A contrast between classical method and finite element method for calculating strength in impeller of centrifugal pump

In order to calculate accurately the stress and the deformation conditions of the closed impeller of centrifugal pumps in the flow field, “direct-calculation method” and the ANSYS Workbench-based finite element method are separately used to calculate the maximum stress that the impeller bears and the strength check of it have been proceed. This paper has made a comparative analysis between the two methods, and it is shown that the finite element analysis method can more comprehensively show the stress concentration, whereas the traditional method is more focused on the average of checking. Therefore, in terms of the results, it is suggested that in addition to the traditional direct-calculation method, modern simulation software such as the finite element method should be used for the proofread of the impeller in the industry, in order to improve the running safety and the reliability of the closed impeller of centrifugal pumps

Research on the Coupled Risk of Key Nodes in Maritime Transport Based on Improved Catastrophe Theory

Defining the degree of risk of maritime transport nodes is an important basis for studying the security status of maritime transport passages. However, some important straits or canals are key nodes in the maritime transport passage, and their system security conditions are affected by the interaction of uncertainty risk factors. This study addresses the issue of the security status of transport nodes from the perspective of the characteristics of influencing factors. With a focus on catastrophes and the mutual coupling characteristics of the factors that influence the security of maritime transport nodes, a model based on principal component analysis (PCA) and catastrophe theory (CT) is constructed, and the coupled risk degree of the key nodes in Chinese maritime transportation is empirically analysed. The results show that the Taiwan Strait has the lowest risk degree and that the Windward Strait has the highest risk degree among the key nodes in Chinese maritime transport. From the perspective of the security status of these key nodes, most nodes are currently in a stable and safe state.</jats:p