Residual behaviour of corroded welded hollow spherical joints subjected to eccentric loads

Abstract

The evaluation of corroded welded hollow spherical joints (WHSJs) under eccentric loads is necessary to ensure the safety of space structures. In this study, the corrosion characteristics and mechanical properties of standard specimens under different corrosion times were investigated through surface measurements and tensile tests. Next, eccentric compressive tests were performed on four WHSJs subjected to different degrees of corrosion to evaluate the mechanical properties. The test results showed that the logarithmic normal distribution and generalized extremum value distribution could be used to describe the pitting depth distribution precisely. Uniform corrosion was the main index that influenced the corrosion and bearing characteristics under the test conditions; the eccentric compressive ultimate load decreased by 3.8%, 9.9% and 11.8% at 100, 131, and 157 days of acetic acid mist corrosion, respectively, which corresponded to approximately 20, 30, and 40 years of environmental corrosion in Qingdao. In addition, a refined corrosion simulation method, based on corrosion morphology, and two simplified simulation methods were developed. Based on one of the simplified methods, the effects of various corrosion and size parameters on the eccentric performance of the joint were evaluated. The analysis results showed that the corrosion depth and wall thickness were the main factors that influenced the degradation of the joint bearing capacity. A simplified method for designing the eccentric performance of corroded WHSJs was developed and validated.