Effects Of Axial Misalignment Research Articles

Effect of Axial Misalignment on Fatigue Properties and Fatigue Crack Growth Rate of Plasma Arc Butt Welded Joints

Effect of Axial Misalignment on Fatigue Properties and Fatigue Crack Growth Rate of Plasma Arc Butt Welded Joints

Prediction of fretting damage and wear fatigue of floating involute spline couplings

In this paper, a finite element model of the floating spline pair is first established, and the distribution of the contact pressure on the tooth surface of the spline with the axis and angular misalignment is analyzed. Then, the effects of axial misalignment and angular eccentricity on tooth fretting damage were evaluated, based on Ruiz fretting damage parameters. Finally, a floating spline wear fatigue damage model considering the wear effect is established based on the energy dissipation and critical plane SWT model, and the fretting fatigue cumulative damage distribution and life of the tooth surface under axial and angular misalignment are analyzed and evaluated. The results show that the misalignment of the axis makes the contact pressure distribution of each tooth uneven, and the RFFDP value of the most dangerous tooth is parabolic along the x direction, that is, serious fretting damage may occur at both ends of the tooth surface, and the crack initiation position on the tooth occurs near x/L=0. The angular misalignment makes the tooth contact only at one end edge, and the RFFDP value of the most dangerous tooth increases along the x direction, showing an exponential growth trend, reaching the maximum at x/L=1, and the crack initiation position occurs at near x/L=1. With the increase of axis or angular misalignment, the damage phenomenon of the floating spline tooth surface becomes more obvious, and the wear-fatigue life decreases sharply.

유한요소해석기법을 이용한 토크 시편의 축 오열 영향 분석

Using three-dimensional (3-D) FE analyses, this paper provides a method for analyzing the effects on stresses and strains produced by angular and concentric misalignment of a test specimen for a torsion test. To quantitativele compare of the FE results, the average bending strain for the angular, concentric, and combined misalignment was proposed. To verify the effects of axial misalignment of the test specimens, we used both circular and tubular specimens. From the FE results, we proposed general predictions for the effects caused by the various types of axial misalignment and its direction. In addition, we confirmed the effect of initial yielding moment based on the initial yielding condition for axial misalignment of specimens in torsion tests.

Effects of system geometry on the axial response of the fibreoptical confocal microscope

The axial imaging properties of a confocal microscope using a single mode fibre as a detector are analysed. The axial response is calculated simply by performing an overlap integral in the back focal plane of the collector objective. The effects of axial misalignment of the fibre are investigated. The behaviour of the system has similarities with that of a confocal system with pinhole aperture and a finite Fresnel number geometry

THE EFFECT OF MISALIGNMENT ON THE FATIGUE STRENGTH OF WELDED CRUCIFORM JOINTS

Abstract— The effect of axial misalignment on the fatigue strength of load‐carrying transverse cruciform welded joints was investigated using experimental and fracture mechanics methods. Where failure occurred by cracking from the weld toe, misalignment significantly reduced the fatigue strength. The reduction could be predicted using a nominal stress concentration factor (SCF). Misalignment had less effect where failure was due to cracking through the weld metal; an expression was deduced for the SCF in this case. For fracture mechanics assessments, an expression for an effective stress intensity factor using the SCF and stress intensity factors for aligned welds was shown to agree with the finite element (FE) results. Predictions of the effect of misalignment using the FE results agreed with experimental data. Misaligned transverse load‐carrying cruciform joints should be assessed for fatigue failure from the toe using the same SCF as for a butt weld with the same misalignment. For failure through the throat, an alternative expression for the SCF is recommended. Fracture mechanics assessments of misaligned joints should be carried out using an effective stress intensity factor derived from the SCF and stress intensity factors for aligned joints. These recommendations are now incorporated in British Standard PD 6493:1991.

Nonlinear Study of a Misaligned Hydrodynamic Journal Bearing

Hydrodynamic/hydrostatic journal bearings have been widely used in various types of high speed rotating machinery. For space applications, the issue of using cryogenic fluids as working lubricants has steadily gained in significance. The main objective of this paper is to study the nonlinear effects in a hydrodynamic journal bearing with special attention to the effects of journal axial misalignment. The numerical model that couples the Reynolds equation with the dynamics of the rotor is solved by means of a finite difference solution technique. Fluid film pressures that resulted from an iterative scheme are integrated to generate bearing supporting forces. A two-dimensional Newton-Raphson iteration method is used to locate the journal equlibrium position from which both linear and nonlinear bearing stiffness are evaluated by means of the small perturbation technique. The effects of axial misalignment on bearing equilibrium position, lubricant fluid film thickness, pressure distribution, and stiffness cha...

Rotational aperture synthesis for x rays

Aperture synthesis for the x-ray region can be accomplished with an array of rotation modulation collimators. A Hermitianizing recipe extracts sine and cosine components from a pair of collimators for each fringe spacing, and Fourier synthesis then reconstructs the images. The point-spread function has low sidelobes and is applicable with extended sources. A Monte Carlo simulation is used to illustrate and evaluate the statistical effects of quantum noise. Even better images may be expected from positively constrained reconstruction. The effects of axial misalignment on the point-spread function are illustrated. The conclusion is a favorable appraisal of the array as an astronomical telescope for hard x rays.

Use of an ADP four-crystal electrooptic modulator in ellipsometry

Some theoretical considerations and experimental techniques in application of an ADP 45° X-cut four-crystal electrooptic modulator (EOM) to fast retardation modulation ellipsometry are described, emphasis being placed on the thermal stabilization. First to solve the thermal instability problem and to analyze systematic errors resulting from use of the EOM, the Jones matrix for the EOM is theoretically constructed which includes the effect of axial misalignment of the ADP crystals, multiple reflection at crystal-matching-dielectric liquid interfaces, temperature differences among the four crystals, and modulator cell windows. As a result, temperature-dependent factors in EOM characteristics are made clear. Second, a practical matrix form of the Jones matrix is determined from experiments on the bias-voltage dependence of the transmitted light intensity. Last, a thermal stabilization technique introduced by the matrix representation is demonstrated in the application of the EOM to ellipsometry, which enables us to obtain ellipsometric parameters of a sample, (Ψ,Δ), independent of the thermal drift and imperfections that accompany the EOM.

Effect of axial misalignment and multiple reflection on jones matrix of a four‐crystal light modulator

AbstractThe latest off‐the‐shelf 45 X‐cut (ADP or KDP) four‐crystal light modulators with low driving voltage consist of four crystal units to accomplish temperature compensation and to make possible a low driving voltage. Therefore, axial misalignment is not uncommon. Also, because there are many interfaces between the crystals and the matching dielectric fluid, multiple reflection may cause problems. the effects of these phenomena on the Jones matrix describing the fundamental characteristics of optical phase modulation are examined. First, the dielectric tensor of the crystals with axial misalignment and the characteristic plarizations in the crystal are derived. Then, using Berreman's 4 × 4 matrix formulation, the Jones matrix representation of a four‐crystal light modulator with axial misalignment is derived. It is pointed out that the off‐diagonal terms arise from axial misalignment, which is one cause of temperature variation of the light modulator characteristics. A numerical estimate is made of the effect of multiple reflection. It is pointed out that the effect of multiple reflection on the off‐diagonal elements of the Jones matrix is negligible while the effect of the diagonal elements is substantial. an experimental example with an actual modulator is given to determine the location of the axial misalignment.