Study on the degradation of mechanical properties of corroded steel plates based on surface topography

• Degradation laws of mechanical properties of corroded steel plates are studied.
• The constitutive model of corroded steel plates is proposed.
• Numerical simulation method based on surface topography is proposed.

Degradation laws of mechanical properties of corroded steel plates were studied by experimental method and numerical simulation method based on surface topography in this paper. First, Q235 steel plate was subject to accelerated corrosion with artificial salt spray, and the characteristics of the surface of corroded steel plate were measured by three-dimensional morphology observation instrument to obtain the values related to corrosion damage parameters, and the relationship between the surface characteristic parameters and the corrosion rate was established. Then the stress-strain curves and mechanical properties of the corroded steel plates were obtained by monotonic tensile test. Finally, the mechanical properties of steel plates with real corroded surfaces were studied by numerical simulation method with reverse engineering software Geomagic Studio and finite element software ANSYS, and the stress concentration phenomenon caused by corrosion pit was discussed. The results showed that: (a) the corrosion rate is within 15%, the stress-strain curves have obvious yield plateaus; (b) and with the increase of corrosion rate, yield plateaus, yield strength, ultimate strength, and fracture strength of corroded steel plates does not decrease much, but ductility significantly decreases; (c) when the corrosion rate is over 15%, all the mechanical property index significantly decreases; (d) the constitutive model was established, and the law of the variations of the parameters of the model was summarized; (e) the numerical simulation method is feasible compared with the experimental results.