多軸応力条件下におけるGRADE 92鋼のクリープ寿命評価

抄録

Creep tests on two kinds of circumferentially notched round bar specimens as well as plain bar specimen of ASME grade 92 steels were performed to obtain the multiaxial and uniaxial creep data. Then creep damage models according to strain fraction rule and energy fraction rule were developed based on the results of these uniaxial and multiaxial creep tests. Additionally, creep damage analyses using a finite element software, MSC Marc, were carried out on notched specimens and creep failure lives were predicted using the classical time fraction rule, as well as the two approaches developed here. Experimental failure lives of all the conditions of notched specimens were compared with analytical results. As a result, creep failure lives obtained by time fraction rule with von Mises equivalent stress were underestimated in the short term region and overestimated in the long term region. On the other hands, the majority of creep failure lives obtained by strain and energy fraction rule showed an agreement within a factor of two with experimental lives.