Critical stresses of radial stability of flexible circular ring with initial plastic bending strains

Authors

  • І. V. Lazariev Electromechanics laboratory of the department for research in electromagnetics, Public joint stock company “Ukrainian research, design and technological transformer institute” (PJSC “VIT”), 11 Dnipropetrovske shose, 69069, Zaporizhzhya, Ukraine., Ukraine https://orcid.org/0000-0002-6338-2793

Keywords:

flexible circular ring, initial plastic bending strains, critical stresses of radial stability

Abstract

Purpose. With regard to plastic bending strains originating during fabrication, there has earlier been studied stability of the flexible circular ring with rectangular cross section without fillets as applied to analysis of transformer winding conductors. Real conductors have fillets in cross section corners. Conductors with round cross section are widely utilised. It is necessary to determine critical stresses of radial stability of flexible circular rings with round and filleted rectangular cross sections with initial plastic bending strains originating during fabrication. Methodology. With regard to initial plastic bending strains, there were determined critical stresses of radial stability of the ring with round cross section. There was developed a numerical method for determining critical stresses of radial stability of the ring with filleted rectangular cross section with initial plastic bending strains. This method covers all conductor cross section types utilised in transformers. Findings. The methods developed were applied to calculation of critical stresses of radial stability of windings with round and rectangular conductors. The obtained results demonstrated that due to the initial plastic bending strains the examined rings (conductors) do not follow Hooke’s law. Therefore, the deformable solid body mechanics formulae based upon it are not applicable to such rings. The initial plastic bending strains cause significant reduction of critical stresses of radial stability, thus the methods that do not take these strains into account cannot be used for analysis of the rings under consideration. Comparison of calculation results and windings test data confirmed validity of the methods developed. Originality. There was developed a generalised numerical method for determining critical stresses of radial stability with regard to initial plastic bending strains that covers the rings with round and filleted rectangular cross section. Practical value. The developed methods for calculation of critical stresses of radial stability of flexible rings with round and filleted rectangular cross section are widely used for stability analysis of transformer winding conductors under the action of radial compressive short circuit forces.

References

Алфутов Н. А. Основы расчета на устойчивость упругих систем / Н. А. Алфутов - М. : Машиностроение, 1978. - 312 с.

Alfutov N. A. Osnovy rascheta na ustoychivost uprugikh sistem [Basics of stability analysis of elastic systems], Moscow, Mashinostroyeniye Publ., 1978. 312 p.

Антонов М. В. Технология производства электрических машин / М. В. Антонов, Л. С. Герасимова. - M. : Энергоиздат, 1982. - 512 c.

Antonov M. V. Tekhnologiya proizvodstva elektricheskikh mashin [Technology of fabrication of electric machines], Moscow, Energoizdat Publ., 1982. 512 p.

Вольмир А. С. Устойчивость деформируемых систем / А. С. Вольмир - М. : Наука, 1967. - 984 c.

Volmir A. S. Ustoychivost deformiruyemykh sistem [Stability of deformable systems], Moscow, Nauka Publ., 1967, 984 p.

Зенова В. П., Стойкость сжимаемых обмоток трансформаторов при действии радиальных усилий короткого замыкания / В. П. Зенова, С. И. Лурье, Л. И. Мильман // Электротехника. - i975. - №4. - C. 39 - 43.

Zenova V. P., Lurye S. I. Stoikost szhimayemykh obmotok transformatorov pri deystvii radialnykh usiliy korotkogo zamykaniya [Stability of compressed transformer windings under the action of radial internal forces of short circuit], Elektrotekhnika [Electric engineering], i975, No. 4, pp. 39 - 43.

Кантор Б. Я. Об устойчивости упруго­ пластического гибкого кольца на упругих опорах под действием нестационарного давления / Б. Я. Кантор, Л. В. Науменко // Расчет напряженно- деформированного состояния пластин и оболочек. - Саратов : Изд-во Саратовского ун-та. - i9 8i. - C. 33 - 35.

Kantor B. YA., Naumenko L. V. Ob ustoychivosti uprugo-plasticheskogo gibkogo koltsa na uprugikh oporakh pod deystviyem nestatsionarnogo davleniya [On stability of elastoplastic flexible ring on elastic supportsunder the action of non-stationary pressure], Raschet napryazhenno-deformirovannogo sostoyaniya plastin i obolochek [Analysis of stress-strain state of plates and shells], Saratov university press, Saratov, 1981, pp. 33 - 35.

