| Popis: |
Marine environment adversely affects the durability of welded steel structures. Generally, it causes corrosion, formation of surface defects that can grow into cracks and cause fracture. In order to study this process, idea of this research was to develop a credible numerical model of welded steel specimen exposed to marine environment and to use this model to perform numerical simulation of mechanical tests. In order to do so, experimental research has been performed first with the aim of assessment of sea environment effect on mechanical properties of steel and surface morphology of the specimen. Standardized specimens have been cut out of welded sheets made of high-strength shipbuilding steel and exposed for prolonged period (6, 12, 24 and 36 months) to real sea environment (sea, sea waves, fresh water). After extracted from experiment site, specimens have been tested to determine the change of mechanical properties of metal. Standardized tensile tests have been performed along with Charpy impact tests and hardness measurements. Additionally, size of corrosion pits on the surface of the specimens has been measured and corroded surface 3D scanned. Results show deterioration of mechanical properties of steel exposed to sea environment when compared with steel kept at room conditions. The most significant deterioration is noticed on specimens exposed to continuous influence of sea waves [1]. Second stage of this research includes building a finite element models of specimens that would have surface morphology modelled according to real situation. Mechanical tests would be simulated numerically and validated according to ones performed experimentally. If completed accurately, this model could be used for further assessment of other types of steel exposed to sea environment. |
