Structural fatigue investigation of thermite welded rail joints considering weld-induced residual stress and stress relaxation by cyclic load

Liu, Yang; Tsang, Kin Shun; Subramaniam, Nellian Alagu; Pang, J.H.L.

doi:10.1016/j.engstruct.2021.112033

Cited by 16 publications

(8 citation statements)

References 27 publications

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“…diffraction method, [50][51][52][53] and X-ray diffraction method. 54 On the other hand, the effects of the residual stress of welded process on fatigue performances have been investigated, including welding size, 55 welding process, 56 fatigue crack propagation, 26,[57][58][59][60] fatigue strength, 61 mean stress, 62 the strain energy density (SED) approach for fatigue life prediction by Ferro et al, 63 Ferro and Berto, 64 and Ferro, 65 fatigue life evaluation, [66][67][68] residual stress relaxation, [69][70][71][72] and cutting process. 73,74 It is clear that some advanced measurement methods have been adopted for measuring residual stresses of welded structures.…”

Section: Modelmentioning

confidence: 99%

“…On the one hand, numerous measurement methods of residual stress have been adopted, such as thermo‐mechanical modelling, 40,41 incremental blind‐hole drilling method, 42–45 digital image correlation approach, 46,47 sharp indentation testing, 48 contour method, 49 wavelength‐dependent neutron diffraction method, 50–53 and X‐ray diffraction method 54 . On the other hand, the effects of the residual stress of welded process on fatigue performances have been investigated, including welding size, 55 welding process, 56 fatigue crack propagation, 26,57–60 fatigue strength, 61 mean stress, 62 the strain energy density (SED) approach for fatigue life prediction by Ferro et al, 63 Ferro and Berto, 64 and Ferro, 65 fatigue life evaluation, 66–68 residual stress relaxation, 69–72 and cutting process 73,74 …”

Section: Introductionmentioning

confidence: 99%

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Experimental study on the verification of adequate fatigue test specimen size of U‐rib‐to‐deck joints in orthotropic steel bridge decks

Yang

2022

Fatigue Fract Eng Mat Struct

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In this study, the distribution of residual stress of the substructure model and small coupon specimens in orthotropic steel bridge structures is experimentally and numerically investigated to validate adequate specimen sizes. Blindhole drilling and X-ray diffraction methods are used to capture longitudinal and transverse residual stresses and evaluate the effects of the cutting process. The maximum LRS and TRS were reduced by 16.6% and 15.6% from those that existed before cutting, verifying the proper size of small voucher specimens. The width-to-thickness ratio of 6-6.25 of small coupon specimens has proven sufficient to capture the effects of stress triaxiality induced by the residual stress. In the spirit of master S-N curves in ASME standard, the role of residual stress was represented in the fatigue process and does not be additionally taken into account when predicting the fatigue performances of welded structures using prediction methods based on the S-N curves. K E Y W O R D Sadequate specimen size, blind-hole drilling and X-ray diffraction methods, orthotropic steel bridge decks, residual stress effect, thermo-structure coupling method

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Section: Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental study on the verification of adequate fatigue test specimen size of U‐rib‐to‐deck joints in orthotropic steel bridge decks

Yang

2022

Fatigue Fract Eng Mat Struct

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“…This results in tensile residual stress, softening, and substantial changes to microstructure, all of which increase the susceptibility to cracking during wheel–rail contact [ 3 ]. Liu et al [ 4 ] considered the influence of weld-induced residual stress and cyclic loading under wheel–rail contact on the fatigue life of rail joints. Regions of high tensile stress in the rail head and web were found to be more susceptible to cracking whilst compressive zones in the web are beneficial in prolonging the fatigue lifetime.…”

Section: Introductionmentioning

confidence: 99%

Application of a New Alloy and Post Processing Procedures for Laser Cladding Repairs on Hypereutectoid Rail Components

et al. 2022

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The development of a laser cladding repair strategy is critical for the continued growth of heavy-haul railway networks. Premium hypereutectoid rails have undergone laser cladding using a new martensitic stainless-steel alloy, 415SS, developed for high carbon rails after standard cladding metals were found to be incompatible. Non-destructive neutron diffraction techniques were used to measure the residual stress in different layers generated across a dissimilar metal joint during laser cladding. The internal stress distribution across the cladding, heat-affected zone (HAZ), and substrate was measured in the untempered rail, after 350 °C and 540 °C heat treatment procedures and two surface grinding operations. The martensitic 415SS depositions produce compressive stress in the cladding, regardless of tempering procedures, which may inhibit fatigue crack propagation whilst grinding operations locally relive surface stress. Balancing tensile stresses were recorded below the fusion boundary in the HAZ due to thermal gradients altering the microstructure. The combination of 540 °C tempering and 0.5 mm surface layer removal produced a desirable combination of compression in the cladding deposition with significantly reduced tensile stresses in the HAZ. A comparison with the current literature shows that this alloy achieves a unique combination of desirable hardness, low tensile stress, and compression in the cladding layer. Data obtained during strain scanning has been used to determine the location of microstructural changes at the fusion boundary and HAZ through correlation of the stress, strain, full width at half maximum (FWHM), and intensity profiles. Therefore, neutron diffraction can be used for both the accurate measurement of internal residual stress and to obtain microstructural information of a metallurgical join non-destructively.

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“…[1][2][3] Quantitatively characterizing RS during fatigue is very significant for reliability assessment but is extremely difficult due to its inevitable variation. [4][5][6] For this reason, relaxation and redistribution of RS have been widely studied by considering various factors, such as initial RS distribution (size and stress-field gradient), 7 applied stress intensity (amplitude and stress ratio), 8,9 and material properties (cyclic hardening/softening). 10 Most researchers consider RS relaxation mainly takes place in the first or first few cycles 5,6 and mainly emphasize relaxation of peak RS.…”

Section: Introductionmentioning

confidence: 99%

Real‐time measurement of welding residual stress relaxation based on strain‐controlled fatigue test

Zhang

Luan

2022

Fatigue Fract Eng Mat Struct

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Fatigue-induced variation of residual stress (RS) in welded joints is inevitable and has significant influence on fatigue behavior. The widely used technologies (e.g., X-ray diffraction) can only test surface RS of specimen at unloading or certain holding load condition. In this study, an approach of measuring equivalent RS in real time during fatigue cycling is proposed based on straincontrolled fatigue with strain ratio of À1. Under applied waveform starting with tensile strain, tensile RS in a welded joint continuously relaxes with fatigue cycles, but compressive RS first increases then relaxes. Both tensile and compressive RSs rapidly change in the first few cycles and then gradually relax to a steady state in which accumulated plastic strain is linearly correlated to amount of RS relaxation during fatigue cycling.

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Structural fatigue investigation of thermite welded rail joints considering weld-induced residual stress and stress relaxation by cyclic load

Cited by 16 publications

References 27 publications

Experimental study on the verification of adequate fatigue test specimen size of U‐rib‐to‐deck joints in orthotropic steel bridge decks

Experimental study on the verification of adequate fatigue test specimen size of U‐rib‐to‐deck joints in orthotropic steel bridge decks

Application of a New Alloy and Post Processing Procedures for Laser Cladding Repairs on Hypereutectoid Rail Components

Real‐time measurement of welding residual stress relaxation based on strain‐controlled fatigue test

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