PREDICTION OF CRANKSHAFT FATIGUE LIMIT LOAD BY CRACK-MODELING TECHNIQUE

2011 ◽  
Vol 10 (01) ◽  
pp. 127-134 ◽  
Author(s):  
XIAO PING CHEN ◽  
XIAO LI YU ◽  
RU FU HU ◽  
JIAN FENG LI
Keyword(s):  
Stress Intensity ◽  
Fatigue Limit ◽  
Material Properties ◽  
Threshold Stress ◽  
Limit Load ◽  
Processing Technology ◽  
Modeling Technique ◽  
Threshold Stress Intensity ◽  
Stress Intensity Range ◽  
Different Types

In this paper, combining the previous crankshaft fatigue test data with Crack-Modeling Technique, the threshold stress intensity range, ΔKth of crankshaft can be derived. The calculated threshold, ΔKth takes the effect of material properties and processing technology into account. Then, using the threshold, ΔKth, we can predict the fatigue limit load of the different types of crankshafts with the same material properties and processing technology by Crack-Modeling Technique. This study shows that the standard crack may be a good equivalent to the crankshaft stress concentration and the prediction of the crankshaft fatigue limit load is accurate.

Some Applications of Fractal Fracture Mechanics to Describe the Fatigue Behaviour of Materials

2008 ◽  
Vol 378-379 ◽  
pp. 355-370 ◽  
Author(s):  
Andrea Carpinteri ◽  
Andrea Spagnoli ◽  
Sabrina Vantadori
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Limit ◽  
Threshold Stress ◽  
Threshold Stress Intensity ◽  
Stress Intensity Range

As is well-known, fatigue limit, threshold stress intensity range and fatigue crack growth rate are influenced by the specimen or structure size. Limited information on size effect is available in the literature. In the present paper, by employing some concepts of fractal geometry, new definitions of fatigue limit, fracture energy and stress intensity factor, based on physical dimensions different from the classical ones, are discussed. Then, size-dependent laws for fatigue limit, threshold stress intensity range and fatigue crack growth rate are proposed. Some experimental results are examined in order to show how to apply such theoretical scaling laws.

Effect of Yield Stress and Grain Size on Threshold and Fatigue Limit

1986 ◽  
Vol 108 (2) ◽  
pp. 174-178 ◽  
Author(s):  
Y. Mutoh ◽  
V. M. Radhakrishnan
Keyword(s):  
Grain Size ◽  
Stress Intensity ◽  
Yield Stress ◽  
Fatigue Limit ◽  
Threshold Stress ◽  
Experimental Investigations ◽  
Threshold Stress Intensity ◽  
Stress Intensity Range ◽  
Intensity Range ◽  
Analytical Relations

Experimental investigations have been carried out to study the effects of grain size and yield stress on fatigue limit and threshold stress intensity range. The relations between fatigue limit and grain size and yield stress and those between threshold stress intensity range and grain size and yield stress which were predicted according to the model proposed in the previous paper agreed quite well with the experimental data. The difference in the dependence of fatigue limit and threshold stress intensity range on yield stress was discussed based on the analytical relations between them.

scholarly journals Effect of TiB Orientation on Near-Threshold Fatigue Crack Propagation in TiB-Reinforced Ti-3Al-2.5V Matrix Composites Treated with Heat Extrusion

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3685 ◽  
Author(s):  
Shoichi Kikuchi ◽  
Shunsuke Tamai ◽  
Takao Kawai ◽  
Yoshikazu Nakai ◽  
Hiroki Kurita ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Stress Intensity ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Threshold Stress ◽  
Matrix Composites ◽  
Threshold Stress Intensity ◽  
Stress Intensity Range ◽  
Intensity Range

TiB-reinforced Ti-3Al-2.5V matrix composites, in which TiB whiskers are oriented parallel to the direction of heat extrusion, were fabricated via mechanical alloying and hot isostatic pressing (HIP). To investigate the near-threshold fatigue crack propagation in TiB-reinforced Ti-3Al-2.5V matrix composites, stress intensity factor K-decreasing tests were conducted for disk-shaped compact specimens having two different orientations of TiB whiskers at force ratios from 0.1 to 0.8 under ambient conditions. The crack growth rates, da/dN, for the composites incorporating TiB whiskers oriented perpendicular to the direction of crack growth were constantly lower than those obtained in the case where the orientation was parallel at the same stress intensity range ΔK, while the threshold stress intensity range, ΔKth, was higher. This effect can be explained by the increase in the degree of roughness-induced crack closure resulting from the perpendicular TiB, because fatigue cracks preferentially propagated across the boundaries between the matrix and the TiB in certain regions. In contrast, the effective threshold stress intensity range, ΔKeff,th, for composites was unaffected by the TiB orientation at low force ratios.

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