A Fractographic Study of Load-Sequence-Induced Mixed-Mode Fatigue Crack Growth in an Al-Cu Alloy

2009 ◽  
pp. 258-258-21 ◽  
Author(s):  
NE Ashbaugh ◽  
WJ Porter ◽  
RV Prakash ◽  
R Sunder
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Mixed Mode ◽  
Fractographic Study ◽  
Cu Alloy ◽  
Load Sequence

Pre-Strain Effects on Mixed-Mode Fatigue Crack Propagation Behaviour of the P355NL1 Pressure Vessels Steel

2018 ◽  
Author(s):  
João Ferreira ◽  
José A. F. O. Correia ◽  
Grzegorz Lesiuk ◽  
Sergio Blasón González ◽  
Maria Cristina R. Gonzalez ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Mixed Mode ◽  
Pressure Vessels ◽  
Mode I ◽  
Pure Mode

Pressure vessels and piping are commonly subjected to plastic deformation during manufacturing or installation. This pre-deformation history, usually called pre-strain, may have a significant influence on the resistance against fatigue crack growth of the material. Several studies have been performed to investigate the pre-strain effects on the pure mode I fatigue crack propagation, but less on mixed-mode (I+II) fatigue crack propagation conditions. The present study aims at investigating the effect of tensile plastic pre-strain on fatigue crack growth behavior (da/dN vs. ΔK) of the P355NL1 pressure vessel steel. For that purpose, fatigue crack propagation tests were conducted on specimens with two distinct degrees of pre-strain: 0% and 6%, under mixed mode (I+II) conditions using CTS specimens. Moreover, for comparison purposes, CT specimens were tested under pure mode I conditions for pre-strains of 0% and 3%. Contrary to the majority of previous studies, that applied plastic deformation directly on the machined specimen, in this work the pre-straining operation was carried out prior to the machining of the specimens with the objective to minimize residual stress effects and distortions. Results revealed that, for the P355NL1 steel, the tensile pre-strain increased fatigue crack initiation angle and reduced fatigue crack growth rates in the Paris region for mixed mode conditions. The pre-straining procedure had a clear impact on the Paris law constants, increasing the coefficient and decreasing the exponent. In the low ΔK region, results indicate that pre-strain causes a decrease in ΔKth.

Mixed mode (I+II) fatigue crack growth in puddle iron

2017 ◽  
Vol 185 ◽  
pp. 175-192 ◽  
Author(s):  
Grzegorz Lesiuk ◽  
Paweł Kucharski ◽  
José A.F.O. Correia ◽  
A.M.P. De Jesus ◽  
C. Rebelo ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Mixed Mode ◽  
Mode I

Numerical Simulation of Fatigue Crack Growth for Curved Cracks Emanating from Fastener Holes in Sheets by the MVCCI Method

2006 ◽  
Vol 324-325 ◽  
pp. 863-866
Author(s):  
Holger Theilig ◽  
M. Goth ◽  
Michael Wünsche
Keyword(s):  
Numerical Simulation ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Plane Stress ◽  
Mixed Mode ◽  
Mixed Mode Loading ◽  
Multiple Crack ◽  
2D Structure ◽  
Predictor Corrector

The paper presents the results of a continued study of curved fatigue crack growth in a multiple arbitrarily pre-cracked isotropic sheet under plane stress loading. The predictor-corrector method (PCM) was extended in order to analyse the growth of multiple crack systems in a finite 2D structure. Together with the recently proposed improved modified virtual crack closure integral (MVCCI) method we can obtain accurate SIF values also for interacting cracks, and furthermore we can simulate fatigue crack growth of multiple crack systems in plane sheets under proportional mixed mode loading conditions. As a result, the program PCCS-2D is written to run within ANSYS to simulate interacting curved cracks. In order to check the accuracy and efficiency of the proposed method several example problems are solved. Especially curved cracks emanating from loaded fastener holes in sheets are analysed.

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