Hypervelocity impact performance of 3D printed aluminum panels

NASA, JSC has been developing a light-weight, multi-functional sandwich core for habitable structure over the last several years. Typically honeycomb-based structures have been and still are a common structural component for many applications in the aerospace industry, unfortunately, honeycomb structures with an ordered, open path through the thickness have served to channel the micro-meteoroid or orbital debris into the pressure wall (instead of disassociating and decelerating). The development of a metallic open cell foam core has been explored to enhance the micro-meteoroid or orbital debris protection, which is heavier than comparable honeycomb-based structures when non-structural requirements for deep space environments (vacuum, micro-meteoroids/orbital debris, and radiation) have not been considered. While the metallic foam core represents a notable improvement in this area, there is an overwhelming need to further reduce the weight of space vehicles; especially when deep space (beyond low earth orbit, or LEO) is considered. NASA, JSC is currently developing a multi-functional sandwich panel using additive machining (3D printing), this effort evaluated the material response of a limited amount of 3D printed aluminum panels under hypervelocity impact conditions. The four 3D printed aluminum panels provided for this effort consisted of three body centric cubic lattice structure core and one kelvin cell structure core. Each panel was impacted once with nominally the same impact conditions (0.34cm diameter aluminum sphere impacting at 6.8 km/s at 0 degrees to surface normal). All tests were impacted successfully, with the aforementioned impact conditions. Each of the test panels maintained their structural integrity from the hypervelocity impact event with no damage present on the back side of the panel for any of the tests. These tests and future tests will be used to enhance development of 3D printed structural panels.