PSI - Issue 2_A

Dong-Jun Kim et al. / Procedia Structural Integrity 2 (2016) 825–831 Dong-Jun Kim et al. / Structural Integrity Procedia 00 (2016) 000–000

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damage criteria, the fracture toughness test at 550 ºC was used. For this reason the prediction of crack growth can be imprecise. 5. Conclusions In this paper, a combined plastic and creep damage model is proposed to simulate creep failure. Note that the proposed model is an extension of the previous model whereby only creep damage is considered. Incremental plastic and creep damage are defined by the ratio of incremental strain and multi-axial ductility using uni-axial inelastic ductility and multi-axial ductility factors for plasticity and creep. Total damage is defined over linear addition of plastic and creep damage. The model developed for P91 at 600 ºC using tensile, creep and J-R test data, is used to simulate creep crack growth test using compact tension specimen. Simulated results using only creep and combined models are compared with the creep crack growth test experimental data. Using combined model simulated creep crack growth are improved closer to experimental data.

Fig. 5. Simulated J-R curves using different k-factor for 0.1mm element size.

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(b)

Fig. 6. Comparison of FE results with experimental data of the compact tension creep tests with P=5.0kN: (a) load line-displacement versus time and (b) crack length versus time.