Contact visco-elastic stress analysis using finite element method

In a high temperature gas-cooled reactor, thermal performance of an annular fuel rod is superior to that of the hollow rod. Differential thermal expansion and shrinkage, however, cause closure of the gap between fuel compact and inner graphite sleeve, producing larger stress of the compact and sleeve than in the hollow rod. The contact between compact and sleeve must be fully considered, in design of the annular fuel rod. Calculational method of this contact visco-elastic problem with the finite element method(FEM) for the annular fuel rod of HTGR is described. FEM results of the simplified problem are compared with those by an analytical one, and adequacy of the former is shown. The FEM is useful for stress analysis of the fuel in multi-purpose experimental very high temperature gas-cooled reactor. It is also applicable to other contact problems such as the pellet clad mechanical interaction in LWR or FBR fuels. (auth.)