Circular Fillet Research Articles

Determination Of Weld Thickness In Hollow Section Connection Under Local Buckling Effect

Hollow section profiles are widely used in the structural steel industry. An important point to take into consideration in such connections is the continuous transfer of internal forces from element to element. One of the measures taken to ensure this continuity is to use end plates. The connection between plates and elements is mainly provided by welds. The aim of this study is to determine an optimum weld thickness for connections subjected to local buckling of box-beam-columns under bending. Corner and circular fillet welds were used to join the designed plates with box columns and beams. Hollow section profile connections were experimentally studied in the Steel Structure Laboratory of the Department of Civil Engineering of Süleyman Demirel University. Results were used to develop numerical models. Ansys Workbench was used in numerical models to analyze the corner welds of different thicknesses and lengths depending on plate dimensions and to examine their behavior.

A Novel Fillet Form for Non-Generation Cutting Gear Teeth

Tooth fillets are commonly made of circular profiles because they are easy to define analytically and have been shown to be superior from a bending perspective to the trochoid fillet. For gears that are cast, forged, or 3D printed, the tooth fillet can be any curve as long as it is capable of providing a smooth mesh without interference. For such design flexibility, the circular fillet may not necessarily be the best fillet profile from a bending stress point of view. Therefore, the first aim of this study is to develop a general mathematical model for defining the tooth fillet profile analytically for gears manufactured by non-generation cutting processes. The mathematical model employed a general fillet transition curve (GFTC) to ensure smooth transition surfaces in the fillet zone and an improved radius of curvature as well as tooth form factor compared to the circular fillet profile. The second aim of this work is to examine if increasing the order of the proposed GFTC can enhance the fillet strength of the gear tooth further. The design method is conducted for involute gear and, for the first time, non-involute gears. Various fillet design parameters and tooth numbers are examined. The results showed that by using the proposed fillet shape, the tooth fillet strength can be enhanced by 18–23% for involute gears and by 30–32% for non-involute gears. Also, the results showed that increasing the order of the fillet curves might not always improve the fillet strength of the gear teeth.

Cause analysis of crack formation in root part of fillet weld of thick-walled joints based on computer simulation of strain-stress state during welding

Computer simulation of thermal deformation processes occurring during welding of circular fillet weld of pipe T-joint made of S355 steel (in accordance with GOST 27772) is performed. Possible reason for the formation of unacceptable sizes discontinuities in the root part of multilayer weld — the growth of discontinuities from small to critical sizes in limited time interval as result of volumetric all-sided stretched stress state during the cooling period of the next root roller is determined based on the kinetics analysis of changes in the strain-stress state during welding.

Gear Bending Stress Analysis of Automatic Transmissions with Different Fillet Curves

Gear bending strength is a core indicator to indicate reliability and operation performances of automotive transmissions. Fillet curve design of dedendum of gear teeth can improve their bending stress and complex tooth contact perfor-mance. Geometrical parameters of gears are considered important for the varia-tion of stresses in the design of gears. Bending stress analysis has been a key area of research to minimize failure and optimize design. This work presents a finite element (FE)-based analysis method of gear bending stress, which can be used for multiple spatial meshing gear teeth simultaneously. Three-dimensional (3D) models of helical gear with double and single circular fillet curves are estab-lished by using Pro/ENGINEER. By changing of meshing positions of gears, tooth contact analysis results along their paths of contact are obtained. Since FE-based tooth contact analysis are performed based on 3D models, the results of bending stress are reliable and authoritative. It is proved that bending stress of the gear with double circular fillet curves is 1.3~1.5 times as that of the gear with single circular fillet curves, which means that gear with single circular fillet curves has better loading capacity than gear with double circular fillet curves. The study will provide a good method for studying gear bending stress to improve gear de-sign of automotive transmissions.

