Applied Mechanics and Materials Vols. 713-715

Abstract: According to the FLUENT simulation results of the 90°elbow pipe fluid flow condition, the influence of the pressure distribution about the variation of the flow parameters (v、P₀ 、ρ) and the geometric parameters (R、d、k=R/d、α、β) is analyzed. By using the dimensionless analysis method, on the basis of the influence of the 32 set of parameter variations on the elbow pipe wall pressure distribution regularity, the pressure qualitative function is established including the geometric parameters and the flow parameters. Through the 155 kinds of the FLUENT simulation results, the fitting software 1stOpt is used to verify the internal pressure model above and fit the undetermined coefficients. The verification shows that the model is of a higher calculation precision and the relative error isn’t exceeding 0.003%. It provides a theoretical basis to check the strength of the bend and design the pipeline with high pressure and speed.

Abstract: This paper proposes the dynamic design method and process of a CNC lathe-bed structure based on ansys. The lathe-bed is an important part of lathe. Structural natural frequency as the objective of optimization, with the element structure and frame structure optimization result as the basis, and with a vertical machining center lathe as an example, we put forward some improvement scheme of the bed structure, and makes a comparative analysis of each scheme.

Abstract: Air velocity in oven box is an important factor. The value of air velocity will affect the result of drying. This paper use the method of numerical simulation to research the effect of orifice plate on flow field and thermal environment in oven box. The results show the change rate of thermal environment & air flow field in oven box is depend on supply air volume, and the use of orifice plate will affect the flow field obviously.

Abstract: Exhaust emission regulations issued by International Maritime Organization (IMO) for marine diesel engines are given and formation mechanisms for several pollutant emissions are introduced. Main denitration and desulfuration technologies for reducing NOx and SOx emissions are seperately summarized. In addition, working mechanism of different emission control technologies and their applications on marine diesel engines are introduced. These different emission control technologies are analyzed by evaluating conversion efficiency, economy and practical performance, and existed problems and future technologies are given. A Combination of different denitration and desulfuration technologies is a inevitable trend for emission reduction of marine diesel engines.

Abstract: According to the mechanical characteristics of bending part casing in horizontal well, established the three-point bending casing mechanical model. By analyzing the stress distribution of casing under three-point bending, considering the effects of shear, extrusion, and bending, using the fourth strength theory and Lame formula, collapsing strength formula of bending part casing in horizontal wells under the three-point bending are derived. Effect of built-up rate on the casing collapsing strength was investigated and evaluated using analytical approach as well as FEM. The results show that built-up rate has a significant impact on casing collapsing strength, and collapsing strength of casing decreases significantly as the increasing of the built-up rate. When built-up rate is large, collapsing strength of thick-walled, large diameter casing decreases faster as the increasing of built-up rate; the casing with bigger wall thickness has bigger collapsing strength under the same borehole curvature and steel grade.

Abstract: This article mainly analyzes the bucket wheel stacker reclaimer slewing mechanism gear cracking. We put the flange as the research object. Through analysis of matrix composition and cracking gear macro fracture morphology, we can preliminarily determine the cracking mechanism and failure cause of the flange. Then, through the carrying capacity of gears calculation by the analytic method and the finite element method, we further identify the failure causes of the flange and put forward the reasonable and feasible solutions.

Abstract: One drill pipe’ tool joint fractured rarely after just servicing ten days in drilling process of one natural gas well. Failure reason of tool-joint pin was researched through visual inspection, mechanical properties testing and working condition analysis. Results show that fracture failure reason is mainly due to the dramatic friction between the tool joint and the accumulated debris during the drill-string’s rotating process. Accumulated debris blocked mud’s circulation channel and leaded to poor circulation. The dramatic friction between the tool joint and accumulated debris leaded tool joint’s local temperature to risen significantly, and reduced its carrying capacity. In the end, tool joint fractured under the effect of tensile and torsional loads.

Abstract: The Long girder end parts are one of the types structure in aerospace equipment, the complex structure parts, machining parts. Usually the parts be processed on the NC milling machine, through the analysis of processing craft, design a kind of quick change type, Multi-station clamp device, instead of processing the parts on the multi-axis nc machine tool; at the same time of guarantee machining accuracy, in order to improve the production efficiency and reduce the cost of production.

Abstract: Silicone oil fan clutch uses viscous shear force of silicone oil to transfer torque. Friction of silicone oil generates a lot of heat. Thermal analysis is an important link in the design and optimization of the clutch performance. The mathematical model of thermal analysis for silicone oil fan clutch is proposed. The analysis is focused on the advantages of thermal boundary layer FEA (nonlinear finite element analysis) method in the clutch thermal property. Comparing the calculated results with the experimental data, the feasibility and accuracy of the FEA method was confirmed. The main factors influencing on the thermal characteristics of silicone oil fan clutch are studied.

Abstract: A torsional dynamic model and testing model for planetary geared systems are established to study the effects on its vibration characteristics as substituting plastic gears for steel ones successively. The dynamic model is solved by using variable step Runge-Kutta method and the vibration testing experiments for four kinds of combined planetary geared systems are carried out under different rotation speed and load torque. The numerical and experimental results show that the high frequency spectra are suppressed effectively as substituting plastic gears for steel ones. The gear mesh dynamic load and vibration intensity caused by the meshing fundamental frequency and side-frequency reduce markedly when the plastic ring and planet gear substitute for steel ones together. The numerical simulations have a better consistency with the experimental results, which verifies the correctness of the conclusions.