scholarly journals Development of a Fatigue Life Assessment Model for Pairing Fatigue Damage Prognoses with Bridge Management Systems

2020 ◽  
Author(s):  
Timothy Saad ◽  
Chung C. Fu ◽  
Gengwen Zhao ◽  
Chaoran Xu
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Assessment Model ◽  
Life Assessment ◽  
Management Systems ◽  
Bridge Management ◽  
Fatigue Life Assessment ◽  
Bridge Management Systems

Fatigue Life Assessment of Crane Reel

2011 ◽  
Vol 383-390 ◽  
pp. 2941-2944
Author(s):  
Wei Ming Du ◽  
Fei Xue
Keyword(s):  
Finite Element Method ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
Residual Life ◽  
Life Assessment ◽  
Life Estimation ◽  
Fatigue Life Assessment ◽  
Weld Fatigue ◽  
Simulation Results ◽  
Cumulative Fatigue Damage

The crane reel is generally manufactured by section welding method when the diameter is over 380mm. With the cumulative fatigue damage principle which is based on stress S-N curve, the fatigue damage of one crane reel is analyzed by finite element method, the reel weld fatigue strength and fatigue life are calculated, and the simulation results are proved to be reliable. This method provides an efficient reference for crane reel design and residual life estimation.

Fatigue Life Assessment for NPS30 Steel Pipe

2012 ◽  
Author(s):  
Jorge Silva ◽  
Hossein Ghaednia ◽  
Sreekanta Das
Keyword(s):  
Fatigue Life ◽  
Test Data ◽  
Crack Depth ◽  
Research Work ◽  
Longitudinal Crack ◽  
Assessment Model ◽  
Life Assessment ◽  
Fatigue Life Assessment ◽  
Remaining Fatigue Life ◽  
Crack Defect

Pipeline is the common mode for transporting oil, gas, and various petroleum products. Aging and corrosive environment may lead to formation of various defects such as crack, dent, gouge, and corrosion. The performance evaluation of field pipelines with crack defect is important. Accurate assessment of crack depth and remaining fatigue life of pipelines with crack defect is vital for pipeline’s structural integrity, inspection interval, management, and maintenance. An experimental based research work was completed at the University of Windsor for developing a semi-empirical model for estimating the remaining fatigue life of oil and gas pipes when a longitudinal crack defect has formed. A statistical approach in conjunction with fracture mechanics was used to develop this model. Statistical analysis was undertaken on CT specimen data to develop this fatigue life assessment model. Finite element method was used for determining the stress intensity factor. The fatigue life assessment model was then validated using full-scale fatigue test data obtained from 762 mm (30 inch) diameter X65 pipe. This paper discusses the test specimens and test data obtained from this study. Development and validation of the fatigue life assessment model is also presented in this paper.

Extreme Value Distribution Theory and its Application in Durability Analysis

2012 ◽  
Author(s):  
Zhigang Wei ◽  
Pingsha Dong ◽  
Litang Gao ◽  
Robert Kurth
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Extreme Events ◽  
Extreme Value Theory ◽  
Value Theory ◽  
Extreme Value ◽  
Life Assessment ◽  
Assessment Process ◽  
Fatigue Life Assessment ◽  
Axial Fatigue

Risk based treatment of degradation and failure in engineering components is an important topic in recent years with an emphasis on obtaining more detailed information for extreme events. Fatigue damage and life degradation caused by variable amplitude cyclic loading is dominated by such extreme events, and can be properly treated with the extreme value theory, which could help understand the damage nature of the fatigue damage process as well as to provide more efficient and robust approaches for engineering applications. In this paper, advanced extreme value theory is reviewed first. Methods such as peak counting, block maxima, and peaks over thresholds are investigated and compared in this paper with an emphasis on the relationship between the extreme value theory and the existing methods for fatigue life assessment. A few simple examples of uniaxial and multi-axial fatigue life assessment process are provided and the results are discussed. It is found that, if properly used, the extreme value theories can improve the efficiency of fatigue life assessment. Finally, a hybrid time- and frequency-based multi-axial fatigue life assessment procedure is proposed for wide band loadings.

Consumed Fatigue Life Assessment of Composite Material Structures by Optical Surface Roughness Inspection

2013 ◽  
Vol 569-570 ◽  
pp. 88-95 ◽  
Author(s):  
Pablo Zuluaga-Ramírez ◽  
Malte Frövel ◽  
René Restrepo ◽  
Rafael Trallero ◽  
Ricardo Atienza ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
Residual Life ◽  
Maximum Load ◽  
Life Assessment ◽  
Fatigue Life Assessment ◽  
Tensile Fatigue ◽  
A New Technique ◽  
Structural Inspection

A strong knowledge of the fatigue state of highly advanced carbon fiber reinforced polymer composite (CFRP) structures is essential to predict the residual life and optimize intervals of structural inspection, repairs, and/or replacements. Current techniques are based mostly in measurement of structural loads throughout the service life by electric strain gauge sensors. These sensors are affected by extreme environmental conditions and by fatigue loads in such a way that the sensors and their systems require exhaustive maintenance throughout system life.This work is focused on providing a new technique to evaluate the fatigue state of CFRP structures by means of evaluating the surface roughness variation due to fatigue damage. The surface roughness is a property that can be measured in the field by optical techniques such as speckle and could be a useful tool for structural health monitoring. The relation between surface roughness and fatigue life has been assessed on CFRP test specimens. A tensile fatigue load with an R=0.1 (T-T) and a maximum load of 60% of the material ultimate strength has been applied. The surface roughness of the specimens has been determined from the surface topography measured by a high precision confocal microscope. Results show that the surface roughness of the specimens increases with the accumulation of fatigue cycles in such a way that the roughness could be taken into account as a fatigue damage metrics for CFRP.

