Current Issue : April - June Volume : 2019 Issue Number : 2 Articles : 5 Articles
There are some issues that should be solved like load shock, vibration, and uneven load distribution during transmission of\ninvolute spur gears. However, common modification methods such as axial modification as well as profile modification could not\nsolve these problems once for all. Hence, a novel method of comprehensive modification was proposed, and the evaluation\nmethodology of transmission performance was drawn up too. Changing modification parameters can control transmission\nperformance of gear unit, which can generate many different modification ways. Besides, based on the orthogonal experiment\nmethod and evaluation methodology, optimal modification ways can be chosen for gear pairs working in different conditions.\nTaking a set of spur gear pair as an example, an ideal modification way was obtained. In addition, analysis results verified that\nconducting comprehensive modification could enhance the meshing performance once for all.\n1. Introduction\nWhen the gear mechanism transmits power, axial deviation\nmay be generated because of assembly error and teeth\ndeformation. Lias et al. [1] and Korotkin and Gazzaev [2]\nfound that axial deviation seriously affects tooth stresses,\nand it may lead to uneven load distribution. In addition,\nthere are some other problems in gear units, such as large\nfluctuation of transmission error (TE) and load shock. They\nmay result in vibration and decreasing the carrying capacity\nand service life of gear units. Aiming at above\nproblems, conducting modification for gears was\nresearched by many researchers. Thus, teeth surfaces of\nmodified gear are adjusted, and it may improve the\nmeshing performance. For instance, profile modification\nwas performed by Velex et al. [3] to reduce load shock, and\nthe phenomenon of vibration was improved. In addition,\naxial modifications are often conducted for gears to relieve\nuneven load distribution. However, most researchers\nusually consider profile modification and axial modification\nas two separate issues, and few people take them as\na problem....
A Fourier-Chebyshev Petrov-Galerkin spectral method is described for high\naccuracy computation of linearized dynamics for flow in a circular pipe. The\ncode used here is based on solenoidal velocity variables and is written in\nFORTRAN. Systematic studies are presented of the dependence of eigenvalues\nand other quantities on the axial and azimuthal wave numbers; the Reynoldsâ??\nnumber of up to 107 and the Weissenbergâ??s number that is considered\nlower here. The flow will be considered stable if all the real parts of the eigenvalues\nobtained are negative and unstable if only one of these values is\npositive....
As a basic mechanical component, the sealing ring is widely used in industrial, aerospatial,\nand other fields. In this study, an elastic metal C-shaped sealing ring with a wave structure was taken\nas an example, and its performance was analyzed theoretically and measured experimentally. First,\nan experimental study was performed on the C-ring seal. The proposed method for experimental\nmeasurement of the contact stress of the C-ring seal involved innovative use of a universal electronic\ntesting machine and pressure sensitive paper, in conjunction with the hueâ??saturationâ??brightness\n(HSB) method. Based on the discoloration of the pressure sensitive paper after contact stress, computer\nsoftware was used for analysis, the discoloration was digitized, and the contact stress was established.\nSecond, a theoretical calculation model of the C-ring seal was established using ANSYS software,\nand a finite element theoretical calculation of the mechanical properties of the sealing ring was\nestablished. Finally, the contact stress results were compared with the model calculation results of the\nC-ring seal. The error between the two was small (4.8%), which proved the validity of the calculation\nmodel and the scientificity of the experimental method....
AISI 1045 has been widely used in many industrial applications requiring good wear resistance and strength. Surface roughness of\nproduced components is a vital quality measure. A suitable combination of machining process parameters must be selected to\nguarantee the required roughness values. The appropriate parameters are generally defined based on ideal lab conditions since\nmost of the researchers conduct their experiments in closed labs and ideal conditions. However, when repeating these experiments\nin industrial workshops, different results are obtained. Imperfect conditions such as the absence of a turning tool with definite\nspecifications as shown in know-how â??tool nose radius 0.4 mmâ? and its replacement with the closest existence tool â??tool nose\nradius 0.8mmâ? as well as the interruption of cutting fluid during work as a result of sudden failure in the coolant pump lead to the\nmentioned different lab-industrial conditions. These complications are common among normal problems that happened during\nthe metal cutting process in realistic conditions and are called noise factors. In this paper, Taguchi robust design is used to select\nthe optimum combination of the cutting speed, depth of cut, and feed rate to enhance the surface roughness of turned AISI 1045\nsteel bars while minimizing the effects of the two noise factors. The optimum parameters predicted by the developed model\nshowed good agreement with the experimental results....
The focus of the study is to examine thermal radiation and viscous dissipative\nheat transfers of magnetohydrodynamics (MHD) stagnation point flow past a\npermeable confined stretching cylinder with non-uniform heat source or\nsink. The formulated equation governing the flow is non-dimensional. The\ndimensionless momentum and energy equation are solved using shooting\ntechnique coupled with fourth-order Runge-kutta integrated scheme which\nsatisfied smoothness conditions at the edge of the boundary layer. The result\nfor the velocity and temperature distributions are presented graphically and\ndiscussed to portray the effects of some important embodiment parameters\non the flow. The Nusselt number and skin friction were obtained and compared\nwith the previous scholarsâ?? results in others to validate the present research\nwork....
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