TY - JOUR
T1 - Evaluation of Tearing Instability by Means of Recrystallization-Etch Technique (Comparison of Fracture Toughness Between Through Crack Specimens and Part-Through Crack Specimens)
AU - Onisawa, Kunio
AU - Shoji, Tetsuo
AU - Takahashi, Hideaki
AU - Ando, Kotoji
PY - 1985/1/1
Y1 - 1985/1/1
N2 - Tearing instability crack growth in low alloy steels was evaluated in a regime of elastic plastic fracture mechanics by use of recrystallization-etch technique. Specimen geometries used here were standard compact and 3pt bend specimen, and 4pt bend type specimen having a part-through surface crack. In order to produce high compliance for a testing machine, disc springs were used where the compliance changes from lkN/mm to 5kN/mm. After the fracture experiments the crack tip strain energy dissipation rate d WP/da (WP : crack tip strain energy absorbed within the intense strain region, a : tearing crack extension) was determined by the recrystallization-etch technique. It is shown that the value of Tw (tearing modulus based on Wp) is constant before and after an onset of tearing instability. In the surface crack specimen, three dimensional profile of the intense strain region along the crack front was observed. This experimental results indicate that the Tw criterion is applicable to the crack extension from the surface flaw, although a singular extension behavior of the intense strain region was observed only near the specimen surface.
AB - Tearing instability crack growth in low alloy steels was evaluated in a regime of elastic plastic fracture mechanics by use of recrystallization-etch technique. Specimen geometries used here were standard compact and 3pt bend specimen, and 4pt bend type specimen having a part-through surface crack. In order to produce high compliance for a testing machine, disc springs were used where the compliance changes from lkN/mm to 5kN/mm. After the fracture experiments the crack tip strain energy dissipation rate d WP/da (WP : crack tip strain energy absorbed within the intense strain region, a : tearing crack extension) was determined by the recrystallization-etch technique. It is shown that the value of Tw (tearing modulus based on Wp) is constant before and after an onset of tearing instability. In the surface crack specimen, three dimensional profile of the intense strain region along the crack front was observed. This experimental results indicate that the Tw criterion is applicable to the crack extension from the surface flaw, although a singular extension behavior of the intense strain region was observed only near the specimen surface.
KW - Fracture
KW - Intense Strain Region
KW - Recrystallization-Etch Technique
KW - Resistance Curve
KW - Surface Crack
KW - Tearing Instability
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U2 - 10.1299/kikaia.51.514
DO - 10.1299/kikaia.51.514
M3 - Article
AN - SCOPUS:0022015050
VL - 51
SP - 514
EP - 517
JO - Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A
JF - Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A
SN - 0387-5008
IS - 462
ER -