In the present work, elasto-plastic creep crack growth simulations are performed using continuum damage mechanics and extended finite element method. Liu–Murakami creep damage model and explicit time integration scheme are used to evaluate the creep strain and damage variable for various materials at different temperatures. Compact tension and C-shaped tension specimens are selected for the simulation of crack growth analysis. For damage evaluation, both local and nonlocal approaches are employed. The accuracy of the extended finite element method solutions is checked by comparing with experimental results and finite element solutions. These results show that the extended finite element method requires a much coarser mesh to effectively model crack propagation. It is also shown that mesh independent results can be achieved by using nonlocal implementation.
Acoustic emission -AEAcoustic Emission burst: A signal oscillatory in shape whose oscillations have a rapid increase in magnitude from an initial reference level (generally that of background noise) followed by a decrease (generally more gradual) to a value close to the initial level. Threshold: It is the user defined value of amplitude in decibels (dB), generally decided and set based on background noise. Counts: Number of times an AE burst crosses the threshold. Peak amplitude: It is the maximum voltage of the AE signal and is measured in decibels. Energy: It is the area under the amplitude-time curve above the threshold value. Rise time: It is the time between the first threshold crossing and maximum peak amplitude. Duration: It is the time between the first and the last threshold crossing.
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