Fatigue performance of modular expansion joints for bridges

2006 ◽  
Vol 33 (8) ◽  
pp. 921-932 ◽  
Author(s):  
Omar Chaallal ◽  
Guillaume Sieprawski ◽  
Lotfi Guizani
Keyword(s):  
Fatigue Testing ◽  
Fatigue Cracks ◽  
Fatigue Performance ◽  
Horizontal Load ◽  
Stress Range ◽  
Expansion Joint ◽  
Load Range ◽  
Fatigue Stress ◽  
Number Of Cycles ◽  
Welded Connection

This paper presents results of an experimental investigation on the fatigue performance of the welded multiple support bar modular bridge expansion joint (MBEJ) used for the recent Jacques Cartier Bridge rehabilitation in Montreal. Three identical subassemblies of the modular joint system were tested in fatigue. Both vertical and horizontal load ranges were applied to the test specimen simultaneously in the following proportions: (i) vertical load range = ΔPv and (ii) horizontal load range = 0.2ΔPv. Different loading ranges were applied to each specimen giving a sufficient number of points to define the experimental fatigue stress range versus the number of cycles (S–N) curve. The number of cycles varied between 567 900 and 3 600 000, while the calculated stress range within the welded connection details varied between 81.4 and 166.7 MPa. Static calibration tests were performed prior to the fatigue testing of each specimen. These calibration tests confirmed the validity of the structural three-dimensional analytical models and also established the repeatability of the experimental data, in conformity with the requirements of the NCHRP-402 report. Fatigue cracks of the same type as those reported by the NCHRP-402 report were observed within the welded connection detail. No fatigue cracks were observed elsewhere. The experimental fatigue curve of the welded connection showed that the fatigue resistance of the welded MBEJ is compatible with category C and C' details, as defined by the AASHTO LRFD 1998 bridge design code. This paper is very useful, as it demonstrates the applicability of the complex requirements of the NCHRP-402 report. These requirements are increasingly gaining wide acceptance among bridge engineers and bridge owners.Key words: modular expansion joint, bridge, deck, test, fatigue, stress range, cycles.

scholarly journals Fatigue Stress-Life Model of RC Beams Based on an Accelerated Fatigue Method

2019 ◽  
Vol 4 (2) ◽  
pp. 16
Author(s):  
Eljufout ◽  
Toutanji ◽  
Al-Qaralleh
Keyword(s):  
Cyclic Loading ◽  
Fatigue Testing ◽  
Three Dimensional ◽  
Rc Beam ◽  
Rc Beams ◽  
Testing Methods ◽  
Load Range ◽  
Fatigue Stress ◽  
Life Model ◽  
Prediction Band

Several standard fatigue testing methods are used to determine the fatigue stress-life prediction model (S-N curve) and the endurance limit of Reinforced Concrete (RC) beams, including the application of constant cyclic tension-tension loads at different stress or strain ranges. The standard fatigue testing methods are time-consuming and expensive to perform, as a large number of specimens is needed to obtain valid results. The purpose of this paper is to examine a fatigue stress-life predication model of RC beams that are developed with an accelerated fatigue approach. This approach is based on the hypothesis of linear accumulative damage of the Palmgren–Miner rule, whereby the applied cyclic load range is linearly increased with respect to the number of cycles until the specimen fails. A three-dimensional RC beam was modeled and validated using ANSYS software. Numerical simulations were performed for the RC beam under linearly increased cyclic loading with different initial loading conditions. A fatigue stress-life model was developed that was based on the analyzed data of three specimens. The accelerated fatigue approach has a higher rate of damage accumulations than the standard testing approach. All of the analyzed specimens failed due to an unstable cracking of concrete. The developed fatigue stress-life model fits the upper 95% prediction band of RC beams that were tested under constant amplitude cyclic loading.

scholarly journals Alloy Development and Optimisation Informed by an Understanding of Cold Dwell Fatigue Sensitivity

2020 ◽  
Vol 321 ◽  
pp. 11043
Author(s):  
M.R. Bache ◽  
M. Thomas
Keyword(s):  
Fatigue Testing ◽  
Fatigue Cracks ◽  
Creep Behaviour ◽  
Fatigue Loading ◽  
Fatigue Performance ◽  
Coarse Grained ◽  
Alloy Development ◽  
Process Route ◽  
Dwell Fatigue ◽  
Grain Orientations

