Dynamics of Initial Penetration in Drilling: Part 2—Motion Models for Drill Skidding and Wandering With Experimental Verification

2005 ◽  
Vol 127 (2) ◽  
pp. 289-297 ◽  
Author(s):  
Yongping Gong ◽  
Cheng Lin ◽  
Kornel F. Ehmann
Keyword(s):  
Experimental Verification ◽  
Weak Form ◽  
Dynamic Force ◽  
The Finite Element Method ◽  
Governing Equations ◽  
Motion Models ◽  
Initial Penetration ◽  
Radial Forces ◽  
Compressive Axial Load ◽  
Definition Of

This part of the paper is aimed at the development of models for the drill tip’s transverse and angular motions, the definition of models for establishing the drilled hole’s profile and, by combining these results with the dynamic force models of Part 1, the formulation of the complete model for drill skidding and wandering. An experimental verification of the models concludes the paper. For the development of the drill motion models the drill is simplified as a pretwisted beam subjected to a compressive axial load and radial forces acting on its tip. The governing equations are developed using Hamilton’s principle. Subsequently, the weak form of the governing equation is formulated to facilitate their solution by the finite element method. The corresponding boundary conditions for the motion model are also defined for three drilling phase, i.e., drill skidding, drill wandering and stabilized drilling. Based on the drill tip’s wandering locus and drill rotation, a mathematical model for describing the drilled hole’s profile is developed.

Analysis of Rotor Dynamic by One-Dimensional Variable Kinematic Theories

2013 ◽  
Vol 135 (9) ◽  
Author(s):  
E. Carrera ◽  
E. M. Filippi ◽  
E. Zappino
Keyword(s):  
Three Dimensional ◽  
Weak Form ◽  
Test Cases ◽  
The Finite Element Method ◽  
Governing Equations ◽  
Beam Section ◽  
Dimensional Variable ◽  
Rotor Dynamic ◽  
Structural Theories ◽  
Beam Theories

In this paper, Carrera's unified formulation (CUF) is used to perform free-vibrational analyses of rotating structures. The CUF is a hierarchical formulation which offers a procedure to obtain refined structural theories that account for variable kinematic description. These theories are obtained by expanding the unknown displacement variables over the beam section axes by adopting Taylor's polynomials of N-order, in which N is a free parameter. Linear case (N = 1) permits us to obtain classical beam theories while higher order expansions could lead to three-dimensional description of dynamic response of rotors. The finite element method is used to derive the governing equations in weak form. These equations are written in terms of few fundamental nuclei, whose forms do not depend on the approximation used (N). In order to assess the new theory, several analyses are carried out and the results are compared with solutions presented in the literature in graphical and numerical form. Among the considered test cases, a rotor with deformable disk is considered and the results show the convenience of using refined models since that are able to include the in plane deformability of disks.

Definition of the Temperature and Heat Flux in Micromilling of Hardened Steel Using the Finite Element Method

2014 ◽  
Vol 39 (10) ◽  
pp. 7229-7239 ◽  
Author(s):  
Sergio Luiz Moni Ribeiro Filho ◽  
Marcelo Oliveira Gomes ◽  
Carlos Henrique Lauro ◽  
Lincoln Cardoso Brandão
Keyword(s):  
Finite Element Method ◽  
Heat Flux ◽  
Finite Element ◽  
Hardened Steel ◽  
The Finite Element Method ◽  
Definition Of ◽  
Element Method

scholarly journals INFORMATIZATION OF CONSTRUCTION MANAGEMENT AS A BASIS FOR PREVENTING MAN-MADE ACCIDENTS

2021 ◽  
Vol 4 (4) ◽  
pp. 11-31
Author(s):  
S. Koryagina
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
The Finite Element Method ◽  
Calculation Results ◽  
Definition Of ◽  
Deep Pits ◽  
Geotechnical Problems ◽  
Seismic Impacts ◽  
Base Structure ◽  
Element Method

the article presents the principles and algorithms of the finite element method in solving geotechnical prob-lems taking into account seismic impacts for determining the stress-strain state of structures and slope stabil-ity, implemented in the Midas GTS NX software package. GTS NX allows you to perform calculations of various types of geotechnical problems and solve complex geotechnical problems in a single software envi-ronment. GTS NX covers the entire range of engineering and geotechnical projects, including calculations of the "base-structure" system, deep pits with various mounting options, tunnels of complex shape, consolida-tion and filtration calculations, as well as calculations for dynamic actions and stability calculations. At the same time, all types of calculations in GTS NX can be performed both in 2D and in 3D. The author does not claim to be the author of the finite element method, but he cannot do without pointing out the basic equa-tions, as this affects the definition of the boundaries of use, the formulation of algorithms for constructing calculation schemes and the analysis of calculation results.

