Letter to the Editor commenting on “Effect of Friction and Specimen Geometry on the Ductile Fracture in Upset Forging” (Samanta, S. K., 1975, ASME J. Eng. Mater. Technol., 97, pp. 14–20)

M. L. Williams; I. Finnie

doi:10.1115/1.3443316

Letter to the Editor commenting on “Effect of Friction and Specimen Geometry on the Ductile Fracture in Upset Forging” (Samanta, S. K., 1975, ASME J. Eng. Mater. Technol., 97, pp. 14–20)

Journal of Engineering Materials and Technology ◽

10.1115/1.3443316 ◽

1975 ◽

Vol 97 (4) ◽

pp. 384-384

Author(s):

M. L. Williams ◽

I. Finnie

Keyword(s):

Ductile Fracture ◽

Specimen Geometry ◽

Letter To The Editor ◽

Upset Forging

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Effect of specimen geometry on the essential work of plane stress ductile fracture

Engineering Fracture Mechanics ◽

10.1016/0013-7944(85)90059-1 ◽

1985 ◽

Vol 21 (1) ◽

pp. 123-128 ◽

Cited By ~ 89

Author(s):

Y.W. Mai ◽

B. Cotterell

Keyword(s):

Ductile Fracture ◽

Plane Stress ◽

Specimen Geometry ◽

Essential Work

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Development of the SENT Test for Strain-Based Design of Welded Pipelines

2010 8th International Pipeline Conference, Volume 4 ◽

10.1115/ipc2010-31590 ◽

2010 ◽

Cited By ~ 19

Author(s):

Huang Tang ◽

Mario Macia ◽

Karel Minnaar ◽

Paulo Gioielli ◽

Sandeep Kibey ◽

...

Keyword(s):

Ductile Fracture ◽

Fracture Resistance ◽

Crack Depth ◽

Crack Tip ◽

Specimen Geometry ◽

Outer Diameter ◽

Specimen Thickness ◽

Crack Tip Opening Displacement ◽

Opening Displacement ◽

Specimen Width

Strain-based design (SBD) pipelines are being considered to develop hydrocarbon resources in severe environments. As part of a research program to develop a SBD methodology, work was conducted to develop a suitable fracture mechanics test that can be used as part of a strain capacity prediction technique. The single edge notched tensile (SENT) specimen geometry has been chosen due to the similarity in crack-tip constraint conditions with that of defects in pipeline girth welds. This paper describes a single-specimen compliance method suitable for measuring ductile fracture resistance in terms of crack tip opening displacement resistance (CTOD-R) curves. The development work included investigation of the following items: specimen geometry, crack geometry and orientation (including crack depth effects), direct measurement of CTOD. The results demonstrate that toughness measurements obtained using a B = W configuration (B = specimen thickness, W = specimen width) with side grooves are similar to those using a B = 2W configuration without side grooves; however, specimens with side grooves and B = W geometry facilitates even crack growth. Studies of crack depth have shown that ductile fracture resistance decreases with increasing ratio of the initial crack depth to specimen width, a0/W. Studies of notch location and orientation (outer diameter (OD) and inner diameter (ID) surface notches and through-thickness notches) have shown an effect of this variable on the CTOD-R curves. This has been partly attributed to crack progression (tearing direction) with respect to weld geometry and this effect is consistent with damage modeling predictions. However the experimentally observed difference of CTOD-R curves between ID and OD notches is believed to be primarily due to the material variability through the pipe thickness.

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Effect of Friction and Specimen Geometry on the Ductile Fracture in Upset Forging

Journal of Engineering Materials and Technology ◽

10.1115/1.3443253 ◽

1975 ◽

Vol 97 (1) ◽

pp. 14-20 ◽

Cited By ~ 5

Author(s):

S. K. Samanta

Keyword(s):

Surface Stress ◽

Room Temperature ◽

Specimen Geometry ◽

Circular Cylinders ◽

Surface Cracks ◽

Interface Friction ◽

Flow Limit ◽

Stress Components ◽

Upset Forging ◽

Ductile Flow

Experiments were conducted to determine the effect of interface friction and specimen geometry on the useful ductile flow limit of 1100 aluminum and 1095 steel at room temperature. The tests consisted of measuring the equatorial strains during simple upsetting of circular cylinders. From the measured strains the surface stress components were calculated. All occurrences of fracture were observed to be the normal type. In some cases no surface cracks were observed and a possible explanation is given in the paper.

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