The primary idea of the article is to analyze whether premature pin failure is connected to cyclic fatigue. The main instruments used in the article are pin made from ph 13-8 Mo stainless steel and other elements that have an impact on the pin failure. According to the article, the first experiment showed that in one week of operation, the shear pin prematurely failed. The high tension in the flocculator drive is the main cause of the shear pin failure. The article is based on the evaluation of deflection, stress and fatigue of the shear pin. According to the authors, during the experiment they faced a failure because the flocculator drive shear pin failed its results. The main reason of the premature failure is the fact that the shear pin is not able to withstand additional tension and stress. Therefore, because the shear pin was made for a particular tension level, it failed to show positive results in the experiment. In fact, it was noticed that despite the fact that the shear pin is designed from ph 13-8 Mo stainless steel, it is still vulnerable to corrosion. Therefore, one of the main recommendations of the research is to redesign the shear pin, so it will be able to withstand higher rates of stress and increase the fatigue strength. Additionally, redesigning of the shear pin will give an opportunity to increase the resistance to corrosion. In conclusion, although the initial experiment failed, the authors were still able to find out the main reason of the failure.
Failure of a conveyor trunnion shaft on a centrifuge
The main purpose of the article is to examine the primary reason of the failure of (Nguyen, Romios and Es-Said) “a conveyor trunnion shaft from a solid bowl centrifuge” (p.401). It also aims to examine the main cause of failures and defects, which led to the fracture between the flange and the hollow shaft (Nguyen, Romios and Es-Said). According to the article, the authors used the following instruments in their experiment: optical pictures, visual inspection and the cause-effect research. It is important to mention that the Solid Bowl Centrifuge is very strong and is able to convey very heavy materials. The authors did the experiment on the conveyor trunnion shaft on a centrifuge. Eventually, the main findings of the research showed the failure which was caused by fatigue fracture. It was inspected that the areas of the shaft had obvious defects in two kinds of metals: the weld metal and the base metal (Nguyen, Romios and Es-Said). It was concluded that the defects, which were numerous cracks, were the main reason of the failure of a conveyor trunnion shaft on a centrifuge. After the closer inspection, it was found that the primary problem was the poorly welded joints. Clearly, the misalignment caused numerous stresses and tensions, which led to the failure of stress resistance. Additionally, it was concluded that the radius of weld bolts was too small; thus, a shaft could not resist the high level of tension, which led to fatigue. In conclusion, in order to prevent further failures of a conveyor trunnion shaft on a centrifuge, it is important to remove all the defects found during this research. Therefore, the trunnion shaft should be redesigned completely, in order to withstand the higher concentrations of stress.
Work cited
Nguyen, T., M. Romios, and O.S. Es-Said. "Failure Of A Conveyor Trunnion Shaft On A Centrifuge".Engineering Failure Analysis 11.3 (2003): 401-412. Web.
Smith, M. et al. "On The Redesign Of A Shear Pin Under Cyclic Bending Loads". Engineering Failure Analysis 14.1 (2006): 138-146. Web.
