scholarly journals Investigation of the Fatigue Stress of Orthotropic Steel Decks Based on an Arch Bridge with the Application of the Arlequin Method

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7653
Author(s):  
Cheng Cheng ◽  
Xu Xie ◽  
Wentao Yu
Keyword(s):  
Fatigue Cracks ◽  
Element Model ◽  
Fatigue Stress ◽  
Traffic Conditions ◽  
Traffic Loads ◽  
Fatigue Durability ◽  
Orthotropic Steel Decks ◽  
Fatigue Evaluation ◽  
Arlequin Method ◽  
Engineering Practices

Orthotropic steel decks are widely used in the construction of steel bridges. Although there are many fatigue-evaluation methods stipulated by codes, unexpected fatigue cracks are still detected in some bridges. To justify whether the local finite element model commonly used in fatigue investigations on orthotropic decks can correctly instruct engineering practices, the Arlequin framework is applied in this paper to determine the full fatigue stress under traffic loads. The convergence on and validity of this application for orthotropic decks are checked. Results show that the Arlequin model for deck-fatigue analysis established in this paper tends to be an efficient method for complete fatigue stress acquisition, whereby the vulnerable sites of orthotropic steel decks under traffic loads are defined. Vehicles near the flexible components, such as hangers or cables, can have adverse effects on the fatigue durability of decks. Additionally, the total number of vehicles and their arrangement concentration also affect fatigue performance. Complex traffic conditions cannot be fully loaded in local models. Regardless of the gross bridge mechanics and deck deformation, the fatigue stress range is underestimated by about 30–40%. Such a difference in fatigue assessment seems to explain the premature cracks observed in orthotropic steel decks.

Fatigue Evaluation of Trough Splice Joints in Orthotropic Steel Decks

2014 ◽  
Vol 1025-1026 ◽  
pp. 17-23
Author(s):  
Huang Yun ◽  
Qing Hua Zhang ◽  
Yi Zhi Bu ◽  
He Liang Liu ◽  
Shao Lin Yang
Keyword(s):  
Tensile Stress ◽  
Fatigue Cracks ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Fatigue Properties ◽  
Systematic Analysis ◽  
Longitudinal Ribs ◽  
Principal Tensile Stress ◽  
Orthotropic Steel Decks ◽  
Fatigue Evaluation

Fatigue tests for full-scale orthotropic steel decks were conducted to evaluate and validate the fatigue performance of welded and bolted splice joints of longitudinal ribs. The test results indicated that the fatigue properties of two splice joints met the design requirements. The bolted splice joints whose principal tensile stress was largely lower than welded splice joints under the same loading conditions appeared to have superior fatigue resistance to the welded one. No fatigue cracks were detected among all the specimens and the principal tensile stress of measuring points had few changes during the whole fatigue tests. Systematic analysis of test data showed that bolted splice joints appeared to be more reasonable for improving the fatigue performance of longitudinal ribs.

scholarly journals Fatigue evaluation of hot spot stress in fatigue vulnerable area of bridge deck structure based on thermal energy modelling

2021 ◽  
Vol 25 (4 Part B) ◽  
pp. 3093-3101
Author(s):  
Fangqin Zhao ◽  
Qinghua Liao
Keyword(s):  
Fatigue Life ◽  
Bridge Deck ◽  
Hot Spot ◽  
Element Model ◽  
Limit States ◽  
Hot Spot Stress ◽  
Vulnerable Area ◽  
Fatigue Stress ◽  
Actual Use ◽  
Fatigue Evaluation

The paper takes a Yangtze River bridge as the object, establishes a finite element model of the highway orthotropic steel deck structure, calculates and analyzes the fatigue stress of specific structural details based on the hot spot stress method, and obtains the fatigue vulnerable area of this type of bridge deck structure. Based on the bridge?s actual use, the thesis calculates and evaluates the fatigue life of the typical welding details of the bridge deck based on the American Highway Bridge Design Code. The results show that the fatigue stress amplitude calculation of the five types of fatigue vulnerable structure details under the Fatigue ? and Fatigue ? limit states. The values are all less than the allowable value, and the fatigue life meets the design requirements.

