鐵道機(jī)車(chē)車(chē)輛相關(guān)英語(yǔ)翻譯.doc

《鐵道機(jī)車(chē)車(chē)輛相關(guān)英語(yǔ)翻譯.doc》由會(huì)員分享，可在線閱讀，更多相關(guān)《鐵道機(jī)車(chē)車(chē)輛相關(guān)英語(yǔ)翻譯.doc（7頁(yè)珍藏版）》請(qǐng)?jiān)谘b配圖網(wǎng)上搜索。

Cut wheel fracture problems and maintenance costs Jorg Villmann looks at the problems of wheel fracture and the development of new designs to reduce failure problems and maintenance costs. In the late 1960s and 1970s axel loads and speeds of railway vehicles increased rapidly. This led to higher thermal an mechanical loads of the wheels. Tiered wheels showed loose types after strong heating during runs on mountainous lines or following to brake irregularities. Maintenance costs for type changing increased more and more. In order to solve these problems solid wheels were introduced. The most common used wheel type was the so-called ORE wheel developed by the European railways under the roof of the ORE (today European Rail Research Institute ERRI) as the research institute of the UIC (International Union of Railways). Following the extended use of solid wheels in connection with a block brake, the unforeseen problem of wheel fracture occurred. Investigation of failured wheels showed that two principal forms of wheel fracture occurred - radial fracture from the wheel rim straight through the web down to the hub or beginning in the rim, running straight in to the web and shared in two branches. It was also found that the fracture was initiated from half-elliptical or fourth-elliptical fatigue cracks, which started on the tread, around the chamfer or due to sharp notches from clamping devices of reprofiling lathes. Detailed investigation showed that all failured wheels were thermally damaged and had high residual tensile stresses in the rim of about 300 MPa. Though the number of failed wheels was relatively small each failure could lead to devastating consequences. Therefore intensive research work was carriued out to improve this situation. Research programme The European Rail Research Institute (ERRI), which is part of the UIC, was selected to lead the project work. The committee responsible for the work was the B 169 specialists committee. Three major problems were considered work programme : * Monitoring of the wheels in service. * Improvement of material characteristics. * Improvement of the residual stress level and the displacement behaviour . With the first problem it was important to summarise the experience of the different railways and to get more detailed knowledge of the condition of the wheels in service. These investigations confirmed the results concerning the residual stresses. Approximately 10 per cent of the wheels had residual stresses of about 300 MPa. On the other hand, the fracture toughness KIC or KQ of the wheels investigated was between 40 and 70 MPa. From fracture mechanics calculation it could be concluded that approximately 10 per cent of the wheels had a potential risk of failure . The analysis also brought up some cases of fatigue cracks in the wheel web and many cases of unacceptable lateral displacements of the wheel rim leading to high maintenance costs. Therefore the first step was to set-up rules for monitoring of the wheels in service including acceptance criteria. The B169 specialists committee developed four characteristics for visual inspection to identify potential wheels thermally overloaded . Criteria for the assessment of the wheels undergoing maintenance were also defined. Wheels with thermal damages must undergo residual stress measuring and, if required, crack detection. The whole procedure is defined in 4. Following to the implementation of the in-service rules and the continuous monitoring an essential reduction of wheel fracture was reached in Europe. In order to be independent from detailed maintenance rules and in-service monitoring, research then focused on the improvement of the wheel material. The results