Durability Analysis of Locking Parts in the Gauge - Adjustable Wheelset System

Transcription

1 Durability Analysis o Locking Parts in the Gauge - Adjustable Wheelset System 1 Chul-Su Kim, 2 Seung-Ho Ahn, 2 Kwang-Woo Chung, 3 Seung-Ho Jang, 4 Jung-Kyu Kim Department o Rolling Stocks Mechanical Engineering, Korea National Railroad College 1 Department o Railroad Operation Mechatronics, Korea National Railroad College, Korea 2 Korea Railroad Research Institute, Korea 3 School o Mechanical Engineering, Hanyang University, Seoul, Korea 4 Abstract To reduce the cost and time o transport in the Eurasian railroad network such as TKR(Trans- Korea Railway), TCR(Trans-China Railway) and TSR(Trans-Siberia Railway) owing to the dierent track gauges(narrow/standard/broad gauge), it is necessary to develop and adapt the gauge-adjustable wheelset system. The gauge - adjustable wheelset system in the transcontinental railway represents a more eective way in comparison with other techniques or overcoming dierence in track gauges. Freight trains having the gauge - adjustable wheelset will be passing various curved tracks in railroad networks. Thereore, to assure the saety o the newly developed gauge-adjustment wheelset system, it is essential to evaluate integrity o locking parts in the system using atigue analysis. In this study, it was perormed to contact stress analysis o locking parts using FEM(Finite Element Method) during the gauge changeover operation and reight trains' service in the curved track, respectively. Based on these results, the atigue lie o locking parts with the variation o the atigue strength, by considering the eect o the surace treatment process, was evaluated by a durability analysis. Introduction According to the previous researches [1-3], the gauge-adjustable wheelset system is the eective way or the connected railroad operation between Europe and Asia which has dierent track gauge. There are several gauge-adjustable systems which were under trial operation, commercial operation or enhanced. The patented Korean gauge-adjustable wheelset system was designed and will be adapting to the brand new reight trains. It is important to evaluate atigue lie o the new reight trains with the gauge-adjustable wheelset system aspect o the sae-lie design. Several studies have been published on the unique gauge-adjustable wheelset systems which were developed by themselves and under commercial operation. [1-6] J.L.Sanchez-gonzalez [2] surveyed the status o development o the European gaugeadjustable wheelset system as a technology and economy. W.Saliger[3] inquired into the necessity o the gauge-adjustable wheelset system and introduced the technical eature o RAFIL/DBAG-V type, SUW2000 and Talgo system. S.H. Jang et al. [4-6] proposed a new design concept o the gauge-adjustable wheelset system which is under developing. The above-mentioned researches have sought to the patented gauge-adjustable system which to avoid the patent right disputation. There are the dierent rail track gauge system on the continental transportation which between Korea (TKR) and Eurasian (TCR/TSR). Thereore, Eurasian reight trains have to adapt the gauge-adjustable wheelset system and should be operating on a lot o gauge-adjustable track as well as on various curved tracks. While traveling on the gauge-adjustable track under normal conditions, the reaction orce history is too low to aect on the atigue lie o the gauge-adjustable wheelset system. However, the reaction orce on traveling in the curved track should be considered to evaluate the saety and atigue lie o those parts. To design the gauge-adjustable wheelset system with a low probability o atigue ailure, it is necessary to evaluate the strength and atigue lie o those components on the curved track service condition. This study was ocused on evaluating the stress and crack initiation lie o the gauge-adjustable wheelset system considering the lateral orce during travel on the curved track. Besides, the eect o surace treatment process on the crack initiation lie o locking parts was investigated.

2 Gauge-adjustable wheelset system The Korean gauge-adjustable wheelset system is in the process o planning and development according to international standard UIC [9]. Fig. 1 shows Korean gaugeadjustable wheelset system and each component. As shown in Fig. 1, the Korean gaugeadjustable wheelset system consist o a axles with the ixed cap, a wheel with groove, a spring, a lange, a locker and a spring holder. Fig. 1 Coniguration o locking parts in the gauge-adjustable wheelset system (a) broad gauge track (b) transition interval (c) transition interval (d) standard gauge track Fig. 2 FE model o the locking parts wheelset and load/boundary conditions

3 The inite element model and analysis. Fig. 3 shows the lowchart o durability analysis process. The inite element (FE) model consists o 15,600 linear solid elements (hex 8), as shown in Fig. 4(a). Fig. 4(b) represents FE model o the locking parts wheelset and load/boundary conditions. The boundary and loading conditions are determined via considering attachment and operating conditions o the gauge-adjustable wheelset system. Finite element model and boundary condition Dynamics Analysis (MSC.ADAMS) Finite element analysis (MSC.MARC) stress or strain tensor Applied load history Fatigue properties Durability analysis (MSC.FATIGUE) Construction o load history databse Fatigue lie Lateral orce (N) Cant: 100mm outer wheel Slack:12m Radius: 300m inner wheel Time (second) Fig. 3 Flowchart o durability analysis process (a) FE model (b) Boundary conditions Fig. 4 FE model o the locking parts wheelset and load/boundary conditions Mechanical properties. The material o specimen in this work is carbon steel, SM 490C and ASTM A53, commonly used as a structure and industrial acilities. The mechanical properties o these materials were summarized in Table 1. Load proile and stress history under operation. Fig. 5 shows lateral wheel load history derived rom dynamic analysis results while a reight wagon travels the curved track in the Kyong-Won line (Democratic People's Republic o Korea) with a speed per hour 5km [8].

