№67-06

Stress distribution along the flank wear surface of the bladeduring cuttingoperation

© Yu. Kravchenko¹, S. Patsera¹

¹Dnipro University of Technology, Dnipro, Ukraine

Coll.res.pap.nat.min.univ. 2021, 67:65-76

https://doi.org/10.33271/crpnmu/67.065

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ABSTRACT

The purpose of the paper is to determine the maximum and average values of normal stresses at the flank wear surface area of the blade and derive a formula for the exponent of distribution function for normal stresses along the length of the wear contact.

The research technique consists in introducing a special distribution function for normalstresses at the flank wear surface area of the blade based on the maximum normal stresses at the cutting edge from the side of the rear surface of the blade and the exponent of the decreasing function. The starting basis for determining the parameters of the mathematical model of distribution of normal stresses on the flank wear surface of the blade and corresponding tangential stresses is the developed system of empirical dependences of the tangential, radial and axial components of the cutting forces on the depth, feed and cutting speed at the certain front rake angle, nose radius and the magnitude of wear with generated exponents of a power, dimensional proportionality factor and correction factors for the grade of the material being machined and cutting conditions.

Research results. Despite the lower strength, austenitic steel 12KH18N9T/12Х18Н9Тin comparison with steel 45 has larger values of normal stresses and exponent of a power in the mathematical model of stress distribution given equal maximum stresses and coefficient of friction.

An increase in the front rake angle leads to a considerable decrease in the average values of stress and the exponent of a power. In this case, the coefficient of friction increases. At the same time, there was no significant dependence of the maximum stresses on the front rake angle.

In general, the calculations showed that the front rake angle significantly affects the magnitude and distribution of normal stresses at the flank wear surface area, suggestive of the relationship of contact stresses at the front and rear surfaces of the blade through the maximum normal stresses on the cutting edge in the chip formation zone.

Scientific novelty. The scientific novelty of the obtained results for determining the stress distribution on the rear surface of the blade wear during cutting is the proposed set of mathematical models and the sequence of their solution, which forms the appropriate algorithmic model.

Practical importance. The obtained calculation results allow the analytical determination of the distribution of shear stresses and the friction force at the flank wear surface of the blade.

Keywords: rear surface wear, stress distribution, exponent of dependence, magnitude of wear, force of friction, front rake angle.

References

1. Poletika, M.F. (1969) Kontaktnye nagruzki na rezhushchikh poverkhnostyakh instrumenta. Mashinostroenie.
2. Ostaf'yev, V.A. (1979) Raschet dinamicheskoy prochnosti rezhushchego instrumenta. Mashinostroenie.
3. Reznikov, A.N. (1981). Teplofizika protsessov mekhanicheskoy obrabotki materialov. Mashinostroenie.
4. Silin, S.S., (1979) Metod podobiya pri rezanii metallov. Mashinostroenie.
5. Kravchenko, Yu.G., Derbaba, V.A. & Kryukova, N.V. (2015). K voprosu empiricheskogo opredeleniya napryazheniya i koeffitsientov treniya pri struzhkoobrazovanii. Rezanie i instrument v tekhnologicheskikh sistemakh, 85, 137–148.
6. Bobrov, V.F. (1975) Osnovy teorii rezaniya metallov. Mashinostroenie.
7. Mazur, M.P. (red.), Vnukov, Yu.M., Dobroskok, V.L., Zaloha, V.O., Novosolov, Yu.K. & Yakubov, F.Ya. (2011) Osnovy teorii rizannia materialiv. Lviv: Novyi svit-2000.
8. Kravchenko, Yu.H. & Derbaba, V.A. (2021) Patent Ukrainy na korysnu model 146482. 24.02.2021. Kyiv: UIIV, Biul. inf. 8/2021.
9. Kravchenko, Yu.H., Derbaba, V.A. & Puhach, R.S. (2018) Patent Ukrainy na vynakhid 118302. 26.12.2018. Kyiv: UIIV, Biul. inf. 24/2018.
10. Kravchenko, Yu.H. & Derbaba, V.A. (2020) Patent Ukrainy na vynakhid 140418. 25.02.2020. Kyiv: UIIV, Biul. inf. 4/2020.
11. Zorev, N.N. (1956) Voprosy mekhaniki protsessa rezaniya metallov. Mashgiz