Meshless Integral Method for Analysis of Elastoplastic Geotechnical Materials

2010 ◽  
Author(s):  
Jianfeng Ma ◽  
Joshua David Summers ◽  
Paul F. Joseph
Keyword(s):  
Boundary Conditions ◽  
Function Approximation ◽  
Integral Method ◽  
Weak Form ◽  
Constitutive Law ◽  
Governing Equations ◽  
Natural Boundary ◽  
Pressure Sensitive ◽  
Support Domain ◽  
Natural Boundary Conditions

The meshless integral method based on regularized boundary equation [1][2] is extended to analyze elastoplastic geotechnical materials. In this formulation, the problem domain is clouded with a node set using automatic node generation. The sub-domain and the support domain related to each node are also generated automatically using algorithms developed for this purpose. The governing integral equation is obtained from the weak form of elastoplasticity over a local sub-domain and the moving least-squares approximation is employed for meshless function approximation. The geotechnical materials are described by pressure-sensitive multi-surface Drucker-Prager/Cap plasticity constitutive law with hardening. A generalized collocation method is used to impose the essential boundary conditions and natural boundary conditions are incorporated in the system governing equations. A comparison of the meshless results with the FEM results shows that the meshless integral method is accurate and robust enough to solve geotechnical materials.

Improving the honing accuracy of the holes of stepped thin-walled cylinders

2021 ◽  
pp. 49-54
Author(s):  
V.A. Ogorodov
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cutting Forces ◽  
Software Package ◽  
The Finite Element Method ◽  
Radial Forces ◽  
Thin Walled ◽  
Hole Machining ◽  
Deform 3D ◽  
Walled Cylinder

Different ways of fixing of stepped thin-walled cylinders during honing are analyzed. The conditions for increasing the accuracy of hole machining are determined on the basis of unevenness of cylinder deformations from clamping forces and radial forces simulating cutting forces. The studies used the finite element method and the DEFORM-3D V6.1 software package. Keywords: honing, stepped thin-walled cylinder, hole, accuracy, fixing method, deformation, unevenness, DEFORM-3D V6.1 software package. [email protected]

scholarly journals Experimental investigation of leak hydraulics

2012 ◽  
Vol 15 (3) ◽  
pp. 666-675 ◽  
Author(s):  
M. Ferrante ◽  
C. Massari ◽  
E. Todini ◽  
B. Brunone ◽  
S. Meniconi
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Network Models ◽  
Water Distribution Network ◽  
Experimental Tests ◽  
Pressure Control ◽  
Pipe Material ◽  
Governing Equations ◽  
The One ◽  
Definition Of

In recent decades the hydraulics of leaks, i.e. the definition of the relationships linking the hydraulic quantities in pipes with leaks, has received increasing attention. On the one hand, the definition of the relationship between the leak outflow and the relevant parameters – e.g. the leak area and shape, the pressure inside the pipe and outside the leak, and the pipe material – is crucial for pressure control and inverse analysis techniques. On the other hand, if the effect of the leakage on the governing equations is not taken into account, i.e. the loss of the flow axial momentum is not considered, significant errors can be introduced in the simulation of water distribution systems. In this paper, the governing equations for a pipe with a leak are derived. The basic equations, obtained within different approaches, are presented in a consistent formulation and then compared with the results of some experimental tests. The leak jet angle and other major features of the results are analysed. The estimated values of the parameters can be used in the water distribution network models when pipes with a diffuse leakage are considered.