Fatigue Crack Initiation and Growth in Stainless Steel Pipe Welds

2009 ◽  
Author(s):  
D. Green ◽  
R. D. Smith ◽  
J. P. Taggart ◽  
D. Beardsmore ◽  
S. Robinson
Keyword(s):  
Crack Initiation ◽  
Crack Growth ◽  
Thermal Loading ◽  
Fatigue Cracks ◽  
Fatigue Crack Initiation ◽  
Cyclic Hardening ◽  
Element Model ◽  
Fatigue Tests ◽  
Welded Pipe ◽  
Pipe Work

Thermal fatigue cracks have been found in austenitic pipe work in many pressurised water reactors, caused by thermal cycling due to the passage of water at different temperatures along the pipe inner surface. The rates of crack initiation and growth for this situation are not well understood because of the stochastic nature of the temperature fluctuations. Therefore, large allowances must be made when assessing the integrity of this pipe work to this failure mechanism. Improved assessment of crack initiation and growth could enable increased plant availability, and better safety cases. A programme of work has been completed consisting of fatigue tests on thick 304L butt-welded pipe specimens, and accompanying predictions of crack initiation and growth. In each test, uniform thermal cycles were generated using a water jet on a small area of the pipe. The magnitude of the cycles differed between the tests. Crack initiation and growth were monitored using a dye penetrant technique, applied to the pipe inner and outer surfaces, together with destructive examination. Crack initiation predictions were made using fatigue data derived from mechanical fatigue tests on the same material as in the pipe specimens. Good predictions were made using a strain-life endurance curve at a temperature corresponding to the average temperature of the metal surface during the thermal cycle. Crack growth predictions were based on an inelastic finite-element model accounting for cyclic hardening, and an enhanced R5 procedure (1) with crack closure taken into account. A linear elastic fracture mechanics definition of a Paris law for crack growth was used, and plastic redistribution effects were included. Predictions were good for all of the experimental scenarios carried out. A further experimental and analytical programme is in hand using the same experimental arrangements, concerning variable amplitude thermal loading.

Investigation of Thermal Fatigue Characteristics of Charging Line of RCV in PWR

2017 ◽  
Author(s):  
Naeem Ahmad ◽  
XiangBin Li ◽  
Iftikhar Ahmad ◽  
Nan Li ◽  
Shahroze Ahmed ◽  
...  
Keyword(s):  
Fatigue Damage ◽  
Thermal Fatigue ◽  
Nuclear Power ◽  
Thermal Loading ◽  
Structural Model ◽  
Fatigue Cracks ◽  
Volume Control ◽  
Piping System ◽  
Thermal Transients ◽  
Fatigue Evaluation

Nuclear Power Plant (NPP) components need to tolerate thermal constraints, internal pressure and thermal transients. These thermal transients being repeated again and again can lead to thermal fatigue of the component. It has significant effect on the degradation of the NPP components in long term. Studies of thermal fatigue on different NPP components such as mixing tees and valves have been carried out before but the charging line in the chemical and volume control system (RCV) of the NPP seems to have been ignored for thermal fatigue analysis. Charging Line is the connection from RCV towards Reactor Coolant System (RCP). To enhance the safety of the charging line, thermal fatigue evaluation of piping system was performed using the Fluid Structure Interaction (FSI) analysis. Temperature distributions in the pipes were determined via thermal hydraulic analysis (CFX) and the results were applied to the structural model of the piping system to determine the thermal stress (Transient Structural). Results revealed the location of fatigue cracks. Types of stress were identified that caused the fatigue damage. The CFD analysis enabled us to clarify the role of turbulence with respect to the thermal loading of the structure. The study will provide valuable information for establishing a permanent methodology to help minimize thermal fatigue damage in NPP components.

