The internal stress and residual strain of Chevrel-phase PbMo
6S
8 wires were analyzed using an elastic-perfect plastic model. Comparing these results with those previously obtained from our experimental results, it was found that the order of size of the residual pre-strains qualitatively agrees with the experimental results except for part of the wires although the analyzed values were 0.2-0.4% larger than the experimental values. Concerning critical current (
Ic) degradation in a small 3-layer PbMo
6S
8 coil using a mandrel made of alumina, the difference between the experimental result and estimated value was argued. It was concluded that it is insufficient to explain the difference even when considering the effects of hoop's strain due to electromagnetic force and the variation in the cross-sectional area of the compound layer. Moreover, the internal stress and residual strain were analyzed for six kinds of assumed MgB
2 wire in which different sheaths were used. As a result, the wire with a Fe sheath had better mechanical characteristic than one with a Cu sheath in the case of using a single sheath. As for adopting composite sheaths, the wire with a Fe-barrier/Cu/Cu-Ni composite sheath had better strain characteristic as compared to the wire using a Nb-barrier/Cu/Cu-Ni sheath.
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