Papers by Keyword: Groove

Abstract: Improving the tribological properties of Inconel 625 is of great significance for its application in slewing bearing and bearing parts of mechanical transmission system in nuclear power plants. In this study, the tribological properties of textured surface (GTSs) and smooth surface (SS-20) of Inconel 625 under different loads during dry sliding friction were researched. The results show that GTSs improves tribological properties of Inconel 625 obviously. The friction coefficient of GTSs is lower than that of SS-20. The grooves on GTSs play a role in capturing wear debris during the friction process, which improve the contact surface characteristics between counterpart ball and substrate, leading to the reduction in wear loss. When the load is 20 N, the Inconel 625 with textured surface has the best tribological performance. The excessive load will cause the big deformation of material and decrease the capacity of capturing wear debris of grooves, resulting in the accumulation of debris and the severe wear of wear track.

Abstract: The article discusses the technologies used in the manufacture of liquid rocket engines filter elements. The analysis of the most widely used methods in the aerospace industry for obtaining grooves and holes in metal filters is carried out, as well as progressive methods for their production are proposed. Special means of technological equipment for the fine filter elements manufacture using electroerosion treatment have been developed.

Abstract: A universal geometric model of the deformation zone during rolling of a "random shape" workpiece in a two-roll groove of a "random shape" is considered in this paper. The level of simplicity of the model should provide, on the one hand, a sufficiently detailed and accurate description of the deformation zone geometry and, on the other hand, ensure the possibility of implementing "fast" algorithms for calculating the necessary characteristics of the rolling process.

Abstract: Rocket motors are used worldwide in both upper and booster stages.Solid rockets can provide high thrust for relatively low cost. Considering the large size of solid motors, these motors are to be designed as segmented motor cases. Segmented motor cases have to be joined by segment joint. Segment joint with tongue and groove configuration provides performance reliability in effective sealing of joints. A tongue-and-groove arrangement employs a pressure-energized metal seal which expands radially when the cylinders are internally pressurized. The radial expansion enhances the sealing effect of the metal seal between the tongue and the groove. Metal end rings welded to the shell motor cases and shear pins for the final assembly provides the sealing. The load sharing among the pins depends on the presence of the slit in a ring, whole & pin dimensional clearances, internal pressure and friction between the metal end rings. Structural analysis of a discontinuous metallic segment ring and shear pins iscarried out in this study. Structural analysis is based on detailed solid model for the segment joint. The load augmentation in the shear pin near the discontinuity is worked out based on a load augmentation factor derived out of FE analysis. The study further extended to a deviation in a nearby hole / pin combination at the vicinity of the discontinuity and is presented in this paper.

Abstract: The existing end mill is hard to balance the tool rigidity, heat dissipation and chip evacuation. In this study, the geometries of groove and micro-blade of the end mill machining titanium are optimized, through imitating the corn leaf’s tooth based on bionics. The peripheral cutting edge is composed of linear first rake, parabolic second rake and rear face. The chip-hold groove is composed of parabolic main groove and cubic curve vice groove. The cutting process of straight tooth and designed composite tooth are simulated by constructing the two-dimensional orthogonal cutting model using ABAQUS. The results show that: compared to the straight tooth, the designed composite tooth inhibits the generation of serrated chip, and the fluctuations of cutting force are smaller, the squeezing effect on the machined surface is weaker.

Abstract: Fine micro grooves of various depths and pitches were fabricated on brass surface by ultraprecision micro cutting, and the effects of groove geometry and orientation on surface wettability were investigated. Results showed that the contact angle of a liquid drop changes significantly with the depth and orientation of the grooves. By optimizing the grooving conditions, the contact angle was increased to about twice that of a flat surface. Effects of crystal grain boundaries in the workpiece material and effects of cutting conditions on burr formation during micro grooving were studied by both experiments and finite element simulation.

Abstract: The research focused on the finite element simulation of the surface residual stress and took an experiment to get cutting temperature and cutting force by changing different groove and coated tools. Then it analyzed the influence of cutting and tool parameters on cutting force and temperature. Finally, the results reached a conclusion about the way that the tools with different groove and coating influenced the residual stress. The coated tools reduced the residual tensile stress in the machined surface. The axial and tangential residual stress was tensile stress and the tangential residual stress was larger than the axial in machining.

Abstract: In general, when evaluating the effect of a sedan vehicle’s tire tread pattern design on the noise generated, the noise is measured by first carving the tires and then using expensive laboratory equipment to perform the measurements. The advantages of using this method are that the experimental results and the noise level produced from the tires (that go into mass production) feature minimal differences and that reliable tested data are produced. The disadvantages of this method are that molds must be created to produce slicks, and that substantial time is invested in the process of artificial carving and performing subsequent experiments, all of which increase the tire development time and cost. Therefore, the effect of a sedan vehicle’s tire tread pattern design on rolling noise was predicted in this study by employing the numerical calculation methods used in calculating fluid mechanics. The experimental results obtained by the Automotive Research & Testing Center (ARTC) were used to test the improved tread pattern designs to validate the reliability of the method proposed in this study and that the tire development time can be effectively shortened

Abstract: This paper studied the methane/moist air combustion characteristics in smooth microtube and microtubes with five different shape grooves and proposed the microtube groove dimensionless shape factor F=4πS/L2. The results show that the appearance of five grooves make combustion components and velocity occur jumping change and the vortex flow appears. The highest methane conversion rate is for the microtube with triangle grooves, which also indicates that the smaller shape factor is more in favor of methane conversion.

Abstract: Contact width is important design parameter for optimizing design of new metal gasket. The contact width was found have relationship with helium leak quantity. Increasing axial force, the contact width will increase and helium leakage will decrease. This study we conducted the surface roughness evaluation of 25A-size metal gasket before and after use. The results denote the real contact width after contact with flange having different surface roughness. The real contact width for the flange having smoother surface roughness is wider than the rougher one.