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Sui R.,Shandong University | Sui R.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | Sui R.,Shandong Agriculture and Engineering College | Wang W.,Shandong University | And 5 more authors.
Engineering Failure Analysis | Year: 2014

Leakage at the tube-to-tubesheet joints occurred in a waste heat boiler. The mode and the root cause of the failure were investigated by chemical composition analysis of the tube material, metallographic structure and crack observation, and corrosion product analysis of the damaged tubes, as well as the operation condition examination of the waste heat boiler. Results revealed that failure of the tubes occurred due to the stress corrosion cracking (SCC), which was caused by tensile stress and chloride-buildup in the narrow and long gap between the tube and tubesheet hole. The gap formation was further analyzed by comparison of the minimum expansion pressure from the common formula provided by the manufacturer, with that from finite element method computations. It is found that the minimum expansion pressure used in manufacture is small and cannot eliminate the initial gap. Meanwhile, the enrichment of chloride in the gap was briefly discussed. © 2014 Elsevier Ltd.


Zhang M.,Shandong University | Zhang M.,University of Jinan | Zhang M.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | Wang W.,Shandong University | And 7 more authors.
International Journal of Fatigue | Year: 2016

The fatigue properties of FV520B-I welding seams with different surface roughnesses up to 109 cycles were tested, and the fatigue behavior and mechanism in a very high cycle regime were studied. The test results showed that FV520B-I smooth welding seams had obvious characteristics of very high cycle fatigue, and cracks mainly initiated from the subsurface when the fatigue life was higher than 107 cycles. As the surface roughness increased to Ra ≈ 0.6, the S-N curve moved downward and cracks usually initiated from the surface. The surface roughness had no effects on the initiation mechanism of subsurface cracks in the welding seam. The initiation modes of cracks in FV520B-I welding seams were more than those of cracks in FV520B-I. The GBF formation mechanism of "dispersive decohesion of spherical carbide" was supported, and the possible crack growth in the GBF was analyzed according to the "effective short fatigue crack criterion". The relationships of a very high cycle fatigue life and sizes of characteristic areas of fractures were further analyzed. The fatigue life increased with a decrease of inclusion diameter and an increase of the ratio of the GBF diameter to the inclusion (pore) diameter. © 2016 Elsevier Ltd. All rights reserved.


Yang Y.,Shandong University | Yang Y.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | Wang W.Q.,Shandong University | Wang W.Q.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | And 2 more authors.
Procedia Engineering | Year: 2015

With the development of petroleum, chemical and energy industries and urban gas network, the amount of pipelines in China has grown rapidly in recent years, meanwhile it leads more accidents. The main reason is that some pipelines have gradually served into their late period or even extend period of the pipeline design or expect life. However, we usually cannot use conventional destructive test methods to measure the performance of pipelines in service, so that we cannot make an accurate assessment of the remaining life of the pipelines. This brings serious challenge to the safety management of pipeline transportation in China. In order to investigate a new method to non-destructively test the mechanical properties of pipe steels, the yield strength and tensile strength of pipe steels including low carbon pipe steels 20, the low carbon micro-alloyed pipe steel L415, L360, and stainless pipe steels used in China were measured through the methods of continuous ball indentation test and conventional tensile test in this paper. The measured results by the destructive and non-destructive test methods were compared and analyzed in detail in this paper. It is concluded that the continuous ball indentation test method can be used to measure the yield strength and tensile strength of pipe steels feasibly and accurately. © 2015 The Authors.


Zhang M.,Shandong University | Zhang M.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | Wang W.,Shandong University | Wang W.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | And 6 more authors.
Strength, Fracture and Complexity | Year: 2015

High cycle fatigue (HCF) and very high cycle fatigue (VHCF) induced by wake flow and other causes are the main failure modes of impellers which are the key component of centrifugal compressors. Research on the fatigue behavior and mechanism of impeller material in the VHCF regime is beneficial to fatigue design and the remanufacturing of impellers, and it also has important significance to ensure a long operation life of centrifugal compressors. OBJECTIVE: The VHCF behavior and mechanism of impeller material FV520B has been studied. METHODS: Fatigue tests were conducted on a Shimadzu USF-2000 at a resonance frequency of 20 kHz and room temperature in air ambient. The fractures were observed by SEM. RESULTS: For FV520B-I, the S-N curve continuously declined, and there was no fatigue limit. Most of cracks initiated from subsurface inclusions in the VHCF regime. For FV520B-S, the S-N curve was far below that of FV520B-I, and there was a conventional fatigue limit. CONCLUSIONS: The fatigue behavior and mechanism of FV520B-I and FV520B-S are very different and determined by heat treatments. Prediction of the fatigue life in the VHCF regime according to the Paris law is not ideal. A new method for prediction of the fatigue life in the VHCF regime should be developed. © 2015 IOS Press and the authors.


