Papers by Keyword: Force

Abstract: The design and mechanical analysis of fracturing string was one of the key technical problems in fracturing operation. Considering contact friction and curvature effect, contact nonlinear problem of fracturing string was solved by space beam element and multidirectional contact gap element method. Contact state, contact reaction force and corresponding frictional resistance between the fracturing string and borehole or inside casing wall could be accurately described by gap element, which generated less simplification in the mechanical model and more precise calculation of force and deformation. The calculations of field examples has shown that while the distance is 10 m, 20 m or 30 m between two packers of fracturing string, maximum axial sliding displacement of the first packer is 0.19 mm and sliding displacement of the second packer is 11.17mm, 23.78mm , or 36.46 mm. The theory basis is provided for the decision of reasonable distance between two packers.

Abstract: Based on nonlinear FEA software ANSYS, thirty-six numerical simulation tower-models that have different initial bend state, bend deflection and intersegment of main-rod were established. Analysis results indicate: Initial bend state of main-rod has influence to force of horizontal auxiliary-rod greatly. With increasing initial bend deflection of main-rod, force of each horizontal auxiliary-rod presents to enlarge trend and is unequal. Force of each horizontal auxiliary-rod is less than 0.015 times endogen force of main-rod, total of each force for horizontal auxiliary-rod is less than 0.06 times endogen force of main-rod. With increasing intersegment of main-rod, total of each force for horizontal auxiliary-rod presents to enlarge trend.

Abstract: Time-domain expressions of nominal component and eccentric component that composing horizontal peripheral milling force are derived from geometry of down milling, they are periodic functions with fundamental frequencies same as tooth-frequency and spindle-frequency respectively. By expanding these two time-domain expressions with Taylor series, the frequency-domain description of periheral milling force is obtained. Further mathematical reasoning is exerted on this frequency-domain description, and it proved that as for four-tooth end mills, even-order harmonics of eccentric milling force do not exist, and the amplitude of spindle-frequency component be linear with eccentric distance, but irrelevant with eccentric angle. Above research results imply that the tooth-frequency component of four-tooth end mills is irrelevant with eccentricity, and that eccentric distance can be estimated with amplitudes of tooth-frequency and spindle-frequency components. Results of milling experiment imply that this eccentric-distance estimating method be effective. Spectral characteristics of eccentric milling force for four-tooth end mills are revealed with theory deduction, and the estimation algorithm for eccentric distance with simple calculation is present. Study conclusions can be used in eccentric-geometry estimating and in milling-force modeling.

Abstract: To investigate the characteristics of material removal mechanism in the continuous contour control grinding. It is simplified as a variable speed single grit scratching the surface of quench hardening AISI 5140 steel. Utilizing optical microscope, optical profiling system and displacement transducers, the scratch morphology and force were analyzed with applied normal load (depth) and scratch separation distance. Piles-up at the sides of the groove is no obvious change with traverse speed pulse. Both the normal force and the tangential force increase with an increase in traverse speed and depth. The change of traverse speed leads to force fluctuating, and then the forces fall down rapidly to a constant value relatively.

Abstract: This research studies the displacement on the windings of transformer due to multiple short-circuit forces. The power transformer winding deformations cumulative impact of multiple short-circuits are studied. the cumulative impact of multiple short-circuit deformation of laminated cylindrical shell with stiffeners model is established, the impact of accumulated deformation of multiple short-circuit of transformer winding is calculated with large deformation elastic-plastic theory , the text introduced by the theoretical formula for power transformer windings of the elastic-plastic deformation analysis of and winding to determine the stability have great significance, To verify the computation results, they are compared with those obtained using ANSYS software simulation.

Abstract: A test method for riveting assembly force, used in hub bearing unit assembly, was present in this study. Based on the test results, the influences of motion trajectory of rivet head, structure of rivet machine and feed rate of rivet head on axial force were analyzed. The corresponding improvement measures were proposed.

Abstract: Friction Stir welding has been attempted to study the feasibility of FSW between aluminium sheet (AA 6061) of 2 mm thick and Zinc coated steel (HIF-GA) sheet of 1 mm thick in lap joint configuration. The interfacial area of dissimilar welds has been analyzed by XRD, EPMA,TEM with EDS and nano indentation technique to identify the IMC distribution pattern depending on the combined effect of rotational speed and travel speed as well as the effect of energy and thermal cycle. The average joint strength is significantly influenced by the thermal cycle, respective torque and combined effect of rotational speed and travel speed as well as energy input. Improved joint strength between Al and coated steel could be obtained within a combination of rotational speed and travel speed as well as energy input. Force and torque response during FSW have been analyzed in terms of parameter optimization and joint performance.

Abstract: The far-flung ocean has abundant resource and the exploitation area of ocean oil and gas is developing from offshore to deepwater and ultra-deepwater following the increase demand for oil and gas resource. Therefore, one of the floating structures for deepwater exploitation is FPSO. The yaw of FPSO is more important problem to solve. This paper use Hydrostar to compute the RAOs, 1st-order and 2nd-order force of FPSO. A comprehensive review is introduced about the research on FPSO hydrodynamic in the world, including the coupling hydrodynamic analysis of deepwater FPSO with the mooring system. The results indicate that the FPSO’s 1st-order force and moment is a little large, however, the RAOs and 2nd-order force and moment are good. The FPSO with single point mooring system can control the displacement of FPSO effectively.

Abstract: A CAD variation geometry approach and force/torque balance equations are proposed for simulation of the accurate active force and passive force of a 3-dof 3UPU-Ⅱspatial parallel manipulator. First, an initial simulation mechanism of the 3UPU-Ⅱspatial parallel manipulator is created. Second, a variable workload which is composed of a central force F and a central torque T is constructed and applied to the center of the platform in the simulation mechanism. Third, the whole F/T (force/torque) simulation mechanism of the 3UPU-II spatial parallel manipulator is created. Finally, the extension of the active limbs, the active forces and passive forces are solved and modified.

Abstract: Burr in drilling plays an important role on product quality, so analysis the burr size is essential at the final production. This paper presents the application of Taguchi method for survey the burr height and burr thickness by adding ultrasonic vibration to the process. In this paper L18 orthogonal array based on Taguchi techniques was used in the design of experiments. Analysis of Variance (ANOVA) was used to determination the effect of drilling parameter on burr formation. Influence of cutting speed, feed rate and percentage of SiC particle was investigated in with and without Ultrasonic assisted drilling. Al/SiCp MMC with 5, 15 and 20 wt% of particulate SiC in dry drilling operation with TiN coated drill tools were investigated.