ERRATA: Corrigenda to ‘Virtual Hull Monitoring: Continuous Fatigue Assessment Without Additional Instrumentation’: Technical Notes

2019 ◽  
Vol 161 (A4) ◽  
Keyword(s):  
Structural Response ◽  
Fatigue Assessment

Following publication of this study, work continued to enable more efficient structural response calculations. As part of that effort, two errors were identified and fixed.

Fatigue Assessment of Work-Over Risers Through Physical Testing

2014 ◽  
Author(s):  
Gerhard Gundersen ◽  
Rolf Hugo Kirkvik ◽  
Christopher Hoen-Sorteberg
Keyword(s):  
Structural Response ◽  
Fe Analysis ◽  
Bending Test ◽  
Measurement Technology ◽  
Fatigue Assessment ◽  
Inner Work ◽  
Physical Testing ◽  
Bending Loads ◽  
Operational Criteria ◽  
Variable Internal Pressure

Critical sections of work over strings, with respect to integrity, are components located close to end terminations, near well heads and above drill floors, where recurring bending moments are prevalent. The lifetime of these components are strongly dependent on the stiffness in the components of the string. Connections between these components are often complex, and of a type where the stiffness is unknown, or hard to reveal based on theoretical analysis. This paper considers the feasibility of applying state-of-the-art measurement technology for testing of the physical behavior of specific connections on a landing string to be used for work over operations in harsh environmental conditions, where low fatigue life of components have proven to be a recurring problem. Behavior of joint-connections revealed through measured response from physical testing serve as input for the global finite element (FE) analysis, where accumulated fatigue damage for each sea state is calculated based on site specific met-ocean data. The present work was carried out in advance of an operation on the Norwegian shelf, where a four-point bending test of the actual landing string to be used during the offshore campaign were performed on a section containing two critical couplings, in order to reveal the actual stiffness of the connections. The test string was subject to variable internal pressure, axial tension and bending loads, representative for the applicable work-over riser operational loads. The performance of the system was monitored through strain, displacement and force sensors, in order to relate applied loads to structural response. The results from these tests where later recreated from local FE analysis, where non linear springs was implemented and modified to fit the experimental results at the connections of interest. These springs was later input to the global fatigue analysis, where the complete system, including marine riser and inner work over string, was implemented in one model. Results from the fatigue assessment where used to determine the operational criteria for the work over operations.

ERRATA: CORRIGENDA TO VIRTUAL HULL MONITORING: CONTINUOUS FATIGUE ASSESSMENT WITHOUT ADDITIONAL INSTRUMENTATION

2021 ◽  
Vol 161 (A4) ◽  
Author(s):  
I M Thompson
Keyword(s):  
Structural Response ◽  
Fatigue Assessment

Following publication of this study, work continued to enable more efficient structural response calculations. As part of that effort, two errors were identified and fixed.

Vortex Induced Vibrations and Fatigue Assessment of Pipe-in-Pipe Systems

2018 ◽  
Author(s):  
Zhengmao Yang ◽  
Fartein Thorkildsen ◽  
Kristian Norland
Keyword(s):  
Numerical Model ◽  
Structural Response ◽  
Mode Shapes ◽  
Pipe Surface ◽  
Fatigue Assessment ◽  
Pipe System ◽  
Vortex Induced Vibrations ◽  
Pipe Systems ◽  
Girth Welds ◽  
Outer Pipe

The high thermal insulation potential of a pipe-in-pipe system makes it the preferred solution for challenging flow assurance conditions. Due to the higher bending stiffness of a pipe-in-pipe system, longer free spans would be expected for pipelines resting on uneven seabed. However, there are no clearly defined standard formulae for the calculation of structural response of free spanning pipe-in-pipe system exposed to vortex induced vibration (VIV) and the resulting fatigue damage. If the same method as for a single wall pipe was applied, the combined equivalent pipe properties would be assumed and the VIV response and stresses of the equivalent pipe could be obtained. However, the longitudinal stresses in the inner and outer pipe to be used for the fatigue assessment of the girth welds would not be easily obtained, especially for sliding pipe-in-pipe systems. Based on previous experience and development work for pipe-in-pipe systems, a numerical model for VIV assessment of sliding pipe-in-pipe systems is proposed giving improved interpretation of individual pipe characteristics. Modal analyses of sliding pipe-in-pipe systems are performed by using this numerical model. The natural frequencies and mode shapes are extracted. According to the numerical analysis results, the longitudinal stress ranges due to VIV are obtained and fatigue assessment of the pipeline girth welds for the inner and outer pipes are performed. In order to understand the interaction between the outer and inner pipe, the effect of friction and initial gap between the centralizers and outer pipe surface are studied.

Ambulatory fatigue assessment: Speech, video, and biosignal based approaches for measuring need for recovery and burnout risk

2011 ◽  
Author(s):  
Jarek Krajewski ◽  
Sebastian Schnieder ◽  
Martin Golz ◽  
Thomas Schnupp ◽  
Christian Heinze
Keyword(s):  
Need For Recovery ◽  
Fatigue Assessment ◽  
Burnout Risk

Fatigue assessment of welded joints by local approaches

2006 ◽  
Author(s):  
D Radaj ◽  
C M Sonsino ◽  
W Fricke
Keyword(s):  
Welded Joints ◽  
Fatigue Assessment

Influence of the distribution of the shear walls on the seismic response of the buildings

2020 ◽  
Vol 15 (1) ◽  
pp. 37-44
Author(s):  
El Mehdi Echebba ◽  
Hasnae Boubel ◽  
Oumnia Elmrabet ◽  
Mohamed Rougui
Keyword(s):  
Structural Analysis ◽  
Seismic Response ◽  
Natural Frequency ◽  
Structural Design ◽  
Structural Response ◽  
Shear Walls ◽  
Structural Elements ◽  
Analysis Software ◽  
Ansys Apdl ◽  
The Impact

Abstract In this paper, an evaluation was tried for the impact of structural design on structural response. Several situations are foreseen as the possibilities of changing the distribution of the structural elements (sails, columns, etc.), the width of the structure and the number of floors indicates the adapted type of bracing for a given structure by referring only to its Geometric dimensions. This was done by studying the effect of the technical design of the building on the natural frequency of the structure with the study of the influence of the distribution of the structural elements on the seismic response of the building, taking into account of the requirements of the Moroccan earthquake regulations 2000/2011 and using the ANSYS APDL and Robot Structural Analysis software.

Analysis and design of thermo-mechanical interfaces

2012 ◽  
Vol 60 (2) ◽  
pp. 205-213
Author(s):  
K. Dems ◽  
Z. Mróz
Keyword(s):  
Optimality Conditions ◽  
Mechanical Loading ◽  
Material Properties ◽  
Structural Response ◽  
External Boundary ◽  
Mechanical Loads ◽  
Internal Interface ◽  
Analysis And Design ◽  
First Order ◽  
Mechanical Nature

Abstract. An elastic structure subjected to thermal and mechanical loading with prescribed external boundary and varying internal interface is considered. The different thermal and mechanical nature of this interface is discussed, since the interface form and its properties affect strongly the structural response. The first-order sensitivities of an arbitrary thermal and mechanical behavioral functional with respect to shape and material properties of the interface are derived using the direct or adjoint approaches. Next the relevant optimality conditions are formulated. Some examples illustrate the applicability of proposed approach to control the structural response due to applied thermal and mechanical loads.

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