Nonlinear Stability Analysis of Sandwich Wide Panels—Part II: Postbuckling Response

2018 ◽  
Vol 85 (8) ◽  
Author(s):  
Zhangxian Yuan ◽  
George A. Kardomateas
Keyword(s):  
Continuation Method ◽  
Weak Form ◽  
Arc Length ◽  
Nonlinear Stability Analysis ◽  
Governing Equations ◽  
Buckling Mode ◽  
The Core ◽  
Global Buckling ◽  
Post Buckling ◽  
Branch Switching

The nonlinear post-buckling response of sandwich panels based on the extended high-order sandwich panel theory (EHSAPT) is presented. The model includes the transverse compressibility, the axial rigidity, and the shear effect of the core. Both faces and core are considered undergoing large displacements with moderate rotations. Based on the nonlinear weak form governing equations, the post-buckling response is obtained by the arc-length continuation method together with the branch switching technique. Also, the post-buckling response with imperfections is studied. The numerical examples discuss the post-buckling response corresponding to global buckling and wrinkling. It is found that due to the interaction between faces and core, localized effects may be easily initiated by imperfections after the sandwich structure has buckled globally. Furthermore, this could destabilize the post-buckling response. The post-buckling response verifies the critical load and buckling mode given by the buckling analysis in part I. The axial rigidity of the core, although it is very small compared to that of the faces, has a significant effect on the post-buckling response.

scholarly journals Entropy Generation and Natural Convection Flow of Hybrid Nanofluids in a Partially Divided Wavy Cavity Including Solid Blocks

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2942 ◽  
Author(s):  
Ammar I. Alsabery ◽  
Ishak Hashim ◽  
Ahmad Hajjar ◽  
Mohammad Ghalambaz ◽  
Sohail Nadeem ◽  
...  
Keyword(s):  
Entropy Generation ◽  
Convection Flow ◽  
Hybrid Nanofluid ◽  
Bejan Number ◽  
The Finite Element Method ◽  
Governing Equations ◽  
Flow And Heat Transfer ◽  
Hybrid Nanofluids ◽  
Wavy Cavity ◽  
Rayleigh Numbers

The present investigation addressed the entropy generation, fluid flow, and heat transfer regarding Cu-Al 2 O 3 -water hybrid nanofluids into a complex shape enclosure containing a hot-half partition were addressed. The sidewalls of the enclosure are made of wavy walls including cold isothermal temperature while the upper and lower surfaces remain insulated. The governing equations toward conservation of mass, momentum, and energy were introduced into the form of partial differential equations. The second law of thermodynamic was written for the friction and thermal entropy productions as a function of velocity and temperatures. The governing equations occurred molded into a non-dimensional pattern and explained through the finite element method. Outcomes were investigated for Cu-water, Al 2 O 3 -water, and Cu-Al 2 O 3 -water nanofluids to address the effect of using composite nanoparticles toward the flow and temperature patterns and entropy generation. Findings show that using hybrid nanofluid improves the Nusselt number compared to simple nanofluids. In the case of low Rayleigh numbers, such enhancement is more evident. Changing the geometrical aspects of the cavity induces different effects toward the entropy generation and Bejan number. Generally, the global entropy generation for Cu-Al 2 O 3 -water hybrid nanofluid takes places between the entropy generation values regarding Cu-water and Al 2 O 3 -water nanofluids.

scholarly journals Helmholtz’s decomposition for compressible flows and its application to computational aeroacoustics

2020 ◽  
Vol 1 (6) ◽  
Author(s):  
Stefan Schoder ◽  
Klaus Roppert ◽  
Manfred Kaltenbacher
Keyword(s):  
Flow Velocity ◽  
Compressible Flows ◽  
Base Flow ◽  
Computational Aeroacoustics ◽  
Helmholtz Decomposition ◽  
The Finite Element Method ◽  
Main Challenge ◽  
Source Data ◽  
Flow Domain ◽  
Definition Of

Abstract The Helmholtz decomposition, a fundamental theorem in vector analysis, separates a given vector field into an irrotational (longitudinal, compressible) and a solenoidal (transverse, vortical) part. The main challenge of this decomposition is the restricted and finite flow domain without vanishing flow velocity at the boundaries. To achieve a unique and $$L_2$$ L 2 -orthogonal decomposition, we enforce the correct boundary conditions and provide its physical interpretation. Based on this formulation for bounded domains, the flow velocity is decomposed. Combining the results with Goldstein’s aeroacoustic theory, we model the non-radiating base flow by the transverse part. Thereby, this approach allows a precise physical definition of the acoustic source terms for computational aeroacoustics via the non-radiating base flow. In a final simulation example, Helmholtz’s decomposition of compressible flow data using the finite element method is applied to an overflowed rectangular cavity at Mach 0.8. The results show a reasonable agreement with the source data and illustrate the distinct parts of the Helmholtz decomposition.

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