scholarly journals Use of Dynamic Analysis to Investigate the Behaviour of Short Neutral Sections in the Overhead Line Electrification

2021 ◽  
Vol 6 (5) ◽  
pp. 62
Author(s):  
John Morris ◽  
Mark Robinson ◽  
Roberto Palacin
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Simulation ◽  
Model Simulation ◽  
Analysis Tool ◽  
Overhead Line ◽  
Element Analysis ◽  
Novel Approach ◽  
Section Model ◽  
The Uk ◽  
Neutral Section

The ‘short’ neutral section is a feature of alternating current (AC) railway overhead line electrification that is often unreliable and a source of train delays. However hardly any dynamic analysis of its behaviour has been undertaken. This paper briefly describes the work undertaken investigating the possibility of modelling the behaviour using a novel approach. The potential for thus improving the performance of short neutral sections is evaluated, with particular reference to the UK situation. The analysis fundamentally used dynamic simulation of the pantograph and overhead contact line (OCL) interface, implemented using a proprietary finite element analysis tool. The neutral section model was constructed using physical characteristics and laboratory tests data, and was included in a validated pantograph/OCL simulation model. Simulation output of the neutral section behaviour has been validated satisfactorily against real line test data. Using this method the sensitivity of the neutral section performance in relation to particular parameters of its construction was examined. A limited number of parameter adjustments were studied, seeking potential improvements. One such improvement identified involved the additional inclusion of a lever arm at the trailing end of the neutral section. A novel application of pantograph/OCL dynamic simulation to modelling neutral section behaviour has been shown to be useful in assessing the modification of neutral section parameters.

Design of a Parametrically Excited Tuning Fork Microgyroscope

2005 ◽  
Author(s):  
Yongsik Lee ◽  
Z. C. Feng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dynamic Analysis ◽  
Nonlinear Analysis ◽  
Tuning Fork ◽  
Simplified Model ◽  
Structure Parameters ◽  
Element Analysis ◽  
Parametrically Excited ◽  
Novel Approach

Parametrically excited tuning fork micro gyroscopes have several attractive features. Most of all, the excitation may be externalized, which could simplify the design and fabrication of micro gyroscopes. However, there are no readily applicable tools to guide the design of these gyroscopes since the gyro structures are more complex than those structures whose responses to parametric excitations are known and since finite element analysis tools are not capable of studying parametric excitations. In this work, we adopt a novel approach to obtain a simplified model of the parametrically excited structure. Parameters in the simplified model are obtained using dynamic analysis capability of typical finite element programs and static nonlinear analysis capabilities.

Flexible Riser Bending Hysteresis Influence on Bend Stiffener Response

2014 ◽  
Author(s):  
Marcelo Caire
Keyword(s):  
Dynamic Analysis ◽  
Segment Length ◽  
Analysis Tool ◽  
Flexible Riser ◽  
Element Analysis ◽  
Irregular Wave ◽  
Global Dynamic ◽  
Flexible Risers ◽  
Curvature Distribution ◽  
Internal Pressures

The bending stiffness response is an important parameter in the lifetime assessment of unbounded flexible risers. Its behavior is governed by interlayer friction mechanisms leading to a non-linear moment x curvature relationship that is highly dependent on the internal pressure. In order to investigate its influence on the critical bend stiffener hang-off region response, a detailed finite element analysis is carried out using a specialized tool for a short segment length of a selected 2.5″ ID riser cross section. Different internal pressures are numerically analyzed and the resulting local hysteretic bending response is then adjusted and directly incorporated into a global dynamic analysis tool that uses an equivalent elasto-plastic formulation with a hardening parameter that controls the behavior of the slippage mechanism. A fully coupled irregular wave dynamic analysis is then carried out and the flexible riser curvature distribution response in the bend stiffener region compared for different bending hysteresis models adopted.

Pipeline Integrity Management System: A New Method for Monitoring Pipeline Structural Integrity During Offshore Pipe-Lay

2007 ◽  
Author(s):  
Vincent Cocault-Duverger ◽  
Brett Howard
Keyword(s):  
Dynamic Analysis ◽  
Real Time ◽  
Structural Integrity ◽  
Structural Response ◽  
Accurate Information ◽  
Element Analysis ◽  
Monitoring Method ◽  
Time Motion ◽  
Novel Approach ◽  
Integrity Management

