Simulating low-frequency and long-term fatigue loading for life-cycle structures

Environmental action and the effect are the main issue of life-cycle structures, but an important reminding is necessary to be drawn that, the environmental action does not exist solely; in fact, it exists together with some mechanical actions, which may result in coupled effects of environment and mechanics. To reveal the complex mechanism of the coupled effect, experimental simulation is necessary, in which the long-term combined action of environment and mechanics is needed to be applied for the specimens. So far, the main difficulty in the long-term simulation of the combined action is to conveniently apply the long-term fatigue load to investigate the issue of corrosion-fatigue or erosion-fatigue. To solve this difficulty, the authors have invented a mechanical fatigue machine which is suitable for long-term fatigue loading. The machine has successfully applied in several experiments with long-term combined action of corrosion/erosion and fatigue. In this paper, the invented fatigue machine and the applications, i.e., a long-term fatigue loading for corrosion-fatigue issue of beam specimens, a long-term fatigue loading for corrosion-fatigue issue of bond specimens, and a long-term fatigue loading for erosion-fatigue issue of little column specimens, are introduced.