Dynamic Response Interaction of Vibrating Offshore Pipeline and Moving Seabed With Varying Geological and Geo-Mechanical Properties

2004 ◽  
Author(s):  
Vincent O. S. Olunloyo ◽  
Ayo A. Oyediran ◽  
Charles A. Osheku
Keyword(s):  
Dynamic Response ◽  
Fluid Velocity ◽  
Time History ◽  
Stress Distributions ◽  
Pipe Burst ◽  
History Effects ◽  
Offshore Pipeline ◽  
Internal Fluid ◽  
Density Analysis ◽  
Sediment Cover

The dynamic response interaction of a vibrating offshore pipeline on a moving seabed is herein investigated where the pipeline is idealized as a beam vibrating on an elastic foundation. In particular the time history effects on physics of the stress distributions on the dynamic interaction predicted on sea state and waves is studied. The spectral density analysis of responses and stress distributions over time is used to predict the anticipated time for pipe burst using the seabed state. The studies also revealed that in general, the seabed acts either as a damper or as a spring and in particular when we have sedimentation, the seabed geology permits the geo-mechanical property of the sediment cover to act only as a damper. As expected, external excitation will increase the response of these pipes for which an amplification factor has been derived. For soft beds, high transverse vibrations were dampened by increasing the internal fluid velocity whereas they became amplified for hard beds.

Dynamic Response Interaction of Vibrating Offshore Pipeline on Moving Seabed

2006 ◽  
Vol 129 (2) ◽  
pp. 107-119 ◽  
Author(s):  
Vincent O. S. Olunloyo ◽  
Charles A. Osheku ◽  
Ayo A. Oyediran
Keyword(s):  
Dynamic Response ◽  
Oil And Gas ◽  
Fluid Velocity ◽  
Gas Industry ◽  
Offshore Pipeline ◽  
Internal Fluid ◽  
Geomechanical Property ◽  
Sediment Cover ◽  
The Subject ◽  
Oil Gas

The dynamic response interaction of a vibrating offshore pipeline on a moving seabed is herein investigated where the pipeline is idealized as a beam vibrating on an elastic foundation. This problem is of relevance in offshore exploration where pipelines are laid either on or buried in the seabed. When such pipes carry oil and gas, the undulating topography of the sea floor and the internal motion of the fluid subject the entire structure to vibration due to bending forces and form the subject of our study. Our analysis revealed that in general, the seabed acts either as a damper or as a spring and in particular when we have sedimentation, the seabed geology permits the geomechanical property of the sediment cover to act only as a damper. As expected, external excitation will increase the response of these pipes for which an amplification factor has been derived. For soft beds, high transverse vibrations were dampened by increasing the internal fluid velocity whereas they became amplified for hard beds. These results are of contemporary interest in the oil/gas industry where deep sea exploration is now receiving significant attention.

Dynamic Response Analysis of Butt Joint of HTS-A Steel Considering Welding Residual Stresses

2013 ◽  
Vol 423-426 ◽  
pp. 944-950
Author(s):  
Wei Shen ◽  
Ren Jun Yan ◽  
Lin Xu ◽  
Kai Qin ◽  
Xin Yu Zhang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Dynamic Response ◽  
Hot Spot ◽  
Time History ◽  
High Strength ◽  
Simulation Method ◽  
Butt Joint ◽  
Welding Residual Stress ◽  
Response Analysis ◽  
Hull Structure

This paper uses both numerical simulation method and experimental research method to study on welding residual stress of high-strength steel of the cone-cylinder hull. Welding is often accompanied by a larger welding residual stress, which directly affects the safety and service life of the hull structure. In order to obtain the distribution of the welding residual stress, the welding procedure was developed by its parameter language by using FE analysis software in this paper. Then the welding residual stress of hot spot region was measured through X-ray nondestructive testing method, and compared it with simulation results. Finally, considering the residual stress as the initial stress, this paper analyzed dynamic response process of the welding structure under combined actions of the welding residual stress and multiaxial loads, which could more accurately determine the stress of welding structure and the location of fatigue risk point. According to the amplitude of damage parameters and strain time-history curve, we can estimate the fatigue life of structure by selecting the corresponding damage models.

