UIC comfort tests - VTI

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9 Possible influences of construction conceptsof vehicle, track and/or system functioning oncomfort9.1 IntroductionCompensation for lateral acceleration is possible in circular curves by tilting thecar body. In transition curves however, ideal compensation is only possible forone perpendicular plane in the coach. Factors that affect the compensation will beexplained in this chapter by examples, indicating influences on the angularposition of the coach and/or the influence on the remaining lateral acceleration.• The length of the coach causes a less ideal angular position of the coach on thetrack and so introduces a difference between theoretical and real angularposition. Compensation by software is in principle possible• A position in the coach away from the ideal perpendicular plane ofcompensation causes higher lateral acceleration• A time delay in the tilting system also causes higher lateral acceleration• Constraints on maximum tilt angle or tilt rate may also give higher lateralacceleration• The influence of dynamic reactions of the coach on the imposed angularpositions shortens the time of full compensation, and so augments periodswith more then necessary lateral acceleration.9.2 Basis for the examples in this chapterThe examples are based on a simplified simulation, with the following assumptions:Radius: 600 mCant: 140 mLength of transition curve: 70mMaximum tilt angle: 8°Equilibrium speed at max tilt: 134.511 kphTilt limitation: variable (100% and 80%) of max tilt usedCompensation level variable: (100% and 80% used)Length of vehicle: 19 mPlace in vehicle: variableTime delay: (0 sec and 0.5 sec used)41 VTI notat 56A-2003
9.3 Study of the car body angle9.3.1 Influence of vehicle lengthThe total roll angle is the sum of two angles;the angle of the track (average angle of first and last bogie)x1 ix2 i0.250.20.150.10.050the tilt angle of the car bodyPrincipleBlue dotted line: angle due to carbody tilt (x 2 )Red solid line: angle due to track(x 1 )Green dashed line: roll angle (x)The roll angle is the sum of theangle due to cant and tiltx it i0.050 1 2 3 4 5Figure 9-1 Roll and tilt angles due to the position: transition curve.x1 ix2 i0.250.20.150.1x i0.0500.050 1 2 3 4 5t iFigure 9-2 Different angles due to position and vehicle length.The red solid line, representingthe induced angle from the trackhas more then one slope (x 1 )The blue dot line, representing thecar body tilting has sameproperties as before. (x 2 )Green dashed line: roll angle (x)At the beginning and the end ofthe transition, the vehicle receivesits roll angle more smoothly. Inthe middle of the transition, onlythe central part of the coach has acorrect roll angle.9.3.2 Influence of the flexibility of the suspension0.1370.1y i0.05y0 i01.177 . 10 30.050 1 2 3 4 5 6 7 80 t 8iThis picture gives the car bodyangle. (y i )The red (bottom) line gives thecar body angle taking account offlexibility of 19% a roll out of thesupension.. (y I )The centrifugal force reduces theimposed car body angle.Figure 9-3 Car body angles with and without supension flexibility.42 VTI notat 56A-2003
Page 1 and 2: VTI notat 56A • 2003VTI notat 56A
Page 3 and 4: ContentsPageAbbrivations and Notati
Page 5 and 6: 10.5.1 Transitions 5311 Evaluation
Page 7 and 8: Abbrivations and NotationsAEAT AEA
Page 9 and 10: chosen test track with a minimum of
Page 11 and 12: 1.8.2 ModelsThree different models
Page 13 and 14: 3 What does comfort mean in the con
Page 15 and 16: Representation of passengers’ opi
Page 17 and 18: 4 How comfort evolves with speed4.1
Page 19 and 20: Each element may provoke a potentia
Page 21 and 22: 5.2.2 Theoretical behaviour of thos
Page 23 and 24: Nominal acceleration in the horizon
Page 25 and 26: 6 Actual evaluation rulesAll the fo
Page 27 and 28: Important variancesS 0 = var(y)Sr =
Page 29 and 30: 7 Choice of the test zone7.1 Choice
Page 31 and 32: 9.008.007.006.00roll velocity5.004.
Page 33 and 34: 8 Description of the test8.1 The tr
Page 35 and 36: 8.3.3 Synchronisation between votes
Page 37 and 38: 8.5 Registration of data, calculati
Page 39: DRIVER CAB8.6.2 Occupied places2224
Page 43 and 44: 9.4.2 Influence of length of the co
Page 45 and 46: 9.4.4 Additional discomfort due to
Page 47 and 48: 10.1.1 ConclusionsThe actual distri
Page 49 and 50: 10.3 Seat positionThe influence of
Page 51 and 52: Average votes for the different tra
Page 53 and 54: Figures 10-5 to 10-10 show the infl
Page 55 and 56: Influence by roll velocity on voteA
Page 57 and 58: 5.0Influence by Pct on voteAll cate
Page 59 and 60: 11 Evaluation of local comfort11.1
Page 61 and 62: 11.1.4 Scaling of votesThe N’ VA
Page 63 and 64: Note that very high values of later
Page 65 and 66: 554433N'vaN'va221100 1 2 3 4Lateral
Page 68 and 69: Multiple regressions have therefore
Page 70 and 71: With the 1.0-second window, the jer
Page 72 and 73: The regression has been repeated wi
Page 74 and 75: (Table 11-12)Object: Simple and adj
Page 76 and 77: simple transitions, and with the re
Page 78 and 79: Table 11-18 Regression for track en
Page 80 and 81: Some characteristic data points of
Page 82 and 83: The probability that all coefficien
Page 84 and 85: Second conclusionThis also proves t
Page 86 and 87: number of real votes3025201510500,2
Page 88 and 89: 11.2.2 ParametersFour parameters we
Page 90 and 91:
There are some observations from th
Page 92 and 93:
Table 11-30 Two-parameter regressio
Page 94 and 95:
Three-parameter regression - N'VA,
Page 96 and 97:
The three-parameter regression was
Page 98 and 99:
12 Evaluation of average comfort12.
Page 100 and 101:
Table 12-2 shows that the correlati
Page 102 and 103:
3.53.5332.52.5NVA21.5NVA21.5110.50.
Page 104 and 105:
Table 12-5 Multiple regression for
Page 106 and 107:
This is the preferred result to be
Page 108 and 109:
12.2.5 Density of importance of eac
Page 110 and 111:
13.3 Conclusions in relationship wi
Page 112 and 113:
An identical observation can be mad
Page 114 and 115:
13.7.3 Evaluation of local comfort
Page 116 and 117:
Appendix 1Page 1 (3)1 Preparing the
Page 118 and 119:
Appendix 1Page 3 (3)2.5 Publish res
Page 120 and 121:
Appendix 2Page 2 (10)For this progr
Page 122 and 123:
Appendix 2Page 4 (10)Vertical accel
Page 124 and 125:
Appendix 2Page 6 (10)Influence of l
Page 126 and 127:
Appendix 2Page 8 (10)Red line : 0.1
Page 128 and 129:
Appendix 2Page 10 (10)Study of aver
Page 130:
Appendix 3Page 2 (2)Evaluation of h
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UIC comfort tests - VTI

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