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Thermal buckling of rail is a complex phenomenon influenced by many factors, including temperature distribution within the rails, relative stiffness of the rail-crosstie interface, structural configuration of the underlying track structure and the highly nonlinear interactions among the rail-tie-ballast interfaces.
Previous research shows that rail temperature, rail-ballast interface friction and rail-crosstie structural configuration must be included within any rail buckling model in order to accurately predict rail buckling.1,2,3 Furthermore, friction between the crossties and ballast has been shown to be highly nonlinear; see Figure 2.
Accounting for all of these contributing factors result in a mathematical model that cannot be solved analytically. Accordingly, the authors are developing a self-contained computational algorithm for predicting lateral buckling in rails4 that is based on the large deformation Euler-Bernoulli beam theory5,6 cast within the finite element method7; see Figure 3. Nonlinearity in the algorithm results from geometric nonlinearities in the rail in the deformed configuration, finite strains and nonlinearities in the friction between the crossties and ballast. This nonlinearity is accounted for using Newton iteration.
Typical results obtained with the model are shown in Figure 4, wherein the...