I know a nice bunch of glazed donut enthusiasts, who are building about a 25 foot static display spaceship, for a movie prop on the new Men in Black 5.
One of the parts of this spaceship, the longeron, was originally extruded on another planet, out of 6061-T6 aluminum. We unfortunately can't visit the other planet to get this extrusion right now, because they sold all of their extrusion stock to other donut enthusiasts on other planets.
The extruded longeron is a moderate radius 90 degree bend, about .070 wall thickness, with slightly thinner extensions (approx .050) that serve as skin riveting flanges. There are two perpendicular stiffening flanges, one approximately at the mid point of each major axis. These stiffening flanges are also about .050 wall thickness.
So I says to the Vice President of Donut Inspection "Y'know, Homer, we can probably fabricate a replacement longeron here on Earth out of 6061-T6 sheet metal that is the same thickness, and it's pretty likely that this replacement spaceship longeron would support the same loads, have the same buckling resistance, stress/strain curves, deflection, etc. etc. as the alien extruded one."
I came up with two potential ideas. One was a press brake fabricated "bent angle" with the same moderate (3/8") radius, that has longer skin flanges, and the ends of the skin flange are bent to serve as the perpendicular stiffeners. The other was a similar bent angle, but with separate (extruded or bent sheet ) angles attached in such a way as to use the same rivets that would be attaching the spaceship skin to the longeron anyway. This second method is a little easier to fabricate, but it is probabbly a little heavier. It puts the stiffeners closer to the same position as in the original extrusion, which may have some effect on the bending/twisting/moment/buckling of the longeron under load.
So although very few of you have experience on alien spaceships (at least that you'd admit), I'd still like to know if any of you structure type people can offer an educated guess.... Is any one of the original or proposed replacement longerons significantly better structurally than the others, and if we have to fabricate a replacement is it likely to perform as well as the original extrusion???
I truly want the spaceship movie prop to be able to withstand the same loads as it would have withstood with the alien extrusion. The thought of it falling on one of our Donut enthusiasts (or Will and Tommy) while we're filming the movie has me awake at night.
One of the parts of this spaceship, the longeron, was originally extruded on another planet, out of 6061-T6 aluminum. We unfortunately can't visit the other planet to get this extrusion right now, because they sold all of their extrusion stock to other donut enthusiasts on other planets.
The extruded longeron is a moderate radius 90 degree bend, about .070 wall thickness, with slightly thinner extensions (approx .050) that serve as skin riveting flanges. There are two perpendicular stiffening flanges, one approximately at the mid point of each major axis. These stiffening flanges are also about .050 wall thickness.
So I says to the Vice President of Donut Inspection "Y'know, Homer, we can probably fabricate a replacement longeron here on Earth out of 6061-T6 sheet metal that is the same thickness, and it's pretty likely that this replacement spaceship longeron would support the same loads, have the same buckling resistance, stress/strain curves, deflection, etc. etc. as the alien extruded one."
I came up with two potential ideas. One was a press brake fabricated "bent angle" with the same moderate (3/8") radius, that has longer skin flanges, and the ends of the skin flange are bent to serve as the perpendicular stiffeners. The other was a similar bent angle, but with separate (extruded or bent sheet ) angles attached in such a way as to use the same rivets that would be attaching the spaceship skin to the longeron anyway. This second method is a little easier to fabricate, but it is probabbly a little heavier. It puts the stiffeners closer to the same position as in the original extrusion, which may have some effect on the bending/twisting/moment/buckling of the longeron under load.
So although very few of you have experience on alien spaceships (at least that you'd admit), I'd still like to know if any of you structure type people can offer an educated guess.... Is any one of the original or proposed replacement longerons significantly better structurally than the others, and if we have to fabricate a replacement is it likely to perform as well as the original extrusion???
I truly want the spaceship movie prop to be able to withstand the same loads as it would have withstood with the alien extrusion. The thought of it falling on one of our Donut enthusiasts (or Will and Tommy) while we're filming the movie has me awake at night.
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