Simulation of Fatigue Initiation and Non-Self-Similar Fatigue Crack Growth under Mixed Mode I/II Loading

2012 ◽  
Vol 224 ◽  
pp. 303-306
Author(s):  
Chen Chen Ma ◽  
Xiao Gui Wang
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Mixed Mode ◽  
Mode I ◽  
Fatigue Initiation ◽  
Self Similar ◽  
Crack Growth Model

The fatigue initiation and non-self-similar fatigue crack growth behavior of three notched compact tension and shear specimens of 16MnR steel under mixed mode I/II loading were investigated. The plane-stress finite element model with the implemented Armstrong-Frederick type cyclic plasticity model was used to calculate the elastic-plastic stress-strain responses. A recently developed dynamic crack growth model was used to simulate the effects of loading history on the successive crack growth. With the outputted numerical results, a multiaxial fatigue damage criterion based on the critical plane was used to determine the location of fatigue initiation. A formula of fatigue crack growth rate, which is based on the postulation that the fatigue initiation and crack growth have the same damage mechanism, was then used to calculate the transient crack growth rate and determine the non-self-similar crack growth path. The predicted fatigue initiation position, crack path and crack growth rate are in excellent agreement with the experimental data.

Effects of Mixed Mode Loading Conditions on Fatigue Crack Growth Rate

2019 ◽  
Vol 814 ◽  
pp. 176-181
Author(s):  
Sang Hyun Hong ◽  
Sang Deok Kim ◽  
Jae Hoon Kim
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Mixed Mode ◽  
Mode I ◽  
Pure Mode ◽  
Intensity Factors

The fatigue crack growth rate is the most important factor in predicting the life of a product when applying the damage tolerance design concept. Studies related to pure mode I for structures under fatigue loading have been actively conducted, while not many studies are conducted on the mixed mode. In this study, therefore, mixed mode fatigue crack growth experiments were designed using the Compact-Tension-Shear (CTS) specimens and the loading devices, proposed by Richard. Furthermore, the finite element analysis was used in determining the stress intensity factors of CTS specimen. As the results, the fatigue crack growth rate using the equivalent stress intensity factors proposed by previous researchers was lower than that of pure mode I at the initial stage of crack growth when the load angle increases.

A CRACK GROWTH MODEL BASED ON FATIGUE DAMAGE ACCUMULATION

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2774-2779 ◽  
Author(s):  
BAOXIANG QIU ◽  
XIAOGUI WANG ◽  
ZENGLIANG GAO
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Damage ◽  
Growth Model ◽  
Damage Accumulation ◽  
Fatigue Damage Accumulation ◽  
Crack Growth Model

A novel model for predicting the fatigue crack growth had been developed based on the concept of the fatigue damage accumulation. Fatigue crack growth was considered as a process of continuous crack nucleation. The crack tip failed to form a fresh crack while the accumulative fatigue damage reached the critical damage. A simplified model of the general crack growth model was proposed with the assumption that the damage zone can be divided into many different zones and each zone had the same crack growth rate. The model was applied to predict the crack growth of the compact specimen made of 16MnR steel under the constant amplitude loading. The predicted crack growth rate was in excellent agreement with the experimental observations.

Analysis of Mixed-Mode Fatigue Crack Growth under Stress Redistribution at Crack Tips

2011 ◽  
Vol 148-149 ◽  
pp. 552-555
Author(s):  
Wen Feng Tu ◽  
Zeng Liang Gao ◽  
Zhao Ji Hu
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Mixed Mode ◽  
Growth Parameters ◽  
Stress Redistribution ◽  
Loading Direction ◽  
Crack Tips

The experiments of mixed-mode I-II fatigue crack growth under stress redistribution at crack tips were conducted with compact specimens made of 16MnR steel. This test consisted of the 1st, the 2nd and 3rd step. When the crack reached a certain length in 1st step, the loading direction was switched to a certain angle. Finally, the loading direction was returned to the original orientation. The stress redistribution of mixed-mode fatigue was formed by altering the loading direction at propagating crack tips. A finite element analysis was also conducted to obtain the and values, and then mixed-mode crack growth parameters were adopted to evaluate the crack growth rate and crack paths. The crack growth paths had a tendency perpendicular and across to the loading axis. Right after the loading direction was changed, the crack growth rate was decreased rapidly, and crack growth paths under the stress redistribution zone (SRZ) were affected.

Effect of Rubber Content on Fatigue Crack Growth Rate under Mode I Loading

2017 ◽  
Vol 25 (4) ◽  
pp. 285-288 ◽  
Author(s):  
Makoto Imanaka ◽  
Hiroshi Asano
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Threshold ◽  
Mode I ◽  
Adhesively Bonded ◽  
Rubber Content ◽  
Paris Region

Rubber-modified adhesives have attracted particular interest recently, owing to their property of dramatically increasing the fracture toughness of adhesively-bonded joints. In many cases, these joints are exposed to cyclic loads, and hence an understanding of the fatigue mechanisms is of paramount importance. This study was conducted to characterize the rubber content-dependent behaviour of rubber-modified epoxy adhesive under cyclic loading. Fatigue crack growth rates under mode I loading were measured using adhesively-bonded double cantilever beam specimens with rubber contents of 0, 5 and 14 wt.%. As a result, in the Paris region, an increase in rubber content reduced the fatigue crack growth rate. Similarly to the Paris region, the fatigue threshold for 5 wt.% was greater than that for 0 wt.%; however, the fatigue threshold of joints with 14 wt.% rubber content was nearly equal to those with 5 wt.%.

Sign in / Sign up

Export Citation Format

Share Document