Abstract: The oilfield need to calculate the packer’s displacement of separated zone water injection string. Analyzed the force of the separated zone water injection string, and established the physical model and mathematical model. Using the traditional boundary processing method of tubular mechanics to calculate the displacement of separated zone water injection string, discovered that the accuracy cannot meet the requirement of the oilfield. Therefore consider the influence of all packer’s frictional force on the water injection string’s stress condition, and propose a new method to deal with the boundary condition, compared the calculation results with magnetic location results, the calculation results can meet the accuracy requirements of oilfield.
Abstract: This paper analyzes the relationship between fuel rail pressure and fuel injection amount and presents a diagnosis algorithm for coherence of injection in cylinders based on the fuel rail pressure. A simplified model of common-rail fuel system in multi-cylinder diesel engine was built and basic analysis was completed based on this model. The analysis induced that the rail pressure drop dp/dt is mainly relevant with QInj. The experimental investigation of common-rail fuel system shows the pressure drop happens during the fuel injection period, which is induced by fuel injection. Both model analysis and experimental investigation show that the rail pressure may be used as the basis of diagnosis for coherence of fuel injection.
Abstract: This paper presents theoretical analysis, numeric calculation and experimental test for a cantilever beam subjected to a moving mass with clearance. Coupled transverse vibration equations of cantilever beam subjected to a moving rigid body with clearance were formulated by discretizing Euler beam based on assumption mode method. Numeric computation code was developed. A test bed for measuring joint clearance was constructed. Dynamic clearance tests were carried out under different work conditions. The accuracy of theoretical analysis was verified by comparison between experimental data and simulated results.
Abstract: The present structure crack analysis method simplifies the crack as type I crack, and put the stress intensity factor (SIF) mathematical expression of infinite plate under the bi-directional even stress load into Paris formula to analyse the fatigue life of crack components. Due to the finiteness and complexity of component shape and the nonuniformity of the stress distribution in the engineering practice, which makes the SIF value inaccuracy according to the present method, so that the result of crack fatigue life has a large error. Considering the shortcomings of the method, this paper offers a new method which is using the finite element method to calculate SIF in different crack length directly. By means of function fitting, this method determines the mathematical relation between SIF and the crack length and changes the form of Paris formula based on the relation. Furthermore, it can analyse the fatigue life of crack components and improve the analysis accuracy theoretically.
Abstract: Advanced water injection can keep a high level of formation pressure, reduce the damage of permeability caused by the drop of formation pressure, and improve the oil displacement efficiency. Through pressure sensitive experiment and Micro-CT scan method, this paper study the influence on rock parameters by formation pressure. The results show that permeability decreases greatly in depressurization development, the permeability restores a small degree after restoring pressure, the change of coordination number and pore throat radius is similar with permeability, and porosity is not sensitive to pressure. Through the research on the influence of oil displacement efficiency by drive pressure, the results show that advanced water injection can improve the oil phase relative permeability, the average increase rate is 5.02%, and also increase oil displacement efficiency, the increase rate is 1%. The core fluorescence images indicate that the remaining oil by advance water injection is obviously less than the conventional production.
Abstract: In order to increase surfactant compound system injection in low permeability reservoir of Chaoyanggou oilfield, we do research into formula of surfactant compound system according to reservoir condition. By contrasting to interfacial tension of different kinds of surfactants, we choose petroleum sulfonate surfactant T720-40# as main agent. As equilibrium interfacial tension of this surfactant cannot meet the requirements, so we add Na2CO3 as auxiliary agent to decrease interfacial tension. The results of laboratory experiment research show that equilibrium interfacial tension of this multiplex surfactant system can reach 2×10-2mN/m. It has good thermal endurance, salt resistance, and also has good compatibility with Chaoyanggou injection water and formation water. It can make rock wettability reverse, reduce threshold pressure and displacement pressure and it can improve recovery by 5% contrasting to water flooding.
Abstract: This paper presents the evaluation of the stress and strain response of the copper ball bond during wire bond shear test using finite element analysis. A 3D non-linear finite element model was developed for the simulation. The effects of the shear ram speed on the stress and strain response of the copper ball bond were investigated. A preliminary investigation confirms that shear ram speed has a significant effect on the von mises stress and equivalent strain response of the copper ball bond during wire bond shear test
Abstract: The work here investigates the height effect during a shearing process of a copper ball bond in a wire bond. Finite element analysis was used to investigate this analysis.The effects of the shear ram height on the stress and strain response of the copper ball bond were investigated. The results obtained hows there is a significant effect of the shear height to the Von Mises stress and equivalent strain response to the copper ball bond during the shearing simulation.
Abstract: Abrasive wear mechanism in HVOF sprayed near-nano and microstructured WC-17wt.%Co coatings was studied. The crack propagation mechanism shows that it propagates only through cobalt matrix in the case of near-nanostructured coatings while both trans-granular and intergranular crack propagation was observed in the microstructured coatings. SEM images show a relatively ductile failure mechanism in the near-nanostructured coating, while a brittle failure mechanism dominated in the microstructured coating. AFM images show that the worn surface is smooth in near-nanostructured coatings with an average roughness value of 19 nm, while the roughness on the microstructured coating worn surface was recorded at 83 nm. Further, the wear debris formed on the near-nanostructured coated surface was mostly spherical and finer, whereas this was irregular and coarser in the microstructured counterpart. The wear behaviour suggested a lower wear rate in the near-nanostructured coatings than the microstructured coating. This was further confirmed by abrasive wear tests results.
Abstract: The research on the analysis of cause and effect relationships in castings has always been a centre of attention in the manufacturing industry. An intelligent diagnosis system should be able to diagnose effectively the causal representation and also justify its diagnosis. Recently, a method, known as the Knowledge Hyper-surface method which used Lagrange Interpolation polynomials has gained more popularity in learning cause and effect analysis in casting processes. The current method show that the belief value of the occurrence of cause with respect to the change in the belief value in the occurrence of effect can be modelled by linear, quadratic or cubic relationships and the method retained the advantages of neural networks and overcomes their limitations in learning the input-output mapping function in the presence of noisy, limited and sparse data. However, the methodology was unable to model exponential increase/decrease in belief values in cause and effect relationships. This paper proposed an enhancement to the current Knowledge Hyper-surface method by introducing midpoints in the existing shape formulation which further constrains the shape of the Knowledge hyper-surfaces to model an exponential rise in belief values but without exposing the dataset to the limitations of ‘over fitting’. The ability of the proposed method to capture the exponential change in the belief variation of the cause when the belief in the effect is at its minimum is compared to the current method on real casting data.