21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-7.7.1

NUMERICAL SIMULATION OF THE TEMPERATURE FIELD DURING FATIGUE PROCESS

Yao L. J., Tong X., Ye D.
Northwestern Polytechnical Univ., Xi'an, PRC

Keywords: low-cycle fatigue, energy dissipation, thermal emission, finite difference

There is a great amount of plastic strain energy changes to heat due to the intensive internal friction during low-cycle fatigue. Thermal emission is the main form of energy dissipation in fatigue. Thus obvious temperature increment is found in fatigue experiments. To investigate the energy dissipation law during fatigue process, a heat conduction equation in the material is established according to the classic thermodynamics theory and the Gibbs local equilibrium assumption. By analyzing the relation of the post-fatigue toughness and the energy stored in materials during fatigue, the heat generation rate in each cycle is obtained. Using finite difference method to simulate the temperature field of a rectangular plate specimen, the authors obtains the law of temperature variation during the whole fatigue process and compares it with the experimental result. Those factors affecting the temperature variation, including stress/strain level, frequency and load wave type, are also analyzed.

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