scholarly journals Statistical Modeling of Microstructural Effects on Fatigue Behavior of α/β Titanium Alloys

2000 ◽  
Author(s):  
A. B. O. Soboyejo ◽  
S. Shademan ◽  
V. Sinha ◽  
W. O. Soboyejo
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Behavior ◽  
Statistical Correlation ◽  
Controlled Cooling ◽  
Modeling Methodology ◽  
Β Phase ◽  
Microstructural Effects ◽  
Crack Growth Rates

Abstract This paper presents the results of combined experimental and theoretical studies of the effects of colony microstructure on fatigue crack growth in Ti-6Al-4V. Colony microstructures with controlled lath widths and colony sizes are produced by controlled cooling from the β phase field. For colony microstructures with approximately 20 vol% of β phase, the fatigue crack growth rates are shown to decrease with increasing α lath and colony size. A new statistical multiparameter modeling methodology framework is proposed for the assessment of the combined effects of mechanical and microstructural random variables on the fatigue crack growth rate. Excellent statistical correlation has been observed between the theoretical model and experimental data. The implications of the results are also discussed for the estimation of fatigue life.

scholarly journals Fatigue-crack growth in fresh-water ice: preliminary results

1991 ◽  
Vol 15 ◽  
pp. 236-241 ◽  
Author(s):  
Wilfrid A. Nixon ◽  
Larry J. Weber
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fresh Water ◽  
Fatigue Behavior ◽  
Compression Tests ◽  
Water Ice ◽  
Preliminary Results ◽  
Ice Failure ◽  
Crack Growth Rates

Very little data exist on the fatigue behavior of ice, yet fatigue may have an important role to play in a number of ice failure situations. Whilst reversed-bending tests and cyclic-compression tests have been performed on ice, no attempts have been made previously to measure fatigue-crack growth rates in ice. This paper presents the results of fatigue-crack growth experiments on S2 (i.e. columnar grained with the c axes randomly aligned within the horizontal plane) fresh-water ice. There is clear evidence that crack growth has occurred under cyclic loading but, as yet, the data are insufficient to determine the validity of da/dΝ versus δK type behavior. Preliminary results are presented and the implications of the results are discussed.

scholarly journals Fatigue-crack growth in fresh-water ice: preliminary results

1991 ◽  
Vol 15 ◽  
pp. 236-241 ◽  
Author(s):  
Wilfrid A. Nixon ◽  
Larry J. Weber
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fresh Water ◽  
Fatigue Behavior ◽  
Compression Tests ◽  
Water Ice ◽  
Preliminary Results ◽  
Ice Failure ◽  
Crack Growth Rates

Very little data exist on the fatigue behavior of ice, yet fatigue may have an important role to play in a number of ice failure situations. Whilst reversed-bending tests and cyclic-compression tests have been performed on ice, no attempts have been made previously to measure fatigue-crack growth rates in ice. This paper presents the results of fatigue-crack growth experiments on S2 (i.e. columnar grained with the c axes randomly aligned within the horizontal plane) fresh-water ice. There is clear evidence that crack growth has occurred under cyclic loading but, as yet, the data are insufficient to determine the validity of da/dΝ versus δK type behavior. Preliminary results are presented and the implications of the results are discussed.

Super-Long Life Fatigue Behavior of Structural Aluminum Alloys

2004 ◽  
Vol 261-263 ◽  
pp. 1287-1294 ◽  
Author(s):  
Qing Yuan Wang ◽  
Norio Kawagoishi ◽  
Nu Yan ◽  
Q. Chen
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Behavior ◽  
Al Alloys ◽  
Stress Intensity Factor Range ◽  
Initiation And Propagation ◽  
Small Cracks ◽  
Long Life ◽  
Crack Growth Rates

The objective of this study is to determine very long life fatigue and near threshold fatigue crack growth behaviors of 7075/T6 and 6061/T6 Al-alloys using piezoelectric accelerated fatigue at 19.5KHz. The experimental results show the fatigue failure can occur beyond 107, even 109 cycles, and endurance limits could not be obtained in the Al-alloys until 109 cycles. Fatigue voids are noticed on fatigue fracture in both alloys. By using scanning electron microscopy (SEM), the crack initiation and propagation behaviors have been examined. Fatigue crack growth rates of small cracks in the Al-alloys are found to be greater than those of large cracks at the same stress intensity factor range.

scholarly journals Effect of Bond-Line Thickness on Fatigue Crack Growth of Structural Acrylic Adhesive Joints

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1723
Author(s):  
Yu Sekiguchi ◽  
Chiaki Sato
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Behavior ◽  
Adhesive Bond ◽  
Bond Line ◽  
Loading Conditions ◽  
Fatigue Crack Growth Resistance ◽  
Line Thickness ◽  
Bond Line Thickness

With an increasing demand for adhesives, the durability of joints has become highly important. The fatigue resistance of adhesives has been investigated mainly for epoxies, but in recent years many other resins have been adopted for structural adhesives. Therefore, understanding the fatigue characteristics of these resins is also important. In this study, the cyclic fatigue behavior of a two-part acrylic-based adhesive used for structural bonding was investigated using a fracture-mechanics approach. Fatigue tests for mode I loading were conducted under displacement control using double cantilever beam specimens with varying bond-line thicknesses. When the fatigue crack growth rate per cycle, da/dN, reached 10−5 mm/cycle, the fatigue toughness reduced to 1/10 of the critical fracture energy. In addition, significant changes in the characteristics of fatigue crack growth were observed varying the bond-line thickness and loading conditions. However, the predominance of the adhesive thickness on the fatigue crack growth resistance was confirmed regardless of the initial loading conditions. The thicker the adhesive bond line, the greater the fatigue toughness.

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.

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