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...