scholarly journals A new formulation for estimating maximum stress intensity factor at the mid plane of a SENB specimen: Study based on 3D FEA

2014 ◽  
Vol 8 (29) ◽  
pp. 419-425 ◽  
Author(s):  
S. K. Kudari ◽  
K. G. Kodancha
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Maximum Stress ◽  
3D Fea ◽  
Maximum Stress Intensity ◽  
New Formulation ◽  
Maximum Stress Intensity Factor ◽  
Senb Specimen

Observation of Crack Growth Behavior of Various Cracks in 4.762mm Diameter Silicon Nitride Balls under Cyclic Compressive Load

2019 ◽  
Vol 971 ◽  
pp. 101-105
Author(s):  
Takumi Toriki ◽  
Tomoya Matsui ◽  
Katsuyuki Kida
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Silicon Nitride ◽  
Intensity Factor ◽  
Maximum Stress ◽  
Compressive Load ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Maximum Stress Intensity ◽  
Maximum Stress Intensity Factor

In order to investigate the effect of pre-crack lengths on strength of silicon nitride balls under cyclic pressure loads, growth behavior of 600~700μm pre-cracks were compared to those of 200μm~300μm and 400~500μm pre-cracks. Furthermore, the change in initial threshold limit of the maximum stress intensity factor was discussed. It was found that the increasing ratio of stress intensity factor during N=0 and N=1000 distinguished the failure and non-failure, and pre-crack length had strong effect on the threshold limits of the increasing ratio.

Consideration on Fatigue Crack Growth Thresholds Under Negative Stress Ratio

2019 ◽  
Author(s):  
Kunio Hasegawa ◽  
Saburo Usami ◽  
Valery Lacroix
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Fatigue Crack Growth ◽  
Intensity Factor ◽  
Crack Growth ◽  
Stress Ratio ◽  
Maximum Stress ◽  
Maximum Stress Intensity ◽  
Maximum Stress Intensity Factor

Abstract Fatigue crack growth thresholds ΔKth are provided by several fitness-for-service (FFS) codes. When evaluating cracked components subjected to cyclic loading, maximum stress intensity factor Kmax and/or minimum stress intensity factor Kmin are required. However, the definitions of the thresholds ΔKth under negative stress ratio R are not clearly written, except for BS (British Standards) 7910. In addition, the ΔKth are given by constant values under negative R. Fatigue crack growth rates under negative stress ratio is recommended to use maximum stress intensity factor Kmax by ASTM (American Society of Testing and Materials) E 647, because of the Kmax being close to crack driving force. Therefore, it deems that the ΔKth under negative R seems to be Kmax. This paper shows that the Kmax converted by the ΔKth are not constant values under negative R based on the survey of experimental data. The Kmax decreases with decreasing the stress ratio R. Therefore, the ΔKth for the FFS codes are less conservative. As experimental data under negative stress ratio R were taken by Kmax – Kmin, the definition of the threshold ΔKth is benefit to use Kmax – Kmin, instead of Kmax.

The Evaluation of the Effects of the Maximum Stress Intensity Factor for Fatigue Crack Opening Behavior by Finite Element Analysis

2007 ◽  
Vol 353-358 ◽  
pp. 1106-1109
Author(s):  
Hyeon Chang Choi ◽  
Hyeon Ki Choi ◽  
Jun Hyub Park
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Maximum Stress ◽  
Crack Opening ◽  
Crack Tip ◽  
Crack Tip Opening Displacement ◽  
Maximum Stress Intensity ◽  
Maximum Stress Intensity Factor

The cyclic crack tip opening displacement is well related to fatigue crack opening behavior. In this paper, we investigate the effect of the maximum stress intensity factor, Kmax, when predicting fatigue crack opening behavior using the cyclic crack tip opening displacement obtained from FEA. The commercial finite element code, ANSYS, for fatigue crack closure analysis in this study is used. We derive the prediction formula of crack opening behavior when using the cyclic crack tip displacement obtained from the FEA. The numerical prediction shows the good results regardless of stress ratios. It is confirmed that the crack opening behavior depends upon the maximum stress intensity factor Kmax.

Fatigue Strength Evaluation of Spot-Welded Multi-Lap Joint by the Maximum Stress Intensity Factor, Kθmax

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1646-1652 ◽  
Author(s):  
Dongho Bae ◽  
Taehun Nam ◽  
Wonseok Jung ◽  
Ilseon Sohn
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Life ◽  
Stress Intensity ◽  
Maximum Stress ◽  
Lap Joints ◽  
Commercial Vehicles ◽  
Fatigue Design ◽  
Maximum Stress Intensity ◽  
Maximum Stress Intensity Factor ◽  
Spot Welded

Fatigue strength and reliability of structural components in railroad commercial vehicles are usually decided by spot weld. Thus, it is very important to develop a fatigue design method for spot welded multi-lap joints in railroad commercial vehicles. The objective of this paper is to provide an integrated fatigue design criterion for spot-welded multi-lap joints used in the body of railroad commercial vehicles. Based on finite element analysis, the fatigue life data for spot-welded multi-lap joints is correlated in terms of the maximum stress intensity factor, K θ max , that is the fracture mechanical parameter. From the results, using Δ K θ max - N f relationship, a proper fatigue life design rule independent on geometric variables and material properties for components having spot welded multi-lap joints can be established.

Stress Intensity Factor and Crack Opening Area of Circumferentially-Cracked Pipe Under Torsion Moment

2020 ◽  
Author(s):  
Yifan Huang ◽  
Xinjian Duan
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Opening ◽  
Three Dimensional ◽  
Bending Moment ◽  
Torsion Moment ◽  
Dimensional Finite Element ◽  
3D Fea ◽  
Three Dimensional Finite Element

Abstract The deterministic leak-before-break (LBB) analysis and probabilistic fracture mechanics (PFM) assessment are two primary approaches for demonstrating extremely low probability of rupture of pressurized piping in the nuclear energy industry. Both stress intensity factor (SIF) and crack opening area (COA) are key components to the LBB and PFM assessments. Most of the studies and engineering practices focus on the SIF and COA due to axial tension, bending moment and internal pressure while limited investigations target on these parameters caused by torsion moment. The objective of this study is to perform three-dimensional finite element analyses (3D FEA) to determine both SIF and COA for through-wall circumferential cracks in the pipe under bending or torsion moment. A range of normalized crack lengths (i.e. θ/π = 1/18 to 4/9) and three pipe radius over thickness ratios (i.e. Rm/t = 5, 10 and 25) are considered. Empirical solutions of the SIF for torsion loading as functions of crack geometry are developed. Comparisons for SIF regarding combined bending and torsion moments evaluated using code-specified solutions are presented. Finally, the COAs regarding the two loading modes are discussed. Such study is expected to be useful for both deterministic LBB analysis and PFM assessment of pressurized pipes.

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