Abstract: In order to develop the green manufacturing and microfabrication, an innovative micro-electrochemical machining (ECM) method¬¬-the electrochemical machining in pure water was studied. On the base of experimentation principle, ECM set up was developed for engineering application. Water dissociation mechanism is found under the function of cation exchange membrane, and many factors to enhance current density were analyzed. As a result of technological test, a micro hole is machined in the thin stainless. It is confirmed that electrochemical machining technology is feasibility to make use of pure water as electrolyte.
Abstract: The objective of this research is to study the lubricating property of oil-air lubrication on sliding friction element. The performance of sliding friction element under different lubrication parameters and preloads were investigated by measuring the element’s temperature and friction coefficient. The results show that oil air lubrication could complete the lubrication and cooling of sliding friction element. As the oil supply is increased at the same load, speed and air supply level, the temperature rise and friction coefficient decrease, but when the oil supply is increased to 15ml/h, they remain unchanged. As the air supply is increased at the same load, speed and oil supply level, the temperature rise decreases monotonically and the friction coefficient remains steady.
Abstract: This paper presents a novel methodology for the construction of fault tree using rough set and clustering algorithm. Taking advantage of the strong ability of RS theory in processing large data and eliminating redundant information, this method can remove irrelevant factors from the original fault data and reduce the dimension of processing data which helps to overcome fuzzy clustering algorithm's defect when process large database. The method is introduced and explained in details and its correctness and completeness is validated by Fault tree construction of oil-immersed traction transformers.
Abstract: The impeller is the important pneumatic part of centrifugal fan, and its structure performances are key factors which affect the whole performances of fan. The CAD module of centrifugal fan can realize the automation of aerodynamic force calculation. According to demands, computer can automatically complete aerodynamic force calculation and further determine major geometric parameters of impeller of fan. Speed coefficient and diametral quotient are two important parameters reflecting the character of ventilating fan. The relation curve between the speed coefficient and diametral quotient of various fans is plotted in this paper. The CAD module of impeller of centrifugal fan can realize such functions as aerodynamic design and parameterization drawing of impeller, and can accomplish rapid response from receiving design parameters to profiled impeller of fan, so that it can improve the quality of drawing.
Abstract: In traditional semi-rigid analysis of extended end plate connections is assumed to be deterministic parameters, most of moment-rotation models of the joint is determined by curve-fitting and statistically regressed with the test data. Those parameters of the models have little physical meanings and the effect of correlations between parameters is neglected. This paper deals with a semi-rigid joint of extended end plate connections based on correlation and sensitivity analysis. A numerical study was carried out and the finite element analysis was validated compared with the experimental results.The relative moment-rotation model was concluded based on correlations in parameters and probabilistic sentivity analysis. The relationship between height and width of steel beam was partial correlation, the relationship between thickness of steel beam flange and thickness of steel beam web was partial correlation. Height and width of steel beam, the distance of upper bolts to axle wire of steel beam were important sensitive parameters for the extended end plate connections.
Abstract: In a direct-drive high-power A / C-axis bi-rotary milling head, torque is transferred by two parallel connected rotary direct drive motors in C-axis, therefore, the length of C axis is inevitable large, moreover, the transmission components of it are bearing high torque. The torsion deformation of C axis must compute accurately during the design process. The torsion deformation of the transmission components of C parts when C-axis is rotating is analyzed by finite element method, the racial deformation and the torsion deformation of the case when C-axis is locking are analyzed either, this computing can provide support for the design and improvement of this type of milling head.
Abstract: Based on viscoplastic Anand’s model, the structural stress of 8×8 InSb infrared focal plane array (IRFPA) detector is systemically analyzed by finite element method, and the impacts of design parameters including indium bump diameters, heights and InSb chip thicknesses on both von Mises stress and its distribution are discussed in this manuscript. Simulation results show that as the diameters of indium bump decreases from 36 μm to 24 μm in step of 2 μm, the maximum stress existing in InSb chip reduces first, increases then linearly with reduced indium bump diameters, and reaches minimum with indium bump diameter 30 μm, the stress distribution at the contacts areas is uniform and concentrated. Furthermore, the varied tendency has nothing to do with indium bump standoff height. With indium bump diameter 30 μm, as the thickness of InSb chip reduces from 21 μm to 9 μm in step of 3 μm, the varying tendency of the maximum stress value in InSb chip is just like the letter U, as the indium bump thickness decreases also from 21 μm to 6 μm in step of 3 μm, the maximum stress in 8×8 InSb IRPFA decreases from 260 MPa to 102 MPa, which is the smallest von Mises stress value obtained with the indium diameter 30 μm, thickness 9 μm and InSb thickness 12 μm.
Abstract: Two-step method is used to research stress and its distribution in 64×64 InSb infrared focal plane array (IRFPA) employing finite element method. First, a small 8×8 InSb IRFPA is systemically studied by varying indium bump diameters, standoff heights and InSb chip thicknesses in suitable range, with indium diameter 30μm, thickness 9μm and InSb thickness 12μm, von Mises stress in InSb chip is the smallest and its distribution is uniform at contacting areas. Then, the sizes of InSb IRFPA is doubled once again from 8×8 to 64×64 to learn the effect from chip sizes, thus, the stress and its distribution of 64×64 InSb IRFPA is obtained in a short time. Simulation results show that von Mises stress maximum in InSb chip almost increases linearly with array scale, yet von Mises stress maximum in Si ROIC decreases slightly with increased array sizes, and the largest von Mises stress is located in InSb chips. Besides, stress distribution on the bottom surface of InSb chip is radiating, and decreases from core to four corners, and stress value at contacting area is smaller than those on its surrounding areas, contrary to stress distribution on top surface of InSb chip.
Abstract: For the sake of improving the third dimension of 3D scenes, we analyze the existent real-time shadow generating algorithms, and improve the Chan’s smoothie soft shadow algorithm, make it based on shadow map, and treat with both the inner and outer penumbra. It not only effectively resolves the problems such as some algorithms can not cast shadow on itself and some are too complex, it also solves the aliasing problems of shadow mapping, and it meet the requirements of real-time in more complex scene. At last, the algorithm is emulated with DirectX, and the experimental results show the feasibility of the algorithm.
Abstract: Based on ships transaction in useful information personalization gain question, proposed that one kind the intelligent recommendation service model which unifies the ASP (Application Service Providers) pattern and the recommendation technology. In this model, the service uses five structures, the intelligence management transfer application service level and the resources component level, cooperates to realize the intelligence mutually. In view of the ships profession electronic commerce pattern's characteristic, the depth limited auto-adapted k close neighbor searching algorithm which uses transforms the user grading non-isotropic space as the isotropic space, obtains the isotropic grading matrix, thus searches the current user k recent neighbor, has current user's forecast grading, and has the recommendation. Has provided the simple direct-viewing practical commercial service for the ships manufacturing firm.