Numerical simulation of material parameters of additively manufactured porous metal parts

Selective Laser Melting is a well-known variant of additive manufacturing. It offers the possibility to design porous, lattice-type structures with desired mesoscale structure properties by varying the hatch distance and the laser scan direction. The porosity of such materials may be exploited e.g. in the design of next-generation gas turbine blades using transpiration cooling. However, the mechanical properties of these new type of materials must be estimated carefully prior to the built process to assure the quality of the finished parts. However, for these structures, analytical homogenization strategies fail as the characteristic mesostructural length scale (i.e. the diameter of the solidified melt pool) becomes comparable to the macroscopic one. Numerical homogenization techniques in combination with the Finite Element (FE) Method provide an efficient alternative to the conventional approach. A difficulty of FE analysis is its necessity to resolve the topologically complex graded lattice structures in a boundary conforming manner - a procedure which is not easily automatable in a robust manner. To address this issue, we utilize the Finite Cell Method for the numerical homogenization of the mesostructure and employ the window method to determine the effective material properties. We will demonstrate by various examples that the combination of these two approaches is an efficient technique and present a road map of an automatized numerical determination of the elastic mechanical properties of graded lattice structures.     «

Selective Laser Melting is a well-known variant of additive manufacturing. It offers the possibility to design porous, lattice-type structures with desired mesoscale structure properties by varying the hatch distance and the laser scan direction. The porosity of such materials may be exploited e.g. in the design of next-generation gas turbine blades using transpiration cooling. However, the mechanical properties of these new type of materials must be estimated carefully prior to the built proce...     »