Papers by Keyword: Curvature Radius

Abstract: TC4 titanium alloy plate was processed under multiple laser shocks and bending deformation was studied. A method was proposed to determine the curvature radius of bending deformation of metal plate under multiple laser shocks based on the theoretical model of curvature radius of bending deformation and the eigenstrain field was calculated by a modified finite element analysis method. Effect of shock wave peak pressure and the number of impacts on the curvature radius was studied. Results show that bending deformation increases rapidly at the beginning and then it stops growing. Bending deformation increases rapidly with the increase of the number of impacts and it cannot increase after three impacts.

Abstract: The oil industry has sought to minimize the environmental impact from mining activities and oil transportation. Oil transportation by pipelines is subject to failures and leaks which cause financial losses and environmental damage, often irreparable. Currently, the study of leaks in pipelines has attracted the attention of many researchers. The aim of this study is to evaluate the influence of the curved curvature radius connection in pipeline leakage. We used a mathematical model of multiphase flow to describe the two-phase flow, based on the particle model. Oil is the continuous phase while water a dispersed phase. To model this effect we used the turbulence model SST. All simulations were carried out using the Ansys CFX ® commercial code. Results of the total pressure and pressure drop are presented and discussed. The results confirm the influence of the bending radius of curved connection on the behavior of the total pressure and the total pressure drop in two-phase flow in pipelines with and without leakage.

Abstract: The paper presents the analysis of plastic indentations resulting after the impact between a steel ball and a disc made of mild steel, rotating about a vertical axis. The imprints are analysed using a laser scanner, the profiles of the mark, in normal and tangent section about the impact point radius, being relevant. It is shown that the use of parabolas is sufficient to approximate the profiles of the imprint. The profiles from the two sections are interpolated and then brought for comparison into the same coordinate system. Finally, the curvature radii of the profiles from the two sections are found and the remark that increasing the angular speed of the disc presents opposite effects to the curvature radius in the two sections.

Abstract: This paper presents a path-planning method of laser tool in 5-axis laser quenching for complicated surface. In this method, two main factors are concerned which include: (1) Planning the CC paths on the complicated surface quenched to maintaining laser tool scanning speed constant easily in quenching process; (2) Diminishing the chord deviation between the actual value and its approximation by choosing different interpolation methods according to the curvature radius of CC points which is being quenched. This method effectively ensures the part’s laser quenching quality.

Abstract: The effect of curvature radius on the mechanical properties of continuous rigid frame bridge with high pier and long span is studied in this paper. Taking the Wayaobao Bridge as the research object, the models including both of the linear rigid frame bridge and the different radius of curvature rigid frame bridge are established by using the finite element software MIDAS/Civil, and the mechanical properties of the finished stage are analyzed, and the influence of the radius of curvature on the deformation and internal force of continuous rigid frame bridge are researched. The alteration in curvature radius almost had no influence on the bridge vertical displacement, vertical bending moment. The tangential displacement gradually become smaller, but little change with the decrease of bridge’s curvature radius.The radial displacement, transverse bending moment, torque of the bridge increased with the decrease of bridge’s curvature radius.The force and deformation of the bridge structure are more unfavorable with the decrease of bridge's curvature radius. The study can provide some suggestions for design and construction control of curved frame bridge.

Abstract: Taking an engineering design case about a three-span uniform section continuous curved box-girders bridge of city viaduct,this paper sets up a finite element calculating model for the curved box-girders bridge by means of finite element analysis program ANSYS and researchs the influence of dynamic characteristic and seismic response on curved box-girders bridge with the different curvature radius under the same span. The analysis results show that in the same span of curved beam , the low-level frequency impact of changes in different curvature radius of the curved beam bridge is larger,the curvature radius is an importance parameter which influence on dynamic characteristic, and have significant influence on tangential stiffness、radial stiffness and seismic response of curved box-girders bridge.

Abstract: Many empirical formulas and diagrams have been employed to determine resistance coefficient of elbow/bend pipes. However, a big discrepancy of calculation results obtained from these formulas/diagrams exists. So it is difficult for users to choose an appropriate formula to calculate resistance coefficient of an elbow/bend pipe. In this paper, a comparison of several common formulas was made. And variations of resistance coefficient with both bend angle and curvature radius were graphically shown for reference of selection. In addition, flow characteristics in elbow pipe were analyzed.

Abstract: In order to obtain a linear explosively formed projectile (LEFP) with a good flying form under large stand-off, the LS-Dyna finite element analysis software and arbitrary Lagrangian - Eulerian (ALE) algorithm were used to simulate the forming process of LEFP with a 30mm charge structure diameter. On the basis of that, the only changed factor was the curvature radius of the liner which was selected as 0.65D, 0.75D, 0.85D, 1.0D and 1.1D for the simulation of LEFP forming progress. The warhead speed-time curves and fracture surfaces of the LEFP are analyzed, with liner radius decreasing, the projectiles become more slender, and instead, the larger radius liner forms flat and wide LEFP. Slender LEFP is conductive to penetration, however the over small radius which cause the reduction of weight and kinetic energy makes fracture easily, oversize radius influence either end of LEFP that warps upward seriously , what means speed grads of both ends differ greatly .The suitable radius ranges from 0.75D to 1.0D.

Abstract: In order to realize the detection of diffractive light after the image segmentation using cylinder grating, the parameters of a cylinder grating was optimized using the wave optics theory. By analyzing the relation of optical path length variation with the diffraction angle of single cylinder lens diffraction, and by Fraunhofer approximation, the analytical expressions of cylinder lens diffraction was given. By setting parameters to calculate and simulate, it was found that to increase the ratio of curvature radius and grating period could effectively reduce the spatial distribution of the diffraction light intensity. For the gratings that already exist, by reducing the ratio of refractive index of the gratings material and environment, the spatial light distribution of the grating could be reduced. If the cylinder grating period is too small, the overlap part of images segmentation light diffraction intensity will increase. But it occupies smaller proportion of the total light intensity. After the optimization design of cylinder grating, the results showed that it could be used for non-contact speed measurement in the range of some parameter.

Abstract: Adjustable form cubic interpolation spline curve, changing its form adjustment coefficient can adjust the curvature radius and shape. Using this spline curve can realize the high-speed smooth connecting between adjacent processing trajectory during NC movement. To internal outline corner transition, use cambered spline transfer curve; To external outline corner transition, can use cambered or toroidal spline transfer curve. During the corner transition process, keep the speed constant, adjust the curvature the curvature radius to control the value of acceleration. Corner smooth transition based on the interpolation spline, can effectively reduce the mutation of acceleration, improve processing efficiency, and weaken the impact to the machine tool.