Tooth flank fracture – basic principles and calculation model for a sub surface initiated fatigue failure mode of case hardened gears

Boiadjiev, I.; Witzig, Jochen; Tobie, Thomas; Stahl, Karsten

doi:10.1533/9781782421955.670

Cited by 26 publications

(21 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A detailed description of the material-physically based FZG-model for the assessment of the risk of tooth flank fracture can be found in (Boiadjiev et al, 2014;Hertter, 2003;Höhn et al, 2010;Oster, 1982;Tobie et al, 2013;Witzig, 2012). The calculation procedure needs comprehensive and detailed input values and some integrations and iteration steps are necessary.…”

Section: Material-physically Based Fzg-model For the Assessment Of Thmentioning

confidence: 99%

“… 500 N/mm² ≤ p H ≤ 3000 N/mm²  5 mm ≤ ρ red ≤ 150 mm  0,3 mm ≤ CHD ≤ 4,5 mm Based on experimental investigations on case-carburized gears and industrial examples (Boiadjiev et al, 2014;Tobie et al, 2013;Witzig, 2012), it is known, that a maximum material exposure A FF,max ≥ 0,8 can lead to tooth flank fractures for gear materials of typical quality and cleanness (quality MQ according to ISO 6336-5 (ISO 6336-5, 2016)). …”

Section: Practical Calculation Approach For Tooth Flank Fracture Loadmentioning

confidence: 99%

See 1 more Smart Citation

Parameter study on the calculated risk of tooth flank fracture of case hardened gears

Hein

Tobie

Stahl

2017

JAMDSM

View full text Add to dashboard Cite

Section: Material-physically Based Fzg-model For the Assessment Of Thmentioning

confidence: 99%

Section: Practical Calculation Approach For Tooth Flank Fracture Loadmentioning

confidence: 99%

Parameter study on the calculated risk of tooth flank fracture of case hardened gears

Hein

Tobie

Stahl

2017

JAMDSM

View full text Add to dashboard Cite

“…[1] A Figura 1a mostra a distribuição da tensão de contato devido à força normal resultante da transmissão de torque. A Figura 1b ilustra a distribuição aproximadamente linear da tensão de flexão ao longo da seção transversal do dente, resultante de um momento fletor devido ao carregamento.…”

Section: Figuraunclassified

“…As tensões residuais não dependem do carregamento e, enquanto não houver deformação plástica significativa na superfície, mantêm-se constantes no tempo. [1] Engrenagens operam sob condição de carregamento cíclico variável, portanto estão sujeitas a dano acumulativo por fadiga. Além do mais, devido ao contato entre os dentes, o desgaste também pode-se tornar um risco de falha.…”

Section: Figuraunclassified

Análise De Falha De Engrenagens De Redutores Grande Porte

Ihara¹,

Tanaka²

2017

Anais Do Congresso Anual Da ABM

View full text Add to dashboard Cite

ResumoForam encontrados vários casos de falha de engrenagens de redutores de grande porte, aplicados em turbogeradores em usinas de cogeração. Este trabalho tem como objetivo a análise de falha dessas engrenagens bihelicoidais. Engrenagens operam sob condição de carregamento cíclico variável, logo seus principais modos de falha são fadiga de contato e por flexão de dentes. A engrenagem estudada, fabricada em aço 18CrNiMo7-6, foi utlizada em campo e apresentou fratura em dois dentes. Realizou-se uma análise de espectrofotometria para confirmação da composição química do material base. Uma análise microestrutural foi realizada utilizando microscopia óptica, revelando que a microestrutura corresponde a martensita com austenita retida. Foi feito um perfil de microdureza no plano transversal do dente, que indicou uma camada cementada efetiva de 2.150 μm e dureza de 715 HV0.1 na superficie. Foi feita uma fractografia macroscópica para determinação das caracteristicas da fratura, o que permitiu identificar marcas de praia e deltas de rio. Aliado a isso, foram feitas imagens por microscopia eletrônica de varredura, determinando o local do início da trinca. A partir dessas evidências, pôde-se concluir que o mecanismo de falha predominante foi fadiga por flexão de dente. Palavras-chave: Análise de falha; Engrenagens; Fractografia; Fadiga. FAILURE ANALYSIS OF GEARS OF LARGE TRANSMISSION SYSTEMS AbstractSeveral cases of gear failure occurred in large transmission systems, applied to turbogenerators in cogeneration power plants. This work aims to do the failure analysis of the material of these double helical gears. Gears operate under variable cyclic stress, hence the main modes of failure are contact and bending fatigue. The studied gear, manufactured in 18CrNiMo7-6 steel, worked on the field and presented fracture of two teeth. An analysis of spectrophotometry confirmed the chemical composition of the base material. A microstructural analysis was conducted by means of an optical microscope, which revealed that the microstructure corresponds to martensite and retained austenite. A microhardness profile was completed, which denoted an effective carburised layer of 2,150 μm and hardness of 715 HV0.1 on the surface. A macroscopical fractography was done, in order to determine features of the fracture, which allowed for identification of beach marks and river deltas. In addition, imaging by scanning electron microscopy determined the crack iniation site. Based on this evidence, it could be concluded that the predominant failure mechanism was tooth bending fatigue.

show abstract

“…Pavlina and van Tyne [15] proposed the relationship between the yield strength and hardness of local material in steel. Boiadjiev et al [16] defined the concept of material exposure and evaluated the risk of contact fatigue failure at each material point along the depth direction. However, this work did not consider the impact of elastic-plastic contact and focused only on the action of shear stress; the multiaxial stress state that occurs during gear contact was neglected.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of contact fatigue risk of a carburized gear considering gradients of mechanical properties

et al. 2019

View full text Add to dashboard Cite

Carburized gears are widely used in geared machines such as wind turbines. Contact fatigue problems occur in engineering practice, reducing reliabilities of machines. Contact fatigue failures are related to many factors, such as gradients of mechanical properties of the hardening layer. In this work, an elastic-plastic contact model of a carburized gear is developed based on the finite element method to evaluate contact fatigue failure risk, considering variations in hardness and strength. The Dang Van multiaxial equivalent stress is calculated via Python coding within the Abaqus framework. The gradient of yield strength along the depth from case to core is considered. The concept of local material fatigue failure risk is defined to evaluate the probability of pitting failure. The effects of design factors, such as the case hardening depth (CHD), surface hardness, and contact pressure on fatigue failure risk, are studied. As the CHD increases or the surface hardness decreases, the risk of deep spalling failure reduces. The increase in surface hardness leads to a decreased risk of pitting failure, while the variation in CHD hardly affects the pitting failure risk.

show abstract

Tooth flank fracture – basic principles and calculation model for a sub surface initiated fatigue failure mode of case hardened gears

Cited by 26 publications

References 4 publications

Parameter study on the calculated risk of tooth flank fracture of case hardened gears

Parameter study on the calculated risk of tooth flank fracture of case hardened gears

Análise De Falha De Engrenagens De Redutores Grande Porte

Evaluation of contact fatigue risk of a carburized gear considering gradients of mechanical properties

Contact Info

Product

Resources

About