Fatigue Analysis of Multi-Spanning Subsea Pipeline

2010 ◽  
Author(s):  
Kosar Rezazadeh ◽  
Liyun Zhu ◽  
Yong Bai ◽  
Liang Zhang
Keyword(s):  
Stress Distribution ◽  
Dynamic Analysis ◽  
Static Analysis ◽  
Fatigue Analysis ◽  
Sensitivity Analyses ◽  
Fe Model ◽  
Analysis Method ◽  
Subsea Pipeline ◽  
Interaction Control ◽  
Integrity Management

Free-span occurs normally in pipeline at uneven seabed, dynamic seabed or pipeline crossing. The analysis of free-span, including static analysis and dynamic analysis, is an important subject in the study of pipeline integrity management. Static analysis of free span for subsea pipeline is to evaluate the stress distribution of spanning pipeline in the ultimate conditions, and qualify the stress with design codes in the engineering analysis. However, dynamic analysis of subsea spanning pipeline is much complicated due to VIV fatigue. In 2006 DNV-RP-F105 suggested a methodology of dynamic analysis for long spanning pipeline with multi-mode responses, but the fatigue analysis method for multi-modes is not detailed. In addition, the fatigue analysis of multi-spanning pipeline is not clear. The gap between the continuous two spans, and the pipe-soil interaction control the fatigue damage of the multi-spanning pipeline. In this paper, a VIV fatigue analysis method for multi-spanning pipeline is suggested based on VIV analysis. In this method, Abaqus FE model is developed first to obtain the stress distribution and the natural frequency of each vibration mode for spanning pipeline on seabed in different configurations with three multi-spans, and then the fatigue analysis of VIV is carried out for the spanning pipeline based on DNV-RP-F105. An example of fatigue analysis for a multi-spanning pipeline is presented; finally, several sensitivity analyses demonstrate the effects of key parameters on the VIV fatigue.

Static and Dynamic Analysis Methods of Position-Keeping Capability for Offshore Supply Vessels With Voith-Schneider Propellers

2017 ◽  
Author(s):  
Ole Detlefsen ◽  
Lasse Theilen ◽  
Moustafa Abdel-Maksoud
Keyword(s):  
Dynamic Analysis ◽  
Static Analysis ◽  
Time Domain ◽  
Degrees Of Freedom ◽  
Dynamic Assessment ◽  
Analysis Method ◽  
Environmental Loads ◽  
Static And Dynamic Analysis ◽  
First Results ◽  
Validation Tests

This paper presents a static and a time-domain method to assess the position-keeping capability of monohull vessels. For the static analysis method, the equlibrium between mean environmental loads and available actuator forces is determined. In case of the dynamic assessment, the motions of the fully actuated ship in all degrees of freedom are simulated in time domain and evaluated by criteria regarding the position and heading of the ship. After first results from validation tests an exemplary application is shown by assessing the positioning capability of a Voith-Schneider propelled offshore supply vessel.

Research of Engine Piston Pin Fatigue Analysis Based on UG

2011 ◽  
Vol 383-390 ◽  
pp. 7312-7315
Author(s):  
Hong Pu Liu ◽  
Hong Ying Wang
Keyword(s):  
Boundary Condition ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Static Analysis ◽  
Fatigue Analysis ◽  
Computational Method ◽  
Analysis Method ◽  
Element Analysis ◽  
Engine Piston ◽  
Conventional Algorithm

Carried on finite element analysis using the UG software to finally carry on the fatigue life’s computational method to carry on the exploration and the research. when carrying on the finite element static analysis to the piston pin, used the different analysis method, because the piston pin’s quality is very slightly oppositeing to the piston quality, produces the force of inertia is very small, the counter stress computed result is not very obvious, therefore to piston pin finite element analysis we uses conventional algorithm that infliction boundary condition.

Wellhead Fatigue Analysis Method

2011 ◽  
Author(s):  
Lorents Reina˚s ◽  
Torfinn Ho̸rte ◽  
Morten Sæther ◽  
Guttorm Gryto̸yr
Keyword(s):  
Fatigue Damage ◽  
Fatigue Analysis ◽  
Response Analysis ◽  
Analysis Method ◽  
Drilling Rig ◽  
Analysis Methodology ◽  
Well Integrity ◽  
Stress Curve ◽  
Integrity Management ◽  
Load Analysis

