The choice of cyclic plasticity models in fatigue life assessment of 304 and 1045 steel alloys based on the critical plane-energy fatigue damage approach

2012 ◽  
Vol 43 ◽  
pp. 217-225 ◽  
Author(s):  
M. Noban ◽  
H. Jahed ◽  
A. Varvani-Farahani
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Life Assessment ◽  
Cyclic Plasticity ◽  
Critical Plane ◽  
Steel Alloys ◽  
Fatigue Life Assessment ◽  
1045 Steel

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.

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.

A New Multiaxial Fatigue Life Prediction Model Under Proportional and Nonproportional Loading

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Jing Li ◽  
Qiang Sun ◽  
Zhong-Ping Zhang ◽  
Chun-Wang Li ◽  
Dong-Wei Zhang
Keyword(s):  
Fatigue Life ◽  
Damage Model ◽  
Cyclic Hardening ◽  
Damage Parameter ◽  
Multiaxial Fatigue ◽  
Life Assessment ◽  
Normal Strain ◽  
Critical Plane ◽  
Nonproportional Loading ◽  
Fatigue Life Assessment

Based on the critical plane approach, the drawbacks of the Wang–Brown (WB) model are analyzed. It is discovered that the normal strain excursion in the WB model cannot account for the additional cyclic hardening well. In order to solve this problem, a new damage parameter for multiaxial fatigue is proposed. In the meantime, the procedure for multiaxial fatigue life assessment incorporating critical plane damage model is presented as well. In the new damage parameter, both strain and stress components are considered, and the effect of the additional cyclic hardening on the fatigue life during nonproportional loading is taken into account as well. In addition, the proposed model is modified when the mean stress is existence. It is convenient for engineering application because of no material constants in this parameter. The capability of fatigue life assessment for the proposed fatigue damage model is checked against the experimental data found in literature for tubular specimens of 1045HR steel, hot-rolled 45 steel, S460N steel, GH4169 alloy at elevated temperature, and the notched shaft of SAE 1045 steel, which is under cyclic bending and torsion loading. It is demonstrated that the proposed criterion gives satisfactory results for all the five checked materials.

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.

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