Advanced Materials Research Vols. 199-200

Abstract: Considering the differences of pressure and temperature along well depth, the distribution law of casing inner wall corrosion rate was calculated with the Norsok model. According to the measured pressure values, the law of well pressure changing with the time can be obtained with the empirical method or the derivative curve method. Then the changing laws of the corrosion rate and the thickness reduction of casing inner wall are derived during the casing service life. Finally, the time-varying characteristic of casing internal pressure strength influenced by corrosion is researched.

Abstract: Petrochemical pressure vessel equipment develops to be large-scale and super large-scale under extreme working conditions such as high temperature and high pressure, which puts forward new demands for the reliability of the pressure vessel. The present paper discusses the fatigue design theory of pressure vessels and analyzes the fatigue design methods of ASME, BS5500 and JB4732. Pressure vessel loads absorbed (pressure, temperature, earthquake, wind, snow, etc.) have significant stochastic dynamic characteristics and coupling characteristics. The random load of the current design is simplified, with a large safety factor in exchange for equipment safety. However, it is difficult to guarantee the rationality and accuracy of the result. With the development of data acquisition, processing and finite element technology, it is inevitable to be based on measured load spectrum and consider the coupling of the random loads to work out fatigue reliability design methods of pressure vessels.

Abstract: under entropy loss function, the E-Bayes estimation and empirical bayes estimation to the parameter of inverse Weibull distribution used conjugate prior are discussed. And we prove the empirical bayes estimation is asymptotically optimal. At last, the MSE of the estimations are compared based on Monte Carlo simulation study. According to these comparisons, it is suggested that the accuracy of E-Bayes estimation is close to the empirical bayes estimation.

Abstract: For structural reliability problems simultaneously involving random variables, interval variables and fuzzy variables, an iteration algorithm is proposed to deal with the propagation of uncertainties. Corresponding to assumed membership value in the membership level interval [0,1], the membership interval of fuzzy variables can be obtained. After the fuzzy variables and the interval variables’ effects on the extreme value of performance function are alternately and iteratively analyzed with the random variables’ effects on statistical properties of the performance function, converged design point can be calculated, and the reliability can be as well calculated by the fourth moment algorithm based on the point estimate method. Finally the membership function of the reliability can be solved. Owing to the faster convergence of the iteration algorithm, the efficiency of the proposed algorithm is highly improved compared to the conventional numerical simulation method. And the adoption of fourth moment method proves much better in accuracy than only applying first order reliability method in the iteration algorithm. After the basic concept and process of the proposed algorithm is detailed, several numerical and engineering examples are studied to demonstrate its advantage both in efficiency and accuracy.

Abstract: In anhydrous dyeing research process, a set of self-developed supercritical CO₂ fluid dyeing equipment was manufactured. With computer control system, temperature and pressure was controlled accurately in dyeing process. As key components of the supercritical dyeing equipment, the coloring matter kettle and the segregator had a close relationship with the dyeing process. The finite element analysis software ANSYS was used to analyze the static stress of supercritical dyeing equipment. The model of the coloring matter kettle and the segregator were established, and the static stress analysis result of the coloring matter kettle and the segregator were obtained. These models not only confirmed the safety of the dyeing equipment, but also offered related parameters and provided the methods for improving the efficiency of dyeing equipment design.

Abstract: The high pressure common rail injection System is one of the most advanced technologies for the diesel engine to reduce fuel consumption exhaust emissions. While the design of the high pressure common rail injector is the key for the whole system. Considering that the working pressure of fuel in the injector, a more accurate injector body model was established with the modeling software Pro/Engineer in this study. Finite element analysis technology in Ansys software was applied to calculate the strength of injector body of the high pressure common rail system under different injection pressures. And then the rationality of structure parameters and material selection of the injector body can be analyzed and verified. The research conclusions can provide the theoretical basis for the optimization design of the injector.

Abstract: In this paper an attempt has been made to identify certain useful parts that will assist to consider reliability during conceptual design phase. The aim is to provide some thoughts and a toolkit for addressing reliability during the early stages of design, influencing design decisions and product reliability, and reducing the relying on the reliability prediction and expensive experiments in later design stage. Therefore high reliability can be cost-effectively achieved.

Abstract: When assessing the reliability parameters, the traditional method is to deal with a large quantity of data obtained through test and to get the result with high confidence. But small sample size and the lack of test data of mechanical items make the traditional method have weakness. If the Bayesian method can be used properly, accurate assessment will be derived even if it is lack of data. What is discussed in this paper are: 1) determination of prior distribution, 2) reliability assessment based on pass/fail data with Beta distribution, Gamma distribution and cut-tail normal distribution as prior distribution, and 3) reliability assessment based on time-to-failure with Weibull distribution and normal distribution as prior distribution.

Abstract: Application of a variety of software construct co-simulation environment, establishment of model of thin seam shearer cutting unit rigid-flexible coupling multimode system, do correctness verification to model from speed characteristics and mechanical properties. Simulation by loading, get characteristics of principal stress and weak links of key parts. Compared to the prototype model simulation under multi-condition, got the best traction speed of shearer when working in a particular coal seam. Axis of the planet given to different materials to comparative simulation and comprehensive analysis, given the best materials of planetary shaft should be selected, improved the reliability of planetary axis under poor conditions.

Abstract: In this paper, the overall design of magnetic levitated thrust bearing experiment table was completed, of which the main experimental parameters those are electromagnetic parameters and structural dimensions were determined, in addition, the joint debugging and deformation measurement are performed. Analysis results showed that theoretical value, ANSYS simulation results and experimental results were similar, which said that it is feasible to perform stiffness check of the thrust collar on the experiment table.