One goal of this thesis is to study the performance and accuracy of an explicit finite element (FE) method for frictional rolling contact in a wider-range of conditions. The other goal is to reveal the physical phenomena of squats and the mechanisms behind, such as cracking mechanisms and development process. The first part studies the applicability of half-space-based methods in non-conforming contact problems and their accuracy by comparing a validated implicit FE method in terms of their solutions. In the second part, spin-rolling contact is analyzed using the explicit FE method for frictional rolling contact, and the solution is verified against two half-space-based methods, i.e., the Hertz theory and the Kalker’s variational theory. The third part of the thesis studies a five-year continual field monitoring on a large number of squats induced by corrugation. Various stages of the life cycle of corrugation-induced squats, from small black depressions without cracks to mature two-lung shaped squats accompanied by Y-shaped and I-shaped cracks, were revealed. Their corresponding mechanisms were also provided. Finally, in the fourth part of this thesis, weld-induced squats are studied based on the five-year continual field monitoring and numerical simulations. Based on the observations, a hypothesis of the formation and development process of squats at welds is proposed. Afterwards, a 3D FE model is built to verify the hypothesis .
|Qualification||Doctor of Philosophy|
|Award date||10 Jul 2019|
|Publication status||Published - 2019|