Stress Redistribution Locus of Perforated Plate Under Displacement-Controlled Loading, Force-Controlled Loading and Thermal Loading

2011 ◽  
Author(s):  
Osamu Watanabe ◽  
Akihiro Matsuda
Keyword(s):  
Fatigue Strength ◽  
Inelastic Deformation ◽  
Thermal Loading ◽  
Perforated Plate ◽  
Stress Redistribution ◽  
Stress And Strain ◽  
Collapse Load ◽  
Strength Based ◽  
Creep Fatigue ◽  
Nonlinear Feature

Stress and strain locus in inelastic deformation is important to evaluate the fatigue strength and creep-fatigue strength. The stress redistribution locus (SRL) of perforated plate under displacement-controlled condition has been studied so far by the present authors. The SRL curve under displacement-controlled loading is almost independent of the employed constitutive equation, and the SRL takes the similar curve as Neuber’s one, if the inelastic stress/strain is non-dimensionalized by elastic solutions. However, the SRL under force-controlled loading is not studied yet, which is closely related to collapse load and fatigue strength. The response under thermal loading is also important for fatigue strength and creep-fatigue strength. Based on the 3D FE solutions under force-controlled loading or thermal loading for the perforated plate, the nonlinear feature will be discussed.

Creep-Fatigue Strength Evaluation of Perforated Plate at Elevated Temperature Using Stress Redistribution Locus Method

2007 ◽  
Author(s):  
Bopit Bubphachot ◽  
Osamu Watanabe ◽  
Nobuchika Kawasaki ◽  
Naoto Kasahara
Keyword(s):  
Elevated Temperature ◽  
Fatigue Strength ◽  
Fatigue Test ◽  
Hold Time ◽  
Perforated Plate ◽  
Stress Redistribution ◽  
Peak Strain ◽  
Locus Method ◽  
Creep Fatigue ◽  
Tensile Hold Time

This study investigates the effects of creep behavior on fatigue strength of the perforated plate at elevated temperature, when Stress Redistribution Locus (abbreviated as SRL) method is applied for the perforated plate. The creep-fatigue test is carried out by using the specimens made of SUS304 stainless steel at the temperature of 550°C. The trapezoidal wave having tensile hold time at peak strain is assumed. The geometry of the perforated plate specimens are changed in the same manner as the fatigue test by varying number or diameter-size of through holes. The linear damage rule for fatigue and creep is assumed, and the comparison between the experimental results, namely the SRL method evaluation at the Campbell’s diagram will be made. Both of the load and displacement are measured in all the cyclic history of the loadings to clarify the relation between crack initiation or propagation and the load decrease from the viewpoint of direct observation of crack at the holes side.

Fatigue Strength Evaluation of Perforated Plate at Elevated Temperature Using Stress Redistribution Locus Method

2007 ◽  
Author(s):  
Osamu Watanabe ◽  
Bopit Bubphachot ◽  
Nobuchika Kawasaki ◽  
Naoto Kasahara
Keyword(s):  
Elevated Temperature ◽  
Fatigue Strength ◽  
Stress Concentration ◽  
Crack Initiation ◽  
Perforated Plate ◽  
Local Strain ◽  
Stress Redistribution ◽  
Experimental Results ◽  
Locus Method ◽  
Crack Initiation Life

This study reports the experimental results carried out at the elevated temperature of 550°C on fatigue strength of the perforated plate. Stress Redistribution Locus (abbreviated as SRL hereafter) Method is applied to predict fatigue life for the specimens having stress concentration. The specimens made of SUS304 stainless steel have through holes with different number and different diameter, accordingly leading to the different stress concentration condition. The inelastic local strain is estimated by the SRL method or the other previous Neuber’s rule, and compared to the experimental results on the crack initiation life at the edge of the hole using the concentrated local strain obtained by these methods. The obtained result is that the SRL method is best used with the onset of failure or crack initiation.