can be summarized as follows5: * Normally no KIC values were found, that are KQ values. * KQ is suitable to describe the material characteristics,. * KQ between 70 and 85 MPa is achievable for steel grade R7T. The third step focused on the reduction of the residual tensile stress level in the rim and on the lateral displacement of the rim. In this regard the shape of the wheel web is essential. Therefore different proposals were developed by the wheel producers and were tested under the roof of the ERRI research programme . Generally it can be stated that a more flexible wheel web is suitable to reduce the residual tensile stresses in the rim. On the other hand it is also possible to hold the displacements in a small tolerance band. Requirements As a result of the research work, a number of new requirements for wheel material and wheel design were defined. These requirements led to new or revised international specifications. The material requirements are defined in UIC-leaflet 812-36 and recently in the European standard EN 132627. For R7T steel grade (or ER7T according to EN 13262) a fracture toughness KIC or KQ of 80 MPa (mean value) and 70 MPa (minimum value) is required. For ER6T the corresponding requirements are 100 MPa (mean value) and 80 MPa (minimum value) given in EN 13262. Regarding the wheel design requirements the UIC published the new UIC leaflet 510-58 which was prepared by the ERRI B 169 specialists committee. This document is also the basis for the development of a new Draft European standard prEN 13979-1 which is in preparation now. The new standards are built up as a specification giving more freedom to the designer. According to these specifications four aspects of a new wheel design have to be considered: * Geometrical aspect: to allow interchangeability. * Thermo mechanical aspect: to manage wheel deformation and to ensure that braking do not induce wheel failure. * Mechanical aspect: to ensure that no fatigue crack in the web will occur. * Acoustical aspect: to ensure that the solution is better or equal compared with a reference wheel. Concerning the interchangeability requirements in three ways are necessary depending on the customer1: * Functional requirements, e.g. wheel diameter, tread profile, asymmetry of the hub with regard to the rim. * Fitting requirements, for example, length of the hub, bore diameter. * Maintenance requirements, e.g. clamping conditions of the wheelset reprofiling lathes. The designer has full freedom regarding the design of the wheel web. For railway vehicles with block brakes the brake power has to be considered. Tests with freight trains running on long mountainous lines through the Alps received an average brake power level of 50kW for a wheel with 920mm diameter. For smaller wheels the brake power is on a corresponding lower level. Therefore wheels for freight wagons have to resist these brake loads. For vehicles with different brake systems, such as disc brakes, an assessment of the thermal behaviour is not necessary. For combined brake systems (block brake and others) modified loads shall be agreed between customer and supplier. The brake loads are reproduced on a brake test bench. In order to check the thermal behaviour the wheel is loaded with a number of brake cycles. For the assessment unified criteria are defined in UIC 510-5 and prEN 13979-1 respectively. For the level of residual tensile stresses in the rim the following criteria are valid: For a wheel with its nominal diameter a stress level of maximum 200MPa (mean value) and maximum 250MPa (for each cross section) is acceptable. For a wheel with its diameter near the wear limit a stress level of maximum 275 MPa (mean value) and maximum 300 MPa is acceptable. Regarding the lateral displacement the analysis of maintenance rules, of the service experience and of the dimension of crossings and points led to allowable values