Dynamic Response of Buried Pipelines—An Elasticity Solution

1990 ◽  
Vol 112 (3) ◽  
pp. 291-295 ◽  
Author(s):  
B. K. Mishra ◽  
P. C. Upadhyay
Keyword(s):  
Dynamic Response ◽  
Shear Deformation ◽  
Theory Of Elasticity ◽  
P Wave ◽  
Wave Number ◽  
Rotary Inertia ◽  
Angle Of Incidence ◽  
Elasticity Solution ◽  
Buried Pipelines ◽  
Surrounding Soil

This paper presents a theory of elasticity solution of the axisymmetric steady-state dynamic response of a buried pipeline excited by a plane longitudinal wave (P-wave) traveling in the surrounding soil. Both the pipeline and the ground have been assumed to be linearly elastic, homogeneous and isotropic. Linear elasticity equations of motion have been solved simultaneously for the pipeline and the surrounding soil. A perfect bond between the pipeline and the ground has been assumed. The midplane deformations of the pipeline have been plotted against the nondimensional wave number of the incident wave, for different soil condition and angle of incidence of the wave. The results of the present work have been compared with those found by using a shell theory which includes the effect of shear deformation and rotary inertia. It has been found that excellent agreement exists between the results obtained by the two approaches. The present work concludes that the use of shell model, including effects of shear deformation and rotary inertia, is justified for the analysis of dynamic response of buried pipelines excited by seismic waves traveling in the ground.

A Comprehensive Fluid Coupled Lateral Drill String Vibration Model Based on Classical Vibration Theories

2018 ◽  
Author(s):  
Abhijeet D. Chodankar ◽  
Abdennour Seibi
Keyword(s):  
Dynamic Response ◽  
Shear Deformation ◽  
Natural Frequency ◽  
Circular Cross Section ◽  
Drill String ◽  
Rotary Inertia ◽  
Compression Load ◽  
String Vibration ◽  
Vibration Model ◽  
Fluid Damping

The drilling industry has been suffering from huge monetary losses and non-productive time due to wear and fatigue of the drill string components. Vibration mitigation plays a pivotal role in extending the life of drill string components. The development of a comprehensive drill string vibration model will help in classifying the causes of drill string vibrations and helps in planning pro-active measures to suppress it. In the past, researchers have developed models based on factors like drill string length, axial compression load, lateral loads, shear deformation, rotary inertia and fluid damping. The four classical engineering vibration theories will be discussed in detail with the addition of fluid stiffness and fluid damping. This paper develops a drill string vibration model considering the effects of bending, translational inertia, rotary inertia, shear deformation, fluid stiffness and fluid damping. The drill string is considered as a cantilever beam of a circular cross-section immersed in water with equal pressure on both sides. The water is considered to be a spring and dash-pot model in parallel. It adopts a classical solution methodology based on D’Almbert’s principle. The eigen values, normalized mode shape, natural frequencies, orthogonality conditions and dynamic response equations are derived for all the theories. Natural Frequency and Dynamic response of the drill string are used to make informed decisions. Numerical simulation results show the influence of all the factors on vibration damping of the drill string. A critical understanding of the effects of all the above factors individually and in tandem will help in adopting a novel drilling strategy. To conclude, a complete step-by-step methodology for the proposed comprehensive drill string vibration model is put forth to determine the natural frequency and dynamic response of the drill string.

Review of Dynamic Response of Buried Pipelines

2021 ◽  
Vol 12 (2) ◽  
pp. 03120003
Author(s):  
Ronghuan Xu ◽  
Ruinian Jiang ◽  
Tie-jun Qu
Keyword(s):  
Dynamic Response ◽  
Buried Pipelines

THREE‐DIMENSIONAL FILTERING WITH AN ARRAY OF SEISMOMETERS

Geophysics ◽  
1964 ◽  
Vol 29 (5) ◽  
pp. 693-713 ◽  
Author(s):  
John P. Burg
Keyword(s):  
Array Processing ◽  
Three Dimensional ◽  
Processing System ◽  
Seismic Signal ◽  
P Wave ◽  
Wave Number ◽  
Theoretical Problem ◽  
Least Mean Square ◽  
Optimum Frequency ◽  
Filtering Theory

