Acoustic Emission Monitoring of Naturally Developed Damage in Large-scale Low-speed Roller Bearings

This article presents an approach to identify naturally developed damage in low-speed bearings using waveform-similarity-based clustering of acoustic emissions (AEs) under fatigue loading. The approach is motivated by the notation that each recorded AE signal from a particular damage is defined by the convolution of the source signal, transfer...

Evaluation of Ultrasonic Stress Wave Transmission in Cylindrical Roller Bearings for Acoustic Emission Condition Monitoring

In the condition monitoring of bearings using acoustic emission (AE), the restriction to solely instrument one of the two rings is generally considered a limitation for detecting signals originating from defects on the opposing non-instrumented ring or its interface with the rollers due to the signal energy loss. This paper presents an approach...

Quantifying uncertainties for Risk-Based Inspection planning using in-service Hull Structure Monitoring of FPSO hulls

In order to obtain valuable information from an Hull Structure Monitoring system, a large data set and consistent analysis of that data is required. The monitoring requires significant efforts over multiple years and as a result, uncertainties obtained from in-service measurements are rarely published. Instead, researchers have to rely on...

Mid- and High-Cycle Fatigue of Welded Joints in Steel Marine Structures: Effective Notch Stress and Total Stress Concept Evaluations

The characteristic far field response spectrum of welded joints – the governing fatigue sensitive locations in steel marine structures – is predominantly linear elastic, meaning mid- and high-cycle fatigue (MCF and HCF) is most important for design. Using the effective notch stress- and the total stress concept, involving respectively S<sub>e...

BEM–FEM coupling for the analysis of flexible propellers in non-uniform flows and validation with full-scale measurements

The first part of the paper presents a partitioned fluid–structure interaction (FSI) coupling for the non-uniform flow hydro-elastic analysis of highly flexible propellers in cavitating and non-cavitating conditions. The chosen fluid model is a potential flow solved with a boundary element method (BEM). The structural sub-problem has been...

Projection and detection of climate change impact on fatigue damage of offshore floating structures operating in three offshore oil fields of the North Sea

Fatigue damage of offshore floating structures is a long-term cumulative process, which is mainly attributed to ocean waves. The natural variability and human-induced climate change may affect the wave climate and consequently result in the change of fatigue damage. This paper aims to investigate the effect of climate change on the fatigue...

A new approach for computing the steady state fluid–structure interaction response of periodic problems

A special type of fluid–structure interaction (FSI) problems are problems with periodic boundary conditions like in turbomachinery. The steady state FSI response of these problems is usually calculated with similar techniques as used for transient FSI analyses. This means that, when the fluid and structure problem are not simultaneously...

Fatigue design of welded double-sided T-joints and double-sided cruciform joints in steel marine structures: A total stress concept

Fatigue is a governing design limit state for marine structures. Welded joints are important in that respect. The weld notch stress (intensity) distributions contain essential information and formulations have been established to obtain a total stress fatigue damage criterion and corresponding fatigue resistance curve; a total stress concept....

Boundary element modelling aspects for the hydro-elastic analysis of flexible marine propellers

Boundary element methods (BEM) have been used for propeller hydrodynamic calculations since the 1990s. More recently, these methods are being used in combination with finite element methods (FEM) in order to calculate flexible propeller fluid–structure interaction (FSI) response. The main advantage of using BEM for flexible propeller FSI...

Applicability of WaveWatch-III wave model to fatigue assessment of offshore floating structures

In design and operation of floating offshore structures, one has to avoid fatigue failures caused by action of ocean waves. The aim of this paper is to investigate the applicability of WaveWatch-III wave model to fatigue assessment of offshore floating structures. The applicability was investigated for Bluewaters’ FPSO (Floating Production,...

Comparative study of multiaxial fatigue methods applied to welded joints in marine structures

Marine structures are particularly prone to action of waves, winds and currents with stochastically varying composition, intensities and directions. Therefore, resultant stresses may cause multiaxial fatigue in specific welded structural details. For the assessment of multiaxial fatigue in welded joints, a wide variety of methods have been...

Structural fatigue life assessment and sustainment implications for a New Class of US Coast Guard Cutters

This paper presents an overview of the US Coast Guard’s Fatigue Life Assessment Project (FLAP) and the application of the results in hull structure lifecycle management of the National Security Cutter class. One of the key measurements of the FLAP instrumentation included a radar based wave data measuring system. These measurements were used to...

Structural longevity of FPSO Hulls

The key challenge of managing Floating Production Storage and Offloading assets (FPSOs) for offshore hydrocarbon production lies in maximizing the economic value and productivity, while minimizing the Total Cost of Ownership and operational risk. This is a comprehensive task, considering the increasing demands of performance contracting, (down...

Cycle compression of imperfect steel plates, Part III: Preparations for experimental investigations

Low strain-rate sensitivity of yield stress of a modern mild steel, Appendix I Load- displacement diagrams

Ductile behaviour of cyclically in-plane compressed imperfect steel plate panels, Part II: Tolerances and statistical model for initial plating deflections in welded steel structures