Traditionally, the monitoring of the pipeline structural response to dynamic loads during offshore installation is performed indirectly by comparing the observed sea-states to a matrix of pre-run dynamic analysis cases. Offshore work is planned within a weather window such that the vessel’s station keeping and equipment capacities are not exceeded and pipeline integrity remains within code limits. Assessment of actual seastate offshore is subject to interpretation, possibly introducing undue conservatism with respect to pipe lay operations in some circumstances. This paper describes a proprietary pipeline integrity monitoring method for managing pipe-lay operations. Technip has developed and tested this approach to optimise installation weather windows for the company’s reel-lay vessel, Apache. The method integrates both office-based analysis and offshore real-time motion monitoring. Limiting equations, which represent pipeline stresses and tensions during pipe-lay as a function of the motion of the pipeline top connection, are defined during pre-campaign finite element analysis. Considerable time savings are achieved over conventional approaches by utilising multi-parametric optimisation techniques. Once offshore, the actual motions are measured in real-time using a motion reference unit mounted on the lay ramp. Recorded data can then be compared against pre-defined multi-variate response surface. The system provides a real-time indication of the stress and tension levels in the pipeline. It is believed this method could introduce greater accuracy to pipeline integrity management in some circumstances, which in turn could provide more accurate information for making operational decisions. This novel approach is presented together with a description of current dynamic analysis philosophy and an alternative approach made possible by recent improvements in analytical software and computer processing capabilities.

Effect of Temperature, Reeling Speed and Pipe Tension on the Performance of Field Joint Coating During Reeling of Offshore Pipelines

2021 ◽  
Author(s):  
Rajaram Dhole ◽  
Ismael Ripoll ◽  
Sabesan Rajaratnam ◽  
Celine Jablonski
Keyword(s):  
Influential Factors ◽  
Influential Factor ◽  
Effect Of Temperature ◽  
Mechanical And Thermal Properties ◽  
Peak Strain ◽  
Element Analysis ◽  
Novel Approach ◽  
Laboratory Test Results ◽  
Coating Design ◽  
Highly Strained

Abstract Pipelines are coated with insulating material that minimizes heat losses to the environment. Reeled pipe can experience nominal bending strain in the order of 1% to 2%. Thick coating on the pipe is inherently more highly strained, because of concentrations that occur at the interface between parent coating and field joint coating. Occasionally, contractors who specialize in pipe-lay using the reeling method have experienced difficulties relating to unexpected disbondment and cracks in coating at these interfaces. Any disbonded coating is routinely identified and repaired, but it is important to understand the influential factors that could lead to this type of coating disbondment. It is known in the industry that parameters such as temperature, reeling speed and pipe tension are influential but the relative influence of the factors is not well understood. In addition, there is currently no industry code or recommended practice that proposes the strain levels that the coating could safely withstand prior to cracking. This paper addresses thermo-mechanical aspects of coating design and presents a novel approach to quantify which parameters have the largest influence. In the presented assessments, coating strain was assessed using finite element analysis. Material input was selected from a combination of typical values and specific laboratory test results for polypropylene (PP) and injection molded polypropylene (IMPP). An essential aspect was that the mechanical and thermal properties of the PP were related to temperature and strain rate. Strain rates in the coating during reeling operations were obtained from global FE models. Detailed local FE models incorporated all the material and load inputs and temperature conditions that are necessary to determine peak strain values in the coating; the peak strain values would indicate the locations of potential coating disbondment. The study is purely a strain assessment and excludes any potential for defects or delamination in the coating that could result from its manufacturing process. This strain-based study revealed that coating temperature during reeling is the most influential factor on strain level in the coating. Reeling speed and pipe tension are parameters providing secondary influences.

Experimental Validation of a Dynamic Simulation

1990 ◽  
Author(s):  
K. Harold Yae ◽  
Su-Tai Chern ◽  
Howyoung Hwang
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Simulation ◽  
Time Domain ◽  
Experimental Validation ◽  
Initial Conditions ◽  
Hydraulic Cylinder ◽  
Force Output ◽  
Inverse Dynamic ◽  
Inverse Dynamic Analysis ◽  
The Time Domain

Abstract Using forward and inverse dynamic analysis, the dynamic simulation of a backhoe has been compared with experiments. In the experiment, recorded were the configuration and force histories; that is, velocity and position, and force output from the hydraulic cylinder-all were measured in the time domain. When the experimental force history is used as driving force in the simulation, forward dynamic analysis produces a corresponding motion history. And when the experimental motion history is used as if a prescribed trajectory, inverse dynamic analysis generates a corresponding force history. Therefore, these two sets of motion and force histories — one set from experiment, and the other from the simulation that is driven forward and backward with the experimental data — are compared in the time domain. The comparisons are discussed in regard to the effects of variations in initial conditions, friction, and viscous damping.

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