The development of the Wiener linear least‐mean‐square‐error processing theory for seismic signal enhancement through use of a two‐dimensional array of seismometers leads to the theory of three‐dimensional filtering. The array processing system for this theory consists of applying individual frequency filters to the outputs of the seismometers in the array before summation. The basic design equations for the optimum frequency filters are derived from the Wiener multichannel theory. However, the development of the three‐dimensional frequency and vector‐wave‐number‐filtering theory results in a physical understanding of generalized linear array processing. The three‐dimensional filtering theory is illuminated by a theoretical problem of P‐wave enhancement in the presence of ambient seismic noise. An analysis of the results shows why optimum three‐dimensional filtering gives greater signal‐to‐noise ratio improvements than achieved by conventional array processing techniques.

A Spectral Finite Element Model for Wave Propagation Analysis in Laminated Composite Plate

2006 ◽  
Vol 128 (4) ◽  
pp. 477-488 ◽  
Author(s):  
A. Chakraborty ◽  
S. Gopalakrishnan
Keyword(s):  
Finite Element ◽  
Wave Propagation ◽  
Shear Deformation ◽  
Mechanical Response ◽  
Laminated Composite ◽  
Wave Number ◽  
Single Element ◽  
Element Formulation ◽  
Frequency Wave ◽  
Spectral Finite Element

A new spectral plate element (SPE) is developed to analyze wave propagation in anisotropic laminated composite media. The element is based on the first-order laminated plate theory, which takes shear deformation into consideration. The element is formulated using the recently developed methodology of spectral finite element formulation based on the solution of a polynomial eigenvalue problem. By virtue of its frequency-wave number domain formulation, single element is sufficient to model large structures, where conventional finite element method will incur heavy cost of computation. The variation of the wave numbers with frequency is shown, which illustrates the inhomogeneous nature of the wave. The element is used to demonstrate the nature of the wave propagating in laminated composite due to mechanical impact and the effect of shear deformation on the mechanical response is demonstrated. The element is also upgraded to an active spectral plate clement for modeling open and closed loop vibration control of plate structures. Further, delamination is introduced in the SPE and scattered wave is captured for both broadband and modulated pulse loading.

Nonlinear Dynamic Response and Buckling of Damaged Composite Pipes Under Radial Impact

2006 ◽  
Author(s):  
Wenyong Tang ◽  
Tianlin Wang ◽  
Shengkun Zhang
Keyword(s):  
Dynamic Response ◽  
Shear Deformation ◽  
Nonlinear Dynamic ◽  
Shear Deformation Theory ◽  
Nonlinear Dynamic Response ◽  
Nonlinear Dynamic Equations ◽  
Geometric Deformation ◽  
Initial Geometric Imperfections ◽  
Set Up ◽  
Composite Pipes

In this paper, the nonlinear dynamic response and buckling of damaged composite pipes under radial impact is investigated. A model involving initial geometric deformation, delamination and sub-layer matrix damage is set up for theoretical analysis. Based on the first order shear deformation theory, the nonlinear dynamic equations of the composite pipe considering transverse shear deformation and initial geometric imperfections are obtained by Hamilton’s theory and solved by a semi-analytical finite difference method. The effects of damage on the dynamic response and buckling of composite pipes are discussed.

A Refined Theory for Laminated Anisotropic, Cylindrical Shells

1974 ◽  
Vol 41 (2) ◽  
pp. 471-476 ◽  
Author(s):  
J. M. Whitney ◽  
C.-T. Sun
Keyword(s):  
Shear Deformation ◽  
Shell Theory ◽  
Theory Of Elasticity ◽  
Small Radius ◽  
Refined Theory ◽  
Normal Strain ◽  
Governing Equations ◽  
Transverse Normal Strain ◽  
Anisotropic Cylindrical Shell ◽  
Good Agreement

A set of governing equations and boundary conditions are derived which describe the static deformation of a laminated anisotropic cylindrical shell. The theory includes both transverse shear deformation and transverse normal strain, as well as expansional strains. The validity of the theory is assessed by comparing solutions obtained from the shell theory to results obtained from exact theory of elasticity. Reasonably good agreement is observed and both shear deformation and transverse normal strain are shown to be of importance for shells having a relatively small radius-to-thickness ratio.

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