Behaviour of Externally Corroded Pipelines Under Axial Deformation

2010 ◽  
Author(s):  
Halima Dewanbabee ◽  
Jorge Silva ◽  
Abu Rafi ◽  
Sreekanta Das
Keyword(s):  
Test Procedure ◽  
Design Guidelines ◽  
Combined Loading ◽  
Axial Deformation ◽  
Current Design ◽  
Axial Compressive Strength ◽  
Pipeline Failure ◽  
Set Up ◽  
Buried Gas Pipeline ◽  
Full Scale Tests

Corrosion is a major cause for buried gas pipeline failure. Current design guidelines are limited to pressure loading for assessing a corroded pipeline’s integrity. A few studies were conducted by other researchers to determine the remaining bending or pressure strength of the corroded pipelines under combined loading. However, no study was conducted to determine the axial compressive strength and ductility of the corroded pipelines although these could be the major cause of the pipeline failure. Therefore, the current study was undertaken to understand how the corrosion geometry influences the structural behavior of externally corroded line pipes when they are subjected to axial deformation and internal pressure. Three full-scale tests have been completed and it was found that the pipe that was used in this study is highly ductile and do not rupture under monotonically increasing axial deformation. This paper discusses test set up, test procedure, and results obtained from these tests.

scholarly journals Behavior and Strength Predictions for CFRP Confined Rubberized Concrete under Axial Compression

2021 ◽  
Author(s):  
Rana Faisal Tufail ◽  
Xiong Feng ◽  
Danish Farooq ◽  
Nabil Abdelmelek ◽  
Éva Lublóy
Keyword(s):  
Compressive Strength ◽  
Axial Compression ◽  
Design Guidelines ◽  
Rubberized Concrete ◽  
Fiber Reinforced ◽  
Conventional Concrete ◽  
The North ◽  
Concrete Confinement ◽  
Current Design ◽  
Axial Compressive Strength

This paper presents experimental versus theoretical comparison of carbon fiber reinforced polymer (CFRP) confined rubberized concrete (a new structural material). A total of sixty six rubberized concrete cylinders were tested in axial compression. The specimens were cast using 0 to 50% rubber replacement. Twenty seven cylinders were then confined with one, two and three layers of CFRP jackets. Axial compression results of the experimental study were compared with the North American and European design guidelines. The results indicate that the addition of rubber content in the concrete leads to premature micro cracking and lateral expansion in concrete. This increased lateral dilation exploited the potential of FRP jackets. The axial compressive strength and strain values for CFRP confined RuC cylinders reached up to unprecedented 600 and 330 percent of unconfined samples. Furthermore, the current international design guidelines developed for conventional concrete confinement failed to predict the compressive strength of rubberized concrete. There is a strong need to re-evaluate the current design codes and their applicability to investigate fiber reinforced confined rubberized concrete. Moreover, the proposed equations in this research can better predict the axial compressive strength of FRP confined RuC.

Front steering design guidelines formulation for e-scooters considering the influence of sitting and standing riders on self-stability and safety performance

2021 ◽  
pp. 095440702199217
Author(s):  
Milan Paudel ◽  
Fook Fah Yap
Keyword(s):  
Preventive Measures ◽  
Recent Trend ◽  
Dynamic Performance ◽  
Design Guidelines ◽  
Safety Performance ◽  
Design Parameters ◽  
Single Track ◽  
Standing Posture ◽  
Last Mile ◽  
Current Design

E-scooters are a recent trend and are viewed as a sustainable solution to ease the first and last mile problem in modern transportation. However, an alarming rate of accidents, injuries, and fatalities have caused a significant setback for e-scooters. Many preventive measures and legislation have been put on the e-scooters, but the number of accidents and injuries has not reduced considerably. In this paper, the current design approach of e-scooters has been analyzed, and the most common range of design parameters have been identified. Thereafter, validated mathematical models have been used to quantify the performance of e-scooters and relate them with the safety aspects. Both standing and seated riders on e-scooters have been considered, and their influence on the dynamic performance has been analyzed and compared with the standard 26-in wheel reference safety bicycle. With more than 80% of the accidents and injuries occurring from falling or colliding with obstacles, this paper tries to correlate the dynamics of uncontrolled single-track vehicles with the safety performance of e-scooters. The self-stability, handling, and braking effect have been considered as major performance matrices. The analysis has shown that the current e-scooter designs are not as stable as the reference safety bicycle. Moreover, these e-scooters have been found unstable within the most common range of legislated riding velocity. The results corroborate with the general perception that the current designs of e-scooters are less stable, easy to lose control, twitchy, or wobbly to ride. Furthermore, the standing posture of the rider on the e-scooter has been found dangerous while braking to avoid any disturbances such as potholes or obstacles. Finally, the front steering design guidelines have been proposed to help modify the current design of e-scooters to improve the dynamic performance, hence the safety of the e-scooter riders and the surroundings.

