole Wall ◽  
Consolidation Settlement

In order to research shrinkage of hole-wall and plastic region around hole-wall of bored pile in drilling process, a porous analysis model was built, and drilling process of bored pile, under dry excavation technology and hydraulic excavation technology, were simulated by element birth and death feature in ADINA software. Numerical analysis results show that to seasonal frozen ground in the west of China, dry excavation technology is not appropriate, consolidation settlement caused by drilling is small and can be taken into no consideration in design, major problem in hydraulic excavation technology is shrinkage of hole-wall, which mainly influenced by density of slurry and excavation depth one time.

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