Damage tolerance analysis of detail fractures in rail

Jeong, David Y.; Tang, Yim H.; Orringer, Oscar

doi:10.1016/s0167-8442(97)00035-9

Cited by 20 publications

(20 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Many investigations (e.g. [96][97][98][99][100]) focussed on elliptical internal cracks (in North American sources also designated as "detail cracks" or "detail fracture"), Figure 55a. Other transverse crack types such as straight and semi-elliptical surface cracks in the rail head (c and d) and in the rail foot (f) and corner cracks at both sites (b, g, d) have also been investigated (e.g.…”

Section: Final Crack Propagationmentioning

confidence: 99%

Introduction to the damage tolerance behaviour of railway rails – a review

Zerbst¹,

Lundén

Edel

et al. 2009

Engineering Fracture Mechanics

176

View full text Add to dashboard Cite

Despite substantial advantages in material development and in periodic non-destructive inspection together with periodic grinding and other measures in order to guarantee safe service, fatigue crack propagation and fracture is still in great demand as emphasised by the present special issue. Rails, as the heart of the railway system, are subjected to very high service loads and harsh environmental conditions. Since any potential rail breakage includes the risk of catastrophic derailment of vehicles, it is of paramount interest to avoid such a scenario. The aim of the present paper is to introduce the most important questions regarding crack propagation and fracture of rails. These include the loading conditions: contact forces from the wheel and thermal stresses due to restrained elongation of continuously welded rails together with residual stresses from manufacturing and welding in the field, which is discussed in Section 2. Section 3 provides an overview of crack-type rail defects and potential failure scenarios. Finally the stages of crack propagation from initiation up to final breakage are discussed.

show abstract

Section: Final Crack Propagationmentioning

confidence: 99%

Introduction to the damage tolerance behaviour of railway rails – a review

Zerbst¹,

Lundén

Edel

et al. 2009

Engineering Fracture Mechanics

176

View full text Add to dashboard Cite

show abstract

“…For this purpose, a particular defect, called a detail fracture, is assumed to be present in the upper gage corner of the rail head because it is most common transverse rail head defect found in continuous welded rail (CWR) in North America. The growth behavior of detail fractures has been studied in previous research sponsored by the FRA [4][5][6]. Moreover, the analyses described subsequently in this paper are based on the results from the previous research.…”

Section: Framework For Estimating Track Capacitymentioning

confidence: 99%

“…The application of engineering fracture mechanics or damage tolerance principles to examine the propagation or growth of detail fractures in the rail head is described in [4][5].…”

Section: Crosstie Spacing Based On Metal Fatiguementioning

confidence: 99%

Estimating Track Capacity Based on Rail Stresses and Metal Fatigue

Jeong

Perlman

2011

ASME 2011 Rail Transportation Division Fall Technical Conference

View full text Add to dashboard Cite

This paper describes a framework to evaluate the structural capacity of railroad track to train-induced loads.The framework is applied to estimate structural performance in terms of allowable limits for crosstie spacing. Evaluation of the load-carrying capacity of track is conducted by examining the state of stress in the rail.Rail stresses are estimated by superimposing the contributions from different sources: (1) live-load stresses, (2) thermal stresses, and (3) residual stresses. Rail bending and thermal stresses are calculated based on assuming that the rail behaves as a beam supported by a linear elastic foundation. The classical beam on elastic foundation analysis is modified in the present work to account for crosstie spacing that exceeds the limits of the classical theory. Finite element methods are used to develop an amplification factor on the bending moment calculated from beam on elastic foundation theory, which is applied when the spacing between crossties becomes discrete and the foundation support is no longer considered as continuous.The rail stress analysis is then used in conjunction with a failure criterion based on the formation and growth of internal defects in rail due to the repeated passage of wheels, i.e. metal fatigue. A similar methodology was applied in previous work to estimate allowable limits for rail head wear in terms of vertical head-height loss and gage-face side wear. Moreover, allowable limits estimated from this methodology are inherently linked with the frequency of rail testing to detect internal rail head defects and mitigate the likelihood of accidents from broken rails.The analyses described in this paper depend on various assumptions regarding operational, structural and environmental factors. These factors include vehicle weight, train speed, rail size, foundation modulus, temperature differential (i.e. difference between the rail temperature and the stress-free or neutral temperature), and rail test interval (i.e. tonnage between rail tests). Sensitivity studies are conducted to examine the relative effect of these factors on the estimation of maximum free span between effective ties. In addition, results from applying the methodology described in this paper are compared to the limits specified in the current track safety regulations.

show abstract

“…When the wheel is not at the joint, the joint characteristics no longer contribute to the dynamic load, and the DLF is equal to that obtained from the AREMA formula in equation (1). Assuming a wheel diameter D of 36 in, the DLF is 1.367 and the dynamic load P TOT is 25,973 lb from equation (2).…”

Section: Dynamic Wheel Load Estimationmentioning

confidence: 99%

“…For example, particular attention has been given to the formation and growth of an internal rail defect called a detail fracture [1,2]. Although research has been conducted to examine bolt-hole cracking [3,4,5], the structural integrity of bolted rail joints has not been studied as thoroughly as that in CWR.…”

Section: Introductionmentioning

confidence: 99%

Estimation of the Fatigue Life of Railroad Joint Bars

Talamini

Jeong

Gordon

2007

ASME/IEEE 2007 Joint Rail Conference and Internal Combustion Engine Division Spring Technical Conference

View full text Add to dashboard Cite

This paper investigates the influence of physical track conditions in the vicinity of a rail joint on the fatigue life of the joint bars. Recent derailments due to broken joint bars, such as the Minot, ND accident in January 2002, have highlighted the need for better understanding of the effects of joint conditions on premature joint bar failure. Fatigue life estimates can be used to guide the selection of inspection intervals for joint bars in service. Engineering approximations are used to infer the dynamic load factor at a rail joint due to joint characteristics including: • rail end gap; • joint efficiency (looseness); • track stiffness (vertical foundation modulus). A three-dimensional finite element analysis of a rail joint is conducted and the dynamic load is applied to develop an estimate of the live (bending) stresses at the joint due to passing wheels. These stresses are then used to estimate the fatigue life of the joint bars. The methodology is demonstrated for 132RE rail with companion joint bars. The effect of thermal expansion (or the temperature difference below the rail neutral temperature) is investigated. Typical wheel loads and railcar speeds are considered and results are presented for a baseline a joint condition.

show abstract

Damage tolerance analysis of detail fractures in rail

Cited by 20 publications

References 2 publications

Introduction to the damage tolerance behaviour of railway rails – a review

Introduction to the damage tolerance behaviour of railway rails – a review

Estimating Track Capacity Based on Rail Stresses and Metal Fatigue

Estimation of the Fatigue Life of Railroad Joint Bars

Contact Info

Product

Resources

About