Experimental Investigation into Driver Behavior along Curved and Parallel Diverging Terminals of Exit Interchange Ramps

2021 ◽  
pp. 036119812199742
Author(s):  
Alberto Portera ◽  
Marco Bassani
Keyword(s):  
Design Stage ◽  
Lane Change ◽  
Age And Gender ◽  
Traffic Conditions ◽  
Current Design ◽  
The Difference ◽  
Safety Countermeasures ◽  
And Gender ◽  
Set Up ◽  
Curve Radius

Current design manuals provide guidance on how to design exit ramps to facilitate driving operations and minimize the incidence of crashes. They also suggest that interchanges should be built along straight roadway sections. These criteria may prove ineffective in situations where there is no alternative to terminals being located along curved motorway segments. The paper investigates driving behavior along parallel deceleration curved terminals, with attention paid to the difference in impact between terminals having a curvature which is the same sign as the motorway segment (i.e., continue design), and those having an opposite curvature (i.e., reverse design). A driving simulation study was set up to collect longitudinal and transversal driver behavioral data in response to experimental factor variations. Forty-eight drivers were stratified on the basis of age and gender, and asked to drive along three randomly assigned circuits with off-ramps obtained by combining experimental factors such as motorway mainline curve radius (2 values), terminal length (3), curve direction (2), and traffic conditions (2). The motorway radius was found to be significant for drivers’ preferred speed when approaching the terminal. Terminal length and traffic volume do not have a significant impact on either longitudinal or transversal driver outputs. However, the effect of curve direction was found to be significant, notably for reverse terminals which do not compel drivers to select appropriate speeds and lane change positions. This terminal type can give rise to critical driving situations that should be considered at the design stage to facilitate the adoption of appropriate safety countermeasures.

HPHT Subsea Connector Verification and Validation Using an API 17TR8 Methodology

2021 ◽  
Author(s):  
Barry Stewart ◽  
Sam Kwok Lun Lee
Keyword(s):  
Failure Modes ◽  
Production Systems ◽  
Three Dimensional ◽  
Full Scale ◽  
Verification And Validation ◽  
Combined Loading ◽  
Load Path ◽  
Capacity Curves ◽  
Industry Standards ◽  
Full Scale Tests

Abstract Wellhead connectors form a critical part of subsea tree production systems. Their location in the riser load path means that they are subjected to high levels of bending and tension loading in addition to internal pressure and cyclic loading. As more fields continue to be discovered and developed that are defined as High Pressure and/or High Temperature (HPHT) these loading conditions become even more arduous. In order to ensure the integrity of HPHT components, industry requirements for components are setout in API 17TR8. This technical report provides a design verification methodology for HPHT products and some requirements for validation testing. The methodology provides detail on the assessment of static structural and cyclic capacities but less detail on how to assess the functional and serviceability criteria for wellhead connectors. Similarly, API 17TR8 does not include prescriptive validation requirements for wellhead connectors and refers back to historical methods. This paper describes a practical application of the API 17TR8 methodology to the development of a 20k HPHT connector and how it was implemented to verify and validate the connector design through full scale tests to failure. A methodology was developed to meet the requirements of the relevant industry standards and applied to the connector to develop capacity charts for static combined loading. Verification was carried out on three dimensional 180° FEA models to ensure all non axi-symmetric loading is accurately captured. Connector capacities are defined based on API 17TR8 criteria with elastic plastic analysis (i.e. collapse load, local failure and ratcheting), functionality/serviceability criteria defined through a FMECA review and also including API STD 17G criteria including failure modes such as lock/unlock functionality, fracture based failure, mechanical disengagement, leakage and preload exceedance. These capacities are validated through full scale testing based on the requirements of API 17TR7 and API STD 17G with combined loading applied to the Normal, Extreme and Survival capacity curves (as defined by "as-built" FEA using actual material properties). Various test parameters such as strain gauge data, hub separation data, displacements, etc. were recorded and correlated to FEA prediction to prove the validity of the methodology. Further validation was carried out by applying a combined load up to the FEA predicted failure to confirm the design margins of the connector. Post-test review was carried out to review the suitability of the requirements set out in API 17TR8 and API STD 17G for the verification and validation of subsea connectors. The results build on previous test results to validate the effectiveness of the API 17TR8 code for verification and validation of connectors. The results show that real margins between failure of the connector and rated loads are higher than those defined in API 17TR8 and show that the methodology can be conservative.

