7 .BS Agriculture Outer hull-endcap Inner hull-endcap Shield-endcap Bulkheads-cylinder Bulkheads-endcap For torsion problem I= Ix 2.259xl0 7 Kg 5.059xl0 7 Kg 4.589xl0 7 Kg 67.310xl0 7 Kg 0.810xl0 7 Kg 1. 736xl0 7 Kg Ix Ix (cylinder) + Ix(endcaps) 2.116xl0 12 Kg-m 2 + 4 .134xl0 12 I = Ix 6.250xlo 12 Kg-m 2 Kg-m 2 Substituting the values of G, J, I, and 1 into the equation for w: w = lfi = 7. 55 rad/sec f =}TI= 1.202.Hertz The colony is designed to sustain a maximum rotational frequency of 3 RPM or 0.05 Hertz. With almost two orders of magnitude between the maximum rotational frequency and the minimum natural frequency in torsion for the colony, there seems little chance of rotational variations exciting large amplitude torsional oscillations. Another important factor is the maximum amplitude that will occur during the torsional vibrations. The working stress of the inner hull is l.7378xl0 7 N/m 2 and the structure has been designed for a 10% alternating stress, 5% plus or minus . Taking 5% of the working stress or 8.69xl0 5 N/ m 2 and the following equation for stress due to torsion: Lr 0 max J The maximum torque/length (T) permitted is 4.920xl0 7 N. This corresponds to a force applied to the outer hull of 4.684xl0 5 N/m.
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