The algorithms FASTSIM and FASTSIM2
Vehicle-dynamic simulation includes solving many millions of contact problems in order to incorporate the wheel-rail creep force behavior. In most circumstances it is acceptable to solve these problems fast and approximately. This is accomplished in FASTSIM using Kalker's simplified theory by schematizing the material elastic behavior using independent springs.
Different variants of the FASTSIM algorithm are used for wheel-rail contact evaluation in SIMPACK Rail, GENSYS and Universal Mechanism. It is currently the best compromise between speed and accuracy when considering non-Hertzian circumstances [Vollebregt2011a], possibly including the falling friction effect [Spiryagin2013]. However, FASTSIM is not well-suited for computing the underlying traction distribution, as needed for wear [Vollebregt2015a].
FASTSIM2 is an improved variant that has reduced discretization error compared to the original FASTSIM algorithm. It is published in [Vollebregt2010b].
- [Spiryagin2013]. M. Spiryagin, O. Polach and C. Cole,
Creep force modelling for rail traction vehicles based on
the Fastsim algorithm. Vehicle System Dynamics, volume
51, pages 1765-1783, 2013.
- [Vollebregt2010b]. E.A.H. Vollebregt and P. Wilders,
FASTSIM2: a second-order accurate frictional rolling contact algorithm.
Computational Mechanics, 2010.
- [Vollebregt2015a]. E.A.H. Vollebregt, FASTSIM with Falling Friction and Friction Memory, in "Noise and Vibration Mitigation for Rail Transportation Systems", Volume 126 of the series "Notes on Numerical Fluid Mechanics and Multidisciplinary Design", pages 425-432, 2015.
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