Probabilistic Fatigue Damage Analysis of Long Span Suspension Bridge Due to Wind Induced Buffeting

2020 ◽  
Vol 980 ◽  
pp. 275-281
Author(s):  
Hu Jun
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Time History ◽  
Suspension Bridge ◽  
Wind Load ◽  
Strong Wind ◽  
Fatigue Reliability ◽  
Long Span ◽  
Fatigue Damage Analysis ◽  
Fluctuating Wind

In order to consider the fluctuating wind load induced fatigue problem of long span suspension bridge, fatigue reliability formula is modified by assuming the fatigue life is accord with the weibull distribution. Based on the accurate bridge buffeting analysis of time history, the stress time history of components of a suspension bridge in east sea China is simulated, and then the fatigue damages and reliabilities are calculated. The results indicate that the main cables and hangers have enough fatigue reliability under the fluctuating wind load, the fatigue failure will not occur; the stiffening girder has larger fatigue damage, under 40 / (m.s-1) mean wind speed action, the girder of mid-support section’s average fatigue life is only 3.103 years, so the girder’s damage under strong wind action should be taken seriously.

Determination Method of a Proper Small-Load-Omitting Criterion Based on the Extreme Load

2013 ◽  
Vol 694-697 ◽  
pp. 278-283
Author(s):  
Zhi Qiang Xu
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
High Frequency ◽  
Life Prediction ◽  
Time History ◽  
Fatigue Life Prediction ◽  
Threshold Theory ◽  
Small Load ◽  
Extreme Load ◽  
Peak Over Threshold

A crucial step to obtain a reliable fatigue life prediction is to determine a proper small load threshold below which the cycles at small loads or stresses with high frequency causing little fatigue damage are truncated from the original load time history. By taking both the peak over threshold theory and the endurance limit threshold into account, a proper small load threshold is proposed in this paper. The optimal threshold should be high enough to remove the high-frequency small cycles and low enough to minimize the loss of the fatigue damage which maybe be truncated by the empirical small-load omitting threshold. Based on this proper threshold, the fatigue life prediction will be more reliable.

scholarly journals Prediction of Fatigue Life of a Continuous Bridge Girder Based on Vehicle Induced Stress History

2003 ◽  
Vol 10 (5-6) ◽  
pp. 325-338 ◽  
Author(s):  
V.G. Rao ◽  
S. Talukdar
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Fatigue Testing ◽  
Damage Index ◽  
Time History ◽  
Stress Range ◽  
Frequency Histogram ◽  
Bridge Span ◽  
History Of ◽  
Bridge Girder

The fatigue damage assessment of bridge components by conducting a full scale fatigue testing is often prohibitive. A need, therefore, exists to estimate the fatigue damage in bridge components by a simulation of bridge-vehicle interaction dynamics due to the action of the actual traffic. In the present paper, a systematic method has been outlined to find the fatigue damage in the continuous bridge girder based on stress range frequency histogram and fatigue strength parameters of the bridge materials. Vehicle induced time history of maximum flexural stresses has been obtained by Monte Carlo simulation process and utilized to develop the stress range frequency histogram taking into consideration of the annual traffic volume. The linear damage accumulation theory is then applied to calculate cumulative damage index and fatigue life of the bridge. Effect of the bridge span, pavement condition, increase of vehicle operating speed, weight and suspension characteristics on fatigue life of the bridge have been examined.