Floor-Beam Web Cutout Shape Analysis to Improve the Fatigue Resistance in Orthotropic Steel Bridge Decks

2010 ◽  
Vol 452-453 ◽  
pp. 161-164 ◽  
Author(s):  
Chun Sheng Wang ◽  
Qin Zhang ◽  
Tao Zhang ◽  
Ya Cheng Feng
Keyword(s):  
Bridge Deck ◽  
Fatigue Cracks ◽  
Bridge Decks ◽  
Steel Bridges ◽  
Steel Bridge ◽  
Analysis Model ◽  
Critical Question ◽  
Static Test ◽  
Orthotropic Steel Decks ◽  
Steel Orthotropic Deck

The modern steel orthotropic decks have been used in steel bridges for 60 years all over the world because of its super structural advantages. Recently, more bridge owners, engineers and researchers pay more attention to the fatigue problem of orthotropic steel decks for a large number of fatigue cracks found in steel bridges. For example, bridge engineers have detected hundreds of fatigue cracks in steel orthotropic deck on the 888-meter long box girder of Humen Bridge only ten years after opening to traffic. How to design or repair the fatigue details in orthotropic steel decks is the critical question to be solved at first step. In current paper, the elaborate numerical analysis model of the orthotropic steel bridge decks was developed using ANSYS software with different floor-beam web cutouts shapes, such as conventional ellipse, circular, trapezoid and Haibach web cutouts. The finite element models were calibrated by static test of one full size orthotropic steel bridge deck model. According to the analysis results, it should select the rational cutout shapes based on actual load and structural conditions in steel bridge deck design and strengthening.

Assessment of Constraint Effects on the Local Behaviour of a Propagating Crack Under Cyclic Loading

2012 ◽  
Author(s):  
M. R. Goldthorpe ◽  
A. H. Sherry
Keyword(s):  
Cyclic Loading ◽  
Best Practice ◽  
Fatigue Cracks ◽  
Fatigue Crack Initiation ◽  
Crack Tip ◽  
Element Model ◽  
Compact Tension ◽  
Stress Constraint ◽  
T Stress ◽  
Constraint Effects

During operation, reactor components experience a range of static and cyclic loading that have the potential to result in environmental-fatigue crack initiation and growth. Recent experimental work has indicated that the ASME XI fatigue ‘in air’ design curves are non-conservative for fatigue cracks propagating in primary water environments at fixed temperatures of relevance to the plant. The approach adopted to assess these tests has, to date, followed current best practice: in which global Linear Elastic Fracture Mechanics (LEFM) loading parameters are used to quantify crack growth rates. To help establish an improved understanding of these data, and to assist in their application to assess plant components, a local crack-tip finite element model has been developed. The model incorporates material constitutive behavior that simulates cyclic deformation of austenitic steel, can take account of plasticity-induced crack closure and can take into consideration cracks in structurally-representative geometries via the T-stress constraint parameter. The results of studies using the model suggest that highly compressive values of the T-stress constraint parameter tend to promote less severe reverse loading of the crack tip compared with high constraint geometries such as pre-cracked compact tension and bend test specimens. These findings indicate that rates of corrosion-fatigue in actual structural geometries might be different from those observed in pre-cracked test specimens.

scholarly journals ANALYSIS OF DIAPHRAGM BEHAVIOUR IN COMPOSITE MULTI GIRDER RAILWAY BRIDGES

2004 ◽  
Vol 10 (2) ◽  
pp. 143-150
Author(s):  
Yannick Sieffert ◽  
Gérard Michel ◽  
Didier Martin ◽  
David Keller ◽  
Jean-François Jullien
Keyword(s):  
Bridge Deck ◽  
Element Model ◽  
Longitudinal Distribution ◽  
Railway Bridge ◽  
Railway Bridges ◽  
Traffic Loads ◽  
Concrete Bridge Deck ◽  
Actual Geometry ◽  
Static Failure ◽  
Concrete Deck

This study focuses on mechanical behaviour of diaphragm in composite multigirders railway bridge. The aim is to predict and to compare, with a numerical simulation, the transverse and longitudinal distribution of traffic loads in different girders and in the slab for the cases with and without intermediary diaphragm. A 3‐D finite element model is developed to represent the actual geometry of multigirder bridge. Durability of the concrete bridge deck is directly related to cracking, so a non‐linear constitutive equation is used for the concrete deck. This study focuses on the response of a bridge with and without dipahragm under a UIC and TGV loading. To achieve this aim, a static failure analysis is performed. Our analysis concluded that diaphragm is not necessary, so it seems to be possible to remove the diaphragms.

