To reduce thermomechanical computational time, the inherent strain (IS) method is popular. It consists in adding layers, at room temperature, with an "inherent strain" representing the plastic deformation undergone during deposition. This approach is less time consuming than the transient thermo-elastic-viscoplastic (TEVP) simulation. An IS method was developed, including a direct determination of the IS tensor based on the TEVP simulation performed on a small-scale workpiece of a few layers. Validation was achieved: taking these full-field inherent strains, the IS method allowed retrieving TEVP predictions. However, application to a more complex geometry (turbine blade manufactured by powder-laser DED), led to poor results, far from references. This expresses the weakness of the method: a lack of underlying physics, preventing reliable prediction. As an alternative, a new "inherent strain-rate" (ISR) method is proposed, consisting in linearizing TEVP resolutions. This is obtained by considering the equivalent viscoplastic strain-rate as the ISR. During simulation, the ISR-based resolutions are combined with TEVP ones, used to allow a regular updating of the ISR. This strategy leads to perfect results for the turbine blade, with a time gain of 5. This makes the proposed ISR method very promising.

Moderated by: Steve Cockcroft / Farzaneh Farhang Mehr