Influence of Temperature and Increasing Traffic Flow on the Fatigue Damage of Welded Bridge Decks

2007 ◽  
Vol 348-349 ◽  
pp. 341-344 ◽  
Author(s):  
Tong Guo ◽  
Ai Qun Li ◽  
Zhao Xia Li
Keyword(s):  
Traffic Flow ◽  
Fatigue Damage ◽  
Suspension Bridge ◽  
Life Assessment ◽  
Element Analysis ◽  
Influence Of Temperature ◽  
Linear Effect ◽  
Long Span ◽  
Traffic Growth ◽  
Using Data

Fatigue life assessment of critical bridge members using online monitoring data has been investigated in recent years. To make a quick and efficient evaluation, a representative block of strain cycles is usually defined. However, such block sometimes fails to cover the change in fatigue damage by temperature fluctuation and traffic growth, which is important to the life prediction of the welds in a long-span suspension bridge. To find the influence of temperature and traffic volume on the fatigue damage, an equivalent vehicle load method is dedicated through finite element analysis, and the statistical disposition of traffic flow has been conducted, using data from the Runyang Bridge. The influence of traffic growth can be estimated and eliminated from the total damage so that the temperature effect on the fatigue damage is finally obtained. It is found that temperature has a linear effect on the fatigue damage. According to the fitted relationship between fatigue damage, temperature and the traffic flow, a more objective fatigue assessment is undertaken, based on the rain-flow counting method and the Palgren-Miner rule.

Fatigue Test on Integral Joint of the Main Truss of the Baling River Bridge

2009 ◽  
Vol 417-418 ◽  
pp. 481-484 ◽  
Author(s):  
Gao Liu ◽  
Wen Ming Wu ◽  
Liang Tang ◽  
Tian Liang Wang
Keyword(s):  
Fatigue Test ◽  
Fatigue Resistance ◽  
Suspension Bridge ◽  
Scale Model ◽  
Fatigue Reliability ◽  
Truss Bridges ◽  
Long Span ◽  
Load Spectra ◽  
Main Girder ◽  
Test Result

The Baling River Bridge is a single-span simply-supported suspension bridge with a main span of 1088 m. The steel stiffening truss is employed as its main girder and comprises the integral joints connecting the chord members. The integral joint is a key structure and determines the safety of the bridge, but it is very complex in detail and has an undefined fatigue resistance. In order to investigate its mechanical behavior and fatigue reliability, a fatigue test was performed on a 1:1.4 scale model of the integral joint of the main truss of the Bridge. With an assumption of the load spectra represented by the standard fatigue vehicle in BS 5400, the test fatigue load was derived accounting for the multiple vehicle effect and the model scale. The test result shows that no cracks were detected in the model when subjected to two million stress range cycles, and the structure has an reliable fatigue resistance satisfying the design requirement. This type of integral joint is an alternative for long-span truss bridges.

Fatigue Life Prediction of Composite Laminates Based on Progressive Damage Analysis

2014 ◽  
Vol 1064 ◽  
pp. 108-114 ◽  
Author(s):  
Jun Kang ◽  
Zhi Dong Guan ◽  
Zeng Shan Li ◽  
Zhun Liu
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Material Property ◽  
Composite Laminates ◽  
Life Prediction ◽  
Shear Failure ◽  
Fatigue Life Prediction ◽  
Progressive Damage ◽  
Damage Analysis ◽  
Fatigue Damage Analysis

A three dimensional analysis model is developed on the fatigue life prediction of composite laminates based on a progressive damage analysis. This model consists of stress analysis, fatigue failure analysis and material property degradation. Teserpe’s failure criteria is used to fatigue damage analysis. Fiber tensile/compressive breakage, matrix tensile/compressive cracking, matrix/fiber shear failure and tension/compression delamination are considered in fatigue damage analysis. The methodologies of sudden degradation and gradual degradation are both applied in the material property degradation. The stiffness and strength gradual degradation is based on the Shokrieh fatigue model, which is based on fatigue test for unidirectional laminates. In order to consider the scatter of the material in the practical structures, the stiffness and strength of the material are randomly distributed using normal distribution in the numerical model. The progressive fatigue damage model is developed in finite element code ABAQUS through user subroutine UMAT, which can simulate the fatigue damage process. Fatigue life of different ply stacking sequences and geometries composite laminates under different cycle loading are predicted. The predicted fatigue life is in good agreement with the experimental results.

