Study of fatigue crack propagation in Ti-1Al-1Mn based on the calculation of cold work evolution

6th International Conference on Fracture Fatigue and Wear

Plekhov, O.A.^1 ; Kostina, A.A.^1

Institute of Continuous Media Mechanics, Ural Branch, Russian Academy of Science, 1 Ac. Koroleva Street, Perm

614013, Russia^1

关键词: Deformation and failures;    Deformation energy;    Fatigue crack rate;    Internal variables;    Lifetime assessment;    Phenomenological modeling;    Second-order tensors;    Statistical descriptions;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/843/1/012034/pdf
DOI  :  10.1088/1742-6596/843/1/012034

来源: IOP

【 摘 要 】

The work proposes a numerical method for lifetime assessment for metallic materials based on consideration of energy balance at crack tip. This method is based on the evaluation of the stored energy value per loading cycle. To calculate the stored and dissipated parts of deformation energy an elasto-plastic phenomenological model of energy balance in metals under the deformation and failure processes was proposed. The key point of the model is strain-type internal variable describing the stored energy process. This parameter is introduced based of the statistical description of defect evolution in metals as a second-order tensor and has a meaning of an additional strain due to the initiation and growth of the defects. The fatigue crack rate was calculated in a framework of a stationary crack approach (several loading cycles for every crack length was considered to estimate the energy balance at crack tip). The application of the proposed algorithm is illustrated by the calculation of the lifetime of the Ti-1Al-1Mn compact tension specimen under cyclic loading.