Prediction of crack-opening stress levels for 1045 as-received steel under service loading spectra

2003 ◽  
Vol 25 (2) ◽  
pp. 149-157 ◽  
Author(s):  
M Khalil
Keyword(s):  
Crack Opening ◽  
Stress Levels ◽  
Service Loading ◽  
Crack Opening Stress

scholarly journals Applicability of the Modified Ritchie-Knott-Rice Failure Criterion to Examine the Feasibility of Miniaturized Charpy Type SE(B) Specimens

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Toshiyuki Meshii ◽  
Teruhiro Yamaguchi ◽  
Yuma Higashino
Keyword(s):  
Cleavage Fracture ◽  
Failure Criterion ◽  
Critical Stress ◽  
Small Difference ◽  
Crack Opening ◽  
Width Ratio ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Crack Opening Stress ◽  
Crack Tip Opening

This paper examined whether the modified Ritchie-Knott-Rice (RKR) failure criterion can be applied to examine the feasibility of miniaturized Charpy type SE(B) specimens of thickness-to-width ratio B/W=1. The modified RKR failure criterion considered in this paper is the (4δt,σ22c) criterion which predicts the onset of cleavage fracture when the midplane crack-opening stress measured at a distance equal to four times the crack-tip opening displacement, denoted as σ22d, exceeds a critical stress σ22c. Specimens with B values of 25, 10, 3, and 2 mm (denoted as 25t, 10t, 3t, and 2t specimens, resp.) manufactured with 0.55% carbon steel were tested at 20°C. The results showed that the modified RKR criterion could appropriately predict the occurrence of cleavage fracture accompanied by negligibly small stable crack extension (denoted as KJc fracture) naturally for the 25t and 10t specimens. The modified RKR criterion could also predict that KJc fracture does not occur for the 2t specimen. The σ22c obtained from specimens for the 25t and 10t specimens exhibited only a small difference, indicating that the Jc obtained from the 10t specimens can be used to predict the Jc that will be obtained with the 25t specimens.

A Model for Determining Crack Opening Stress Intensity Factor Ratio under Tri-Axial Stress State

2005 ◽  
Vol 297-300 ◽  
pp. 1572-1578
Author(s):  
Yu Ting He ◽  
Feng Li ◽  
Rong Shi ◽  
G.Q. Zhang ◽  
L.J. Ernst ◽  
...  
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Stress State ◽  
Intensity Factor ◽  
Present Model ◽  
Axial Stress ◽  
Crack Opening ◽  
Factor Ratio ◽  
Crack Opening Stress ◽  
Good Agreement

When studying 3D fatigue crack growth behaviors of materials, to determine the crack opening stress intensity factor ratio is the key issue. Elastic-plastic Fracture Mechanics theory and physical mechanism of cracks’ closure phenomena caused by plastic deformation are employed here. A model for determining the crack opening stress intensity factor ratio under tri-axial stress state is presented. The comparison of the present model with available data and models shows quite good agreement.

scholarly journals A Novel Methodology for Calculating Crack Opening Stress under Tension-Compression Cyclic Load

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Lin Zhang ◽  
Xiaohui Wei
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Closure ◽  
Crack Opening ◽  
Compressive Load ◽  
Load Effect ◽  
Compression Load ◽  
Fatigue Crack Growth Life ◽  
Crack Opening Stress

Crack closure model has been used in several applications on the prediction of fatigue crack growth life, with expression of crack opening stress often serving as milestones. A typical difficulty in calculating the crack opening stress is the phenomenon of crack closure caused by the compressive load effect. Compressive load effect, resulting in the change of residual stress status at the unloading stage and the decrease of crack opening stress, is a long-term challenge for predicting fatigue crack growth life. We propose the expression of crack opening stress to predict fatigue crack growth life based on the analysis of compact tensile specimen with elastoplastic element method. It combines the characteristics of material and load to deal with the phenomenon of crack closure and uses stress ratio and normalized maximum applied load variable to construct the expression of crack opening stress. In the study of tensile-compression fatigue crack growth experiments, the proposed expression is proved to improve, by comparative analysis, the predictive ability on the whole range of experiment data. The novel expression is accurate and simple. Consequently, it is conducive to calculate the crack opening stress under tension-compression load.

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