between -1 mm and +3 mm (during braking) and between -0.5 mm and +1mm (in cold condition). For the mechanical aspect8 determine a relative conventional procedure. First step is a stress calculation using the finite element method. Three conventional load cases are to be considered representing straight track full curves and points and crossings. Based on these loads the normal stresses for each node of the FE mesh is calculated. Comparing the stresses for the different load cases a stress range or a stress amplitude can be calculated. The stress of the most stressed node shall be compared with the decision criteria, which are 180 MPa for wheels with fully machined web and 145 MPa for wheels with unmachined web. In addition to the calculation fatigue tests can be required. This depends on the results of the calculation and on the validity of the conventional loads. Two methods for fatigue tests are possible, either a random fatigue test or a one-stage fatigue test8. For both methods the test loads are derived from measured loads during field tests. Concerning the acoustical aspect it is, of course, not a target that new developed wheels have higher sound radiation compared with existing designs. Therefore a sound level is described which is comparable with the former ORE standard wheels8. The sound level can be determined by a calculation. The acoustical requirements are informative only. Product development and verification The stress ranges for the various designs are calculated as follows: * Wheel 21.061.00 (BA 004)/21.061.10 (BA 304) 240.9 MPa (25 t axle load), * Wheel 21.431.01 (BA 378) 175.9 MPa, * Wheel 21.430.01 (BA 375) 168.9 MPa, * Wheel 21.463.00 185.2 MPa (exceptional lateral forces for the calculation required). Therefore for the wheel designs 21.061.00 (BA 004)/21.061.10 (BA 304)and 21.463.00 additional fatigue tests are necessary. The results of both fatigue tests and field tests showed sufficient mechanical characteristics. Conclusion Due to increased service loads especially increased thermal loads, Radsatzfabrik Isenburg GmbH developed a family of wheel designs for different applications. They meet the requirements of the new or revised specifications. Up to now no failure of these designs occurred. The residual stress level is lower compared with the former designs. Therefore the residual stress measurement during the maintenance can be cancelled. Due to the low lateral displacements no wheelset has to be replaced. The wheels meet the interchangeability requirements ensuring an easy change of wheels. The new designs help the customer to reduce maintenance costs. For the future modifications of Radsatzfabriks designs are possible depending on specific customer requirements. 車(chē)輪斷裂問(wèn)題及維修費(fèi)用 Jorg Villmann研究車(chē)輪斷裂問(wèn)題,開(kāi)發(fā)新的設(shè)計(jì),以降低故障維修費(fèi)用問(wèn)題。 In the late 1960s and 1970s axel loads and speeds of railway vehicles increased rapidly.在60年代末和70年代鐵路機(jī)車(chē)車(chē)輛重載和高速程度迅速提升。 This led to higher thermal an mechanical loads of the wheels.這導(dǎo)致了機(jī)械車(chē)輪要承載更高的熱負(fù)荷。 輪箍Tiered wheels showed loose tyres after strong heating during runs on mountainous lines or following to brake irregularities.輪箍車(chē)輪在山區(qū)線路入下坡道反復(fù)制動(dòng)運(yùn)行時(shí)受到強(qiáng)熱負(fù)荷出現(xiàn)松動(dòng)。Maintenance costs for tyre changing increased more and more.維修費(fèi)用為換輪箍的增加而越來(lái)越多。 In order to solve these problems solid wheels were introduced.為了解決這些問(wèn)題，發(fā)展出了整體車(chē)輪。 The most common used wheel type was the so-called ORE wheel developed by the European railways under the roof of the ORE (today European Rail Research Institute ERRI) as the research institute of the UIC (International Union of Railways).最常用的輪型，是所謂的ORE車(chē)輪，是ORE下屬的發(fā)達(dá)的歐洲鐵路開(kāi)發(fā)的(今天的歐洲鐵路研究院ERRI)，作為UIC(國(guó)際鐵路聯(lián)盟)的研究所。 隨著整體車(chē)輪的進(jìn)一步使用，由于制動(dòng)的原因，F(xiàn)ollowing the extended use of solid wheels in connection with a block brake, the unforeseen problem of wheel fracture occurred.