Unsteady Thermal Stress Analysis of a Cryogenic Foam Insulation Element

摘要

The unsteady temperature and the accompanying deformation and stress fields in a cryogenic foam element of polyurethane and polystyrene were simulated numerically. The model, based upon the minimum potential energy method, was compared with the standard computer code STARDYNE. The joint heat-transfer problem is considered with a fourth kind boundary condition. The very weak interaction between the temperature and deformation fields is neglected. The temperature dependence of both of the physical and mechanical properties of the insulation element are taken into consideration. The difference between the numerical results was within 10 percent and the simplified method used five times less CPU time than the STARDYNE code. The results of the structure crack analysis carried out on the basis of the computed stress field show that the dynamical change of the temperature in the element (cool down) can be more dangerous than the steady-state (cooled down state).