Кантор Б. Я. Динамика несовершенных гибких колец на упругих опорах, нагруженных апериодическим давлением / Б. Я. Кантор, Л. В. Науменко // Пробл. машиностроения. - 1982. - Вып. 17. - C. 39 - 44.

Kantor B. YA., Naumenko L. V. Dinamika nesovershennykh gibkikh kolets na uprugikh oporakh, nagruzhennykh aperiodicheskim davelniyem [Dynamics of imperfect flexible rings upon elastic supports loaded by aperiodic pressure], Problemy mashinostroyeniya [Mechanical engineering problems], 1982, issue No. 17, pp. 39 - 44.

Корбут Б. А. Собственные колебания кольца на упругих опорах / Б. А. Корбут, Л. В. Науменко // Динамика и прочность машин. - 1977. - Вып. 26. - C. 44 - 48.

Korbut B. A., Naumenko L. V. Sobstvennyye kolebaniya koltsa na uprugikh oporakh [Natural vibrations of the ring upon elastic supports], Dinamika i prochnost mashin [Dynamics and strength of machines], 1977, issue No. 26, pp. 44 - 48.

Корбут Б. А. Радиальная устойчивость сжимаемых обмоток трансформаторов при работе за пределом упругости / Б. А. Корбут, В. И. Лазарев // Электротехника. - 1979. - №1. - C. 20 - 22.

Korbut B. A, Lazarev V. I., Radialnaya ustoychivost szhimayemykh obmotok transformatorov pri rabote za predelom uprugosti [Radial stability of compressed transformer windings in operation beyond the limit of elasticity], Elektrotekhnika [Electric engineering], 1979, No. 1, pp. 20 - 22.

Лазарев В. И. Уравнения колебаний круговых колец / В. И. Лазарев, В. Е. Рущак // Пробл. прочности. - 1982. - №12 - C. 86 - 88.

Lazarev V. I., Rushchak V. YE. Uravneniya kolebaniy krugovykh kolets [Equations of vibrations of circular rings], Problemy prochnosti [Strength of materials], 1982, No. 12, pp .86 - 88.

Лазарев В. И. Динамическая устойчивость гибкого кольца с сосредоточенными массами приапериодическом нагружении / В. И. Лазарев, B. Е. Рущак // Пробл. прочности. - 1986. - №10. -C.104 - 108.

Lazarev V. I, Rushchak V. YE. Dinamicheskaya ustoychivost gibkogo koltsa s sosredotochennymi massami pri aperiodicheskom nagruzhenii [Dynamic stability of flexible ring with concentrated masses under aperiodic loading], Problemy prochnosti [Strength of materials], 1986, No. 10, pp.104 - 108.

Лазарев В. И. Устойчивость кольца на опорах с сухим трением при динамическом нагружении / В. И. Лазарев, В. Е. Рущак // Динамика и прочность машин. - 1986. - Вып. 43. - C. 108 - 112.

Lazarev V. I., Rushchak V. YE., Ustoychivost koltsa na oporakh s sukhim treniyem pri dinamicheskom nagruzhenii [Stability of ring upon supports with dry friction under dynamic loading], Dinamika i prochnost mashin [Dynamics and strength of machines], issue No. 43, 1986, pp.108 - 112.

Лазарев В. И. Радиальная устойчивость обмоток трансформаторов при коротких замыканиях / В. И. Лазарев, В. Е Рущак, М. В. Сорока // Техническая электродинамика. - 1991. - №1. - С. 78 - 84.

Lazarev V. I., Rushchak V. YE., Soroka M. V. Radialnaya ustoychivost obmotok transformatorov pri korotkikh zamykaniyakh [Radial stability of transformer windings under short circuit], Tekhnicheskaya elektrodinamika [Technical electrodynamics], No. 1, 1991, pp. 78 - 84.

Науменко Л. В. Об устойчивости упруго­пластического гибкого кольца на упругих опорах под действием нестационарного давления / Л. В. Науменко // Пробл. машиностроения. - 1982. - Вып. 16. - C. 34 - 40.

Naumenko L. V. Ob ustoychivosti uprugo-plasticheskogo gibkogo koltsa na uprugikh oporakh pod deystviyem nestatsionarnogo davleniya [On stability of elastoplastic flexible ring on elastic supports under the action of non-stationary pressure], Problemy mashinostroyeniya [Mechanical engineering problems], issue No. 16, 1982, pp.34 - 40.

Published

2015-04-20

Issue

Section

Proceedings in memory of Starodubov