The ASME Section III Design-by-Analysis rules for pressure-retaining components include a detailed fatigue evaluation based on elastically predicted primary, secondary, and peak stresses. A prerequisite for the fatigue analysis is that the primary-plus-secondary stress range does not exceed $3Sm$. If this limit is exceeded, the code provides “Simplified Elastic-Plastic Analysis” rules for the fatigue evaluation. A $Ke$ penalty factor is applied to the elastically predicted alternating stress. The maximum value of $Ke$ (3.3 or 5) is a severe design limitation. Test data indicate that the code specified maximum value of $Ke$ is very conservative. The simplified elastic-plastic rules were originally developed for piping and published in B31.7. When the piping rules were incorporated into Section III in 1971, the B31.7 procedure was replaced by a less complex procedure. The development of the simplified elastic-plastic analysis approach is reviewed to establish the technical basis for the present code rules. The concepts of fatigue, shakedown to elastic action, thermal bending, elastic follow-up, notch factor, and strain redistribution are discussed. Recommendations for changes to the plastic strain correction factor are provided.

1.
ASME Boiler and Pressure Vessel Code Section III, 1963 ed., “
Rules for Construction of Nuclear Vessels
.”
2.
Criteria of the ASME Boiler and Pressure Vessel Code for Design by Analysis in Sections III and VIII, Division 2, 1969, ASME, New York.
3.
USA Standard Code for Pressure Piping, USAS B31.7-1969, “
Nuclear Power Piping
,” ASME.
4.
ASME Boiler and Pressure Vessel Code Section III, 2004 ed., “
Rules for Construction of Nuclear Facility Components
.”
5.
Langer
,
B. F.
, 1972, “
Design-Stress Basis for Pressure Vessels
,” in
Pressure Vessel and Piping: Design and Analysis, A Decade of Progress, Volume 1, Analysis
,
ASME
,
New York
, pp.
84
94
6.
Grandemange
,
J. M.
,
Heliot
,
J.
,
Vagner
,
J.
,
Morel
,
A.
, and
Faidy
,
C.
, 1991, “
Improvements on Fatigue Analysis Methods for the Design of Nuclear Components Subjected to the French RCC-M Code
,”
Weld. Res. Counc. Bull.
0043-2326,
361
.
7.
Tagart
,
S. W.
, 1972, “
Plastic Fatigue Analysis of Pressure Components
,” in
Pressure Vessel and Piping: Design and Analysis, A Decade of Progress, Volume 1, Analysis
,
ASME
,
New York
, pp.
209
226
(reprint of ASME Paper No. 68-PVP-3, 1968).
8.
Krempl
,
E.
, 1967, “
Low-Cycle Fatigue Strength Reduction in Notched Flat Plates
,” General Electric Report GEAP-5410.
9.
Gerber
,
T. L.
, 1974, “
Effect of Constraint and Loading Mode on Low-Cycle Fatigue Crack Initiation—Comparison with Code Design Rules
,” General Electric Report GEAP-20662.
10.
Iida
,
K.
,
Kitagawa
,
M.
,
Tamura
,
K.
,
Matsushita
,
A.
,
Fukagawa
,
M.
, and
Saiga
,
Y.
, 1980, “
Safety Margin of the Simplified Elasto Plastic Fatigue Analysis Method of ASME B and PV Code Section III
,”
Institution of Mechanical Engineers
, UK, C35/80.