Near α titanium alloys have demonstrated a sensitivity to fatigue loading when incorporating a dwell period at peak applied stress under room temperature. Historically, this was first reported for the relatively coarse grained variant IMI685 and later exemplified when characterising TIMETAL® 834 (Ti-834). Various mechanical factors have been identified as key drivers for the phenomenon, including time on load and high R ratios. This indicates that sub-critical damage is accumulated via creep style mechanisms and has led to analogies with “cold creep” behaviour. The propensity of quasi-cleavage faceting at the initiation sites of fatigue cracks formed under dwell conditions eventually led to an understanding of stress redistribution between strong and weak grains. This mechanism can be accentuated by more extensive regions of common crystallographic grain orientation in the form of “macrozones”. Through this fundamental understanding, new alloys can now be developed with the intent to circumvent dwell sensitivity. The present paper will focus on the fatigue performance of TIMETAL® 575 (Ti-575), a recently developed alloy optimised for aero-engine applications. Ti-575 was designed for improved strength and fatigue performance. The alloy’s susceptibility to dwell fatigue has been avoided through control of the microstructural evolution kinetics and associated thermo-mechanical process route to induce fine scaled, bi-modal microstructure containing equiaxed primary grains and secondary α laths with inherent random grain orientations, thus minimising the formation of macrozones. This work will detail the dwell fatigue testing, interpretation of data and associated microstructural characterisation, including EBSD, and compare this analysis with similar results from more conventional alloys such as Ti-6Al-4V and Ti-834.

Study on Bending Ultrasonic Fatigue Behavior of Sinter-Hardened Fe-2Cu-2Ni-1Mo-1C Materials Prepared by Warm Compaction

2010 ◽  
Vol 638-642 ◽  
pp. 1848-1853 ◽  
Author(s):  
Zhi Yu Xiao ◽  
Ling Zhou ◽  
Yuan Xun Shen ◽  
Tungwai Leo Ngai ◽  
Yuan Yuan Li
Keyword(s):  
Fatigue Strength ◽  
Crack Propagation ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Bending Fatigue ◽  
Warm Compaction ◽  
Ultrasonic Fatigue ◽  
Number Of Cycles ◽  
Rupture Mode

Bending fatigue behavior of a sinter-hardened high density (7.4 g/cm3) Fe-2Cu-2Ni-1Mo-1C material fabricated by die-wall lubricated warm compaction of partially-diffuse alloyed powder was studied by bending ultrasonic fatigue testing. Results showed that fatigue strength decreases continuously with the increasing number of cycles. The fatigue failure yet occurs in the regime of exceeding 107 cycles and exhibits no traditional horizontal plateau between 106 and 107 cycles. Fatigue strength was 194 MPa, 239 MPa and 293 MPa at 108, 107 and 106 cycles respectively. Scanning electron microscopy revealed that cracks initiated from large pores on the surface and from pore clusters near the sub-surface. The fatigue cracks initiated both at single and multiple sites. Crack propagation was mainly in a trans-crystalline rupture mode. Fatigue striation and cleavage plane were observed in the crack propagation region and dimples were observed in the fracture zones.

Assessment of thermal behavior of a cooling system to reduce thermal fatigue cracks in aluminum injection molds

2020 ◽  
pp. 75-86
Author(s):  
Sergio Antonio Camargo ◽  
Lauro Correa Romeiro ◽  
Carlos Alberto Mendes Moraes
Keyword(s):  
Thermal Fatigue ◽  
Cooling System ◽  
Fatigue Cracks ◽  
Cooling Water ◽  
Thermal Conditions ◽  
Thermal Gradients ◽  
Ansys Software ◽  
Cooling Systems ◽  
Thermal Fatigue Cracks ◽  
Number Of Cycles

The present article aimed to test changes in cooling water temperatures of males, present in aluminum injection molds, to reduce failures due to thermal fatigue. In order to carry out this work, cooling systems were studied, including their geometries, thermal gradients and the expected theoretical durability in relation to fatigue failure. The cooling system tests were developed with the aid of simulations in the ANSYS software and with fatigue calculations, using the method of Goodman. The study of the cooling system included its geometries, flow and temperature of this fluid. The results pointed to a significant increase in fatigue life of the mold component for the thermal conditions that were proposed, with a significant increase in the number of cycles, to happen failures due to thermal fatigue.

