Additive manufacturing of hot bonded inserts in sandwich structures with metal 3D printingWednesday (08.11.2017) 15:00 - 15:20 Part of:
Hot bonded inserts in sandwich configurations are widely used in spacecraft structures. These inserts are co-cured with the sandwich panels and are commonly used for highly loaded interfaces. A new lightweight revolutionary design of the hot bonded inserts can be realised thanks to the FEA and optimization tools. The inserts are commonly made of aluminium alloy since the mass of this interface solution is an important design parameter. The thermo-elastic stresses which occur during the curing process could affect the insert strength capability. To reduce this manufacturing risk, titanium alloy (Ti6Al4V) hot bonded inserts are chosen when the sandwich is made up of Carbon Fiber Reinforced Plastic (CFRP) skins reducing the thermo-elastic effect. Metal 3D Printing (M3DP) provides the opportunity to improve this kind of structural elements in three main areas: mass, thermo-elastic behaviour and bonding capability. Using M3DP a part’s costs are primarily depending on the printed volume and not the part’s complexity. The iterative manufacturing process is based on a local melting and solidification of defined layers in a powder bed according to a digital part’s slicing information. The layer wise manufacturing reduces complex three-dimensional manufacturing tasks into simple two-dimensional steps. Due to the tool-less nature of the manufacturing process, moreover, an amortization of tools is not necessary. M3DP opens a new way of thinking and defining design solutions; the result of the simulation driven design process can be introduced into part manufacturing with relatively few manufacturing limitations. In this case, topology optimization is used to reduce weight in combination with several thermal and structural validation FEA loops to maintain the strength of the part and to prevent de-bonding during the curing process. Lattice structures are included in the study to investigate their advantages and limitations in this product. This joint study by Atos Engineering and Materialise combines the complete design loop with the subsequent additive manufacturing of an optimized aerospace part. Additive manufacturing removes traditional design limitations, FEM simulation and optimization are imperative to meet these new engineering challenges.