Fatigue crack growth behavior of rib-to-deck double-sided welded joints of orthotropic steel decks

2020 ◽  
pp. 136943322096175
Author(s):  
Yang Liu ◽  
Fanghuai Chen ◽  
Da Wang ◽  
Naiwei Lu
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Crack Growth ◽  
Welded Joints ◽  
Mixed Mode ◽  
Fatigue Cracks ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Behavior ◽  
Orthotropic Steel Decks

Innovative double-sided welding is expected to improve the fatigue resistance of rib-to-deck welded joints of orthotropic steel decks (OSDs). Welding crack-like defects are the crucial issue affecting the fatigue performance of rib-to-deck double-sided welded joints. This study presents a numerical simulation of three-dimensional (3D) mixed mode fatigue crack growth behavior of rib-to-deck double-sided welded joints of OSDs. Maximum tensile stress theory and equivalent stress intensity factor (SIF) were used to simulate mixed mode fatigue cracks growth. The Paris law model was employed to predict the fatigue life. Fatigue cracks of rib-to-deck double-sided welded joints were characterized by the presence of mixed mode cracks of modes I (open), mode II (shear), and mode III (tear), which was dominated by mode I. The equivalent SIF was found to be complex at the growth stage with the maximum value at the two ends of the crack front and the minimum value at the midpoint of the crack front. The crack shape became flatter in the later phase of the crack growth. The fatigue crack surface underwent deflections during crack growth, making the final crack shape exhibiting the characteristic of a spatial curved surface. The initial crack geometry showed a significant impact on the fatigue life.

scholarly journals Numerical and Experimental Investigation of the Effect of Traffic Load on the Mechanical Characteristics of HDPE Double-Wall Corrugated Pipe

2020 ◽  
Vol 10 (2) ◽  
pp. 627 ◽  
Author(s):  
Hongyuan Fang ◽  
Peiling Tan ◽  
Xueming Du ◽  
Bin Li ◽  
Kangjian Yang ◽  
...  
Keyword(s):  
Small Diameter ◽  
Earth Pressure ◽  
Element Model ◽  
Traffic Load ◽  
Von Mises Stress ◽  
Flexible Pipe ◽  
Traffic Loads ◽  
Major Factors ◽  
Von Mises ◽  
Double Wall

The high-density polyethylene (HDPE) double-wall corrugated pipe, which is a kind of flexible pipe, is widely used in municipal drainage networks. The characteristics of the surrounding soil and pipe bed, pipe cover depth, backfill compaction, type of pavement and pavement design, and traffic loads are some of the major factors that affect the stress and deformation of pipes. In this study, the ABAQUS 3D finite element model was used to analyze the influence of backfill compactness, traffic loads, diameter, and hoop stiffness on the mechanical characteristic of an HDPE pipe under traffic loads. A series of full-scale tests were carried out to verify the validity of the simulation results. For the conditions tested, the results showed the following: (1) the Von-Mises stress of the pipe was mainly determined by the earth pressure at the crown, and the stress caused by backfill compaction increased significantly but had a short duration and limited impact on the pipe; (2) traffic load alone had little influence on the mechanical behavior of the pipe: while under the action of the loose backfill in contact with the pipe, the pipes were more sensitive to the traffic load response; (3) the fluctuations in the Von-Mises stress of the pipe mainly depended on the magnitude and speed of the traffic load; (4) for pipes with a small diameter, non-compacted backfill easily caused stress concentration in the pipe, while the degree of backfill compaction had almost the same effect on the distribution of stress for pipes with different hoop stiffness.

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