100 likes | 277 Views
Development of Flaw Interaction Rules for Ductile Behavior - Crack Growth Behavior for Offset Flaws -. Kunio Hasegawa, Katsumasa Miyazaki and Koichi Saito Hitachi, Ltd., Japan ASME Code Section XI, WG on Pipe Flaw Evaluation Orlando, FL. , May 9, 2005. l. H. l. S. Experiments.
E N D
Developmentof Flaw Interaction Rules for Ductile Behavior- Crack Growth Behavior for Offset Flaws - Kunio Hasegawa, Katsumasa Miyazaki and Koichi Saito Hitachi, Ltd., Japan ASME Code Section XI, WG on Pipe Flaw Evaluation Orlando, FL. , May 9, 2005
l H l S Experiments Material: JIS SM 400A Carbon steel plates Mechanical properties: sy = 304 MPa, su = 449 MPa Applied load: Static tensile load Temperature: Ambient temperature Parameters: H, S and l Failure mode: Ductile fracture [JIS SM : Rolled steels for welded structure] W=108 600 PB=199kN l = 20 t=5.7 PB/(W-l) t = 397 MPa t = 5.7 Offset through wall flaws [slit width = 0.1 mm] 108 Flow stress (sy+su)/2 = 377 MPa Limit Load Criteria is applicable Unit: mm
Example of Collapse Load If H >12.5 mm Offset Flaws PC PC = sf(W-2a2)t = 377(108-30)5.7 = 168 kN or 2a2=30 PC = sf(W-2a1)t = 377(108-78)5.7 = 64 kN Code Rule H a1=39 a1=39 If H <12.5 mm Coplanar Flaws W=108 PC = 0 kN (t=5.7)
l=10 l=10 S=10 Experimental Results (two flaws) W=108 This results were reported at Birmingham meeting in Feb. 2005 H=12.4, 17, 22 DN-06 DN-07 DN-02
l=30 l=30 S Experimental Results (two flaws) W=180 H=10, 20 (t=5.8) DNW-04 DNW-03 DNW-02
(t=5.8) 30 H 39 39 [S=0, H=10, 15, 20, 35] W=108 Experimental Results (S = 0 mm) TOH-8 P= 62 kN TOH-7 P= 42 kN TOH-5 P=16 kN TOH-6 P= 45 kN
(t=5.8) 30 H 19 19 20 20 W=108 [S=20, H=10, 20, 30] Experimental Results (S = 20 mm) TSH-11 P=92kN TSH-9 P=92kN TSH-7 P=75kN
(t=5.8) 60 15 15 H 39 39 [H=10, 20] W=108 Experimental Results (S = Overlap) TL-5 P=14kN TL-2 P=6kN
Summary From the experimental data, ASME current offset rules of S<1/2 inch (12.5 mm) seems to be less conservative. Wideness of plastic zone at the crack tip is connected to the offset rule. It is suggested that offset rules shall be classified into two types; large scale yielding and small scale yielding (K- basis).