Papers by Keyword: Piping

Abstract: In this paper, the author selected the optimal welding parameters, which allow to achieve a stable production of high-quality welded joints and gave the calculation method of welding parameters depending on the spatial position of the weld pool.

Abstract: The purpose of this paper is to present a new approach to finding a risk-informed safety factor for the “fail-safe” design of a high-consequence engineering system. The new approach is based on the assumption of a 99.99 % confidence level and a 99.99 % coverage, and the application of the classical theory of tolerance limits, error propagation, and a method of statistical model parameter estimation known as the bootstrap method. To illustrate this new approach, we first apply the methodology to the UTS data of six materials ranging from glass, ceramics, to a high-strength steel at both 20 C and 600 C, and then to the fatigue life estimation of a BK-7 glass using two available additional sets of laboratory test data. Significance and limitations of our new approach to the “fail-safe” UTS design and fatigue life prediction of an aging PVP or aircraft are presented and discussed.

Abstract: Only the preliminary stage of piping process can be simulated by current seepage-erosion coupled piping model. In order to enhance the simulation capability, a modified piping model is presented. Theory analysis shows that the governing equations of the modified piping model have significant advantages in practicality and solution accuracy. The solving process of the model is analyzed, with the result showing that the out-of-bounds appearance of the field variables is the major factor interrupting the solving process. Then a new solution technique called dynamic constraint is proposed, which can ensure the validity of field variables. Numerical example indicates that the new governing equations and dynamic constraint technique can enormously enhance the simulation capability of the model, and the piping process can be effectively simulated.

Abstract: Vibration protection of the piping in nuclear power plants (NPPs) is critical for safety operation of NPPs. In order to improve the anti-shock ability of pipes in NPPs, the application feasibility of the elastomer damper in piping protection is investigated. The numerical analysis and the shock test are utilized to compare performances between the elastomer damper and the hydraulic oil damper, which is widely utilized in NPPs currently. The comparison results prove that the recoil force of the elastomer damper to the system is smaller. Moreover, the shock mitigation process of the elastomer damper is more smoothly. Therefore, the performance characteristics of the elastomer damper can well meet the requirements of vibration protection for pipes in NPPs. It can be used in NPPs in the future.

Abstract: Excessive piping vibrations are a major cause of machinery downtime, leaks, fatigue failure, high noise, fires and explosions in refineries and petrochemical plants. In piping system, vibration excitation sources may come from mechanical sources, hydraulics sources or can be the combination of both. Low level vibration amplitude can be amplified when acoustic natural frequency of piping system coincide with the mechanical natural frequency of the piping system of which could lead to piping failure. To address these issues, several condition monitoring techniques to assess and detect excessive piping vibration is discussed in this paper.

Abstract: This paper describes the design and implementation of piping functionality for multi-process micro-kernel embedded operating system on ARM, including overview of message passing and piping, pipe creation, pipe accessing via message passing, and pipe termination. The ways to implement piping for micro-kernel or mono-kernel are markedly different and this paper focuses on the piping implementation for multi-process micro-kernel. At the final, the paper provides a demo example to show the effect of piping. Based on the piping functionality described in this paper, more powerful shell interpreter with piping function can be designed.

Abstract: This paper describes the design and implementation of piping functionality for ARM based multi-process mono-kernel embedded operating system, including overview of inter-process communication, key techniques of designing piping routines such as getting i-node for piping, creating pipe, reading and writing pipe, and terminating pipe, etc. At the final, the paper provides a demo example to show the effect. Based on the piping routines described in this paper, more powerful shell interpreter with redirecting and piping functionalities as well as other shell commands analogous to that of embedded Linux can be implemented.

Abstract: Show the layout of subsea manifold piping system, whose design base on the relevant parameters of the E oil and gas field in West Africa. The piping system adapt to the sea situation. The maximum stress of the piping system is within the allowable range under wind load, the pressure and temperature stress of circulating medium and wave load, even in the splash zone, and passed the stress test.

Abstract: The occurrence of underground piping is a pluralistic and complex problem. Due to the great difficulty of the 3D dynamic simulation of piping both by theoretical and numerical analysis, currently there is no satisfactory mathematical model and numerical analysis software for it. In order to simulate the piping development process of sluice or dike foundation, in this paper, the 3D steady-unsteady saturated-unsaturated FEM seepage simulation method is used, and the concepts of destroyed element and variable grid method are introduced. The destroyed elements are removed from the original grid during the iterative calculation process, and the corresponding procedure for the 3D steady-unsteady piping process of sluice foundation is designed. Using appropriate post-processing program, the whole piping development of a sluice foundation can be displayed. A piping test of a sluice foundation model is simulated by the method provided in this paper. For the comparison of the experimental result and the simulation result, they showed very good agreement, which can verify the correctness of the piping simulation and programming methods given in this paper.

Abstract: On the basis of presenting the piping and seepage detection by magnetic-electric prospecting method, the authors analyzed and testified validity of the method. According to calculated results, the magnitude of magnetic field of artificial current was smaller on section if electrodes and cables were set rationally. Usually, the magnetic field magnitude of piping had several times to more than decuple comparing with magnetic field of artificial current. So, the magnetic abnormity could be detected easily by high-precision magnetometers. At the same time, their curves’ characteristics were different evidently. The analysis result shows that the piping and seepage of dyke can be detected by combining method of direct current supplying and high-precision magnetic survey.