510 Fatigue and Creep-Fatigue Strength for Perforated Plate by Changing Geometrical Parameters

2005 ◽  
Vol 2005.18 (0) ◽  
pp. 835-836
Author(s):  
Osamu WATANABE ◽  
Bopit BUBPHACHOT ◽  
Naoto KASAHARA ◽  
Kyotada NAKAMURA
Keyword(s):  
Fatigue Strength ◽  
Perforated Plate ◽  
Geometrical Parameters ◽  
Creep Fatigue

Creep-Fatigue Life Evaluation Method for Perforated Plates at Elevated Temperature

2005 ◽  
Vol 128 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Osamu Watanabe ◽  
Takuya Koike
Keyword(s):  
Elevated Temperature ◽  
Fatigue Strength ◽  
Stress Concentration ◽  
Evaluation Method ◽  
Three Dimensional ◽  
Perforated Plate ◽  
Dimensional Structure ◽  
Creep Process ◽  
Plastic Behavior ◽  
Creep Fatigue

The accurate evaluation scheme for creep-fatigue strength is one of the continuing main issues for elevated temperature design; particularly, the three-dimensional structure having stress concentration is becoming more important. The present paper investigates fatigue strength and creep-fatigue strength of perforated plate having stress concentration as an example. The specimens are made of type 304 SUS stainless steel, and the temperature is kept to 550°C. The whole cycles of the experiment record are analyzed, and the characteristics of the structure having stress concentration are discussed. The present paper employs stress redistribution locus (abbreviated as SRL) in evaluation plastic behavior in cyclic fatigue process as well as stress relaxation in creep process, and the feasibility is discussed in conjunction with the comparison to experimental results.

Stress and Strain Locus of Perforated Plate in Inelastic Deformation—Strain-Controlled Loading Case

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Osamu Watanabe ◽  
Bopit Bubphachot ◽  
Akihiro Matsuda ◽  
Taisuke Akiyama
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Stress Concentration ◽  
Cyclic Loading ◽  
Perforated Plate ◽  
Stress And Strain ◽  
Life Evaluation ◽  
Simplified Method ◽  
Creep Fatigue ◽  
Fatigue Life Evaluation

Plastic strain of structures having stress concentration is estimated by using the simplified method or the finite element elastic solutions. As the simplified methods used in codes and standards, we can cite Neuber’s formula in the work by American Society of Mechanical Engineers (1995, “Boiler and Pressure Vessel Code,” ASME-Code, Section 3, Division 1, Subsection NH) and by Neuber (1961, “Theory of Stress Concentration for Shear Strained Prismatic Bodies With Arbitrary Nonlinear Stress-Strain Law,” ASME, J. Appl. Mech., 28, pp.544–550) and elastic follow-up procedure in the work by Japan Society of Mechanical Engineers [2005, “Rules on Design and Construction for Nuclear Power Plants, 2005, Division 2: Fast Breeder Reactor” (in Japanese)]. Also, we will cite stress redistribution locus (SRL) method recently proposed as the other simplified method in the work by Shimakawa et al. [2002, “Creep-Fatigue Life Evaluation Based on Stress Redistribution Locus (SRL) Method,” JPVRC Symposium 2002, JPVRC/EPERC/JPVRC Joint Workshop sponsored by JPVRC, Tokyo, Japan, pp. 87–95] ad by High Pressure Institute of Japan [2005, “Creep-Fatigue Life Evaluation Scheme for Ferritic Component at Elevated Temperature,” HPIS C 107 TR 2005 (in Japanese)]. In the present paper, inelastic finite element analysis of perforated plate, whose stress concentration is about 2.2–2.5, is carried out, and stress and strain locus in inelastic range by the detailed finite element solutions is investigated to compare accuracy of the simplified methods. As strain-controlled loading conditions, monotonic loading, cyclic loading, and cyclic loading having hold time in tension under strain-controlled loading are assumed. The inelastic strain affects significantly life evaluation of fatigue and creep-fatigue failure modes, and the stress and strain locus is discussed from the detailed inelastic finite element solutions.

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