Assessment of Free Spanning Pipeline Strength

2013 ◽  
Vol 310 ◽  
pp. 194-197
Author(s):  
Hong Jun Zhu ◽  
Xing Qi ◽  
Yong Chuang Yang ◽  
Ming Yang Wang ◽  
Xiao Xu Liu ◽  
...  
Keyword(s):  
Yield Strength ◽  
Fatigue Failure ◽  
Assessment Method ◽  
Submarine Pipeline ◽  
Strength Assessment ◽  
Buckling Strength ◽  
Safety Design ◽  
Pipeline Failures

Submarine pipeline failures usually occur at free span part, and free spanning pipeline is easily induced vibration by vortex, which accelerates the fatigue failure of pipe. Therefore, it is necessary to assess the strength of free spanning pipeline at regular intervals. In this paper, considering the effects of VIV, resonance assessment and yield strength assessment as well as buckling strength assessment are enumerated. And an illustration is calculated to verify the reliability of assessment method. This research may provide a guide for safety design, installation and maintenance of submarine pipeline.

Study on the Wave Loads and Strength Assessment Method on Semi-Submersible Platform

2009 ◽  
Author(s):  
Hui Li ◽  
Huilong Ren ◽  
Tao Wei ◽  
Guoqing Feng
Keyword(s):  
Fatigue Strength ◽  
Assessment Method ◽  
Wave Method ◽  
Wave Loads ◽  
Strength Assessment ◽  
Buckling Strength ◽  
Comprehensive Comparison ◽  
Comparison Of The Results ◽  
Classification Society

In this paper, the wave loads of a semi-submersible platform is calculated by the deterministic design wave method and the stochastic design wave method based on the rules established by ABS and DNV classification society respectively. Then, the yielding strength, buckling strength and fatigue strength of important members are assessed according to these different rules. Through the comprehensive comparison of the results of wave loads and strength assessment, the differences between these rules are summarized. Then some significant suggestions are given.

Computational Process Simulation and Energy Parameter Analysis From Mechanical Deformation of Aerospace Alunimum Alloys

2002 ◽  
Author(s):  
James M. Fragomeni ◽  
Giridhar Venugopal
Keyword(s):  
Yield Strength ◽  
Experimental Testing ◽  
True Strain ◽  
Energy Parameter ◽  
True Stress ◽  
Parameter Analysis ◽  
Dissipated Energy ◽  
Strain Hardening Exponent ◽  
Element Analysis ◽  
Buckling Strength

Many systems that work on the processing of energy can be modeled in terms of that energy. The energy that is given to the system may be stored or dissipated in the form of heat. It was proposed to extend this concept to attainment of critical level of stored energy and/or dissipated energy for occurrence of buckling of a metal column under compressive loading. The fact that Energy Factor Parameter (E.F.P.) computed from the experimental true stress-true strain values, suddenly decreased and approached value close to zero indicated either buckling and/or softening, but deviated with the E.F.P. computed from the theoretical true stress and true strain values. The 7050-T7451 (Al-Zn-Mg-Cu-Zr) and Al-Li-Cu aluminum alloys in longitudinal and transverse grain orientations were compression tested for mechanical properties of yield strength, buckling strength, strength coefficient, strain hardening exponent. Correlation between ratio of buckling strength and yield strength with aging time for preaged ASTM compression specimens was established. The compression deformation of aluminum alloy 7050 was modeled using finite element analysis, with the experimental testing parameters and the database in the software package.

A Methodology to Assess Elbow Fittings With Localized Material Variations

2019 ◽  
Author(s):  
Pritha Ghosh ◽  
Mandar Kulkarni ◽  
Brent Vyvial ◽  
James Ferguson
Keyword(s):  
Heat Treatment ◽  
Yield Strength ◽  
Internal Pressure ◽  
Load Capacity ◽  
Axial Strain ◽  
Assessment Method ◽  
Assessment Procedure ◽  
Lower Yield ◽  
Analytical Methodology ◽  
Yield Zone

Abstract Elbow fittings are manufactured using quenching and tempering heat treatment processes. Such fittings can occasionally exhibit localized regions with lower yield strength than the design target, potentially due to non-uniform heat treatment. This paper presents an analytical methodology to examine the influence of these localized lower yield zones on the load capacity of the affected pipe fitting. In parallel, full-scale testing has been performed to quantify the actual response of the elbows under a combination of different loading conditions. The experimental data is used to validate the analytical approach. Details of the analytical method include a two-fold criterion: a global failure based on elastic–plastic stress analysis and a local failure based on the tri-axial strain limit per ASME Boiler and Pressure Vessel Code Section VIII, Division 2. This paper presents the details of the finite element model development, assessment procedure, validation and parametric analysis of the size and location of the low yield zones in the elbow fittings. The fittings are analyzed for three possible operating scenarios: internal pressure, internal pressure with opening moment and internal pressure with closing moment. To characterize the influence of the low yield zone on the strength of the pipe, a parameter termed as “effective yield strength” is introduced. This approach is further demonstrated and found suitable for predicting burst pressures of components with lower yield zones of various diameters and thicknesses. This assessment method can be further extended to assess other pipeline components that exhibit similar behavior.

