Advanced Materials Research Vol. 703

Abstract: For natural gas well, effect of flow velocity on corrosion in gas well tubing is an important factor of gas well life. In this paper, we mainly introduce corrosion problem of insufficient gas-flow velocity in tubing, multiphase flow erosion and corrosion, erosion and corrosion problem of in-tubing gas flow velocity higher than erosion flow velocity, application on selection and determination method of minimum tubing size avoiding erosion due to excessive flow velocity in gas well. For application, the technology above has a good practicality.

Abstract: The stress study and material analysis for well hole structure of nonstandard casing size series in oil and gas well is developed aimed at helping the oil and gas well production engineers to analyze and design in oil and gas well production. This paper presents the development background, hole structure of nonstandard casing size series, hole structure design of nonstandard casing size series for reducing the stress level, stress study, material analysis, steel grades of corrosion-resistant nonstandard casing and application. It will provide a useful tool for oil and gas well production engineers.

Abstract: This paper presents an approach for robot motion path planning in Cartesian space. The motion trajectories are specified by a group of parameter equations in Cartesian coordinates. The time interval [0, is divided into m segments, and the coefficients of polynomial at each segment can be obtained in recursive form. The problem of minimum-time path planning and the determination of m are also studied.

Abstract: By its application environments and structure features,the five key technology issues in foundation design of offshore wind turbines including structure mechanical mechanics analysis,foundation type selection,pile design,wave force calculation,structure fatigue analysis are discussed in this paper.The corresponding technical resolution and research methods are also provided.It is aimed to provide a useful reference for the foundation design of offshore wind turbines.

Abstract: Numerical simulation is an effective approach for identifying and analyzing elastic wavefields in subsurface. From the first-order stress-velocity elastic wave equations in VTI medium, this paper use high-order stagger-grid finite-difference scheme to compute 3C wavefields in 2D space, performing 2.5D simulation. A method of establishing geological model is presented. Boundary reflections are suppressed successfully by PML. Characteristics of synthetic data by this method are coincident with field data in both kinematics and dynamics

Abstract: Damping and denoising of diesel engine is on the premise that we acquire the accurate excitation source information, and the main bearing force is major excitation source of diesel engine body vibration. When crankshaft rotating, elements of the diesel engine colliding each other, which resulted in slight deformation of the element and complicated applied force one another. It is difficult to meet the needs of calculation accuracy in structural dynamics analysis method of classical mechanics and trail analysis method is infeasible, so many-body dynamics method was put forward, the method could increase efficiently calculation accuracy, and the diesel engine excitation source of vibration and noise could be accurate predicted.

Abstract: This study presents a first attempt to develop a numerical three-dimensional multilayered (more than 2 composite layered coatings) elasticperfectly plastic rough solids model to investigate the contact behavior under combined normal loading and tangential traction. Contact analyses are performed to study the effects composite thin film layers. Local contact pressure profiles, von Mises stresses, and shear stresses as a function of material properties and applied normal and tangential friction loads are calculated.

Abstract: According to the calculation of sealing pressure ratio in the ball valves seat sealing surface, Companies generally adopt the experience and the correction formula. The above methods can not reflect the real distribution of sealing pressure ratio in the ball valves seat sealing surface. Through the UG Nastran finite element analysis environment, This study simulates the actual working environment, precise Calculated the real distribution of Sealing pressure ratio, In order to improve the development speed and quality of enterprise's new product.

Abstract: In order to more effectively solve some difficult problems in gearbox failure diagnosis, a gearbox fault diagnosis method based on Relevance Vector Machine (RVM) is proposed. RVM is developed in Bayesian framework. It does not need to estimate the regularization parameter with less relevance vectors, and its kernel function does not need to satisfy Mercer condition. Simulation results show that: compared with the traditional BP neural network, RVM has the faster modeling speed, more accurate diagnosis, and is worthy of promotion and application in fault diagnosis of the gearbox.

Abstract: Friction and wear tester is an important device for detecting friction and wear properties of materials. There is inadequacy of research on friction and wear behavior of geological drilling mechanisms serving under complicated liquid circumstances like water, oil and mortar. This article describes an accessory mechanism for commonly used ball-on-disc tribometer which can be applicable in liquid medium. A new oil cup is designed and composed of oil cup sleeve, oil cup lid, transition station, worktable and etc. Interference connection is adopted between oil cup and rotary test bench of tester. Materials are chosen so as to meet requirement from actual working conditions and to simulate the friction and wear test in liquid medium. The mechanism designed share characters of convenient operation, in-situ observation and friendly environment.