Function Of Corrosion Rate Research Articles

Deterioration of fatigue strength of bolted connection plates under combined corrosion and fatigue

In this paper, the combined effect of corrosion and fatigue on the fatigue strength of steel connection plates is thoroughly investigated through a comprehensive experimental program. A model for fatigue strength degradation as a function of corrosion rate is developed. The mechanism of fatigue strength degradation is also examined to gain a insightful understanding of fatigue strength degradation under simultaneous corrosion and fatigue environments. It is found in the paper that the simultaneous corrosion and fatigue environment can lead to higher degradation in fatigue strength of connection plates than those subjected to pre-corrosion and fatigue test afterward. It is also found that the reduction in grain size of steel plates is one of main mechanisms for the degradation in fatigue strength of the connection plate. The significance of the paper lies in developing a testing methodology to create a simultaneous corrosion and fatigue environment for connections and study its effect on fatigue strength. The knowledge of degradation mechanism of fatigue strength of steel connections under simultaneous corrosion and fatigue environment contributes to corrosion science of steel structures.

Effect of Corrosion Damage on the Performance Level of a 25-Year-Old Reinforced Concrete Building

Corrosion is a long-term process resulting in the deterioration of the reinforced concrete (RC) structures. Most of the structural problems observed under the impact of either earthquakes or service loads might occur due to corrosion. Therefore, prediction of the remaining service life of a corroding RC structure plays an important role to prevent serious premature damage. In this study, a corroded, 25-year-old high school building which has been demolished at an earlier time was analyzed as a function of corrosion rate. Bond-slip relationships were taken into account in nonlinear analyses as a function of corrosion rate for different time periods (i.e., non-corroded (t: 0), existing (t: 25) and 50 years after construction); and they were used to ensure the effect of time-dependent slip rotation on the global structural behaviour by modifying the target post-yield stiffness of each structural member. Nonlinear push-over analyses were performed by defining the time-dependent plastic hinge properties as a consequence of corrosion effects. In order to define the performance levels of three different time periods, nonlinear incremental dynamic analyses (IDA) were performed for 20 earthquake ground motion records as a function of corrosion rate. Results showed that bond-slip relationship between concrete and steel is very important in evaluating the non-linear behaviour of corroded RC structures.

Effect of corrosion damage on the performance level of a 25-year-old reinforced concrete building

Corrosion is a long-term process resulting in the deterioration of the reinforced concrete (RC) structures. Most of the structural problems observed under the impact of either earthquakes or service loads might occur due to corrosion. Therefore, prediction of the remaining service life of a corroding RC structure plays an important role to prevent serious premature damage. In this study, a corroded, 25-year-old high school building which has been demolished at an earlier time was analyzed as a function of corrosion rate. Bond-slip relationships were taken into account in nonlinear analyses as a function of corrosion rate for different time periods (i.e., non-corroded (t: 0), existing (t: 25) and 50 years after construction); and they were used to ensure the effect of time-dependent slip rotation on the global structural behaviour by modifying the target post-yield stiffness of each structural member. Nonlinear push-over analyses were performed by defining the time-dependent plastic hinge properties as a consequence of corrosion effects. In order to define the performance levels of three different time periods, nonlinear incremental dynamic analyses (IDA) were performed for 20 earthquake ground motion records as a function of corrosion rate. Results showed that bond-slip relationship between concrete and steel is very important in evaluating the non-linear behaviour of cor- roded RC structures.

Mathematical Modeling and Simulation of Corrosion Processes in Nigerian Crude Oil Pipelines

In this work, a corrosion prediction mathematical model for risk assessment in oil and gas production and transportation facilities has been created. This work focuses on partial pressure of carbon (iv) oxide, CO2 and the operating temperature in process equipment and transportation facility pipes as a function of corrosion rate. The model equation formulated was based on the principle of multiple linear regressions of data. The final model representing the corrosion rate of crude oil equipment was obtained CR = b o + b 1 T + b 2 P (CO 2). The model was simulated using polymath software. The correlation between the experimental and simulated resulted obtained using root mean square deviation (coefficient of determination) was 99.74% which is high, suggesting that the relationship between the predictor and response variables is linear. The variation in the model equation is 0.0066374. This low value of the variance shows that the model is accurate.