Evaluation of Fatigue Crack Growth in Solder Layer of IGBT Module under Power Cycle by Using J-integral Method

2021 ◽  
Author(s):  
Kai Yang ◽  
Longzao Zhou ◽  
Fengshun Wu ◽  
Yi Zhang ◽  
Yang Han ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Integral Method ◽  
J Integral ◽  
Power Cycle ◽  
Igbt Module ◽  
Solder Layer

scholarly journals Advantageous Description of Short Fatigue Crack Growth Rates in Austenitic Stainless Steels with Distinct Properties

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 475
Author(s):  
Lukáš Trávníček ◽  
Ivo Kuběna ◽  
Veronika Mazánová ◽  
Tomáš Vojtek ◽  
Jaroslav Polák ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stainless Steels ◽  
Growth Rates ◽  
Large Scale ◽  
J Integral ◽  
Scale Yielding ◽  
Residual Fatigue ◽  
Crack Growth Rates

In this work two approaches to the description of short fatigue crack growth rate under large-scale yielding condition were comprehensively tested: (i) plastic component of the J-integral and (ii) Polák model of crack propagation. The ability to predict residual fatigue life of bodies with short initial cracks was studied for stainless steels Sanicro 25 and 304L. Despite their coarse microstructure and very different cyclic stress–strain response, the employed continuum mechanics models were found to give satisfactory results. Finite element modeling was used to determine the J-integrals and to simulate the evolution of crack front shapes, which corresponded to the real cracks observed on the fracture surfaces of the specimens. Residual fatigue lives estimated by these models were in good agreement with the number of cycles to failure of individual test specimens strained at various total strain amplitudes. Moreover, the crack growth rates of both investigated materials fell onto the same curve that was previously obtained for other steels with different properties. Such a “master curve” was achieved using the plastic part of J-integral and it has the potential of being an advantageous tool to model the fatigue crack propagation under large-scale yielding regime without a need of any additional experimental data.

scholarly journals Short fatigue crack growth in welded joints described by the effective cyclic J-integral

2018 ◽  
Vol 165 ◽  
pp. 09002
Author(s):  
Désiré Tchoffo Ngoula ◽  
Michael Vormwald
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Crack Growth ◽  
Residual Stresses ◽  
Crack Growth ◽  
Welded Joints ◽  
Driving Force ◽  
J Integral ◽  
Crack Driving Force ◽  
Short Fatigue Crack

The purpose of the present contribution is to predict the fatigue life of welded joints by using the effective cyclic J-integral as crack driving force. The plasticity induced crack closure effects and the effects of welding residual stresses are taken into consideration. Here, the fatigue life is regarded as period of short fatigue crack growth. The node release technique is used to perform finite element based crack growth analyses. For fatigue lives calculations, the effective cyclic J-integral is employed in a relation similar to the Paris (crack growth) equation. For this purpose, a specific code was written for the determination of the effective cyclic J-integral for various lifetime relevant crack lengths. The effects of welding residual stresses on the crack driving force and the calculated fatigue lives are investigated. Results reveal that the influence of residual stresses can be neglected only for large load amplitudes. Finally, the predicted fatigue lives are compared with experimental data: a good accordance between both results is achieved.

A new cyclic J-integral for low-cycle fatigue crack growth

2006 ◽  
Vol 27 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Hong-jiu Hu ◽  
Xing-ming Guo ◽  
Pei-ning Li ◽  
Yu-jun Xie ◽  
Jie Li
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Low Cycle Fatigue ◽  
J Integral ◽  
Cycle Fatigue

Effects of Stress Ratio and Hold-Time on Fatigue Crack Growth in Alloy 718

1979 ◽  
Vol 101 (3) ◽  
pp. 224-230 ◽  
Author(s):  
P. Shahinian ◽  
K. Sadananda
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stress Ratio ◽  
Hold Time ◽  
Creep Crack Growth ◽  
Time Dependent ◽  
J Integral ◽  
Alloy 718 ◽  
Test Conditions

Crack growth rate da/dN in Alloy 718 at 650°C, compared on the conventional ΔK basis, increased with increase in R (Kmin/Kmax) and also generally with inclusion of hold time at Kmax and Kmin. An exception, however, was that a 1-min hold at a Kmin just below the threshold K for creep crack growth caused retardation of crack growth. Correlation of da/dN for various R levels was better with Kmax than with other parameters such as Kmin, ΔK, and Δ J-integral. Fatigue crack growth in the alloy was found to be time dependent and Kmax controlled under these test conditions and consequently the best overall correlation was given by da/dt with Kmax. An unusual observation was that the addition of hold time to the loading cycle at near zero Kmin (R = 0.05) caused an increase in da/dN, as the result of an environmental interaction.

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