Prediction the Shear Strength for FRP Shear Strengthened RC Beams Based on Optimised Truss Models

2014 ◽  
Vol 567 ◽  
pp. 469-475
Author(s):  
Hor Yin ◽  
Teo Wee
Keyword(s):  
Shear Strength ◽  
Load Ratio ◽  
Design Guidelines ◽  
Test Results ◽  
Total Strain Energy ◽  
Truss Model ◽  
Large Dispersion ◽  
Proposed Model ◽  
Significant Difference ◽  
Current Design

This paper presents the analytical optimised truss model based on the principle of the minimum total strain energy theorem. The model was validated against 90 experimental data collected from the literature. The predicted shear strength in the analysis showed a very satisfactory correlation with the test results, with the average experimental/analytical failure load ratio of 1.09 and the coefficient of variation (C.O.V) of 14.1%. Furthermore, a comparison between the accuracy of the proposed model and the current design guidelines was also demonstrated in this study. It was observed that the optimised truss model led to be more viable than the standard 45-deg truss model in the design guidelines. A large dispersion of the results was found in ACI 440 with the C.O.V as far as 31.4%; whilst the TR 55 and fib 14 showed no significant difference with the C.O.V of 29.3% and 21.5%, respectively.

Investigating Novel Foundations for Offshore Windpower Generation

2002 ◽  
Author(s):  
B. W. Byrne ◽  
G. T. Houlsby
Keyword(s):  
Wind Turbines ◽  
Oil And Gas ◽  
Wind Farms ◽  
Design Guidelines ◽  
Engineering Problem ◽  
Offshore Wind ◽  
Combined Loading ◽  
Loading Conditions ◽  
Moment Load ◽  
The Uk

In recent years there has been a worldwide increase in the pressure to develop sources of renewable energy. The UK government is committed to ensuring that ten percent of UK energy consumption will be supplied by renewables by the year 2010. Central to this commitment is the need to develop wind farms particularly in the offshore environment. Moving offshore will allow very large wind turbines capable of supplying 2 MW (first generation) to 5 MW (second generation) of power to be installed in large farms consisting of up to fifty or more turbines. In contrast to typical oil and gas structures the foundation may account for up to forty percent of the projected installed cost. The weight of each structure is very low, so the applied vertical load on the foundation will be small compared to the moment load derived from the wind and waves. Further, it will be necessary to have a single design that can be mass-produced over each site rather than have each foundation individually engineered. In combination these points lead to a very interesting engineering problem where the design of the foundation becomes crucial to the economics of the project. One solution is to use conventional piling. However, at some sites it may prove more economical to use shallow foundations, and, in particular suction installed skirted foundations [1]. It will be necessary to develop an adequate design framework for these no vel foundations under the relevant combinations of load so that the optimum structural configuration can be achieved. At Oxford University a program of research on skirted foundations has been underway for the last five years, and much progress has been made on the understanding of this type of foundation under combined loading. This progress has been in both experimental and theoretical areas. This paper explores various structural options that might be used for the wind turbine application. These different options lead to different loading conditions on the foundations. Experiments investigating these different loading conditions are explored. A theoretical approach that describes the experimental results in a way that can be implemented in typical structural analyses programs is outlined. Finally details of a major research program into developing the necessary design guidelines for foundations for offshore wind turbines is described.

A KNN Based Collapse Methodology and Recent Qualification of Flexible Pipes in Deepwater Application

2020 ◽  
Author(s):  
Linfa Zhu ◽  
Victor Pinheiro Pupo Nogueira ◽  
Zhimin Tan
Keyword(s):  
Structural Characteristics ◽  
Design Guidelines ◽  
Flexible Pipe ◽  
Collapse Pressure ◽  
Collapse Strength ◽  
Flexible Pipes ◽  
Collapse Model ◽  
Testing Data ◽  
Collapse Prediction ◽  
Current Design

Abstract As the flexible pipe industry targets more on deepwater applications, collapse performance of flexible pipes becomes a key challenge due to the huge hydrostatic pressure during installation and service. The collapse strength of flexible pipes largely depends on the structural characteristics of carcass, pressure sheath and pressure armor layers. Therefore, the collapse prediction methodology involving a sound modeling of these layers is essential. Over the years, Baker Hughes have collected a large amount of collapse testing data. The prediction tool needs to be validated and calibrated against all the collapse tests for best accuracy. In this paper, the latest progress of the collapse prediction methodology and qualification tests are presented. A generalized collapse model was developed to predict the collapse pressure of flexible pipes. This model incorporates the advantages of both the weighted kNN regression technique and an analytical collapse model. It is able to reproduce the exact collapse pressure on the pipes tested and can predict the collapse pressure of other pipe designs not tested. As part of the qualification process, the capacity to prevent collapse must be demonstrated. Several flexible pipes were designed based on this generalized prediction methodology for deep water application, and pipe samples were manufactured using industrial production facilities for collapse tests. The results show that flexible pipes following current design guidelines are suitable for deepwater applications.