Tunable self-jumping of melting frost on macro-patterned anisotropic superhydrophobic surfaces

Controllable fast self-removal of frost pieces from surfaces can effectively reduce energy consumption and residual droplets during defrosting. In this work, a tuning strategy of melting frost directional self-jumping on regular macro-patterned anisotropic superhydrophobic surface (MASS) was proposed. Under high-rate cooling condition, patterned frost on MASS with significantly different thickness distribution was observed, due to the water vapor gradient in and out of the deep grooves. During defrosting process, L-shaped melting frost on MASS shrank independently with two arms retracting inward, which further caused the melting frost's centroid/mass center to shift out of the pillar top. Partial contact with pillar tops and circular fillet introduced directional lifting force and enabled the directional self-jumping of the melting frost. Influencing factors on directional self-jumping of melting frost on MASS were also discussed. Utilizing macro-patterned anisotropic structure, the frost splitting process and its jumping direction were both tuned, which could promote the self-jumping of melting frost and thus improve the efficiency of defrosting.

Viscous flow simulations through multi-lobe progressive cavity pumps

Computational fluid dynamics (CFD) simulations of multi-lobe progressive cavity (PC) pumps are limited in the literature due to the geometric complexity of the pump, which places numerous restrictions on the grid generation process. The present study attempts to alleviate such restrictions by developing a detailed numerical procedure for the numerical simulations of multi-lobe progressive cavity pumps. The profile equations for the multi-lobe configuration at any section at each instant of rotation are presented. A structured grid generation method is developed to generate mesh files required for CFD simulations of multi-lobe PC pumps. Results from the present procedure are validated against single-lobe PC pump numerical results available in the literature. Finally, a numerical parametric study is carried out to investigate the effect of the number of lobes, the stator pitch, the circular fillet and clearance on the volumetric efficiency of PC pumps with viscous oils.

Shape optimization of the fillet under a bolt’s head

The stress concentration in the fillet under a bolt’s head is a critical issue for the fatigue life of this component. Remembering the variable notch radius solution observed in many biological structures to lower stress concentrations due to normal loads, this work proposes, examines and optimizes a double circular arc fillet, not re-entering the head. The work implements an ad hoc shape optimization procedure that combines a genetic algorithm (the particle swarm optimization) and a parametric, axisymmetric finite-element model of the bolt: by focusing on an M12 bolt, the analysis focuses on two issues: first, the optimization of the radius of each arc in the fillet; second, the optimization of the bolt’s head height and head’s diameter in combination with the fillet radiuses. By comparing the proposed solution with the fillet geometries for the bolt’s heads from the literature, it appears a noticeable stress reduction, about 14% lower than the standard circular fillet, combined with an easy manufacturing.

Reducing stress concentration on the cup rim of hip implants under edge loading.

High stress concentration under edge loading on the cup rim contact due to micro-separation causes accelerated striping wear, fracture, and fatigue in hip implant components. While continuous effort is devoted into improving bearing design and surgical procedure to tackle the problem, the concern still has remained forcing biomedical engineers to seek for new and alternative solutions. The current paper aims to investigate the effect of a new geometry "spline" introduced at the cup's rim corner to minimise stress concentration under edge loading. Three-dimensional finite element modelling of a metal-on-metal hip implant is developed, where contact pressure, von Mises stress, and strain are predicted for three spline geometries, ie, equivalent characteristic arc radius (R=0.5, 1.0, and 1.5mm) at four micro-separations (of 1.0, 1.5, 2.0, and 2.5mm) simulating edge loading on the rim contact via the application of a constant vertical load of 3kN. The efficacy of the spline is compared with that of circular arc and sharp corner (ie, no arc) geometries. Overall, the spline outperforms both sharp corner and circular arc in reducing contact pressure, stress, and strain. The benefit of the spline over the circular arc is quite promising at larger micro-separation but fairly marginal at smaller arc radius and micro-separation. The findings indicate that, as an alternative to the circular fillet, the spline can be considered a potential geometry to be incorporated at the rim corner of the cup.