Neural networks for lateral torsional buckling strength assessment of cellular steel I-beams

2019 ◽  
Vol 22 (9) ◽  
pp. 2192-2202 ◽  
Author(s):  
Yasser Sharifi ◽  
Adel Moghbeli ◽  
Mahmoud Hosseinpour ◽  
Hojjat Sharifi
Keyword(s):  
Neural Networks ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Strength Assessment ◽  
Buckling Strength

The Effect of Soil on the Structural Response and Fatigue Life of Free Span for Submarine Pipeline

2015 ◽  
Author(s):  
Jie Dong ◽  
Chen Xuedong ◽  
Bing Wang ◽  
Weihe Guan ◽  
Tiecheng Yang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Flow Velocity ◽  
Fatigue Damage ◽  
Fatigue Failure ◽  
Failure Modes ◽  
Structural Response ◽  
Submarine Pipeline ◽  
Velocity Data ◽  
Measured Flow ◽  
Stiffness And Damping

Free span resulting from unevenness of seabed or scour of current is a dangerous status for submarine pipeline. Fatigue failure caused by vortex induced vibration (VIV) is one of the main failure modes for free span. Because of the contact between soil and pipeline, the effect of soil must be considered for the fatigue analysis of free span. In this paper, aimed at one in-service submarine pipeline, the research on the VIV response of free span was investigated considering the effect of stiffness and damping of soil. Furthermore, fatigue damage and fatigue life of free span were evaluated based on the actual measured flow velocity data varied with time. The analysis results have provided support for the maintenance of free span for the submarine pipeline.

Fitness for Purpose Assessment of Girth Weld Defect Based on In-Line Inspection

2016 ◽  
Vol 853 ◽  
pp. 524-528
Author(s):  
Jian Chen ◽  
Zheng Qiang Lei ◽  
Fu Xiang Wang ◽  
Ting Wang ◽  
Ming Fei Li
Keyword(s):  
Oil And Gas ◽  
Assessment Method ◽  
Assessment Procedure ◽  
Defect Characterization ◽  
Strong Impact ◽  
Plastic Collapse ◽  
Fitness For Purpose ◽  
Strength Assessment ◽  
Weld Defects ◽  
Weld Defect

The girth weld defect is one of the most common types of defects on oil and gas pipelines, which can have a strong impact on the operation safety. Several girth weld failure accidents have occurred on PetroChina’s pipelines in recent years. In this paper, PetroChina’s current work on inspection and fitness for purpose assessment of girth weld defects is summarized. The in-line inspection has been proved to be the best practice for oil and gas pipeline defect inspection, but there are still some technical issues such as defect characterization and parameter selection. Fitness for purpose assessment methods for girth weld defects include strength assessment method based on plastic collapse, FAD method based on both plastic collapse and fracture, simplified factor method and numerical analysis method based on finite element. It is critical to identify the actual type of defects detected in in-line inspection to select an appropriate assessment method. The identification of various loads and the selection of appropriate material parameters are also important issues in assessment procedure. The key techniques to be developed include defect characterization, load identification, assessment of defects on high grade steel pipes, reliability-based assessment, etc.

Study on the Measurement Method and Safety Design of Ultrasonic Cleaning Equipment

2012 ◽  
Vol 546-547 ◽  
pp. 1568-1573
Author(s):  
Cai Yuan Wang ◽  
Ai Hui Zhou ◽  
Zhen Sheng Xia
Keyword(s):  
Measurement Method ◽  
Aluminum Foil ◽  
Assessment Method ◽  
Performance Parameters ◽  
Design Data ◽  
Destructive Effect ◽  
Ultrasonic Cleaning ◽  
Safety Design ◽  
Cleaning Machine ◽  
Long Time

To the question that it was hard to measure and verify the safety design rationality of the performance parameters for the ultrasonic cleaning machine, the destructive effect mechanism of the ultrasonic cleaning was analyzed. It was indicated that the cleaning power and time were the two main factors for damaging the insulating layer of the cleaning objects. The measuring technology was presented by aluminum foil, and it analyzed feasibility and an area assessment method for the measurement method by aluminum foil. The practical long time test of the motor demonstrated that the measurement method by aluminum foil can provide safety design data support and experimental verification to the performance parameters design of the ultrasonic cleaning machine.

Fatigue Analysis of Free Span for Submarine Pipeline

2013 ◽  
Author(s):  
Jie Dong ◽  
Xuedong Chen ◽  
Bing Wang ◽  
Weihe Guan ◽  
Tiecheng Yang ◽  
...  
Keyword(s):  
Failure Mode ◽  
Fatigue Failure ◽  
Oil And Gas ◽  
Cross Flow ◽  
Fatigue Analysis ◽  
Submarine Pipeline ◽  
Actual Service ◽  
Offshore Oil And Gas ◽  
Offshore Oil

The offshore oil and gas are mainly gathered and transported by submarine pipeline due to its merits of continuity, convenience and less effect of climate. Free span often occurs because of the unevenness and scour of seabed and endangers the safe running of pipeline. Fatigue is one main failure mode for free span. In this paper, combined with the actual service status of submarine pipeline, considering the variation of velocity with time, the load of wave and current, the effect of cross-flow vibration to the in-line vibration, the fatigue failure of the detected free span is analysed primarily and detailedly by correlated standard, and the results are given.

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