The project is divided into 5 work packages (WP). WP1 is related with project management and WP5 is related to knowledge protection, exploitation and dissemination activities.
Regarding RTD activities, WP2 faces the development of rapid distortion prediction. WP3´s goal is the development of rapid distortion prediction methods for additive layer manufacturing. WP4 copes with the topology optimization accounting for distortion.
The work performed in the project will be summarized in the following lines:
Related to WP2:
1. A simplified mechanical approach was developed; the machining induced residual stresses has been mapped in the contour of the final geometry by means of different elements: shell elements, membrane elements and layer solid elements and boundary layers elements.
2. Machining experimental trials has been carried out for Al7075 and Ti6Al4V rolled plates.
3. Correlation of experimental trials and FEM models prediction has been carried out for aluminium and titanium mock ups. the mean absolute error between experimentally measured distortions and the FEM model predicted is below 10%.
As for WP3:
4. Different simplified and rapid modelling approaches have been investigated. Inherent strains calibration/validation methodology has been established: based on cantilever beam geometry experimental results and iterative fitting algorithm.
5. Validation coupons have been manufactured by SLM, following different scanning strategies. Additionally, a mock up with more complex geometry has been manufactured
6. Post-process distortion measurements of each coupon have been performed in order to validate the numerical model against these measurements.
7. After the preliminary validation of FEM model, a use case has been defined for further development. Pclip geometry has been defined as a use case. Based on the original design, different optimized designs have been manufactured by SLM. SLM process induced distortion field has been predicted for each optimized design.
8. Comparison methodology for numerical distortion prediction results with the experimental results has been determined in WP3.
Related to WP4:
9. General optimization framework with an embedded, single-step machining process simulation developed, implemented, and subjected to initial testing.
10. Adjoint sensitivity formulation of general distortion response function with respect to topology (density) and process parameter variables developed, implemented, and compared with common `virtual work' response function.
11. A linearized transient AM process simulation is formulated for inclusion in a topology optimization design loop.. Small-scale support structure topology optimization has been demonstrated. Structural topology optimization of a combined AM process and in-service distortion formulation is demonstrated. The novelty is found in the exploitation of the seemingly detrimental AM process distortions to compensate a priori for in-service distortion.
12. Use case redesign, pclip, for manufacture and support-structure optimization is carried out by means of topology optimizations with embedded AM process simulation in the optimization loop.
13. The feasibility of gradient-based topology optimization procedures has been demonstrated to address fabrication issues due to AM.
14. A user guide for the topology optimization code developed during the DISTRACTION project has been defined and summarized in a document.
