高温クリープ疲労き裂進展のひずみ範囲分割法による取扱い

概要

論文の詳細を見る
The strain range partitioning analysis of creep-fatigue cracks is conducted for the normalized and tempered 2 1/4Cr-1 Mo steel at 550℃ and for SUS 304 stainless steel at 700℃, assuming that creep-fatigue life relations can be simply obtained by integrating creep-fatigue growth rate equations. For Δε_<ij> straining, crack growth rate equations in air and vacuum are respectively given by (1/a) (da/dN)_<ij>=In(a_f/a_0)_<ij>(Δε_<ij>/A_<ij>)^<1/m_<ij>> and (1/a)(da/dN)_<ij>=In(a_f/a_0)_<ij>(Δε_<ij>/α_<ij>D_i)^2, where respective partitioned strain versus life relations are given by Δε_<ij>=A_<ij>N_<ij>^<-m_<ij>> and Δε_<ij>=α_<ij>D_iN_<ij>^<-0.5>, and (a_f/a_0)_<ij> is the ratio of final half crack length to initial one. For (Σ<Δε_<ij>) straining, it is assumed that the crack growth rate is given by Σ(da/dN)_<ij>. It is shown based on air data that In(a_f/a_0)_<pp>=13.7, In(a_f/a_0)_<pc>=5.5, In(a_f/a_0)_<cp>=5.4 and In(a_f/a_0)_<cc>=5.2 for SUS 304 steel. Furthermore, (a_0)_<ij> and (a_f)_<ij> of very small size evaluated on the basis of the obtained values of (a_f/a_0)_<ij>. It is suggested that four types of inelastic strain range, Δε_<ij>, are new and useful parameters that will help us to evaluate the crack initiation life,the remaining life and the material damage in future.
社団法人日本材料学会の論文
1986-09-15