scholarly journals Assessment of the Lateral Vibration Serviceability Limit State of Slender Footbridges Including the Postlock-in Behaviour

2020 ◽  
Vol 10 (3) ◽  
pp. 967 ◽  
Author(s):  
Rocío G. Cuevas ◽  
Javier F. Jiménez-Alonso ◽  
Francisco Martínez ◽  
Iván M. Díaz
Keyword(s):  
Limit State ◽  
Sudden Onset ◽  
Design Guidelines ◽  
Comfort Level ◽  
Lateral Vibration ◽  
Vibration Serviceability ◽  
Current Design ◽  
Common Criterion ◽  
Lock In Effect ◽  
Lock In

The lateral vibration serviceability of slender footbridges has been the subject of many studies over the last few decades. However, in spite of the large amount of research, a common criterion has not been set yet. Although the human–structure interaction phenomenon is widely accepted as the main cause of the sudden onset of high amplitudes of vibration, the current design recommendations do not include an expression for the auto-induced component of the pedestrian action and, as a consequence, it is not possible to evaluate the footbridge comfort once the lock-in effect has developed. Hence, the purpose of this paper is to propose a general formulation, which allows the analysis of the different load scenarios that the footbridge will experience during its overall life cycle. An important advantage over most current design guidelines is that the procedure permits the evaluation of the comfort level of the footbridge, even with crowd densities above the “critical number”, and thus takes informed decisions about the possible use of external devices to control the vibration response, depending on the probability of occurrence of the problem. The performance of the proposed method is successfully evaluated through numerical response simulations of two real footbridges, showing a good agreement with the experimental data.

Bending Fatigue Strength of Innovative Gear Materials for Wind Turbines Gearboxes: Effect of Surface Coatings

2012 ◽  
Author(s):  
Carlo Gorla ◽  
Francesco Rosa ◽  
Franco Concli ◽  
Horacio Albertini
Keyword(s):  
Bending Strength ◽  
Test Procedure ◽  
Base Material ◽  
Fatigue Tests ◽  
Research Project ◽  
Bending Fatigue ◽  
Gear Manufacturing ◽  
Tungsten Carbide Coating ◽  
Traditional Manufacturing ◽  
Set Up

In order to better exploit the available resources, wind turbine size is constantly increasing: the need of bigger gearboxes is an obvious and immediate consequence of this evolution tendency. The traditional manufacturing methods exhibit some difficulties for a mass-production of such large and high quality gears. The aim of the XL-Gear research project is to identify an alternative gear manufacturing procedure. This procedure mainly relies on the selection of innovative and adequate materials to manufacture the gears. Two innovative materials (Jomasco and Metasco) have been identified. A common gear material has been selected to define a baseline from which variations can be evaluated. In addition, the effects of a thermal spray tungsten carbide coating on the base material will be also investigated. In the first part of this research project, the bending resistance is evaluated, while, in the second part, the pitting resistance will be evaluated. In order to assess to bending strength, adequate gear geometry has been designed and some parts manufactured with the above mentioned materials. These gears have then been used to perform STF (Single Tooth Fatigue) bending fatigue tests. In the paper, the STF test procedure design and set-up will be described and the STF tests results on the baseline and coated gear will be presented and discussed.

Comparative Field Measurements of Tire Pavement Noise of Selected Texas Pavements

1998 ◽  
Vol 1626 (1) ◽  
pp. 78-84 ◽  
Author(s):  
Michael T. Mcnerney ◽  
B.J. Landsberger ◽  
Tracy Turen ◽  
Albert Pandelides
Keyword(s):  
South Africa ◽  
Research Effort ◽  
Traffic Noise ◽  
Test Procedure ◽  
Field Measurements ◽  
Field Testing ◽  
The United States ◽  
Noise Barriers ◽  
Set Up ◽  
Pavement Noise

The effects of traffic noise are a serious concern in the United States and in the rest of the world. One significant component of traffic noise is tire-pavement interaction. If tire-pavement noise can be reduced at the source instead of through the use of traffic noise barriers set up to protect individual receivers, then potential savings can accrue. This research effort conducted field testing on 15 different pavement types found in Texas, and on six pavement types found in South Africa. A test procedure was developed with roadside microphones and microphones mounted on a test trailer to record and analyze the differences in tire-pavement noise. The test procedure was designed to develop comparisons of pavements while other variables were kept constant. The results, measured on the standard A-weighted scale, indicated for the 15 test pavements in Texas a difference of roadside noise levels of up to 7 dBA. Additionally, a roadside noise level of one pavement measured in South Africa was more than 2 dBA quieter than any Texas pavement.

Sign in / Sign up

Export Citation Format

Share Document