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題 名 | 高匹配銲接接頭疲勞裂紋擴展及裂紋閉合的研究=Study on the Fatigue Crack Propagation and Crack Closure of Over-Matched Welding Joints |
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作 者 | 李曉延; 張祥武; 田錫唐; 朱鴻官; | 書刊名 | 銲接與切割 |
卷 期 | 8:3 1998.05[民87.05] |
頁 次 | 頁33-38 |
分類號 | 472.14 |
關鍵詞 | 銲接接頭; 高匹配; 疲勞; 裂紋擴展; 裂紋閉合; Welded joints; Overmatching; Fatigue; Crack growth; Crack closure; |
語 文 | 中文(Chinese) |
中文摘要 | 本文將銲縫中含有縱向裂紋的高匹配銲接接頭簡化為SHS軟夾硬中心裂紋體模型。 通過實驗和彈塑性有限元方法研究了宏觀力學不均勻性對疲勞裂紋在這一模型中的擴展與裂 紋閉合的影響。研究發現,裂紋尖端尾紋中的殘留塑性變形是引起疲勞裂紋閉合的主要原因 ,這一殘留塑性變形受裂紋尖端附近軟區材料屈服的影響;力學不均勻體裂紋尖端塑性區的 形狀及裂紋尖端前方應力場分佈與均勻材料中的情況不同;可通過觀察疲勞負載過程中裂紋 尖端張開位移的變化來評估裂紋張開與閉合載荷的大小;由於力學不均勻性對疲勞裂紋張開 位移與非疲勞裂紋張開位移有不同的影響,傳統定義的CTOD的概念不能真實反映軟夾硬不均 勻裂紋體裂紋尖端的變形情況。本文還提出了裂紋張開的一個新模型。 |
英文摘要 | Overmatched welded joint with a crack in hard weld is simplified as a cracked body of CCP type SHS (a hard layer sandwiched between two soft material heterogeneity on fatigue crack growth and crack closure of this model are studied by experimental and elastic-plastic finite element methods. It is found that, residual plastic deformation remaining in the wake of a growing crack tip, which causes crack closure, is affected by the plastic deformation in adjacent soft material near by the crack tip. Both the shape of crack tip plastic zone and stress distribution ahead of crack tip in heterogeneous cracked body ard different from that of homogeneous one. Crack closure(opening)loads are estimated by investigating the changes of crack tip opening displacement during fatigue loading, and a new model of crack tip opening displacement during fatigue loading, and a new model of crack opening process is presented. Because of the difference in the effect of mechanical heterogeneity on displacement of non-fatigue crack and fatigue crack, conventional CTOD can not rflect the real deformation at crack tip of SHS specimens. |
本系統中英文摘要資訊取自各篇刊載內容。