scholarly journals The relationship between the Dang Van criterion and the traditional bulk fatigue criteria

2003 ◽  
Vol 38 (3) ◽  
pp. 201-206 ◽  
Author(s):  
G Peridas ◽  
A. M Korsunsky ◽  
D. A Hills

A formal relationship is established between the traditional bulk fatigue criteria such as the Goodman rule and the Sines criterion, and the recent crack initiation criterion of Dang Van. The constants implied by the Dang Van procedure may be formally connected to the fatigue limit and mean stress dependence given by the Goodman rule, under conditions of uniaxial loading. The biaxial fatigue criterion of Sines is also compared with the Dang Van procedure. The similarity in the approaches may be further extended to permit finite initiation times to be estimated by the Dang Van criterion when the fatigue limit is exceeded.

2008 ◽  
pp. 463-463-19 ◽  
Author(s):  
DF Socie ◽  
LA Waill ◽  
DF Dittmer

2019 ◽  
Vol 16 (5) ◽  
pp. 875-893 ◽  
Author(s):  
Jinzhu Hu ◽  
Xingyu Zhang ◽  
Yubing Gao ◽  
Zimin Ma ◽  
Xinzeng Xu ◽  
...  

Abstract Directional presplit blasting (DPB) technology for an innovative no-pillar mining approach is introduced. First, a mechanical model is established to analyze crack initiation and coalescence using the new technology. The explosion pressure formula containing tress concentration factor explains the relationship between the quantity of explosives and the crack initiation and coalescence. Subsequently, a dynamic finite element simulation method is used to study the stress and damage evolution process of the blasthole wall in ordinary explosion and DPB. The simulation results indicate that the stress concentration factor is approximately 4c10 for the same quantity of explosives. Finally, a field test was conducted in the Fucheng coal mine of China. Based on the field test, the concept of cracking ability is proposed, the relationship between the quantity of explosives and cracking ability is determined, and the quantity of explosives is divided into four stages that are compatible with the roof rock strength. The results can provide some clinical guidance for application of DPB in other projects of the gob-side entry retaining by roof cutting.


2019 ◽  
Vol 60 (2) ◽  
pp. 181-189
Author(s):  
A. Akai ◽  
D. Shiozawa ◽  
T. Yamada ◽  
T. Sakagami

Abstract Recently, a technique for rapidly determining a material’s fatigue limit by measuring energy dissipation using infrared thermography has received increasing interest. Measuring the energy dissipation of a material under fatigue loading allows the rapid determination of a stress level that empirically coincides with its fatigue limit. To clarify the physical implications of the rapid fatigue limit determination, the relationship between energy dissipation and fatigue damage initiation process was investigated. To discuss the fatigue damage initiation process at grain size scale, we performed high-spatial-resolution dissipated energy measurements on type 316L austenitic stainless steel, and observed the slip bands on the same side of the specimen. The preprocessing of dissipated energy measurement such as motion compensation and a smoothing filter was applied. It was found that the distribution of dissipated energy obtained by improved spatial resolution measurement pinpointed the location of fatigue crack initiation. Owing to the positive correlation between the magnitude of dissipated energy and number of slip bands, it was suggested that the dissipated energy was associated with the behavior of slip bands, with regions of high dissipated energy predicting the location of fatigue crack initiation.


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