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Additive Fertigungsverfahren beruhen auf dem Grundgedanken des Schicht-oder elementweisen Aufbaus.Die Fertigung der Geometrien erfolgt aus formlosen Materialien (Flüssigkeiten, Pulver) oder formneutralen Materialien (Band, Draht, Papier, Folie) mittels chemischer und/oder physikalischer Prozesse über eine CAD/CAM-Kopplung direkt aus den digital erzeugten CAD-Datenmodellen (vgl. V D I3405).

Abstract. The growing market for additive manufacturing processes such as laser beam melting (LBM) poses new challenges. With more difficult product requirements, the need for a deeper understanding of the resulting stress states and the underlying physical principles increases. To gain a deeper understanding of the residual stress states of LBM-manufactured parts, simulations of the build-up process were carried out and validated by means of neutron diffraction (ND), X-ray diffraction (XRD) as well as incremental hole-drilling (IHD). The gathered data is also intended to serve as a validation case for other simulation models and tools. 469Bayerlein et al.

The Finite Element Method results in inaccuracies for temperature changes at the boundary if the mesh is too coarse in comparison with the applied time step. Oscillations occur as the adjacent elements balance the excessive energy of the boundary element. An Extended Finite Element Method (XFEM) with extrinsic enrichment of the boundary element by a parameterized problem-specific ansatz function is presented. The method is able to represent high thermal gradients at the boundary with a coarse mesh as the enrichment function compensates for the excessive energy at the element affected by the temperature change. The parameterization covers the temporal change of the gradient and avoids the enrichment by further ansatz functions. The introduced parameterization variable is handed over to the system of equations as an additional degree of freedom. Analytical integration is used for the evaluation of the integrals in the weak formulation as the ansatz function depends non-linearly on the parameterization variable. Highlights Parameterized problem-specific ansatz functions. Avoidance of a fine mesh in the area of high gradients. Representation of high gradients with one additional DOF.