Mechanism of Fibrous Crack Growth under Constant Loading :

NDLデジタルコレクション

この論文をさがす

抄録

Constant loading tests for double edge-cracked tensile specimens and round bar tensile specimens of mild steel hare been carried out at room temperature, and monotonic loading tests and an extremely low rate monotonic loading test for above specimens have been carried out. After unloading test, crack-tip profile and crack-tip strain distributions at mid-cross section have been measured. According to the results and visco-elasticity theory, time-dependent deformation behaviors hale been revealed. The COD at original crack tip almost uniquely determines fibrous crack length, crack-tip profiles and crack-tip strain distribution regardless of loading history. Under constant loading, time-dependent strain i.e. creep strain appears; and plastic strain in tile vicinity of crack tip increases with time. This time-dependent strain contributes to fibrous crock initiation and crack growth under constant loading. The crack growth continues until time-dependent strain is saturated due to strain-hardening in the vicinity of crack tip, that is, fibrous crack extension under constant loading reaches that obtained at the same load level under extremely low rate monotonic loading. Crack growth is arrested when time-dependent strain is saturated, but unstable fracture occurs when the holding load level is higher than maximum load under externally low rate loading. Accordingly, the time-dependent strain and strain-hardening behavior plays an important role in the mechanism of stable fibrous crack growth under constant loading.

収録刊行物

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