Re-completion and re-drilling of existing wells and introduction of new large drilling rig systems are elements that have led to renewed focus on the fatigue capacity for existing and new subsea wells. Due to lack of applicable codes and standards for such fatigue calculations, a unified analysis methodology has been developed and described in a Wellhead Fatigue Analysis Method Statement (MS). The intention of this work is to reflect the best practice in the industry and to provide an important contribution to well integrity management. The analysis methodology is limited to fatigue damage from dynamic riser loads present during subsea drilling and work over operations. The analysis procedure may be divided into three parts. i) A local response analysis that includes a detailed finite element model from wellhead datum and below. Interaction between the structural well components and soil structure interaction is properly accounted for. The main result from this analysis is the load-to-stress curve that describes the relationship between the riser loads at the wellhead datum and the stress at the fatigue hot spots. The analysis also provides the lower boundary conditions of the global load analysis model. ii) A global load analysis where the floating mobile drilling unit (MODU) motions and wave loads on the riser are taken into account. The results are time series or load histograms of the loads at wellhead datum, with focus on the bending moment, in all relevant environmental sea states. iii) Fatigue damage assessment, where a mapping of the loads with the relevant load to stress curve is carried out together with subsequent fatigue damage calculation. Appropriate S-N curve is applied together with wave scatter diagrams for the relevant operations and durations. The final result is the accumulated fatigue damage. With a unified analysis methodology in place particular attention is placed on a structured and specified analysis input and output. Results are suggested presented as a function of time and also as a function of key analysis input parameters that are associated with uncertainty. These are prerequisites from a well integrity management perspective in ensuring analysis results that are comparable. This paper presents the essence of the Wellhead Fatigue Analysis Method that was developed in cooperation between Statoil and DNV. Currently this analysis methodology is under extension and revision in the joint industry project (JIP) “Structural Well Integrity During Well Operations”. 11 operators participate in this JIP which also has structured cooperation with equipment suppliers, drilling companies and analysis houses. The aim is to form a wellhead analysis recommended practice document.

Dynamic Analysis Method for Electromagnetic Artificial Muscle Actuator under PID Control

2011 ◽  
Vol 131 (2) ◽  
pp. 166-170 ◽  
Author(s):  
Yoshihiro Nakata ◽  
Hiroshi Ishiguro ◽  
Katsuhiro Hirata
Keyword(s):  
Dynamic Analysis ◽  
Pid Control ◽  
Artificial Muscle ◽  
Analysis Method

scholarly journals Automatic Malicious Code Classification System through Static Analysis Using Machine Learning

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 35
Author(s):  
Sungjoong Kim ◽  
Seongkyu Yeom ◽  
Haengrok Oh ◽  
Dongil Shin ◽  
Dongkyoo Shin
Keyword(s):  
Machine Learning ◽  
Static Analysis ◽  
Information And Communication Technology ◽  
Communication Technology ◽  
Classification System ◽  
Daily Life ◽  
Malicious Code ◽  
Access To Information ◽  
Analysis Method ◽  
Information And Communication

The development of information and communication technology (ICT) is making daily life more convenient by allowing access to information at anytime and anywhere and by improving the efficiency of organizations. Unfortunately, malicious code is also proliferating and becoming increasingly complex and sophisticated. In fact, even novices can now easily create it using hacking tools, which is causing it to increase and spread exponentially. It has become difficult for humans to respond to such a surge. As a result, many studies have pursued methods to automatically analyze and classify malicious code. There are currently two methods for analyzing it: a dynamic analysis method that executes the program directly and confirms the execution result, and a static analysis method that analyzes the program without executing it. This paper proposes a static analysis automation technique for malicious code that uses machine learning. This classification system was designed by combining a method for classifying malicious code using a portable executable (PE) structure and a method for classifying it using a PE structure. The system has 98.77% accuracy when classifying normal and malicious files. The proposed system can be used to classify various types of malware from PE files to shell code.

scholarly journals Hypervisor-assisted dynamic malware analysis

Cybersecurity ◽  
2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Roee S. Leon ◽  
Michael Kiperberg ◽  
Anat Anatey Leon Zabag ◽  
Nezer Jacob Zaidenberg
Keyword(s):  
Dynamic Analysis ◽  
Static Analysis ◽  
Cyber Security ◽  
Malware Analysis ◽  
Analysis Tools ◽  
Significant Performance

