Shugen Xu

Modified Formulation of Layer Stresses Due to Internal Pressure of a Layered Vessel With Interlayer Gaps

In this paper, the modified formulae have been provided. They can be used to calculate the stress in layers with gaps of a layered cylinder. In order to obtain the modified formulae, a detailed derivation process has also been presented in this paper. Meanwhile, we have clarified the derivation process and application range of Pimshtein’s formulae and corrected the errors. We have also indicated the shortcomings of the formulae given by Huang, Chen and Lai, and the ASME code. Finally, a practical example is presented to show how the modified formulae are applied. Calculation results obtained from the modified formulae have been compared with those obtained by finite element method and above mentioned formulae; it shows that the results from the modified formulae are in accordance with finite element results. DOI: 10.1115/1.4001658

Failure analysis of a twin-screw pump shaft

A failure analysis was performed on a fractured twin‐screw pump shaft. Through the analysis of the macromorphology and microstructure of the fracture, the analysis of the chemical compositions of shaft material, the metallographic test of the specimens cut from the fracture, the investigation of the operating condition of the pump, the main reason for the fracture can be described as the increased rotating and bending load caused by low viscosity medium. Corresponding preventive measures were put forward.

Failure Analysis of Authentic Stainless Steel Tubes in a Vertical Fixed Shell–Tube Heat Exchanger

The vertical fixed shell–tube heat exchanger failed to work in one chemical plant, and the leakage of the heat exchanger tubes were found after the examination. To figure out the failure mechanism of the tubes, a series of investigations were performed including the specification verification, the visual examination, the analysis of the chemical composition, metallographic, scale layer composition, and the work fluid examination. The pits and cracks were observed on the tube end, which was welded to the upper sheet. It could be classified as the pitting corrosion and stress corrosion cracking of authentic stainless steel. Due to the substandard expansion process on the tube end, the crevices between the tube end and the upper tube sheet holes were not eliminated thoroughly. The high-temperature steam, mixed with the chloride ion and salts, entered into the crevices, and the chloride ion sufficiently gathered and absorbed on the surface of the tube end. Additionally, the stress was generated on the tube end from the operating pressure and welding process. The stress condition and high-temperature chloride condition on the tube end eventually led to the pitting corrosion and stress corrosion cracking.

A New Method to the Elastodynamic Response of a Spherical Shell Under the Impact Load

In this paper, a new methodology for solving response of a spherical shell based on developed solution structure theorem has been proposed. It can be used to solve the wave equation about the structural dynamic response of a spherical shell under the impact pressure. The proposed method can be used to solve a batch of partial differential equations having the similar governing equation with different initial and boundary conditions. A detailed solving procedure has been provided to show how to use this method correctly. Finally, a practical example is provided to show how to use the proposed method to solving the elastodynamic response of a spherical shell under inner impact load.