太径チェーンの大気および海水中における疲労強度の推定

抄録

It takes long time for fatigue test on an actual chain and the test is very difficult for large chains such as 100 mm over in diameter. This paper describes the relationship between the fatigue strength of an actual chain and those of the specimens cut out of the chain.
The fatigue failure of a chain often occurs at the toe of stud-weld or at the corner of indentation produced by the stud other than the bend part of the link. In these cases, the fatigue strength of the chains was lower than that of the chains failed at the bend part. Moreover, it was found that the fatigue strength of the chain even failed at the bend part in air was lower than that estimated from the result of small specimens, because of the effects of decarburizing and roughness of the chain surface.
In the artificial sea water, the fatigue strength of chains was rather close to that estimated from the results of small specimens. It is considered that this is due to the fact that the condition of the surface of chains and specimens becomes similar for the two cases by corrosion. Consequently, it is concluded that the result of small specimens may be applied to estimate the fatigue strength of chains in the sea-water.