Authors: S.J. Kokkins, A. Purple, G. Samavedam

Date of Publication:  1994

Sponsoring Agency:  U.S. Department of Transportation, Federal Railroad Administration, Volpe National Transportation Systems Center

Abstract:

This report presents a theoretical analysis predicting the temperature distributions, thermal deflections and thermal stresses that may occur in typical steel Maglev guideways under the proposed Orlando, FL thermal environment. Transient, finite element heat transfer analyses are used to predict the thermal response of a typical steel guideway design similar to the Transrapid design being finalized for the Orlando, FL Maglev system. Parametric studies are conducted to examine the sensitivity of the temperature distributions and thermal deflections to time varying changes in the sun's position, seasonal changes, and changes in the guideway orientation and surface treatment. Related safety issues are also addressed.

The results of these analyses indicate that the depthwise temperature gradient is steep and nonlinear, which can result in thermal deflections up to 13 mm for single spans. Parametric study results indicate that the vertical deftections are greatest at the spring/fall equinox for East-West orientations, but are also in the 10 to 11 mm range in summer when the guideway is oriented in the North-South direction. The horizontal deflections up to 8 mm are greatest in winter when the guideway is oriented in the East-West direction. The use of double spans is shown to reduce the guideway deflections, but also increase the bending stresses. Application of a white coating to the guideway is shown to reduce the guideway temperatures, deflections and stresses and is strongly dependent on thermal properties of the coatings. The effects of vehicle heating may be expected to worsen guideway deflections but detailed study is required in further work. The effects of ground radiation slightly reduce the guideway deflections, and are shown to affect the guideway primarily when it is mounted close to ground Level on short pylons.
 

No. of Pages:  88