Influence of drive side pressure angle on fracture characteristics of asymmetric spur gear

Namboothiri, Nandu V.; Marimuthu, P.

doi:10.1016/j.engfailanal.2021.105865

Cited by 5 publications

(3 citation statements)

References 25 publications

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“…High performance under harsh operating conditions is demanded from modern gear transmission systems. 56–59 In this regard, the asymmetric tooth concept emerges as an important research area, considering its advantages over symmetric designs. The researchers have so far reported that the asymmetric gears outperformed the standard designs in many aspects, such as bending strength, impact resistance, and fatigue life.…”

Section: Resultsmentioning

confidence: 99%

“…The researchers compared their model’s findings with those obtained through FE simulations and concluded that the TVMS increased with the increment of the DSPA. Namboothiri and Marimuthu 58 studied the combined influence of gear parameters such as gear ratio, DSPA, and the number of teeth on the fracture characteristics of spur gears with asymmetric teeth. Their study determined the stress intensity factor for each gear pair based on the strain energy release rate method.…”

Section: Resultsmentioning

confidence: 99%

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Influence of tooth root cracks on the mesh stiffness of asymmetric spur gear pair with different backup ratios

Doǧan

Kalay

Karpat

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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Gears are critical machine elements that transmit power and motion in diverse implementation fields. Over time, gears may produce a series of faults due to harsh operating conditions, fatigue, manufacturing errors, etc., leading to severe performance degradation. During the meshing process, the stiffness of a single tooth controls the load sharing, vibration, and noise characteristics of a geared system. An undetected fault could decrease the gear stiffness and thus may lead to a fatal breakdown, substantial economic losses, or even human casualties in safety-critical applications such as helicopters, high-speed trains, and wind turbines. Hence, the accurate quantification of the gear stiffness emerges as an important research area to obtain reliable gear designs. With this in mind, the asymmetric tooth concept offers superior bending strength, fatigue propagation life, and the ability to lessen vibration over the standard (symmetric) designs in applications where unidirectional loadings are predominant. This study investigates the influence of tooth root cracks on the single-tooth and meshing stiffness characteristics of the standard and asymmetric involute spur gears. To this end, the numerical crack propagation paths obtained in our previous works were introduced to the created 3D CAD geometries. Subsequently, the single tooth stiffness of both healthy and cracked (2 5%-50%-75%-100%) gears was calculated through the ANSYS® Workbench, and the time-varying mesh stiffness was obtained. The present study evaluated the effects of backup ratio and the tooth asymmetry on the spur gears’ meshing stiffness characteristics simultaneously and further expanded the scope of the research work. The results indicated that the single tooth stiffness and mesh stiffness could be improved by 35% and 22%, respectively, as the drive side pressure angle increased from 20° to 35°. It has been noted that the gear stiffness decreased as the crack level increased, while the increment of the backup ratio further increased the reduction in the stiffness. The findings could provide significant outputs for a better understanding of the influence of tooth asymmetry on the gear dynamics characteristics, life prediction, and early fault diagnosis.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Influence of tooth root cracks on the mesh stiffness of asymmetric spur gear pair with different backup ratios

Doǧan

Kalay

Karpat

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…Taking the above into consideration and in order to reduce the tensile stresses of ceramic gears high pressure angle involute gears are proposed and examined. High pressure angles beyond the 25° limit of ISO are employed extensively in asymmetric gears 30,31 and are shown to produce lower tensile root stress than conventional 20° gears as shown in the parametric study of Doğan et al 32 Weber et al 33 showed experimentally that increased pressure angle gears (28°) can provide higher transmittable torque ratings while exhibiting higher scuffing resistance that their 20° counterparts. 2D, quasi static analyses in accordance with Zhan et al 34 are performed for ceramic spur gear pairs with 35° pressure angle to evaluate the root and flank stresses along the mesh cycle.…”

Section: Introductionmentioning

confidence: 99%

Fully ceramic versus steel gears: Potential, feasibility and challenges

Vasileiou,

Rogkas,

Markopoulos

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part C:

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The most common gear strength calculations performed in accordance with ISO/TC 60/SC 2 include surface durability and root bending strength. Typical geared power transmissions are characterized by high Hertzian contact stresses (surface durability) on the flanks – frequently in the order of 103 MPa – versus almost half an order magnitude lower first principal stresses on the tooth root (tooth bending strength). Therefore, the use of high strength special steel alloys is almost mandatory, especially in high-end applications, mainly to withstand the high contact stress values. Ceramic materials are typically characterized by high compressive strength versus very low flexural strength that at first glance makes them inefficient for gear transmissions since they are unlikely to withstand the tensile root stresses. Nevertheless, ceramic materials possess a number of advantages that makes them potential candidates for geared transmissions, such as their exceptional thermal properties, their low density (weight), their excellent wear characteristics and limited lubrication demands. The present work investigates the main challenges of using high-end ceramic gears and attempts to provide an insight on defining the design envelope of such gears to counter the main disadvantages. The increase of the normal pressure angle beyond the 25° limit set by ISO 6336 is primarily investigated, since in minimizes the tensile tooth root stresses, while also increasing the curvature of the contact surfaces without greatly increasing Hertzian stresses. Comparative assessment of the performance of fully ceramic gear designs versus their conventional steel counterparts is performed through quasi-static FEA simulations to set the basic design requirements for such gears and to promote further investigation of the feasibility of their usage in high power density applications.

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Balanced bending fatigue life for helical gear drives to enhance the power transmission capacity through novel rack cutters

Rajesh

Marimuthu

Бабу

et al. 2023

Engineering Failure Analysis

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Influence of drive side pressure angle on fracture characteristics of asymmetric spur gear

Cited by 5 publications

References 25 publications

Influence of tooth root cracks on the mesh stiffness of asymmetric spur gear pair with different backup ratios

Influence of tooth root cracks on the mesh stiffness of asymmetric spur gear pair with different backup ratios

Fully ceramic versus steel gears: Potential, feasibility and challenges

Balanced bending fatigue life for helical gear drives to enhance the power transmission capacity through novel rack cutters

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