Vibration and Stability Behaviour of Sandwiched Viscoelastic Pipes Conveying a Non-Newtonian Fluid

2010 ◽  
Author(s):  
Vincent O. S. Olunloyo ◽  
Charles A. Osheku ◽  
Sidikat I. Kuye
Keyword(s):  
Newtonian Fluid ◽  
Fluid Velocity ◽  
Linear Equations ◽  
Steel Pipes ◽  
Flow Parameters ◽  
Internal Fluid ◽  
Reduction Mechanisms ◽  
Internal Fluid Flow ◽  
Flow Induced Vibrations ◽  
Flow Variables

Internal fluid flow parameters in conjunction with elastomechanical properties of conveyance systems have significantly modulated flow induced vibrations in pipeline and riser systems. Recent advances on the mechanics of sandwich elastic systems as effective vibration and noise reduction mechanisms have simulated the possibility of replacing traditional steel pipes with sandwich pipes in deepwater environment. The dynamic behaviour and stability of sandwich elastic pipes conveying a non-Newtonian fluid are investigated in this paper. For this problem, a set of generalised non-linear equations governing the vibration of sandwich pipes held together in pressurised environment and conveying a non-Newtonian fluid is presented. By linearizing the governing partial differential equation matching the problem physics, under slight perturbation of the internal fluid velocity and other flow variables closed form analytical results for the system dual natural frequencies and stability under external excitation are computed for field designs and applications. Results show that for a given length of pipe, beyond the critical velocity, instability increases with the velocity of conveyance.

Dynamic Test of Bird Strike on a Flat Plate Made from LY-12 Aluminium

2013 ◽  
Vol 765-767 ◽  
pp. 3158-3161
Author(s):  
Jun Liu ◽  
Zheng Li Zhang
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Dynamic Test ◽  
Time History ◽  
Aircraft Design ◽  
Bird Strike ◽  
Test Results ◽  
Valuable Data ◽  
Good Agreement ◽  
Peak Value

Tests of bird strike have been carried out on plate made from LY-12 Aluminium. The test was down with the projectile impacting the target perpendicularly at velocity of 40m/s, 80m/s, 120m/s respectively. The displacement-time history curves and strain-time history curves of on LY-12 Aluminium plate were measured. The good agreement of the results between two specimens in one group indicated that the results tested in the presnet paper are reliable. The dynamic response of the plate and damage modes of the bird influenced by striking velocity were analyzed. The peak value of the displacement linear enlarged with the increasing of the striking velocity. The test results in the present paper provided valuable data for aircraft design impacted by bird, and also provided abundant test datas for the numerical simulation model applied in bird striking.

scholarly journals Spectral analysis of multiple cracked beam subjected to moving load

2014 ◽  
Vol 36 (4) ◽  
pp. 245-254
Author(s):  
N. T. Khiem ◽  
P. T. Hang
Keyword(s):  
Dynamic Response ◽  
Moving Load ◽  
Time History ◽  
Theoretical Development ◽  
Multiple Cracks ◽  
Spectral Approach ◽  
Cracked Beam ◽  
Time History Response ◽  
Numerical Case Study

In present paper, the spectral approach is proposed for analysis of multiple cracked beam subjected to general moving load that allows us to obtain explicitly dynamic response of the beam in frequency domain. The obtained frequency response is straightforward to calculate time history response by using the FFT algorithm and provides a novel tool to investigate effect of position and depth of multiple cracks on the dynamic response. The analysis is important to develop the spectral method for identification of multiple cracked beam by using its response to moving load. The theoretical development is illustrated and validated by numerical case study.