scholarly journals Fatigue Strength Analysis of S34MnV Steel by Accelerated Staircase Test

2020 ◽  
Vol 10 (1) ◽  
pp. 394-400 ◽  
Author(s):  
I. M. W. Ekaputra ◽  
Rando Tungga Dewa ◽  
Gunawan Dwi Haryadi ◽  
Seon Jin Kim
Keyword(s):  
Standard Deviation ◽  
Fatigue Strength ◽  
Fatigue Limit ◽  
Fatigue Testing ◽  
Reliability Estimation ◽  
Test Method ◽  
Strength Analysis ◽  
Staircase Method ◽  
Staircase Test ◽  
Number Of Cycles

AbstractThis paper presents the reliability estimation of fatigue strength of the material used for crank throw components. The material used for crank throw components is forged S34MnV steel and subsequently heat-treated by normalising and tempering. High cycle fatigue testing under fully reversed cycling (R = −1) was performed to determine the fatigue limit of the material. The staircase test method is used to obtain accurate values of the mean fatigue limit stress until a number of cycles up to 1E7 cycles. Subsequently, the fatigue test results depend strongly on the stress step and are evaluated by the Dixon-Mood formula. The values of mean fatigue strength and standard deviation predicted by the staircase method are 282 MPa and 10.6MPa, respectively. Finally, the reliability of the design fatigue strength in some selected probability of failure is calculated. Results indicate that the fatigue strength determined from accelerated staircase test is consistent with conventional fatigue testing. Furthermore, the proposed method can be applied for the determination of fatigue strength and standard deviation for design optimisation of S34MnV steel.

Lifetime Enhancement of Propulsion Shafts Against Corrosion-Fatigue by Laser Peening

2018 ◽  
Author(s):  
Lloyd A. Hackel ◽  
Jon E. Rankin
Keyword(s):  
Corrosion Fatigue ◽  
Fatigue Testing ◽  
Salt Water ◽  
Fatigue Cracks ◽  
Water Immersion ◽  
High Energy ◽  
General Corrosion ◽  
Laser Peening ◽  
Corrosion Pits ◽  
Deep Pits

This paper reports substantially enhanced fatigue and corrosion-fatigue lifetimes of propulsion shaft materials, 23284A steel and 23284A steel with In625 weld overlay cladding, as a result of shot or laser peening. Glass reinforced plastic (GRP) coatings and Inconel claddings are used to protect shafts against general corrosion and corrosion pitting. However salt water leakage penetrating under a GRP can actually enhance pitting leading to crack initiation and growth. Fatigue coupons, untreated and with shot or laser peening were tested, including with simultaneous salt water immersion. Controlled corrosion of the surfaces was simulated with electric discharge machining (EDM) of deep pits enabling evaluation of fatigue and corrosion-fatigue lifetimes. Results specifically show high energy laser peening (HELP) to be a superior solution, improving corrosion-fatigue resistance of shaft and cladding metal, reducing the potential for corrosion pits to initiate fatigue cracks and dramatically slowing crack growth rates. At a heavy loading of 110% of the 23284A steel yield stress and with 0.020 inch deep pits, laser peening increased fatigue life of the steel by 1370% and by 350% in the corrosion-fatigue testing.

scholarly journals Shot Peening Effects on Subsurface Layer Properties and Fatigue Performance of Case-Hardened 18CrNiMo7-6 Steel

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
H. S. Ho ◽  
D. L. Li ◽  
E. L. Zhang ◽  
P. H. Niu
Keyword(s):  
Fatigue Life ◽  
Shot Peening ◽  
Fatigue Testing ◽  
Subsurface Layer ◽  
Fatigue Performance ◽  
Single Shot ◽  
Depth Study ◽  
Enhanced Properties ◽  
Integrity Analysis ◽  
The Way

The present study is conducted with a dual-aim: firstly, to examine the effect of several single shot peening conditions on the subsurface layer properties and fatigue performance of the case-hardened 18CrNiMo7-6 steel, and secondly, to propose an optimized peening condition for improved fatigue performance. By carrying out the subsurface integrity analysis and fatigue testing, the underlying relationships among the peening process, subsurface layer property and fatigue performance are investigated, the way peening conditions affect the fatigue life and its associated scatter for the case-hardened 18CrNiMo7-6 steel is quantitatively assessed. The in-depth study shows that dual peening can be an optimized solution, for it is able to produce a subsurface layer with enhanced properties and eventually gain a significant improvement in fatigue performance.

