Effect of cleaned corrosion surface topography on mechanical properties of cold-formed thin-walled steel

Corrosion damages have an important effect on the safety design of cold-formed steel structures, resulting in the rapid reduction of the load carrying capacities. Therefore, an experimental study was undertaken to investigate the influence on mechanical properties of corroded cold-formed thin-walled steel with different corrosion degrees and types. The tested specimens came from cold-formed thin-walled C steel purlin with a service life for 9 years under industrial environment According to comparing the fracture morphology, stress-strain curve, mechanical property index of corroded steel with corrosion degrees and types, the constitutive model of cold-formed thin-walled steel was established. Furthermore, the reverse engineering software Geomagic Studio and finite element software ABAQUS were used to simulate the mechanical properties of monotonic tensile under the real corroded surface morphology. The results showed that the fracture mode of pitting corrosion was the flat fracture, whereas that of the overall corrosion was diversified such as the oblique fracture, circular fracture and staircase fracture. All the pitting specimens showed that the yield platform and necking segment disappeared, whereas the overall corrosion specimens occurred only when the corrosion rate reached 36.14%. When the corrosion rate reached 36%, the strength decreased at a ratio of 21% and the elongation decreased by about 70%. The numerical simulation method is feasible and to provide the technical basis for the prevention and reduction of civil engineering disaster. (C) 2019 Elsevier Ltd. All rights reserved.