GS43 Study of the Test Specimen Thickness Effect on Fracture Toughness of Ductile-Brittle Transition Temperature Region : Applicability of the (4δ_t,σ_) Criterion to Predict the Effect with Standard Test Specimens

2013 ◽  
Vol 2013 (0) ◽  
pp. _GS43-1_-_GS43-5_
Author(s):  
Yuki FUJIWARA ◽  
Toshiyuki MESHII
Keyword(s):  
Fracture Toughness ◽  
Transition Temperature ◽  
Temperature Region ◽  
Test Specimen ◽  
Standard Test ◽  
Thickness Effect ◽  
Specimen Thickness ◽  
Brittle Transition ◽  
Ductile Brittle Transition Temperature ◽  
Brittle Transition Temperature

Validating the Mechanical Nature of the Test Speicmen Thickness Effect on Fracture Toughness in the Transition Temperature Region

2013 ◽  
Author(s):  
Toshiyuki Meshii ◽  
Kai Lu ◽  
Ryota Takamura
Keyword(s):  
Fracture Toughness ◽  
Transition Temperature ◽  
Temperature Region ◽  
Standard Test ◽  
Thickness Effect ◽  
Specimen Thickness ◽  
Weakest Link ◽  
Standard Specimens ◽  
Out Of Plane ◽  
Crack Tip Constraint

This paper considered the test specimen thickness (TST) effect on the fracture toughness of a material Jc, in the transition temperature region, for 3PB (i.e., SE(B) for ASTM standard) specimens. Fracture toughness tests and elastic-plastic finite element analyses (FEA) with non-standard test specimens, on the point that the specimen thickness to width to ratio B/W was varied in the range of 0.25 to 1.5, were conducted. Based on these tests and FEA results, it was demonstrated that Jc showed tendency to saturate to some lower bound for B/W = 1.5. This tendency was similar with that predicted by our previous work, which assumed the TST effect on Jc as an out-of-plane crack-tip constraint issue. Because the TST effect on Jc (such as Jc ∝ B(−1/2)) together with Jc’s bounding nature for large B could not be predicted by the weakest link model but out-of-plane constraint assumption worked, it was concluded that the TST effect is mainly mechanical in nature.

Framework to Correlate Test Specimen Thickness Effect on Fracture Toughness With T33-Stress

2011 ◽  
Author(s):  
Toshiyuki Meshii ◽  
Tomohiro Tanaka
Keyword(s):  
Fracture Toughness ◽  
Transition Temperature ◽  
Temperature Region ◽  
Test Specimen ◽  
Crack Tip ◽  
Thickness Effect ◽  
Specimen Thickness ◽  
Out Of Plane ◽  
Elastic Crack ◽  
Crack Tip Constraint

This paper considered the test specimen thickness effect on the fracture toughness of a material Jc, in the transition temperature region, for CT and 3PB specimen. Framework to correlate test specimen thickness effect on fracture toughness with T33-stress, which is the out-of-plane elastic crack tip constraint parameter, was proposed. The results seemed to indicate a possibility of improving the existing methods to correlate the fracture toughness obtained by test specimen with the toughness of actual cracks found in the structure, in use of T33–stress.

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