Analysis on the fatigue cracks in the bogie frame

De-long, FU; Wang, Wenjing; Dong, Lei

doi:10.1016/j.engfailanal.2015.09.004

Cited by 32 publications

(11 citation statements)

References 9 publications

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“…The shortcoming of the conventional design is that it considers the material as a homogeneous continuum without defects. In fact, initial defects are almost (4) inevitable in such structures, thereby in turn making the actual strength lower than the nominal value. In contrast, the fracture mechanics-based approach considers that the structure is defective, which forms the basis for investigating the fracture failure mechanism and carrying out the safety evaluation.…”

Section: Damage Tolerant Approachmentioning

confidence: 99%

“…The welding process may not only lead to a strength/ geometry mismatch, but may also induce various defects such as inclusions, pores, cracks, and undercuts, thereby resulting in serious stress concentration under fatigue load [4][5][6]. Nevertheless, it is widely reported that some failures usually originate from extrinsic defects probably due to abnormal impact and vibration, and not from welded joints [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…However, it is well-known that the fatigue assessment based on the endurance limit approach provides relatively conservative results for the allowable stress and accumulation damage; nevertheless, such an approach serves as a quick and standard procedure for the safe life analysis of railway safety-critical components [17][18][19]. Moreover, most studies have employed the simplified bogie frame model composed of hybrid solid and plate elements for the residual life prediction in the presence of defects [4,20,21]. Novel assessment methods using the master S-N curve, hot spot stress, and notch stress have been proposed to consider the uneven stress distribution due to geometry discontinuity or strain gradient [14,[22][23][24].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Damage Tolerance Assessment of a Brake Unit Bracket for High-Speed Railway Welded Bogie Frames

Yang

Duan

et al. 2019

Chin. J. Mech. Eng.

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The brake unit bracket of a bogie frame is an important load-carrying component, particularly under emergency start/stop conditions. Conventional infinite/safe life approaches provide an over-conservative recommendation for the allowable strength and lifetime, which hinders the lightweight design of modern railway vehicles. In this study, to ensure the reliability and durability of a brake unit bracket, an attempt was made to integrate the nominal stress method and an advanced damage tolerance method. First, a complex bogie frame was modelled using solid elements instead of plate and beam elements. A hot spot stress region on the bracket was found under an eight-stage load spectrum obtained from the Wuhan-Guangzhou high-speed railway line. Based on the probability of foreign damage, a semi-elliptical surface crack was then assumed for residual life assessment. The results obtained by the cumulative damage and damage tolerance methods show that the brake unit bracket can operate for over 30 years. Moreover, even if a 2-mm depth crack exists, the brake unit bracket can be safely operated for more than 2.27 years, with the hope that the crack can be detected in subsequent maintenance procedures. Finally, an appropriate safety margin was suggested which provides a basis for the life prediction and durability assessment of brake unit brackets of high-speed railways.

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Section: Damage Tolerant Approachmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Damage Tolerance Assessment of a Brake Unit Bracket for High-Speed Railway Welded Bogie Frames

Yang

Duan

et al. 2019

Chin. J. Mech. Eng.

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“…With regard to the crack of bogie frame [24,25], initial works have been made through multi-body dynamic system [26] and finite element simulations [27]. In this paper, on-track tests including the dynamic stress and acceleration were performed under different loading conditions to elucidate the cracking mechanism of metro bogie frames.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigations on the Effects of Fatigue Crack in Urban Metro Welded Bogie Frame

Wang

Bai

et al. 2020

Applied Sciences

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The welded bogie frame is the critical safety part of the urban metro vehicle. This paper focuses on finding out the factors inducing the fatigue cracks initiated from the positioning block weld toe of metro bogie frame. Fracture morphology and metallographic analysis were conducted to identify the failure modes, and on-track tests about the dynamic stress at the positioning block weld toe and vibration acceleration were performed. The typical signals of dynamic stress and acceleration were analyzed from time and frequency domain. The relationship between wheel polygon, rail corrugation, running speed and dynamic stress in amplitude and frequency are investigated in details. Research results show that the micro cracks induced by welding at the weld toe of positioning block propagate to the spring sleeve under relatively high alternating dynamic stress, which is strongly influenced by the wheel polygon, rail corrugation and the train running speed.

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“…The speed and efficiency of train travel has been continually modernized over recent decades, so the real load situation of vehicles may differ substantially from the standard. Furthermore, the vehicle structures may crack unexpectedly during the service period [14]. The load situation of railway vehicles have been researched recently.…”

Section: Introductionmentioning

confidence: 99%

Methodology to Evaluate Fatigue Damage of High-Speed Train Welded Bogie Frames Based on On-Track Dynamic Stress Test Data

Yang

Wang

et al. 2019

Chin. J. Mech. Eng.

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The current method of estimating the fatigue life of railway structures is to calculating the equivalent stress amplitude based on the measured stress data. However, the random of the measured data is not considered. In this paper, a new method was established to compute the equivalent stress amplitude to evaluate the fatigue damage based on the measurable randomness, since the equivalent stress is the key parameter for assessment of structure fatigue life and load derivation. The equivalent stress amplitude of a high-speed train welded bogie frame was found to obey normal distribution under uniform operation route that verified by on-track dynamic stress data, and the proposed model is, in effect, an improved version of the mathematical model used to calculate the equivalent stress amplitude. The data of a long-term, on-track dynamic stress test program was analyzed to find that the normal distribution parameters of equivalent stress amplitude values differ across different operation route. Thus, the fatigue damage of the high-speed train welded bogie frame can be evaluated by the proposed method if the running schedule of the train is known a priori. The results also showed that the equivalent stress amplitude of the region connected to the power system is more random than in other regions of the bogie frame.

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Analysis on the fatigue cracks in the bogie frame

Cited by 32 publications

References 9 publications

Damage Tolerance Assessment of a Brake Unit Bracket for High-Speed Railway Welded Bogie Frames

Damage Tolerance Assessment of a Brake Unit Bracket for High-Speed Railway Welded Bogie Frames

Experimental Investigations on the Effects of Fatigue Crack in Urban Metro Welded Bogie Frame

Methodology to Evaluate Fatigue Damage of High-Speed Train Welded Bogie Frames Based on On-Track Dynamic Stress Test Data

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