No abstract

In this study, through a vibration table test, finite element simulation, and research on the rationality of the wave-height fortification of national storage tank specifications, the sloshing response of vertical storage tanks under the action of near-fault ground motion was analyzed. The test results showed that the sloshing wave height of a vertical storage tank was larger under near-fault or long-period ground motions, and the relationship between the sloshing wave height and the peak acceleration of input ground motions was approximately linear. The numerical simulations of the model tank showed that the simulation wave height and the test wave-height data were well fitted. Therefore, it was feasible to simulate the sloshing of large vertical storage tanks using ADINA software. In addition, a large number of sloshing simulations of near-fault ground motions on 10,000 m3 vertical storage tanks were performed. The simulated wave height had a high correlation with the predominant period or pulse period of near-fault ground motions. Under the calculation with similar parameters, the wave height of the tank standard in several countries had a lower fortification of the near-fault excitation wave height. Through the root mean-square method using a small sample size, a wave-height correction under a near-fault effect was applied to the wave-height formula for the Chinese tank seismic specification. Finally, the problem of a double-damping correction was addressed by adjusting China’s GB50341 wave-height formula. This work provides a reference value for practical engineering applications.

The aim of this paper is to study the stress distribution law of corrosion defects in pipelines before and after repair of thin-walled lining and the effect of repair. The calculation model for corrosion defects in pipelines was established by the equilibrium differential equation of elastic–plastic mechanics. Based on ABAQUS finite element software, the pipeline model with a single corrosion defect was established. The material of the pipeline was API 5L X52N with an outer diameter of 324[Formula: see text]mm and a thickness of 10[Formula: see text]mm. The material constitutive relation was an ideal elastic–plastic model. We changed the depth-to-thickness ratio of corrosion defects ([Formula: see text], 0.1, 0.5, 0.8) and used the different lining repair materials (stainless steel and FRP). At the same time, ignoring the thickness of bonding layer and its influence on the filling of corrosion pit, the interface interaction analysis model was established by the bonding behavior between layers. We compared the stress at the corrosion defect before and after repair. It is found that with the increase of the depth-to-thickness ratio of corrosion defects, the radial stress, circumferential stress, and Mises stress at the corrosion defect all tend to increase. The circumferential stress at the defect before the repair is the largest, and its value is similar to the Mises stress. After the repair of stainless steel lining, the circumferential stress at the defect is reduced by 11.01%, and the Mises stress is reduced by 14.18%; after the repair of FRP lining, the circumferential stress at the defect is reduced by 7.01%, and the Mises stress is reduced by 3.54%. The depth-to-thickness ratio of corrosion defects has a significant impact on the stress distribution of pipelines. Therefore, the influence of corrosion depth should be paid attention to in the pipeline safety assessment. Before and after repair, the control stress at the corrosion defect of the pipeline is always the circumferential stress. The failure can be judged according to the circumferential stress; after the repair of thin-walled lining, the stress at the original defect is redistributed, and the circumferential stress and Mises stress are reduced, and the repair effect is obvious.

This paper introduces a double-walled hollow pipe (DWHP) that demonstrates good corrosion resistance and mechanical properties and that can be used in pipeline transportation and structural stress components in marine, freshwater, and corrosive environments. We designed and machined the specimens to meet the bending bearing capacity using a cross section method. We conducted low-cycle loading tests of the specimens to investigate the energy dissipation capacity of the DWHP, the effects of different geometrical parameters, and the concrete-filled strength of the DWHP on energy dissipation capacity. The results show that the failure forms of the specimens are similar. The geometrical characteristics of the specimens, the cohesive function between the concrete and the steel plate, and the strength of the concrete-filled pipe showed a significant influence on the mechanical properties of the specimens. Hysteretic curves are plump and possess a high capacity for energy dissipation. The energy dissipation capacity of the specimen decreases with an increase in the slenderness ratio. The slope of strength degradation decreases with any increase in the strength of the concrete-filled pipe. We optimized the section design of the component by improving the constraint effect coefficient, and we effectively improved its stability by adding stiffeners to the inner side of the outer wall of steel.