Experimental Study on Fatigue Fracture Damage of Symmetric Spur Gear Tooth

There are many studies on the involute profile symmetric gears in the literature. In many studies done, the critic tooth root stress was emphasized. Studies have been carried out on the calculations of tooth root stress and these studies have been tried to be verified by using the finite element method. Although there are different approaches to calculate the tooth root stress, the most widely used equations are those expressed in ISO and AGMA standards.The studies in the literature have mostly been carried out on the gears that have trochoid curve in the tooth root. In parallel with these studies, experimental studies were done to determine the fatigue life performance of these gears.In this work, involute gears tooth root was manufactured using the circular fillet method which have better tooth root stress than trochoid according to static analyses in literature. Fatigue damage on symmetric gear tooth under cyclic loading and effect of material hardness on fatigue life of gear tooth were investigated.Fatigue tests were performed with specially designed single-tooth bending fatigue test (STBFT) apparatus. The results obtained from fatigue tests at low cycles and high cycles were evaluated comparatively.

Optimization of Tooth Root Profile Using Bezier Curve with G2 Continuity to Reduce Bending Stress of Asymmetric Spur Gear Tooth

This research describes simple and innovative approach to reduce bending stress at tooth root of asymmetric spur gear tooth which is desire for improve high load carrying capacity. In gear design at root of tooth circular-filleted is widely used. Blending of the involute profile of tooth and circular fillet creates discontinuity at root of tooth causes stress concentration occurs. In order to minimize stress concentration, geometric continuity of order 2 at the blending of gear tooth plays very important role. Bezier curve is used with geometric continuity of order 2 at tooth root of asymmetric spur gear to reduce bending stress.

Fatigue Fracture Behaviour of Asymmetric Spur Gear Tooth Under Cyclic Loading

When the research on the gears are investigated, it is seen that there are different studies on the design and analysis. In the majority of research studies, the tooth root curve is designed as a trochoid curve as a results of production method. According to literature, application of the circular fillet method instead of the trochoid curve in the tooth root would increase the strength of the tooth root.Fatigue life will also be positively affected with increase of tooth strength. Because the less stress will develop in the tooth root, the fatigue life of the gear tooth will increase. In this study, we have designed and manufactured involute profile asymmetric spur gears using the circular fillet method in tooth root region.Involute profile asymmetric gears tooth have lower contact stress and superior tooth root strength than symmetric gears tooth. In this work, fatigue damages on asymmetric gear tooth caused by cyclic loads and effects of material hardness on fatigue life of gear tooth were investigated.In the extent of the study, a new single-tooth bending fatigue test apparatus (STBFT) was developed to investigate the fatigue performance of the gears. Low-cycle and high-cycle tests were done to detect the fatigue performance of the asymmetric gears.

An investigation on supersonic bevelled nozzle jets

This paper reports upon a numerical and experimental study on supersonic jets exhausting from bevelled nozzles with 30° and 60° exit inclination angles. To begin with, a simple but effective method to design a shock-free convergent–divergent circular jet nozzle to produce a well-conditioned supersonic Ma = 1.5 jet based on simple circular fillets is presented. Subsequently Reynolds-Averaged Navier–Stokes simulations of circular non-bevelled and bevelled nozzle jets were performed at over-expanded, perfectly expanded and under-expanded conditions. Lastly, these supersonic jets were visualized experimentally using a modified Z-type Schlieren system. Results show that the shock cell structure within the jet potential core changes from a diamond pattern to triangular and rectangular patterns as the nozzle pressure ratio and inclination angle are varied. Furthermore, jet plumes are deflected differently when the bevelled nozzles were operated at off-design conditions, with changes to the supersonic jet potential core length. Finally, quantitative analysis of the results reveals that bevelled nozzles are able to reduce the intensity of the supersonic jet shock cell structure considerably, which is potentially useful for broadband shock-associated noise mitigation purposes.

