Abstract In this research, two stress-based finite element methods including the curvature-based finite element method (CFE) and the curvature-derivative-based finite element method (CDFE) are developed for dynamics analysis of Euler-Bernoulli beams with different boundary conditions. In CFE, the curvature distribution of the Euler-Bernoulli beams is approximated by its nodal curvatures then the displacement distribution is obtained by its integration. In CDFE, the displacement distribution is approximated in terms of nodal curvature derivatives by integration of the curvature derivative distribution. In the introduced methods, compared with displacement-based finite element method (DFE), not only the required number of degrees of freedom is reduced, but also the continuity of stress at nodal points is satisfied. In this paper, the natural frequencies of beams with different type of boundary conditions are obtained using both CFE and CDFE methods. Furthermore, some numerical examples for the static and dynamic response of some beams are solved and compared with those obtained by DFE method.

Nowadays, the rail fastening systems play an important role for preserving the connection between the rails and sleepers in various conditions. In this paper, stress based concept is used to develop a comprehensive approach for fatigue reliability analysisof fastening spring clip. Axle load, speed and material properties are assumed to be random variables. First, track and train models are analyzed dynamically in order to achieve displacement time history of fas-tening spring clip. Then this displacement time history is applied to the fastening spring clip in FE software to obtain variable ampli-tude of stresses. Crack nucleation life is calculated by rain-flow method and Palmgren-Miner linear damage rule. First Order Relia-bility Method (FORM) and Monte-Carlosimulation technique are employed for the reliability index estimations. The influences of various random variables on the probability of failure are investi-gated by sensitivity analysis. The results show that the equivalent stress range and material parameter have significant effect on fa-tigue crack nucleation.