The problem of two cracks in a semi-infinite sheet is analyzed. The critical conditions when adjacent plastic zones just coalesced are obtained. Also, the conditions when a plastic zone just reached the sheet edge are obtained. Assuming the crack and plastic zones as a fictitious crack, the integral equations are formulated in terms of surface traction, nonsingular stress, and zero crack face displacement at the coalescent point or at the sheet edge. By solving the equations, critical remote stress, plastic zone sizes, and crack tip opening displacements are obtained. Numerical results are presented.

1.
Isida
,
M.
, 1965, “
Stress-Intensity Factors for the Tension of an Eccentrically Cracked Strip
,”
ASME J. Appl. Mech.
0021-8936,
33
, pp.
674
675
.
2.
Tada
,
H.
,
Paris
,
P. C.
, and
Irwin
,
G. R.
, 2000,
The Stress Analysis of Cracks Handbook
, 3rd ed.,
ASME
,
New York
.
3.
Hartranft
,
R. J.
, and
Sih
,
G. C.
, 1973, “
Alternating Method Applied to Edge and Surface Crack Problems,“
in
Methods of Analysis and Solutions of Crack Problems
,
Noordhoff International
,
Groningen
, pp.
179
238
.
4.
Chen
,
Y. Z.
, 1985,
”Solutions of Multiple Crack Problems of Elastic Half-Plane
,”
ASME J. Appl. Mech.
0021-8936,
52
, pp.
979
981
.
5.
Nishimura
,
T.
, 1995,
”Collinear Internal Cracks and Edge Crack in a Semi-Infinite Sheet Subjected to Arbitrary Tractions
,”
ASME J. Pressure Vessel Technol.
0094-9930,
117
, pp.
256
259
.
6.
Nishimura
,
T.
, 2000,
”Strip Yield Analysis of Plastic Zone Coalescence for Collinear Edge Crack and Internal Crack in a Semi-Infinite Sheet
,”
ASME J. Pressure Vessel Technol.
0094-9930,
122
, pp.
86
89
.
7.
Nishimura
,
T.
, 2002, “
Strip Yield Analysis of Two Collinear Unequal Cracks in an Infinite Sheet,“
Eng. Fract. Mech.
0013-7944,
69
, pp.
1173
1191
.
8.
Dugdale
,
D. S.
, 1960,
”Yielding of Steel Sheets Containing Slits
,”
J. Mech. Phys. Solids
0022-5096,
8
, pp.
100
104
.
You do not currently have access to this content.