Sunday, September 14, 2014

Contained But Not Stressed

Theoretically, from the post "Young And On Heat", for a sphere of 1m,

\(D.\cfrac{\partial (d_s)}{\partial T}=4\pi E\cfrac{\alpha}{\rho}\Delta L\)

For a given material such that  \(T_{max}<T_{melting}\),

\({\cfrac{\partial (d_s)}{\partial T}|_{T_{o}} \over\cfrac{\partial (d_s)}{\partial T}|_{T_{max}}}=\cfrac{\Delta L|_{T_{o}}}{\Delta L|_{T_{max}}}\)

and so,

\(F_{T_{max}}-F_{T_{o}}={F_{T_{max}}}\left\{1-\cfrac{L^2_e}{L^2_i}.{\cfrac{\partial (d_s)}{\partial T}|_{T_o}\over\cfrac{\partial (d_s)}{\partial T}|_{T_{max}}}\right\}\)

from the post "KaBoom", becomes,

\(F_{T_{max}}-F_{T_{o}}={F_{T_{max}}}\left\{1-\cfrac{L^2_e}{L^2_i}.\cfrac{\Delta L|_{T_{o}}}{\Delta L|_{T_{max}}}\right\}\)

this implies

\(\cfrac{L^2_e}{L^2_i}=\cfrac{\Delta L|_{T_{max}}}{\Delta L|_{T_{o}}}\)

The containment shell would have an external to internal radius ratio given by,

\(\cfrac{L_e}{L_i}=\sqrt{\cfrac{\Delta L|_{T_{max}}}{\Delta L|_{T_{o}}}}\)

for a containment without internal stress differential,

\(F_{T_{max}}-F_{T_{o}}=0\)

Big kaBoom!