Section G Fatigue Strength Reduction Factors on Stress Basis. Results of LCF Tests

2009 ◽  
pp. 45-45-8
Keyword(s):  
Fatigue Strength ◽  
Strength Reduction ◽  
Reduction Factors

Fatigue-Strength-Reduction Factors for Welds in Pressure Vessels and Piping

2000 ◽  
Vol 122 (3) ◽  
pp. 297-304 ◽  
Author(s):  
Carl E. Jaske
Keyword(s):  
Fatigue Strength ◽  
Weld Joint ◽  
Pressure Vessels ◽  
Strength Reduction ◽  
Current Status ◽  
Published Data ◽  
Weld Joints ◽  
Class 1 ◽  
Asme Code ◽  
Reduction Factors

Fatigue-strength-reduction factors (FSRFs) are used in the design of pressure vessels and piping subjected to cyclic loading. This paper reviews the background and basis of FSRFs that are used in the ASME Boiler and Pressure Vessel Code, focusing on weld joints in Class 1 nuclear pressure vessels and piping. The ASME Code definition of FSRF is presented. Use of the stress concentration factor (SCF) and stress indices are discussed. The types of welds used in ASME Code construction are reviewed. The effects of joint configuration, welding process, cyclic plasticity, dissimilar metal joints, residual stress, post-weld heat treatment, the nondestructive inspection performed, and metallurgical factors are discussed. The current status of weld FSRFs, including their development and application, are presented. Typical fatigue data for weldments are presented and compared with the ASME Code fatigue curves and used to illustrate the development of FSRF values from experimental information. Finally, a generic procedure for determining FSRFs is proposed and future work is recommended. The five objectives of this study were as follows: 1) to clarify the current procedures for determining values of fatigue-strength-reduction factors (FSRFs); 2) to collect relevant published data on weld-joint FSRFs; 3) to interpret existing data on weld-joint FSRFs; 4) to facilitate the development of a future database of FSRFs for weld joints; and 5) to facilitate the development of a standard procedure for determining the values of FSRFs for weld joints. The main focus is on weld joints in Class 1 nuclear pressure vessels and piping. [S0094-9930(00)02703-7]

Fatigue Strength Reduction Factors for Welds Based on Nondestructive Examination

1999 ◽  
Vol 121 (1) ◽  
pp. 6-10 ◽  
Author(s):  
J. L. Hechmer ◽  
E. J. Kuhn
Keyword(s):  
Fatigue Strength ◽  
Weld Metal ◽  
Base Metal ◽  
Pressure Vessels ◽  
Strength Reduction ◽  
Initial Development ◽  
Nondestructive Examination ◽  
Additional Information ◽  
Visual Testing ◽  
Reduction Factors

Based on the author’s hypothesis that nondestructive examination (NDE) has a major role in predicting the fatigue life of pressure vessels, a project was initiated to develop a defined relationship between NDE and fatigue strength reduction factors (FSRF). Even though a relationship should apply to both base metal and weld metal, the project was limited to weld metal because NDE for base metal is reasonably well established, whereas NDE for weld metal is more variable, depending on application. A matrix of FSRF was developed based on weld type (full penetration, partial penetration, and fillet weld) versus the NDE that is applied. The NDE methods that are included are radiographic testing (RT), ultrasonic testing (UT), magnetic particle testing (MT), dye penetrant testing (PT), and visual testing (VT). The first two methods (RT and UT) are volumetric examinations, and the remaining three are surface examinations. Seven combinations of volumetric and surface examinations were defined; thus, seven levels of FSRF are defined. Following the initial development of the project, a PVRC (Pressure Vessel Research Council) grant was obtained for the purpose of having a broad review. The report (Hechmer, 1998) has been accepted by PVRC. This paper presents the final matrix, the basis for the FSRF, and key definitions for accurate application of the FSRF matrix. A substantial amount of additional information is presented in the PVRC report (Hechmer, 1998).

J0320602 Fatigue Strength Reduction Factors of Engineering Plastics PBT and PEEK

2014 ◽  
Vol 2014 (0) ◽  
pp. _J0320602--_J0320602-
Author(s):  
Yoshio FUKUDA ◽  
Tomohiro KASE ◽  
Shotaro KURASHINA ◽  
Kiyohide SAKAMOTO ◽  
Shigeo AOKI
Keyword(s):  
Fatigue Strength ◽  
Strength Reduction ◽  
Engineering Plastics ◽  
Reduction Factors

Low-Cycle Fatigue of Large-Diameter Bolts

1967 ◽  
Vol 89 (1) ◽  
pp. 53-60 ◽  
Author(s):  
A. L. Snow ◽  
B. F. Langer
Keyword(s):  
Fatigue Strength ◽  
Yield Strength ◽  
Low Cycle Fatigue ◽  
Large Diameter ◽  
Fatigue Curve ◽  
Fatigue Tests ◽  
Strength Reduction ◽  
Additional Information ◽  
Thread Root ◽  
Reduction Factors

New constant-deflection amplitude fatigue data on bolting materials are presented. The relationship of cyclic yield strength to static yield strength is examined. Several series of full-size stud fatigue tests are analyzed and compared to the basic failure curve to obtain experimental fatigue strength reduction factors for bolts and studs. The variation of fatigue strength reduction factors with thread root radius, stud size, thread taper, and other variables is noted. A new design fatigue curve for bolts is proposed which reflects the additional information available at the present time.

scholarly journals Evaluation of Weldment Creep and Fatigue Strength-Reduction Factors for Elevated-Temperature Design

1990 ◽  
Vol 112 (4) ◽  
pp. 333-339 ◽  
Author(s):  
J. M. Corum
Keyword(s):  
Elevated Temperature ◽  
Fatigue Strength ◽  
The United States ◽  
Fatigue Tests ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
Nuclear Component ◽  
American Society ◽  
Reduction Factors

New explicit weldment strength criteria in the form of creep and fatigue strength-reduction factors were recently introduced into the American Society of Mechanical Engineers Code Case N-47, which governs the design of elevated-temperature nuclear plant components in the United States. This paper provides some of the background and logic for these factors and their use, and it describes the results of a series of confirmatory creep-rupture and fatigue tests of simple welded structures. The structures (welded plates and tubes) were made of 316 stainless steel base metal and 16-8-2 weld filler metal. Overall, the results provide further substantiation of the validity of the strength-reduction factor approach for ensuring adequate life in elevated-temperature nuclear component weldments.

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