Fatigue Safety Factors for Deepwater Risers

2002 ◽  
Author(s):  
B. Stahl ◽  
H. Banon
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Safety Factor ◽  
Damage Index ◽  
Rational Approach ◽  
Fatigue Reliability ◽  
Safety Factors ◽  
Fatigue Design ◽  
Uncertainty Parameters ◽  
Deepwater Risers

Fatigue life is governed by a number of variables that are highly uncertain. The safety factor on fatigue life is used in a deterministic way to account for the estimated fatigue damage uncertainty. High uncertainties lead to high fatigue safety factors, and vice versa. Evaluation of the uncertainties in the variables governing fatigue design provides a grip on what the safety factor should be. This paper addresses riser fatigue using a fatigue reliability model that is relatively simple but still captures the important elements of the fatigue problem. The bias and uncertainty of stress range are extremely important parameters in design against fatigue. This is due not only to the fact that these parameters are highly uncertain, but also to the fact that they are greatly amplified in the fatigue damage equation by the ‘slope’ m of the S-N curve. The Palmgren-Miner fatigue damage index and the intercept value of the S-N curve are additional important variables in fatigue design. A model for combining wave-induced and vortex-induced vibration (VIV) is introduced together with the best available data and reference to industry work in this technology area. A recently completed joint industry project on riser reliability provides good calibration points for the critical fatigue reliability variables. Reliability and sensitivity studies are performed to demonstrate the effect of the uncertainty parameters. An approach to selecting deterministic fatigue design factors that yield specified reliability targets is developed and illustrated. The study provides a rational approach to selecting safety factors for design of deepwater risers, taking into account both wave and VIV-induced fatigue damage.

Rise Steel Wind-Induced Response Analysis

2014 ◽  
Vol 1006-1007 ◽  
pp. 56-60
Author(s):  
Ya Nan Hu ◽  
Qing Xu ◽  
Guo Qiang Wu
Keyword(s):  
Shear Deformation ◽  
Dynamic Characteristics ◽  
Response Curve ◽  
Time History ◽  
Wind Load ◽  
Induced Response ◽  
Response Analysis ◽  
Response Curves ◽  
Pressure Time ◽  
Fluctuating Wind

Taking a rise steel as a study, study response of the structure to the dynamic characteristics under fluctuating wind load. The results showed that: deformation of structure under the fluctuating wind load is shear deformation; Structural displacement response curve is similar to the curve of the pressure time history. Because of consider different heights the structure of spatial correlation affect, Displacement positions on different floors response curves are differ.

scholarly journals Umbilical Fatigue Analysis for a Wave Energy Converter

2020 ◽  
Author(s):  
Billy Ballard ◽  
Yi-Hsiang Yu ◽  
Jennifer Van Rij ◽  
Frederick Driscoll
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Wave Energy ◽  
Degrees Of Freedom ◽  
Oil And Gas ◽  
Time History ◽  
Fatigue Analysis ◽  
Offshore Wind ◽  
Wave Energy Converters ◽  
Energy Technologies

Abstract Unique umbilical designs for wave energy converters (WECs), including the ability to handle significantly larger motions and loads over long deployments, are often required when conventional marine umbilical designs for offshore oil and gas and offshore wind may not meet the design and cost needs of wave energy technologies. This study details a fatigue analysis of a dynamic power umbilical attached to a two-body floating point absorber WEC system, using the sea states provided for the PacWave testing facilities. The 6 degrees of freedom motion time history for the WEC was simulated, and the motions of the attachment point for the umbilical on the WEC and respective sea states were used to analyze the dynamic motions and fatigue of the connected power umbilical to predict the fatigue life. The results show that the fatigue damage observed is more significant in shallow water, and extensive fatigue damage may occur because of the larger curvature response of the umbilical. The umbilical configurations departing at 90 deg off incoming waves were found to have the highest fatigue life attributed to less extension or compression of the umbilical. However, additional bend stiffener/limiter features may need to be incorporated into the buoyancy section and touchdown regions to minimize curvature-induced fatigue.

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