Loading…
Euler angles and numerical representation of the railroad track geometry
The geometry description plays a central role in many engineering applications and directly influences the quality of the computer simulation results. The geometry of a space curve can be completely defined in terms of two parameters: the horizontal and vertical curvatures , or equivalently, the cur...
Saved in:
Published in: | Acta mechanica 2021-08, Vol.232 (8), p.3121-3139 |
---|---|
Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Summary: | The geometry description plays a central role in many engineering applications and directly influences the quality of the computer simulation results. The geometry of a space curve can be completely defined in terms of two parameters: the
horizontal
and
vertical curvatures
, or equivalently, the curve
curvature
and
torsion
. In this paper, distinction is made between the track angle and space-curve bank angle, referred to in this paper as the
Frenet bank angle
. In railroad vehicle systems, the
track bank angle
measures the track
super
-
elevation
required to define a
balance speed
and achieve a safe vehicle operation. The formulation of the track space-curve differential equations in terms of Euler angles, however, shows the dependence of the
Frenet bank angle
on two independent parameters, often used as inputs in the definition of the track geometry. This paper develops the general differential equations that govern the track geometry using the Euler angle sequence adopted in practice. It is shown by an example that a curve can be twisted and vertically elevated but not super-elevated while maintaining a constant
vertical
-
development angle
. The continuity conditions at the track segment transitions are also examined. As discussed in the paper, imposing curvature continuity does not ensure continuity of the tangent vectors at the curve/spiral intersection. Several curve geometries that include planar and helix curves are used to explain some of the fundamental issues addressed in this study. |
---|---|
ISSN: | 0001-5970 1619-6937 |
DOI: | 10.1007/s00707-020-02903-4 |