VESTNIK of Samara University. Aerospace and Mechanical EngineeringVESTNIK of Samara University. Aerospace and Mechanical Engineering2542-04532541-7533Samara National Research University460210.18287/2541-7533-2017-16-1-129-136UnknownEvaluation of low cycle fatigue based on the use of Coffin-Manson dependence under zero-to-“soft” loading cyclePavlovV. F.<p><span lang="EN-US">Doctor of Science (Engineering), Professor</span></p>
<p><span lang="EN-US"> Head of the Department of Strength of Materials</span></p>sopromat@ssau.ruKirpichyovV. A.<p><span lang="EN-US">Doctor of Science (Engineering)</span></p>
<p><span lang="EN-US">Professor of the Department of Strength of Materials</span></p>dean_fla@ssau.ruKocherovaE. E.<p><span lang="EN-US">Postgraduate student of the Department of Strength of Materials</span></p>kocherova_2020@mail.ruZlobinA. S.<p><span lang="EN-US">Postgraduate student of the Department of Strength of Materials</span></p>as.zlobin@mail.ruSamara National Research University310520171611291360106201701062017Copyright © 2017, VESTNIK of Samara University. Aerospace and Mechanical Engineering2017<p>To calculate the durability of gas turbine engine parts damaged by low-cycle fatigue (LCF), according to the Structural codes of turbine engine strength it is necessary to test specimens cut from respective parts (or test coupons) under hard loading. Hard here means there is a fixed strain cycle. The tests are conducted with different asymmetry coefficients of the strain cycle and with different exposure time at the maximum cycle strain (to take into account the effect of creep at high temperatures). The tests carried out are to provide sufficient statistics to ensure the reliability of the calculation. We suggest a method of assessing the durability of gas turbine engine parts based on testing standard specimens at zero-to-soft loading cycle using modified Manson-Coffins equation. The results of the work confirm the possibility of achieving the required adequacy of assessing the durability of parts damaged by the LCF mechanism with the use of a modified Manson-Coffin equation. Some recommendations concerning its application are given.</p>Gas turbine engineslow cycle fatiguefatigue testscyclic durabilityManson-Coffin equationsoft loadinghard loadingГазотурбинный двигательмалоцикловая усталостьиспытания на усталостьциклическая долговечностьуравнение Мэнсона-Коффина«мягкое» нагружение«жёсткое» нагружение[1. Normy prochnosti aviatsionnykh gazoturbinnykh dvigateley grazhdanskoy aviatsii [Strength standards of aviation gas turbine engines of civil aviation]. Moscow: CIAM Publ., 2004. 260 p. (In Russ.)][2. Teren’t’ev V.F, Petukhov A.N. Ustalost’ vysokoprochnykh metalicheskikh materialov [Fatigue of high-strength metallic materials]. Moscow: CIAM Publ., 2013. 515 p.][3. Parton V.Z., Borisovskiy V.G. Dinamika khrupkogo razrusheniya [Dynamics of brittle fracture]. Moscow: Mashinostroenie Publ., 1988. 240 p.][4. Anurov U.M., Fedorchenko D.G. Osnovy obespecheniya prochnostnoy nadezhnosti aviatsionnykh dvigateley i silovykh ustanovok [The principles of ensuring the strength reliability of aircraft engines and power units]. St.-Peterburg: Peter the Great Saint-Petersburg Polytechnic University Publ., 2004. 390 p.][5. Kudryavtsev I.V., Naumchenko N.E., Savvina N.M. Ustalost' krupnykh detaley mashin [Fatigue of large machine parts]. Moscow: Mashinostroenie Publ., 1981. 240 p.][6. Kolmogorov V.L. Napryazheniya, deformatsii, razrushenie [Stresses, deformations, destruction]. Moscow: Metallurgiya Publ., 1970. 229 p.][7. Kudryavtsev P.I. Nerasprostranyayushchiesya ustalostnye treshchiny [Non-propagating fatigue cracks]. Moscow: Mashinostroenie Publ., 1982. 174 p.][8. GOST 25.502-79. Strength analysis and testing in machine building. Methods of metals mechanical testing. Methods of fatigue testing. Moscow: Standartinform Publ., 1983. 50 p. (In Russ.)][9. Makhutov N.A., Gadenin M.M., Burak M.I, Daunis M.A., Zatsarini V.V., Zlochevsky A.B., Kagan V.A., Larionov V.V., Levin O.A., Novikov V.A., Pokrovsky V.V., Romanov A.N., Troschenko V.T., Filatov V.M. Mekhanika malotsiklovogo razrusheniya [Mechanics of Low-Cicle Fracture]. Moscow: Nauka Publ., 1986. 264 p.][10. Makhutov N.A. Deformatsionnye kriterii razrusheniya i raschet elementov konstruktsiy na prochnost' [Deformation fracture criteria and strength calculation of structural components]. Moscow: Mashinostroenie Publ., 1981. 272 p.]