Xu S.,China University of Petroleum - East China | Xu S.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | Wang W.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | Wang W.,Shandong University | And 2 more authors.
Journal of Pressure Vessel Technology, Transactions of the ASME | Year: 2012

In this paper, a modified weld structure of the layered urea reactor has been provided. In the modified structure, new circumferential weld can improve the stress status of the urea reactor. It has the both advantage of separated and integrated layered pressure vessel. This modified design is based on the stress status analysis and the requirement of leak detection. In order to evaluate the modified structure, stresses of original and modified urea reactor shell with interlayer gaps were calculated via Finite element software ANSYS 12.0. The calculation result shows that the maximum stress of the modified structure is reduced obviously in the same condition, and the leak of liner also can be detected effectively. © 2012 American Society of Mechanical Engineers.


Xu S.,China University of Petroleum - East China | Xu S.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | Wang W.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | Wang W.,Shandong University
Journal of Pressure Vessel Technology, Transactions of the ASME | Year: 2012

In this paper, the formulae for elastoplastic stress distribution in layered cylindrical vessel layers with gaps have been provided. These formulae are based on the modified Pimshtein formulae for the elastic stress of layers. Plane strain with ideal elastoplastic model of materials is adopted. A practice example is presented to show how the formulae can be used for elastoplastic stress calculation. The hoop, radial, axial, and Von Mises equivalent stresses are obtained. The calculation result showed that the stress state of layered cylindrical vessel is more complex than that of monobloc cylindrical shell due to the interlayer gaps. The stress distribution is discontinuous. Calculation results obtained theoretically were compared to those obtained by finite element method (FEM). It shows that the results from the proposed formulae are in good agreement with finite element results. © 2012 American Society of Mechanical Engineers.


Zhang T.R.,Shandong University | Zhang T.R.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | Wang W.Q.,Shandong University | Wang W.Q.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | And 2 more authors.
Procedia Engineering | Year: 2015

A hot pure water storage container made by an equipment manufacturing company in Jinan, Shandong for a chemical company in Dezhou, Shandong spilled during its operation. By analyzing the chemical composition and metallographic structure of the sending sample and observing the crack morphology, we find it being the typical stress corrosion cracking of stainless steel in medium with chloride ion, which caused the leaking of this hot pure water storage container. Based on this, further analysis shows the concentration of chloride ion in hot water and the improper selection of hot pure water storage container's material, as well as the residual stress after cold working are the main causes of the stress corrosion cracking in this hot pure water storage container. The work presented in this paper may provide an approach to prevent similar accidents. © 2015 The Authors.


Sui R.J.,Shandong University | Sui R.J.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | Wang W.Q.,Shandong University | Wang W.Q.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | And 2 more authors.
Procedia Engineering | Year: 2015

The influence and mechanism of microscopic pit initiation on austenitic stainless steels were analyzed. Based on the electrochemical theory, a model was proposed to judge the pit initiation on austenitic stainless steels in the weak acidic chloride solution. Although the model was developed based on deterministic equations, it can be used to analyze the randomness of pit initiation. Furthermore the probability distribution of major parameters was also discussed. This study enriches the stochastic theory of pit initiation. © 2015 The Authors.


Chang F.,Shandong University | Chang F.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | Wang W.Q.,Shandong University | Wang W.Q.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | And 2 more authors.
Procedia Engineering | Year: 2015

Efficiency has been sacrificed in existing tools for the implementation of new Isogeometric Analysis (IGA) methods. As widely applied in the fields of science and engineering calculation, Fortran with inherent superiority in easy accessibility and computational efficiency is intended to optimize the issue. The Fortran programming in this paper mainly based on Non-Uniform Rational B-Splines (NURBS) is implemented in modularization, while being flexible to be transplanted, modified and extended. Two Kirchhoff-Love shell examples with small deformation are given in order to verify the accuracy of the implementation in comparison with the theoretical solutions and the efficiency which is tested in contrast to a Matlab software used for IGA. © 2015 The Authors.


Sui R.,Shandong University | Sui R.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | Wang W.,Shandong University | Wang W.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | And 4 more authors.
International Journal of Pressure Vessels and Piping | Year: 2016

The minimum hydraulic expansion pressure for the tube and tubesheet hole is calculated using the common theoretical formula and the finite element method. The effects of the tube and tubesheet hole dimensional deviations on the minimum hydraulic expansion pressure are analyzed. The minimum hydraulic expansion pressure obtained from the theoretical formula cannot guarantee a fit between the tube and tubesheet hole because the effects of dimensional deviations are not taken into account. Even if the dimensional deviations are taken into the formula, the correct pressure values cannot be obtained. Finite element analysis show that the deviations of the tubesheet hole diameter and tube outer diameter, the initial radial gaps, have significant effects on the minimum hydraulic expansion pressure. At the same time, the wall thickness deviation has a linear effect. By fitting the finite element analysis results, a correction coefficient of the theoretical formula is proposed. © 2016 Elsevier Ltd.

Loading Engineering and Technology Research Center for Special Equipment Safety of Shandong Province collaborators
Loading Engineering and Technology Research Center for Special Equipment Safety of Shandong Province collaborators