Numerical models

Numerical models

Numerical analysis of a train passage along one of the finite element models of a railway catenary sectino, showing forces as arrows. Model and animation by NTNU/Petter Nåvik.

Numerical models of structures is a very important tool for exploring structures behaviour in more detail than can be done, practically, with built structures. We make three-dimensional finite element models of railway catenary sections using the commercial software Abaqus. The models we have and can make can describe both parts of a section as well as complete sections, see Figure 1 and 2. Due to the number of existing railway catenary sections it has in the development of the procedures for making these models focused on how they can be made fast, but correct. The pantograph model can also move along complex geometry, see Figure 3 for a schematic model Some of the models have been used in published research about how to evaluate and assess dynamic behaviour of railway catenary sections [1,2]. The numerical model was validated by comparison with field measurements in [3]. This paper also studied the variation in contact force prediction depending on filtering and sampling, see Figure 4. Numerical studies of the pantograph-catenary interaction have also been presented in conferences and conferences papers [4–7]. 

Figure 1 Numerical model of railway catenary system at Soknedal. Model and illustration by NTNU/Petter Nåvik.

 

Figure 2 Numerical model of NTNU Railway catenary model. Model by NTNU/Petter Nåvik.

Figure 3 Schematic model of the numerical pantograph used in the analyses.

Relative changes in the mean, standard deviation, minimum and maximum contact forces time series related to the low-pass cut-off frequency limit. Relative to the results at 20 Hz. [3]

References:

[1] Rønnquist A, Nåvik P. Dynamic assessment of existing soft catenary systems using modal analysis to explore higher train velocities: a case study of a Norwegian contact line system. Veh. Syst. Dyn. 53 (2015) 756–774. doi:10.1080/00423114.2015.1013040.

[2] Nåvik P, Rønnquist A, Stichel S. The use of dynamic response to evaluate and improve the optimization of existing soft railway catenary systems for higher speeds. Proc. Inst. Mech. Eng. Part F J. Rail Rapid Transit . (2015). doi:10.1177/0954409715605140.

[3] Nåvik P, Rønnquist A, Stichel S. Variation in predicting pantograph-catenary interaction contact forces, numerical simulations and field measurements. Veh Syst Dyn 2017;55:1265–82. doi:10.1080/00423114.2017.1308523.

[4] Nåvik P, Rønnquist A. Dynamic behaviour of an existing railway catenary system for extreme low passage at exceeding design velocities. In: Cunha Á, Caetano E, Ribeiro P, Müller G, editors. Proc. 9th Int. Conf. Struct. Dyn. EURODYN, Porto, Portugal: 2014.

[5] Rønnquist A, Nåvik P. Dynamic Assessment of a Norwegian Contact Line: Exploring Higher Speed in Sharp Curves. In: Pombo J, editor. Proc. Second Int. Conf. Railw. Technol. Res. Dev. Maint., Stirlingshire, UK: Civil-Comp Press; 2014. doi:10.4203/ccp.104.139.

[6] Navik P, Ronnquist A. Dynamic Optimization of an Existing Catenary System when Exceeding Design Speed. In: Pombo J, editor. Proc. Second Int. Conf. Railw. Technol. Res. Dev. Maint., Stirlingshire, UK: Civil-Comp Press; 2014. doi:10.4203/ccp.104.138.

[7] Rønnquist A, Nåvik P. Dynamic implications for higher speed in sharp curves of an existing Norwegian overhead contact line system for electric railways. In: Cunha Á, Caetano E, Ribeiro P, Müller G, editors. Proc. 9th Int. Conf. Struct. Dyn. EURODYN, Porto, Portugal: 2014.