Pre-cracking development of weld-induced squats due to plastic deformation: Five-year field monitoring and numerical analysis

Weld-induced squats are a major damage type in high-speed railways as well as in conventional railways. They incur high maintenance costs and endanger operational safety. This paper first presents and analyzes five-year continual field monitoring observations and measurements of squats at rail welds. A hypothesis of the formation and development...

Investigation of the formation of corrugation-induced rail squats based on extensive field monitoring

Rail squats originate from a number of sources, such as corrugations, indentations and welds. A five-year continual field monitoring study was performed on squats induced by corrugations. This study indicated that a small black depression formed at the corrugation under wheel-rail dynamic forces, and then, a primary crack typically initiated...

Triple-action self-healing protective coatings based on shape memory polymers containing dual-function microspheres

In this study, a new self-healing shape memory polymer (SMP) coating was prepared to protect the aluminum alloy 2024-T3 from corrosion by the incorporation of dual-function microspheres containing polycaprolactone and the corrosion inhibitor 8-hydroxyquinoline (8HQ). The self-healing properties of the coatings were investigated via scanning...

Applicability of half-space-based methods to non-conforming elastic normal contact problems

The half-space assumption has been employed in many solution methods for non-conforming contact problems in elasticity such as the Hertz theory and the Kalker's variational theory. It is generally believed that to guarantee acceptable accuracy in these half-space-based methods, the characteristic size (twice length of one semi-axis) of the...

Dual-action smart coatings with a self-healing superhydrophobic surface and anti-corrosion properties

This work introduces a new self-healing superhydrophobic coating based on dual actions by the corrosion inhibitor benzotriazole (BTA) and an epoxy-based shape memory polymer (SMP). Damage to the surface morphology (e.g., crushed areas and scratches) and the corresponding superhydrophobicity are shown to be rapidly healed through a simple heat...

Residual fatigue life evaluation of rail at squats seeds using 3D explicit finite element analysis

A modeling procedure to predict the residual fatigue life of rail at squats seeds is developed in this article. Two models are involved: a 3D explicit Finite Element (FE) model to compute the stress and strain at squats in rail, and the J-S fatigue damage model to determine the residual fatigue life on the basis of the computed stress and strain...

Influences of characteristic size of contact bodies on rolling contact

The rolling contact of elastic bodies (upper body and lower body) can be analyzed with the Hertz theory and the Kalker’s model. It is generally believed that the width of the contact area should be much smaller than the characteristic size of each elastic body, to ensure that the half-space assumption is valid. However the definition of “much...