4 outer wheel, 0.015% percentile (5s) inner wheel, 0.015% percentile (5s) Lateral orce (N) outer wheel inner wheel Time (second) Cant: 100mm Slack:12m Radius: 300m Lateral orce (N) Cant: 100mm Slack:12m Radius: 300m Time (second) (a) raw load history (b) iltered load history based on the UIC 518 Fig. 5 Lateral wheel load history in the curved track derived rom dynamic analysis results[8] Fig. 6 shows the stress histories o hot spot region at lange, locker and wheel, by lateral orce at outside o wheel patch or passing through in the curved track, under standard gauge and broad gauge condition, respectively. With the previous research [8], the curvature o standard track gauge in North Korea and the width o broad track gauge is 300m and 1,520mm respectively. The operation condition is 5km/h considering the weight o a railway vehicle. The lateral orce history was obtained by MSC.ADAMS [9], commercial multi-body dynamics sotware, and then it was transerred according to the international standard UIC 518 [10]. Table 1 Mechanical properties Young s Modulus [MPa] Yield Strength [MPa] Tensile Strength [MPa] Elongation [%] SM 490C ASTM A (a) Standard gauge (b) Broad gauge Fig. 6 Contact Stress history o the locking parts in the gauge-adjustable wheelset during a reight train s service in the curved track.

5 (a) Standard gauge (b) Broad gauge Fig. Stress contour o the locking part in the gauge - adjustable wheelset during a reight train's service in the curved track with standard gauge and broad gauge During travel on the curved track, the hot spot stress occurs simultaneously at the langelocker contact point, locker-wheel contact point and lange. Fig. shows the result o the structural analysis on the locking part under dierent gauge types. In Fig. (a) and (b), stress level o the locking part under broad gauge condition is higher than that under standard gauge condition. Consequently, the service load condition under broad track gauge is more severe than that under standard track gauge condition. Fatigue characteristics. Fig. 8 shows the strain-lie curve o the SM 490C and ASTM A53 respectively which were used or atigue analysis o the locking parts. The relation o stain-lie and atigue constant o each material is illustrated in Table 2. This strain-lie curve is the summation o two separate curves or elastic strain amplitude-lie and or plastics strain amplitude-lie, as shown in equation (1). Δε σ b c = (2 N ) + ε (2 N ) (1) 2 E The quantities σ, b, ε, and c are considered to be material properties. Table 2 Material constants o Strain-lie curves σ [MPa] b ε c SM 490C 1, ASTM A Durability analysis. Fig. 9 shows the result o durability on the locking part o the gaugeadjustable system or traveling on the curved track. The stress distribution and atigue lie o the locking parts are calculated by inite element method based on the commercial package MSC.Marc and MSC.Fatigue respectively. In addition, the atigue lie, using inite element method, was estimated with two track gauge conditions. The critical point o that, which is made o ASTM A53 and under lateral orce history on broad track gauge, is the contact region between the locker and the lange as shown in Fig.. Table 3 summarizes the atigue lie o the locking part derived rom Fig. 9 under standard gauge condition and broad gauge condition, respectively. As seen in Table 3, the atigue lie under broad gauge condition is shorter than that under standard gauge condition. As seen in Table 3, the estimated lie to ailure data o the

6 5 locking parts with ASTM A53 was cycles with 50% conidence reliability on the broad track gauge. (a) SM 490C Fig. 8 Strain vs. lie curves (b) ASTM A53 (a) Full scale (b) Detail Scale Fig. 9 Fatigue lie contour o the locking part in the gauge - adjustable wheelset during a reight train's service in the curved track Table 3 Expected atigue lie o the locking part in gauge-adjustable wheelset system Expected atigue lie (Cycles) Standard track gauge Broad track gauge No treatment No treatment Water Corroded Shot peening Nitriding SM 490C ASTM A

7 Summary The ollowing results have been drawn 1. The service load condition under broad track gauge is more severe than that under standard track gauge condition. 2. In case o SM 490C use or the locking part, it has a inite lie on the standard track gauge as well as on the broad track gauge The atigue lie o the locking parts with ASTM A53 was estimated cycles with 50% conidence reliability on the broad track gauge. 4. The compressive residual stress, which was produced through shot peening and nitriding process, increase the atigue lie. Acknowledgement This research has accomplished by the support o the Korea Ministry o Construction and Transportation as part o the National Transportation Key Technology Development. Reerences [1] H.S. Na, S.H. Jang and J.S. Han: Journal o Korean Society or Railway(2004), pp. 645~651 [2] J. L Sanchez-Gonzalsez. "Variable gauge axle", Rail International(1984), pp.139~148 [3] W. Saliger. "Gauge-Adjustable Wheelsets", Rail International(2000), pp.~13 [4] D.W. Lee, D.S. Bae, J.S. Han, S.H. Jang and H.S. Na. Journal o Korean Society or Railway (2004), pp.3~ [5] Y.J. Lee, D.S. Bae, W.K. Kim, S.H. Jang and J.S. Han. Journal o Korean Society or Railway (2005), pp.39~384 [6] S.H. Jang, H.S. Na and J.S. Han. Journal o Korean Society or Railway(2005), pp.281~284 [] N. E. Dowling: Mechanical Behavior o Materials, Prentice-Hall, New Jersey(1999), pp. 401~404 [8] The Korean Ministry o Construction and Transortation : "Development o the Gauge- Adjustable Wheelset System", The 5th Year Report o National Transortation Key Technology Development(2006) [9] MSC. Sotware: MSC.Adams User s Guide (2005) [10] UIC 518: "Testing and approval o railway vehicles rom the point o view o their dynamic behavior - Saety - Track atigue - Ride quality" [11] MSC. Sotware: MSC.Fatigue User s Guide (2005)