ABAQUS user subroutines for the simulation of viscoplastic - loicz
ABAQUS user subroutines for the simulation of viscoplastic - loicz
ABAQUS user subroutines for the simulation of viscoplastic - loicz
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Fig. 14. Maximum. principal damage after 34000 h Fig. 15. Crack initiation at a cavity<br />
Fig. 16. Max. principal strain after 34000 h Fig. 17. Max. principal stress after 34000 h<br />
5.4 TiAl turbine blade — CHABOCHE model coupled with damage<br />
A model turbine blade made <strong>of</strong> a TiAl intermetallic alloy developed at <strong>the</strong> GKSS Research<br />
Centre is used as object <strong>of</strong> <strong>the</strong> FE-calculation. The blade has a length <strong>of</strong> 224 mm. The material<br />
parameters <strong>of</strong> <strong>the</strong> CHABOCHE model have been estimated by MOHR [1999], as listed in Table 5. Table<br />
6 gives <strong>the</strong> corresponding material parameters <strong>of</strong> <strong>the</strong> damage model used <strong>for</strong> <strong>the</strong> calculation. The<br />
continuum element C3D4 <strong>of</strong> <strong>the</strong> element library <strong>of</strong> <strong>ABAQUS</strong> is used. The number <strong>of</strong> nodes is 1476 and<br />
<strong>the</strong> number <strong>of</strong> elements is 4825. The blade is subject to centrifugal <strong>for</strong>ces, only, at a constant rotation<br />
speed <strong>of</strong> 40000 1/min; <strong>the</strong> density <strong>of</strong> TiAl is 3.8 g/cm 3 . Geometric non-linearity has been considered.<br />
The distribution <strong>of</strong> <strong>the</strong> maximum damage at t = 9060 hours is shown in Fig. 18. It obviously ocurs at <strong>the</strong><br />
root <strong>of</strong> <strong>the</strong> blade which after all has not been modelled realistically. The calculation is just supposed to<br />
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