Mode I crack growth rate of a ferromagnetic elastic strip in a uniform magnetic field

2006 ◽  
Vol 54 (19) ◽  
pp. 5115-5122 ◽  
Author(s):  
Yasuhide Shindo ◽  
Fumio Narita ◽  
Katsumi Horiguchi ◽  
Tetsu Komatsu
2012 ◽  
Vol 224 ◽  
pp. 303-306
Author(s):  
Chen Chen Ma ◽  
Xiao Gui Wang

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.


2015 ◽  
Vol 1120-1121 ◽  
pp. 1008-1013
Author(s):  
Hui Fang Li ◽  
Yuan Hong ◽  
Cai Fu Qian

In this paper, I+II mixed mode notch-crack fatigue propagation in titanium alloy steel TA2 was tested with the emphasis on the crack mode transition and retardation under constant amplitude loading or overloading. Finite element method was employed to calculate the stress distribution at the crack tip in order to explain the crack growth behavior. It is found that after initiation from the crack tip, the new formed crack propagates in a mode I form, regardless of the magnitudes of the inclined angle of the crack and the overloading applied. The relationship between the fatigue crack growth rate and mode I stress intensity factor range was calculated. After overloading, crack initiation and propagation will be significantly slowed, or in other words, there exists overloading retardation. Calculation shows that after overloading, a plastic zone with residual compressive stress is formed which is responsible for the retardation of the crack growth rate. Micro-morphologies of the crack growth path and the crack fracture surface were also observed and analyzed.


Author(s):  
Kiminobu Hojo ◽  
Shinichi Kawabata

Ductile crack growth calculation method under excessive cyclic loading in a fitness for service rule has not been established even in Mode I. The authors simulated ductile crack growth behavior of CT specimens under cyclic loading executed in a committee of the Japan Welding Society. Sensitivity of the used stress-strain curves by monotonic or cyclic loading and the effect of the hardening rule were investigated. For evaluation of the crack growth rate under excessive cyclic loading, the parameter ΔJ was applied and compared with the rate of the JSME rules for FFS.


2019 ◽  
Vol 814 ◽  
pp. 176-181
Author(s):  
Sang Hyun Hong ◽  
Sang Deok Kim ◽  
Jae Hoon Kim

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.


Author(s):  
Kiminobu Hojo

Abstract Ductile crack growth calculation method under excessive cyclic loading in a fitness for service rule has not been established even in Mode I. Since 2017 to 2019 the author had tried to establish how to determine the parameters of the combined hardening rule and applied it to simulate the ductile crack growth behavior of the 1TC(T) specimens of the different loading levels for ferritic steel. Also ΔJ calculation using the reference stress method, and the transferred crack growth rate from a code were applied to estimate the ductile crack growth. Several equations of the reference stress method were tried to apply in the previous paper. Further the prediction procedure using the ΔJ, the reference stress method and da/dN-ΔJ curve based on the JSME rules on fitness for service (FFS) was applied to the pipe fracture tests under cyclic loading and its applicability was discussed for the case of a pipe structure in the previous paper. In this paper similar procedures were applied to 1TC(T) specimens of stainless steel. The combined hardening rule was applied for the constitution law of stress-strain curve. The numerical simulation with the combined rule traced the load-load line displacement curve under the cyclic loading experiments of 1TC(T). Also austenitic stainless fatigue crack growth rate (FCGR) in air condition from the JSME rules on FFS bounded the experimental crack growth rate, which means the FCGR of the JSME rules is applicable to fatigue crack growth calculation.


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