A simple method to determine crack opening stress for the center cracked plate under cyclic tensile loads

2018 ◽  
Vol 160 ◽  
pp. 389-396 ◽  
Author(s):  
Jingjie Chen ◽  
Meng You ◽  
Yi Huang
2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Toshiyuki Meshii ◽  
Teruhiro Yamaguchi ◽  
Yuma Higashino

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.


Author(s):  
E. Smith

In the context of the formulation of a leak-before-break case for a component in a pressurized system, this paper is concerned with the quantification of the crack opening area associated with a two-dimensional crack that is subjected to tensile stresses. We present a simple method, based on the strip yield representation of plastic deformation, for calculating the area. The method is validated against the known result for the ease of an isolated crack in a uniformly stressed infinite solid. It is then used for a general stress distribution, as might arise from a combination of pressure induced and weld residual tensile stresses, with the considerations being focussed on the case where plastic deformation is limited, as is usually appropriate for normal operating situations; application of the method is then especially simple.


2005 ◽  
Vol 297-300 ◽  
pp. 1572-1578
Author(s):  
Yu Ting He ◽  
Feng Li ◽  
Rong Shi ◽  
G.Q. Zhang ◽  
L.J. Ernst ◽  
...  

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.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Lin Zhang ◽  
Xiaohui Wei

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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