INNOTRACK Deliverable 4.2.4 -- Improved model for loading and subsequent deterioration due to squats and corrugation
In this research a hybrid multibody-finite element model was developed and applied to the analyses of the initiation and growth of squats, and to the identification of the most influential parameters of squatting. The growth process of squats was postulated based on numerical simulation, and was subsequently validated by field monitoring. Further a critical size for small rail top geometrical defects to grow into squats has been derived and validated. This critical size may be directly applied to visual inspection and classification of squats so that false reporting of squats can be avoided. The critical size can be applied as a minimum action rule for preventive or early corrective maintenance actions, such as rail grinding. The model may also have the capability to relate the severity of some track short defects quantitatively to some measurement of the dynamic wheel-rail interaction at the defects so that automatic detection of the defects at their early stage is possible. Finally corrective and preventive measures against squats are discussed.