Lightweighting in Metal Additive Manufacturing

Metal additive manufacturing techniques such as Direct Metal Laser Sintering (DMLS) and Directed Energy Deposition (DED) allow for complex geometry fabrication of metal parts, a capability that is of special interest from a design point of view. Means to minimize material consumption, build time and consequently, manufacturing costs is constantly being sought after in Additive Manufacturing (AM). Lightweight design is considered one of the most promising methods to achieve this objective and it is actualized through topology optimization or generating lattice structures.

In addition to the above mentioned benefits, the application of these designs in aerospace industry is of outmost importance. Weight reduction capabilities of both approaches is well known, however, the mechanical performance of these models has yet to be studied.In this work, we aim to characterize the mechanical properties of additively manufactured, optimized, load-bearing functional parts. Design and optimization is done using Pareto software, developed at UW-Madison. These designs are later manufactured using a DMLS system and a DED system. Finally, mechanical tests are performed to quantify the performance of each design and to identify the existing trade-offs in terms of performance versus weight.

2/3 of 12 million oil barrels/day imported in 2009 used for transportation fuels
Road transportation and aviation consumes ~1/4 fo global energy supply
Topological optimization using additive manufacturing should enable specific strength better than A1 alloys
Solidification of Near Net Shape Parts:
High T gradients
Energy efficiency during processing
Reduced design cycle

Background and Context
Lightweighting has a relevant energy context that can be achieved using topological optimization combined with additive manufacturing for enhanced functionality

1. Topological optimization can offer increased functionality with reduced qualification requirements (proper safety factor)
2. Extruded 2.5D structures were used to standardized comparisons of different AM techniques
3. Topologically optimized structural components at 50% density can challenge specific properties of A1 alloys
4. Experimental results validate the calculated scenarios, with stiff designs and strong designs achieving desire objectives
5. Microstructure can be incorporated into models at a reduced scale (next step)

The EOS M290 was supported with UW2020 WARF Discovery Initiative funds
The Grainger Institute for Engineering seeded the research activity
Pareto software was used for topology optimizations