Steve Jackson Games Forums - View Single Post - [Spaceships] Nanocomposite and structural materials

Agemegos · 12-16-2018, 07:09 PM

I'm doing a bit of modelling of the engineering requirements of space habitats with spin gravity (for FLAT BLACK, where there is no synthetic gravity). In particular, I'm investigating how thick (and therefore massive) you have to make the hull of a cylinder spinning on its axis to support its own mass and that of a load (of armour, habitat, radiation shielding &c.) against the centrifugal effect of their inertia. It turns out (unsurprisingly) that the necessary thickness (and therefore mass and cost) of the structural hull depends strongly on the density and tensile strength of the structural material. I figure that:

t = r(P₁ + a₁λ)/(σ - ra₁ρ)

where
t = minimum thickness of the structural hull
P₁ = air pressure at the deck level
a₁ = centripetal acceleration at the deck level
λ = areic mass of the load (armour, shielding, habitat fittings, landscaping etc.)
r = radius of the cylinder
σ = tensile strength of the hull material (safe limit)
ρ = density of the hull material

I can find figures for the strength and density of some of the materials mentioned in GURPS Spaceships, such as mild steel and high-tensile steel, high-strength aluminium alloy, and titanium. Also, for polyester reinforced with glass fibre (a surprisingly good material for the purpose at TL7), epoxy reinforced with aramid fibre, epoxy reinforced with graphite fibre, diamond, cubic boron nitride, and carbon nanotubes (buckytubes). But there are some posited futuristic materials mentioned in Spaceships of which the identities are artfully vague, and for which figures are supplied implying their relative effectiveness as armour but not their actual density and tensile strength: metallic laminate (TL8), advanced metallic laminate (TL9), nanocomposite (TL10), space-adapted wood, living tissue, living bioplastic (TL10), exotic laminate.

Armour materials might not be the same as structural materials, of course.

Can anyone suggest what structural materials might correspond to the armour materials listed in Spaceships and what their densities and tensile strengths might be? Since FLAT BLACK is TL10 I'm most interested in what might correspond to nanocomposite.

12-16-2018, 07:09 PM	#1
Agemegos Join Date: May 2005 Location: Oz	[Spaceships] Nanocomposite and structural materials I'm doing a bit of modelling of the engineering requirements of space habitats with spin gravity (for FLAT BLACK, where there is no synthetic gravity). In particular, I'm investigating how thick (and therefore massive) you have to make the hull of a cylinder spinning on its axis to support its own mass and that of a load (of armour, habitat, radiation shielding &c.) against the centrifugal effect of their inertia. It turns out (unsurprisingly) that the necessary thickness (and therefore mass and cost) of the structural hull depends strongly on the density and tensile strength of the structural material. I figure that: t = r(P₁ + a₁λ)/(σ - ra₁ρ) where t = minimum thickness of the structural hull P₁ = air pressure at the deck level a₁ = centripetal acceleration at the deck level λ = areic mass of the load (armour, shielding, habitat fittings, landscaping etc.) r = radius of the cylinder σ = tensile strength of the hull material (safe limit) ρ = density of the hull material I can find figures for the strength and density of some of the materials mentioned in GURPS Spaceships, such as mild steel and high-tensile steel, high-strength aluminium alloy, and titanium. Also, for polyester reinforced with glass fibre (a surprisingly good material for the purpose at TL7), epoxy reinforced with aramid fibre, epoxy reinforced with graphite fibre, diamond, cubic boron nitride, and carbon nanotubes (buckytubes). But there are some posited futuristic materials mentioned in *Spaceships* of which the identities are artfully vague, and for which figures are supplied implying their relative effectiveness as armour but not their actual density and tensile strength: metallic laminate (TL8), advanced metallic laminate (TL9), nanocomposite (TL10), space-adapted wood, living tissue, living bioplastic (TL10), exotic laminate. Armour materials might not be the same as structural materials, of course. Can anyone suggest what structural materials might correspond to the armour materials listed in Spaceships and what their densities and tensile strengths might be? Since FLAT BLACK is TL10 I'm most interested in what might correspond to nanocomposite. __________________ Decay is inherent in all composite things. Nod head. Get treat.