Wavelet-Based Feature Extraction Algorithm for Fatigue Strain Data Associated with the k-Means Clustering Technique

2014 ◽  
Vol 891-892 ◽  
pp. 1717-1722
Author(s):  
Teuku Edisah Putra ◽  
Shahrum Abdullah ◽  
Dieter Schramm ◽  
Mohd Zaki Nuawi ◽  
Tobias Bruckmann
Keyword(s):  
Feature Extraction ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
Extraction Process ◽  
Life Assessment ◽  
Original Signal ◽  
Statistical Parameters ◽  
Fatigue Life Assessment ◽  
Extraction Algorithm ◽  
Strain Data

The study presents the development of a wavelet-based segmentation algorithm for fatigue life assessment. Strain data was extracted using the Morlet family. The extraction process identified damaging segments, and it was able to shorten the original signal by 74.3%, with less than 10% difference with statistical parameters. The extraction algorithm was able to retain at least 97.9% of fatigue damage. The damaging segments drawn were clustered using the k-means method to provide three groups of segments, i.e., lower, moderate, and higher groups representing statistical values. The approach was suggested as an alternative method for evaluating and clustering fatigue strain signals.

scholarly journals A State-of-the-Art Review on Fatigue Life Assessment of Steel Bridges

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
X. W. Ye ◽  
Y. H. Su ◽  
J. P. Han
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Condition Assessment ◽  
Steel Bridges ◽  
Probabilistic Methods ◽  
Life Assessment ◽  
Current Status ◽  
Fatigue Life Assessment ◽  
Remaining Fatigue Life ◽  
Unsolved Issue

Fatigue is among the most critical forms of damage potentially occurring in steel bridges, while accurate assessment or prediction of the fatigue damage status as well as the remaining fatigue life of steel bridges is still a challenging and unsolved issue. There have been numerous investigations on the fatigue damage evaluation and life prediction of steel bridges by use of deterministic or probabilistic methods. The purpose of this review is devoted to presenting a summary on the development history and current status of fatigue condition assessment of steel bridges, containing basic aspects of fatigue, classical fatigue analysis methods, data-driven fatigue life assessment, and reliability-based fatigue condition assessment.

Methodology for Time Domain Fatigue Life Assessment of Risers and Umbilicals

2010 ◽  
Author(s):  
Oddrun Steinkjer ◽  
Nils So̸dahl ◽  
Guttorm Gryto̸yr
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Time Domain ◽  
Life Assessment ◽  
Statistical Uncertainty ◽  
Short Term ◽  
Fatigue Assessment ◽  
Fatigue Life Assessment ◽  
Non Linear ◽  
Selection Of

Risers and umbilicals are exposed to dynamic loading from waves and floater motions. These structures are known to have a pronounced non-linear response characteristic. Non-linear time-domain finite element analyses is in general required to give an adequate description of the non-linearities involved. Analyses of a large number of short-term environmental conditions considering stochastic wave loading are required to give a representative description of the long-term fatigue loading on the structure. Short term fatigue damage is established by means of rain-flow cycle (RFC) counting in each stationary short-term condition. It is has been experienced that significant statistical uncertainties can be present in the short-term fatigue damage estimates. This is because the accumulated fatigue damage in a stationary condition normally has significant contribution from the largest stress cycles in the realisation. Selection of proper simulation length is hence essential to obtain reliable fatigue life estimates. Applicable codes and standards for risers and umbilicals provide Design Fatigue Factors (DFF) to secure adequate safety against failure due to wave induced fatigue. The total uncertainty in the calculated fatigue damage comes from various sources and the DFFs in e.g. DNV-OS-F201 “Dynamic Risers” and API-RP-2RD corresponds to a certain uncertainty level in the fatigue damage estimate. A recommended target value for the statistical uncertainty of the fatigue damage estimates is given with basis in these design codes. The objective of this paper is to give a description of a methodology recommended for time domain fatigue assessment. Special focus will be on the importance of adequate simulation time for predicting the short-term fatigue damage and selection of the short-term seastates in the scatter diagram. Statistical uncertainty is one source that the analyst actually can influence by selecting proper analysis methodology. A statistical uncertainty meassure can be used to evaluate the robustness in the estimated fatigue life. Assessment of statistical uncertainty in fatigue damage estimate is demonstrated by case studies. The fatigue assessment methodology discussed in this paper, will be described in an update of DNV-RP-F204 “Riser Fatigue” 2010.

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