隨著陸 ，，，車(chē)輪斷裂這一不可預(yù)見(jiàn)的問(wèn)題發(fā)生了。Investigation of failured wheels showed that two principal forms of wheel fracture occurred - radial fracture from the wheel rim straight through the web down to the hub or beginning in the rim, running straight in to the web and shared in two branches.調(diào)查裂損的車(chē)輪顯示有兩種主要損傷形式，車(chē)輪發(fā)生輻射狀損傷，從輪緣直透過(guò)輪輻傳給到輪轂或從輪輞開(kāi)始，直線運(yùn)行到輪輻上，并分成兩個(gè)分支。 It was also found that the fracture was initiated from half-elliptical or fourth-elliptical fatigue cracks, which started on the tread, around the chamfer or due to sharp notches from clamping devices of reprofiling lathes (see Table 2).還發(fā)現(xiàn)是從半橢圓形或四橢圓疲勞裂紋開(kāi)始的，開(kāi)始于踏面并圍繞倒角處或由于車(chē)床側(cè)面夾緊裝置造成的尖銳缺口處展開(kāi)。 Detailed investigation showed that all failured wheels were thermally damaged and had high residual tensile stresses in the rim of about 300 MPa.詳細(xì)的調(diào)查表明，所有裂損車(chē)輪均被熱破壞，在輪輞處有較高的約300兆帕的殘余應(yīng)力。Though the number of failed wheels was relatively small each failure could lead to devastating consequences.雖然失穩(wěn)車(chē)輪數(shù)量相對(duì)較小，但是每次失穩(wěn)可能導(dǎo)致災(zāi)難性的后果。 Therefore intensive research work was carriued out to improve this situation.因此,深入研究工作被提出來(lái)以改善這種狀況。 Research programmme研究過(guò)程 The European Rail Research Institute (ERRI), which is part of the UIC, was selected to lead the project work.歐洲鐵路研究院(ERRI)，是歐洲鐵路聯(lián)盟的一部分，被選定承擔(dān)這一項(xiàng)目工作。The committee responsible for the work was the B 169 specialists committee.該委員會(huì)負(fù)責(zé)的工作是B169專家委員會(huì)。Three major problems were considered work programme:三大問(wèn)題分別審議的工作方案： * Monitoring of the wheels in service.*維護(hù)中監(jiān)測(cè)車(chē)輪； * Improvement of material characteristics.*改善材料的特性； * Iimprovement of the residual stress level and the displacement behaviour.*改善殘余應(yīng)力等級(jí)和橫向穩(wěn)定性。 針對(duì)With the first problem it was important to summarise the experience of the different railways and to get more detailed knowledge of the condition of the wheels in service.針針對(duì)性第一個(gè)問(wèn)題，重要的是要總結(jié)各種鐵路運(yùn)用經(jīng)驗(yàn)并得到更詳細(xì)的車(chē)輪維護(hù)狀況的信息。 These investigations confirmed the results concerning the residual stresses.這些調(diào)查確認(rèn)的結(jié)果就殘余應(yīng)力。 Table 3 shows an example for the residual stress distribution in the wheel rim [1].Approximately 10 per cent of the wheels had residual stresses of about 300 MPa.大約有百分之十的車(chē)輪殘余應(yīng)力約300兆帕。On the other hand, the fracture toughness KIC or KQ of the wheels investigated was between 40 and 70 MPam.在另一方面, 被調(diào)查的車(chē)輪斷裂韌性KIC或KQ值在40至70兆帕之間。From fracture mechanics calculation it could be concluded that approximately 10 per cent of the wheels had a potential risk of failure [2].從斷裂力學(xué)計(jì)算可以得出結(jié)論認(rèn)為，大約有百分之十的車(chē)輪有潛在失穩(wěn)的危險(xiǎn) 。 The analysis also brought up some cases of fatigue cracks in the wheel web and many cases of unacceptable lateral displacements of the wheel rim leading to high maintenance costs1.分析報(bào)告也提出了一些在輪輻處出現(xiàn)疲勞裂紋的案件和多例受側(cè)位移的輪輞導(dǎo)致高維修費(fèi)用的案例。 Therefore the first step was to set-up rules for monitoring of the wheels in service including acceptance criteria.因此，第一步是設(shè)置規(guī)則的監(jiān)測(cè)車(chē)輪的維護(hù)情況，包括驗(yàn)收標(biāo)準(zhǔn).BB169的專家委員會(huì)，制定了4個(gè)特色的目視檢查，以確定潛在的車(chē)輪熱負(fù)荷?，F(xiàn)行的車(chē)輪維修模式的評(píng)估標(biāo)準(zhǔn)也被Criteria for the assessment of the wheels undergoing maintenance were also defined.現(xiàn)行定義。Wheels with thermal damages must undergo residual stress measuring and, if required, crack detection.車(chē)輪與熱損失必須經(jīng)過(guò)殘余應(yīng)力的測(cè)量，如果需要，還要進(jìn)行裂縫檢測(cè)。The whole procedure is defined in4.整個(gè)程序被定義為四個(gè)階段。Following to the implementation of the in-service rules and the continuous monitoring an essential reduction of wheel fracture was reached in Europe.以下為在歐洲已貫徹了的現(xiàn)行制度和連續(xù)監(jiān)測(cè)這對(duì)減少車(chē)輪失穩(wěn)是至關(guān)重要的已洲 裂