Analysis of Dynamic Response of a Railway Locomotive Using ANSYS

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
Srihari Palli ◽  
Raghuveer Dontikurti ◽  
Rakesh Chandmal Sharma ◽  
Neeraj Sharma
Keyword(s):  
Dynamic Response ◽  
Time History ◽  
Time History Analysis ◽  
Surface Irregularity ◽  
Transient Dynamic Analysis ◽  
Element Analysis ◽  
Car Body ◽  
History Analysis ◽  
Track Surface ◽  
General Time

Transient dynamic analysis (sometimes called time-history analysis) is a technique used to determine the dynamic response of a structure under the action of any general time-dependent loads. The time scale of the loading is such that the inertia or damping effects are considered to be important. Present work is focused on performing the time history analysis of a typical locomotive coach using finite element analysis in Indian railroad conditions. Track surface irregularity in the form of an ellipsoidal bump is modelled with assumptions that the vehicle passes over the bump in 0.144 seconds, variation in displacement at different key locations of the truck and car body models is plotted against time under standard loading conditions. The response pattern of the front and rear portions of the locomotive truck and car body indicate that these locations are more susceptible to wheel excitations compared to that of the centre portions of it as they are away from the centre of gravity of the vehicle due to unbalanced mass distribution.

Application of functional analysis to oscillatory ship model testing

1973 ◽  
Vol 332 (1588) ◽  
pp. 37-49 ◽  
Keyword(s):  
Functional Analysis ◽  
Time History ◽  
Model Testing ◽  
Ship Model ◽  
Fluid Forces ◽  
General Acceptance ◽  
History Effects ◽  
Interpretation Of Results

The need for data relating to fluid forces and moments has led to general acceptance of oscillatory testing of ship models. Although the technique is well established, certain problems still attend the interpretation of results. The nature of the difficulties is explained and they are elucidated by making allowance for time history effects, using functional analysis. Allowance for these effects in this way also establishes that certain results which have hitherto been assumed to require nonlinear representations are in fact capable of very accurate linear specification.

Dynamic Response of a Semi-Submersible Floating Offshore Wind Turbine in Storm Condition

2012 ◽  
Vol 260-261 ◽  
pp. 273-278 ◽  
Author(s):  
Hai Tao Wu ◽  
Jin Jiang ◽  
Jing Zhao ◽  
Xiao Rong Ye
Keyword(s):  
Dynamic Response ◽  
Wind Turbine ◽  
Time History ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Offshore Platforms ◽  
Hydrodynamic Load ◽  
Floating Offshore Wind Turbine ◽  
The Time Domain ◽  
Storm Condition

The paper focuses on a semi-submersible floating offshore wind turbine (FOWT) and analyses its dynamic response in storm condition. The wind load is calculated based on wind block model; the hydrodynamic load is modeled using Potential Theory and Morison Equation. The time-domain dynamic response of the FOWT is simulated by SESAM software with duration of 3 hours. The performance of the FOWT is analyzed based on time history responses and response spectrums. The results show some unique characteristics that differ from offshore platforms and the analysis proofs that the performance is acceptable and the design is reliable.

Simulation of Time Histories of Second-Order Wave Effects by Pseudo-Linear Transformation

1995 ◽  
Vol 117 (2) ◽  
pp. 78-84
Author(s):  
Y. Li
Keyword(s):  
Dynamic Response ◽  
Time History ◽  
Second Order ◽  
Hilbert Transforms ◽  
Structural Dynamic ◽  
Quadratic Transformation ◽  
Wave Effects ◽  
Time Histories ◽  
Component Wave ◽  
The Time Domain

Simulation of the time histories of second-order wave effects is often performed by quadratic transformation of a wave time history. By the present approach, the quadratic transformation of waves is approximated by linear combinations of the products of component wave time records and their Hilbert transforms. The computational efficiency is greatly enhanced. The efficient quadratic transformation of a time history is for the time domain solution of structural dynamic response, and can also be used as a post-processor of the frequency domain solution for obtaining statistic parameters of dynamic response.

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