AbstractMalware analysis is a task of utmost importance in cyber-security. Two approaches exist for malware analysis: static and dynamic. Modern malware uses an abundance of techniques to evade both dynamic and static analysis tools. Current dynamic analysis solutions either make modifications to the running malware or use a higher privilege component that does the actual analysis. The former can be easily detected by sophisticated malware while the latter often induces a significant performance overhead. We propose a method that performs malware analysis within the context of the OS itself. Furthermore, the analysis component is camouflaged by a hypervisor, which makes it completely transparent to the running OS and its applications. The evaluation of the system’s efficiency suggests that the induced performance overhead is negligible.

scholarly journals Applicability of a Three-Layer Model for the Dynamic Analysis of Ballasted Railway Tracks

Vibration ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 151-174
Author(s):  
André F. S. Rodrigues ◽  
Zuzana Dimitrovová
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Dynamic Analysis ◽  
Shear Stiffness ◽  
Shear Resistance ◽  
Railway Track ◽  
Fe Model ◽  
Inertial Effects ◽  
Layer Model ◽  
3D Finite Element

In this paper, the three-layer model of ballasted railway track with discrete supports is analyzed to access its applicability. The model is referred as the discrete support model and abbreviated by DSM. For calibration, a 3D finite element (FE) model is created and validated by experiments. Formulas available in the literature are analyzed and new formulas for identifying parameters of the DSM are derived and validated over the range of typical track properties. These formulas are determined by fitting the results of the DSM to the 3D FE model using metaheuristic optimization. In addition, the range of applicability of the DSM is established. The new formulas are presented as a simple computational engineering tool, allowing one to calculate all the data needed for the DSM by adopting the geometrical and basic mechanical properties of the track. It is demonstrated that the currently available formulas have to be adapted to include inertial effects of the dynamically activated part of the foundation and that the contribution of the shear stiffness, being determined by ballast and foundation properties, is essential. Based on this conclusion, all similar models that neglect the shear resistance of the model and inertial properties of the foundation are unable to reproduce the deflection shape of the rail in a general way.

Hybrid Fatigue Analysis Method for Railway Carbody Structure

2008 ◽  
Vol 44-46 ◽  
pp. 733-738 ◽  
Author(s):  
Bing Rong Miao ◽  
Wei Hua Zhang ◽  
Shou Ne Xiao ◽  
Ding Chang Jin ◽  
Yong Xiang Zhao
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Hybrid Method ◽  
Dynamic Stress ◽  
Stress Test ◽  
Fatigue Analysis ◽  
Railway Vehicle ◽  
Analysis Method ◽  
Structure Dynamic ◽  
Multi Body

Railway vehicle structure fatigue life consumption monitoring can be used to determine fatigue damage by directly or indirectly monitoring the loads placed on critical vehicle components susceptible to failure from fatigue damage. The sample locomotive carbody structure was used for this study. Firstly, the hybrid fatigue analysis method was used with Multi-Body System (MBS) simulation and Finite Element Method (FEM) for evaluating the carbody structure dynamic stress histories. Secondly, the standard fatigue time domain method was used in fatigue analysis software FE-FATIGUE and MATLAB WAFO (Wave Analysis for Fatigue and Oceanography) tools. And carbody structure fatigue life and fatigue damage were predicted. Finally, and carbody structure dynamic stress experimental data was taken from this locomotive running between Kunming-Weishe for this analysis. The data was used to validate the simulation results based on hybrid method. The analysis results show that the hybrid method prediction error is approximately 30.7%. It also illustrates that the fatigue life and durability of the locomotive can be predicted with this hybrid method. The results of this study can be modified to be representative of the railway vehicle dynamic stress test.

Dynamic Analysis of the Pipe Lifting Mechanism on the Deepwater Pipelaying Vessel

2011 ◽  
Vol 199-200 ◽  
pp. 251-256
Author(s):  
Kai An Yu ◽  
Ke Yu Chen
Keyword(s):  
Numerical Analysis ◽  
Dynamic Analysis ◽  
High Efficiency ◽  
Transport Systems ◽  
Kinematic Pair ◽  
Analysis Method ◽  
Numerical Analysis Method ◽  
Upper Limit ◽  
Lifting Capacity ◽  
Limit Position

Based on requirements of pipe transport systems on deepwater pipelaying vessel, a new pipe lifting mechanism was designed. It was composed of crank-rocker and rocker-slider mechanism with good lifting capacity and high efficiency. When the slider went to the upper limit position, the mechanism could approximatively dwell, meeting the requirement for transverse conveyor operation. According to the theory of dynamics, numerical analysis method was used to the dynamic analysis of the mechanism. The results showed the maximum counterforce was at the joint between the rocker and ground, and this calculation could be a guideline for the kinematic pair structure designing.

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