Seite - 137 - in 3D Printing of Metals

Metals 2017,7, 113 Figure7. (a)Test set-upforhole-flanging; (b) specimengeometrywithandwithoutcladding. Table2.Overviewofhole-flangingexperiments. Thickness [mm] CladdingPosition HoleDiameter [mm] HoleExpansion[%] 2.0/2.5 None 8.0 25.0 2.7 inside/outside 8.0 25.0 2.0/2.5 None 7.5 33.3 2.7 inside/outside 7.5 33.3 2.0/2.5 None 7.0 42.9 2.7 inside/outside 7.0 42.9 3.Results 3.1. Results forDemonstrator I—StiffnessManagement 3.1.1. Resultsof theSizingOptimization The solution of the sizing optimization is shown in Figure 8 in terms of thickness increase vs. thicknessof basematerial. Anoptimal increase in stiffnessunder thegivenmass constraint is obtainedbyanon-linear increase in sheet thickness ina ring-shapedarea close to the centralhole. Sizingoptimizationyields a smooth transitionbetween thickenedareaand theflat top faceof the component towardstheouterradiusof thepart,anda jumpinsheet thickness towardsthecentralhole. Figure8.Resultofsizingoptimization. (a)Optimumthicknessdistribution; (b)Optimumunder the constraint thatan innerradiusof15mmisnotusedforcladding. 137