Design, Optimization, and Prototyping of a Transverse Flux-Type-Switched Reluctance Generator With an Integrated Rotor

This paper presents the design, optimization, and prototyping of a transverse flux-type-switched reluctance generator (TFSRG) with an integrated rotor consisting of the main and permanent magnet (PM) auxiliary poles. In the initial model, an integrated rotor has a simple structure, consisting of one magnet core and a yoke bar. The yoke bar was radially laminated and inserted in the rotor yoke to minimize loss of the magnetic flux, which flows along the axial direction. We analyzed the cogging torque and back-EMF characteristics of the proposed TFSRG using the finite-element analyses (FEA). The cogging torque in the analysis results for the initial model of the proposed TFSRG was relatively high cogging. To reduce a cogging torque, both corners of the stator and PM auxiliary poles were optimized using a circular fillet shape. To satisfy a design condition, the design variables of a circular fillet shape were effectively determined using the optimization algorithm, and the initial and optimal models were compared with the analyzed results by a FEA for steady state and a dynamic performance simulation for transient state, respectively. To verify the analyzed results, an optimized prototype TFSRG was manufactured and measured. The measurement results were in good agreement with analysis results, and the output performance of the prototype was verified by the experiment set.

Circular fillet weld tracking in GMAW by robots based on rotating arc sensors

In order to reduce the welding cost, improve the welding quality, and enhance the automation level of the welding, the circular fillet weld tracking algorithm was studied based on the coordinated movement between wheels and a horizontal slider, and the tracking algorithm can eliminate the impact on the welding quality due to roundness errors of the circular fillet weld in the plane. Furthermore, the circular fillet weld tracking algorithm was studied based on the vertical slider moving up or down, and this algorithm can eliminate the influence on the welding quality due to flatness errors of the circular fillet weld in the vertical direction. By using the circular fillet weld tracking algorithm that robots track the circular fillet weld based on the coordinated movement among wheels, the vertical and horizontal sliders, a large number of experiments have been done in the laboratory and the factory. For example, robots tracked the circular fillet weld with different diameters in the laboratory, and the circular fillet weld of the flat bottom container was tracked by robots in the factory. At last, the deviation that the arc welding gun deviated from the weld seam was analyzed, and the experimental results show that the robot based on the rotating arc sensor can track the circular fillet weld with high accuracy and good reliability by using the designed algorithm in gas metal arc welding.

The Undercut Criterion of Pinion Shaper Cutters: And an Improvement by Modifying the Basic Rack Profile

The fillet of the gear tooth is highly stressed in operation; so for heavily loaded gears, the fillet geometry must be controlled. The manufacturer's task is to, within acceptable tolerances, produce the gear to the designer's specifications regardless of the manufacturing method. Most often gear cutting tools are used that work under generating conditions. The tool will form the gear tooth; so to produce the specified gear geometry and, especially, the fillet geometry, this tool must be conjugated to the same basic rack as the gear to cut. However, this gives a risk that the tooth tip of the tool will be undercut, and if this occurs the tool will not cut the intended gear fillet. In this report, novel analytical equations are derived, which predict the limit when the tool tip will be undercut. It is shown that if the gear tooth should be conjugated to the standard basic rack with a circular fillet, which is the normal case, very large tool-tooth numbers are needed for pinion shaper cutters and gear skiving cutters to avoid this type of undercut. However, the minimum tooth number to achieve a smooth continuous tool-tooth profile is reduced by modifications to the fillet of the basic rack profile.