Fatigue Testing of Large-Scale Models of Submarine Structural Details

1965 ◽  
Vol 2 (03) ◽  
pp. 299-307
Author(s):  
Frank W. Dunham
Keyword(s):  
Cyclic Loading ◽  
Large Scale ◽  
Fatigue Testing ◽  
Fatigue Cracks ◽  
Pressure Variation ◽  
Test Tank ◽  
Initiation And Propagation ◽  
Scale Models ◽  
Structural Details

The conversion of a 30-ft-dia test tank to a facility for subjecting large-scale models of submarine structural details to cyclic loading is described. By means of automatically controlled valves, models were subjected to a pressure variation simulating a submarine diving to its test depth and returning to the surface. The cyclic rate was slightly less than one per minute. The system was so designed that the test tank itself was not subjected to the pressure variations. Details of a series of models designed to simulate particular structural details of interest in recent submarine construction are described. Results of the tests to date are summarized, and several observations relative to the initiation and propagation of fatigue cracks in submarine structural details are presented.

The Evaluation of Bending Fatigue Testing of Austempered Ductile Iron Spur Gear

2019 ◽  
Author(s):  
Qi Zhang ◽  
Jianhua Lv ◽  
Rizwanulhaque Syed ◽  
Jing Zhang ◽  
Yang Xu ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Ductile Iron ◽  
Fatigue Testing ◽  
Spur Gear ◽  
Austempered Ductile Iron ◽  
Spur Gears ◽  
Reliability Design ◽  
Bending Fatigue ◽  
Bending Fatigue Strength ◽  
Number Of Cycles

Abstract An experimental evaluation of bending fatigue strength for austempered ductile iron (ADI) spur gears have been performed using Zwick fatigue tester. The gear material was manufactured by vertically continuous casting, in which the radius of the graphite grains is smaller. The Stress-Number of Cycles curve (S-N curve) for the bending fatigue strength of the ADI spur gears are manufactured without any specific surface treatments, and have been obtained by post-processing software. It was observed that when the reliability was 50%, the fatigue limit was 304.89 MPa. It has provided a reliable basis to rate the reliability design of the small gearboxes in automation later.

Cost Effective Fabrication of Large Diameter High Strength Titanium Catenary Riser

2002 ◽  
Author(s):  
Agnes Marie Horn ◽  
Mons Hauge ◽  
Per-Arne Ro̸stadsand ◽  
Bjarne Bjo̸rnbakk ◽  
Peer Dahlberg ◽  
...  
Keyword(s):  
Fatigue Testing ◽  
Fatigue Cracks ◽  
Large Diameter ◽  
High Strength ◽  
Cost Effective ◽  
Full Scale ◽  
Scale Production ◽  
Wear Properties ◽  
Field Development ◽  
Main Challenge

A large diameter high strength titanium free-hanging catenary riser was evaluated by the Demo 2000 Ti-Rise project, from initiative of the Kristin Field development license. In order to reduce the uncertainties related to the schedule, cost, and special technical issues identified in the work related to a similar riser for future installation on the A˚sgard B semi-submersible platform, a fabrication qualification of a full scale riser in titanium was run. Several full-scale production girth welds were made in an in-situ fabrication environment. The welding was performed on extruded titanium grade 23 (ASTM) pipes with an ID of 25.5″) and wall thickness of 30 mm. The main challenge was to develop a highly productive TIG orbital welding procedure, which produced welds with as low pore content as possible. It is well known that sub-surface pores often are initiation sits for fatigue cracks in high strength titanium welds. This paper describes how a greatly improved productivity was obtained in combination with a high weld quality. NDT procedures were developed whit the main on the reliability to detect and locate possible sub-surface weld defects, volumetric defects such as pores and tungsten particles and planar defects such as lack of fusion. The results from the actual Non Destructive Testing (NDT), the mechanical testing, and the fatigue testing of the subjected welds are presented. The response of the catenary is optimised by varied distribution of weight coating along the riser’s length. A satisfactory weight coating with sufficient strength, bond strength, and wear properties was developed and qualified. The riser is planned to be fabricated from extruded titanium pipes, welded together onshore to one continuous piece. The field coating is added and the riser is loaded into the sea and towed offshore and installed.

Sign in / Sign up

Export Citation Format

Share Document