Numerical Modelling of Crack Growth in a Gear Tooth Root

Podrug, Srđan; Glodež, Srečko; Jelaska, Damir

doi:10.5545/sv-jme.2009.127

Cited by 16 publications

(10 citation statements)

References 20 publications

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“…Figure 14 presents the trajectories of cracks observed in the tests and the respective values of maximum load. The curves of the trajectories of fatigue cracks at gear tooth base observed in the tests corroborate the results obtained on the basis of numerical calculations [2,6,13,16].…”

Section: Experimental Tests Of Fatigue Life Of Gearssupporting

confidence: 84%

See 1 more Smart Citation

Fatigue testing of transmission gear

Weresa

Seweryn

Szusta

et al. 2015

Eksploatacja i Niezawodnosc - Maintenance and Reliability

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INTRODUCTIONWorking loads of construction elements, especially cyclically changing loads, cause nucleation and the development of damage in the material, which often leads to fatigue destruction of the whole element [9,10]. In the case of uniaxial or proportional biaxial loads, the damage cumulates on privileged surfaces; the life of material is determined on the basis of the results of standard tests presented in the form of fatigue curves [14,15]. The prediction of fatigue life of construction elements that operate in conditions of nonproportionate loads (which occurs in the case of cylindrical gears) is a huge computational problem [5,12]. The difficulties are connected with the necessity to formulate and experimentally verify general criteria descriptions allowing for the cumulation of damage on different physical surfaces, and to establish the surface of crack initiation and the crack criterion [10,19].The development of damage, and then the initiation of fatigue cracking in gears is particularly intensive in two areas: in the area of contact of gear teeth (from contact pressures) and at the base of the loaded tooth (from twisting and shearing).In the former case, gear damage is the result of local crumbling on the surfaces of the mating teeth (mainly pitting wear caused by high values of contact, normal, and tangential stresses) [18]. In the latter case, damage to the element is the result of fracture to the teeth base (propagation of fatigue cracking until the whole of the tooth breaks off). It should be added that fatigue cracking in mating gears may appear both in the outer layer of the tooth, and inside the material -near the border between the outer layer and the core [4].Prediction of the development of fatigue damage in gears as early as at the stage of their design allows to determine the lifespan of a given gear in conditions of normal operation, and avoid serious damage to the whole device. Fatigue calculations for gears usually consist in determining the fatigue life of the tooth base [7]. The computational procedure consists in determining the infinite fatigue life of a gear, which is expressed as the value of the normal stress at tooth base which the rim material can transfer without breaking it during at least 3x106 loading cycles [3]. This value is too small, as gears often work in such manner that the number of loading cycles is considerably higher. For comparative calculations, the values of infinite fatigue life obtained in tests of smooth samples at uniaxial tension-compression or uniaxial pulsation from-zero bending are used [17]. Another method for the determination of fatigue life of gear teeth requires the creation of a fatigue life curve on the basis of experimental tests of real gear pairs in operating conditions [10]. Most of the available papers connected with fatigue tests of gears are based on calculations with the use of the finite element method. There are fewer papers devoted to experimental verification and fatigue tests of real life gears. This paper proposes an own design...

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Section: Experimental Tests Of Fatigue Life Of Gearssupporting

confidence: 84%

“…Line 1 represents infinite fatigue life. In the case of curve 2 the necessity for determining fatigue life also in the range of a very high number of cycles can be easily observed [13].…”

Section: Stands For Fatigue Testing Of Gearsmentioning

confidence: 99%

Fatigue testing of transmission gear

Weresa

Seweryn

Szusta

et al. 2015

Eksploatacja i Niezawodnosc - Maintenance and Reliability

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“…Tooth root failure is one of the most important failure modes in plastic gears. 15,29 The mechanical results are summarized in Table 2, and graphical representations are shown in Figure 14. All configuration stresses greater than 50% of the material limit are shown.…”

Section: Mechanical Resultsmentioning

confidence: 99%

Optimized use of cooling holes to decrease the amount of thermal damage on a plastic gear tooth

Koffi

Bravo

Toubal

et al. 2016

Advances in Mechanical Engineering

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The full potential of plastic gear usage is limited by not only poor mechanical properties but also equally poor temperature limits and poor heat conduction properties. Cooling holes were developed to decrease the amount of thermal damage on the contact surface. These cooling holes promote increased stress and tooth deflection, thus exerting a negative effect. This article compares various cooling holes for plastic gear configurations and proposes novel cooling holes. Thermal and mechanical simulations that consider specific aspects of plastic gear meshing were performed. The main objective of this article was to verify the best methods for reducing thermal damage through cooling holes. The results indicate the best compromise between the temperature reduction and the mechanical properties of the new tooth geometry. The results also indicate that the simple variations in the cooling holes proposed can improve tooth performance.

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“…The major problem is limited data for the polymer materials. There are some specific calculation methods that also consider the viscoelastic behaviour of the material and load sharing [29,30].…”

Section: Gear Calculation Methodsmentioning

confidence: 99%