構造的応力集中部における欠陥のCTOD評価法に関する研究

概要

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Japan Welding Engineering Society (JWES) Standard WES 2805 which is based on CTOD criterion established in 1976 has been under revision through the WR-3 Committee organized in JWES. WES 2805 has shown some difficulties in crack assessment for complicated structural geometries and, in this work single and double stiffener specimens as experimented by the FTR Committee are computed by means of elastic and elastic plastic three dimensional finite element method. For the analysis of the computed models the revised version of CTOD design curve of WES 2805 was used. An investigation of the local strain parameter (ε) was carried out and proposals for its appropriate definition are made. The parameters related to the "local strain" (K^^〜_e, K^^〜_t, K^^〜_σ) are investigated and their influence in the estimation of the local strain are shown. A new concept of net stress (σ_<net>) evaluation, designated as "Net Section Stress Effect" is proposed and estimations ofσ_<net> based on this new concept are carried out. Also, using the newly proposed net stress concept a new equation to estimate K^^〜_e. is proposed and evaluated with the computed models. Proposals to include the definitions performed in this work and the introduction of the "Net Section Stress Effect" on the WES 2805 procedure are done.
社団法人日本船舶海洋工学会の論文