Microstructure and mechanical properties of ALPORAS closed-cell aluminium foam

In recent years, closed-cell foam has drawn increasing attention in applications ranging from energy absorption devices to serving as the core material of light-weight structures. Although closed-cell foams are critical in many applications, the microstructural characteristics and mechanical properties of these foams are not fully understood. In this paper, we performed a comprehensive study on the commercially available ALPORAS closed-cell aluminium foam by means of experiment. First, inspection of the foam microstructure was systematically performed. Based on this inspection, the geometric features of the foam were characterised. Crushing experiments were subsequently conducted on specimens under various conditions to examine the effect of each of the testing parameters such as the specimen size and geometry as well as the loading direction, on the mechanical response of closed-cell foam. We found that the cells were irregular polyhedra with approximately 14 faces and that each face had approximately 5 sides. The cell wall was thinnest in the middle section, became increasingly thicker towards the edges, and eventually formed circular fillets as it intersected with neighbouring walls. The foam was geometrically and mechanically anisotropic. The factors that most influenced the mechanical properties were the loading direction and relative density. In this paper, we also compare the experimental results on the foam mechanical properties with existing equations from the literature.

Seismic Behavior of Concrete-Filled Square Steel Tubular Column-to-Beam Connections with through Diaphragm

This paper studies seismic behavior of concrete-filled square steel tubular column-to-beam connection with through diaphragm, which is popular in Japan, but rarely used in China. Four full-scale cruciform specimens are tested under low-cyclic reversed load and the result of study indicates that diaphragm-through joints have stable hysteretic characteristics and enough energy dissipation capacities to be used in the field. Details of the steel beam flange connecting with the diaphragm have obvious effects on joint ductility and energy dissipation, and the seismic behavior of joints with circular fillet at the connecting zone are better than that reinforced by taper plate welded to the beam flanges. For the specimens failed in the beam, diaphragm thickness, size of concrete cast holes, width-to-thickness ratio of the tube, and the level of axial load in the column have less influence on joint seismic behavior.

Analysis of Stresses and Deflection of Sun Gear by Theoretical and ANSYS Method

Gearing is one of the most critical components in mechanical power transmission systems. This article examines the various stresses and deflection developed in sun gear tooth of planetary gearbox which is used in Grabbing Crane. Article includes checking sun gear wear stresses and bending stresses using IS 4460 equations. Also calculate various forces acting on gear tooth. In this study, perform the calculation for sun gear tooth to calculate bending, shear, wear & deflection using theoretical method. 3D model is created of circular root fillet & trochoidal root fillet of gear tooth for simulation using ProE Wildfire 3. In Pro-E, the geometry is saved as a file and then it is transferred from Pro-E to ANSYS 10 in IGES format. The results of the 3 D analyses from ANSYS are compared with the theoretical values. Comparison of ANSYS results in circular root fillet & trochoidal root fillet also carry out.

Robustness of isogeometric structural discretizations under severe mesh distortion

This paper investigates higher-order and higher-continuity functions in isogeometric structural analysis under distortion of the control and physical meshes. First, the concepts behind isogeometric analysis are briefly reviewed. The effect of perturbing control points upon the geometrical mapping is observed in the one-dimensional setting. The concept is extended to multiple dimensions with a series of cases where the interior of a cube is distorted in different ways and patch tests are performed to assess accuracy. A circular fillet patch is introduced through the appropriate degeneration of a control mesh in order to address the problem of modeling small features in finite element models. The fillet patch is tested with two problems of linear elasticity and is shown to be accurate. The investigation is further extended to the setting of large-deformation nearly incompressible nonlinear elasticity with two examples which make use of the recently proposed F ¯ projection method.

Four-Parametric Design Study of the Bending Strength of Circular-Fillet Versus Trochoidal-Fillet in Gear Tooth Design Using BEM

Circular fillet pinions are designs of superior bending strength evolved as substitutes to the standard trochoidal fillet design. However this has only been verified considering gears of nominal thickness coefficient and addendum. This paper makes a comparative four-parametric study of the achieved bending strength of the two designs (circular fillet/trochoidal fillet) taking into consideration the large range of pinion and gear numbers used in engineering practice. The results are calculated using an automated BEM process and presented in generalised diagrams, called ‘stress map’, which are used to observe optimal application and usage restrictions of each design.