This paper proposes the use of vertical accelerations of a moving train to detect local track irregularities produced by weaker sections of the infrastructure. By analysing the vehicle accelerations using the wavelet transform, it is possible to clearly identify the location of damaged sections. A wavelet-based indicator is proposed to facilitate an algorithm for recognition of deteriorated segments. The proposed indicator is validated by means of a 2-DOF vehicle model excited by randomly generated track irregularities together with the presence of various local track defects. A Monte Carlo analysis is performed to evaluate the performance of the proposed indicator for a variety of model parameters, including vehicle mechanical properties, shape of isolated track irregularities and levels of damage.

Publication informationMechanical Systems and Signal Processing, 66-67 : 314-338 Publisher ElsevierItem record/more information http://hdl.handle.net/10197/7727 Publisher's statement þÿ T h i s i s t h e a u t h o r s v e r s i o n o f a w o r k t h a t

Abstract:11 12 This paper proposes a novel level I damage detection technique for short to medium span

Train-track-bridge modelling and review of parameters This paper gathers into one single document all the necessary information to construct a model to calculate the coupled dynamic response of train-trackbridge systems. Each component of the model is presented in detail together with a review of possible sources for the parameter values, including a collection of vehicle models, a variety of track configurations and general railway bridge properties. Descriptions of the most important track irregularity representations are also included. The presented model is implemented in Matlab and validated against a commercially available finite element package for a range of speeds, paying particular attention to a resonant speed. Finally, the potential of the described model is illustrated with two numerical studies that address interesting aspects of train and bridge dynamic responses. In particular, the effect of the presence of a vehicle on the bridge's fundamental frequency is studied, as well as the influence of the wavelength of the rail irregularities on the dynamic effects of the bridge and the vehicle.