The Canadian prairies are renowned for their substantial agricultural contributions to the global food market. Harrow tines are indispensable in farming equipment, especially for soil preparation and weed control before planting crops. During operation, these tines are exposed to repetitive cyclic loading, which eventually causes fatigue failure. Commercially available three different harrow tines named 0.562HT, 0.625HT, and 0.500HT undergo an experimental fatigue evaluation and are validated through Finite Element Analysis (FEA). Fatigue life estimation for different deflections under various real-field deflections was carried out where 0.562HT showed groundbreaking life compared with others. The study results showed that the fatigue life is highly dependent on geometry, number of coils, pitch angle, leg length, and coil diameter. The 0.354HT model, developed to investigate the effect of wire diameter, closely resembles the 0.500HT model. The harrowing ability of the four different harrow tine models against identical deflections has been analyzed. Experimental fractured surfaces went through morphological investigation. This research has an impeccable impact on prairies' agricultural acceleration by saving time and mitigating unpredictable fatigue failure often faced by farmers. Even the observed failure phenomena can serve as motivation to develop more reliable and durable harrow tines, which could increase agricultural efficiency. Higher coil diameter and lower pitch results in higher spring stiffness and load-carrying capability.Harrow tines have shorter lifespans with smaller diameters within a range and with larger or smaller diameters beyond thresholds.Higher tapered angles reduce cyclic load capacity due to increased stress concentration from the smaller surface area of each coil.
In saline soil areas, the concrete piers of concrete bridges experience long-term corrosion, mainly caused by chloride salts due to alternating temperature changes. Waterborne concrete coatings are prone to failure in this aggressive salt environment. Implementing coating protection measures can improve the durability of concrete and enhance the service life of bridges. However, the effectiveness and longevity of coatings need further research. In this paper, three types of waterborne concrete anti-corrosion coatings were applied to analyze the macro and micro surface morphology under wet-dry cycles and long-term immersion conditions. Various indicators such as glossiness, color difference, and adhesion of the coatings were tested during different cyclic periods. The chloride ion distribution characteristics of the buried concrete coatings in saline soil, the macro morphology analysis of chloride ion distribution regions, and the micro morphology changes of the coatings under different corrosion times were also investigated. The results showed that waterborne epoxy coatings (ES), waterborne fluorocarbon coatings (FS), and waterborne acrylic coatings (AS) all gradually failed under long-term salt exposure, with increasing coating porosity, loss of internal fillers, and delamination. The chloride ion content inside the concrete decreased with increasing depth at the same corrosion time, while the chloride ion content at the same depth increased with time. The chloride ion distribution boundary in the cross- of concrete with coating protection was not significant, while the chloride ion distribution boundary in the cross- of untreated concrete gradually contracted towards the concrete core with increasing corrosion time. During the corrosion process in saline soil, the coatings underwent three stages: adherence of small saline soil particles, continuous increase in adhered material area, and multiple layers of uneven coverage by saline soil. The failure process of the coatings still required erosive ions to infiltrate the surface through micropores. The predicted lifespans of FS, ES, and AS coatings, obtained through weighted methods, were 2.45 years, 2.48 years, and 2.74 years, respectively, which were close to the actual lifespans observed in salt environments. The developed formulas effectively reflect the corrosion patterns of different resin-based coatings under salt exposure, providing a basis for accurately assessing the corrosion behavior and protective effectiveness of concrete under actual environmental factors.
Recently, several UHV transmission lines that have been operational for over 15 years, transmitting power from Yunnan and Guizhou to Guangdong Province, suffered severe damage to their tower foot due to soil corrosion. Consequently, this study conducted accelerated corrosion simulation research on the UHV transmission tower foot in a laboratory setting. The electrolytic corrosion acceleration simulation method and the dry and wet cycle acceleration simulation method were proposed as two approaches to simulate tower foot corrosion in this study. The corrosion morphology and products resulting from electrolytic and natural corrosion of the carbon steel substrate exhibited remarkable similarities. Notably, the acceleration ratio of electrolytic corrosion exceeded 100, thereby adhering to the fundamental principles and evaluation characteristics of accelerated corrosion. The experimental design involved a simulation test that replicated the on-site environmental conditions, specifically targeting the dry and wet cycles. This test effectively mimicked the corrosion process of metal surfaces and generated rust layers exhibiting similar characteristics to those observed in field corrosion. By conducting an analysis of the polarization curve for the rusted sample, a comparison was made regarding the corrosion rates observed in different sections of the tower foot. The outcomes obtained from AC impedance analysis revealed that soil corrosion predominantly relied on diffusion processes, thereby enabling us to derive equivalent circuitry and component parameters pertaining to carbon steel soil corrosion.