Advanced Materials Research Vols. 503-504

Abstract: Along with the wide application of pressure energy, large scale reciprocating compressor unit is becoming one of the necessary key equipments in petrochemical industry. The reciprocating compressor has complicated structure and it is very difficult to carry out measurement & analysis to the operation status of various components. Above all, as the most important fastener of the compressor, once fracture of cylinder head bolt of the reciprocating compressor occurs, major disaster will occur. Metal magnetic memory testing technology is a nondestructive examination technology based on magneto-mechanical effect principle. Specific change of leakage magnetic field will occur in stress & deformation concentrated region under combined action of alternate work load and geomagnetic field, macroscopic cracking can be detected and stress concentration and early state damage can be evaluated by utilizing this specific change, We carried out on-site examination on the fractured bolt of cylinder head of hydrogen gas compressor unit in refinery of certain petrochemical corporation with latest metal magnetic memory testing technology. On the basis of intensity analysis and dynamic load calculation to cylinder head bolt of the reciprocating compressor, we analyzed the cause of bolt fracture by using metal magnetic memory testing technology and drew out the magnetic memory signal distribution characteristics of the bolt and its fracture. We verified the correctness of testing result of the metal magnetic memory technology on cylinder head bolt and its fracture with metallographic examination technology; furthermore, we studied the reliability of bolt fatigue crack & fracture analysis and investigation of accident cause by using magnetic memory characteristic distribution signal.

Abstract: It presents the design of overtravel protection device for engine lathe C6140.When the cross slide runs to the limit position,the stop dog touches the contact blade of limit switch, which cuts off the power supply of machine and provides protection for lathe.The experiment proved that the device is reliable.

Abstract: carbonation rate of concrete structures are influenced by CO2 emissions and climate conditions. Carbonation depth prediction model was proposed and CO2 emission scenarios influence on concrete structures' carbonation damage was studied. As there are significant uncertainty and variability of CO2 emissions, deterioration mechanisms, material properties, dimensions and environments, the time-dependent structural reliability analysis was employed to predict the probability of corrosion initiation from 2000 to 2100, considering several IPCC future atmospheric CO2 emission scenarios. Results show:(1)carbonation depth in A1F1 and A1B scenarios is 36% higher than that invariant CO2 concentration, and A1B scenarios is 21%; (2)The corrosion initiation probability of RC structures in A1F1 and A1B scenarios are 84% and 67% higher than that invariant CO2 concentration , respectively.

Abstract: In this paper, the shear force in the shearing process of the drum type linear blade flying shear is done. Two different approaches were taken to establish the shear force formula, and then the finite element simulation. The comparison results of the calculated values and simulated values can be seen that as the thickness increases, the maximum shear force calculated by the pure shear force formula increases rapidly, the shear force calculated by the energy release rate formula is relatively small, and the finite element simulation values and calculated values close to each other when the plate thickness is small. The derived formula in this paper not only can be applied to complex engineering problems, but also has provided a theoretical basis for drum type linear blade flying shears on the shear force calculations and equipment design.

Abstract: To know the stress distribution of tubing connections with varied inner pressures for further understanding of the influence of pressures to the connection and seal ability, finite element model of API tubing connection was established and the Von Mises stresses and contact pressures of tubing connection was analyze by full make-up torque and varied inner pressures with nonlinear finite element method. It was found that the contact pressures and stresses on engagement threads may be increased with limited inner pressure. Meanwhile, stresses of engagement threads on both ends increased more sharply than others. And plastic deformation even breakage of engagement threads may occur if the inner pressure exceeds 70MPa

Abstract: Compared with the traditional mechanical gear, permanent magnetic gear has some unique advantages, such as high efficiency, noise free, zero friction, and overload protection and so on. However, its applications are always constrained due to its unstable or not smooth torque produced by this kind of magnetic gear. Based on the structure of the magnetic gear, this paper introduces a coaxial magnetic gear with a double-layer structure composition, which could provide the higher and stable or smooth torque.

Abstract: To establish a CFD model of far infrared tunnel, get numerical simulation dates of far infrared tunnel by using Fluent soft, compared with experimental dates. The results show that the numerical simulation can attend the temperature distribution inside the tunnel, Simulated and experimental temperature curve trend of the measured data.

Abstract: Introduces the general twist drill analysis, Through the continuous experiment and practice, obtained some processing key question method. As a result of small and deep hole parts of the scene processing efficiency is low, the improper selection of cutting quantity will cause premature wear of cutting tool. The traditional method is the empirical method and experimental method to solve the waste of material and time comparison. This article mainly is the finite element analysis software, the analysis of the ordinary drill thermal stress, transient dynamics, to solve the optimization of cutting parameters before processing, improve processing efficiency, save cost.

Abstract: Structure design and material selection of weapons is the key of the weapon design. The dynamic strength are studied of the weapon’s key parts by finite element simulation in Elastic plastic mechanics. The results show that the body can withstand the maximum pressure, and the simulating results are well coincident with the experiment ones, which confirms the reliability and availability of the virtual prototype model advanced here. Current research work will be helpful in further this kind of designers to select material and the frame optimization design.

Abstract: The Normal clearance magnitude of the shroud in the engine cooling pump influences greatly on the performance of the pump. As yet there has been no any appropriate theory on it. The dimension of the clearance is now designed depending on plentiful experiments which may consume a great deal of manpower, materials and funds. The boundary-layers in shroud clearance of impeller can be considered as 3D symmetrical and rotational boundary layers which can be converted into 2D boundary by coordinate conversion. Then the Boundary-layers thickness in clearance can be calculated by the more mature method of computing 2D boundary-layers thickness. This method first breached conventional experiment way in determine the shroud clearance magnitude and supplied scientific theory to the engineering design. As a result, this method can save many of all kinds of the industrial resources, and give the more precise scientific reference to relative research about pump.