Fatigue Crack Growth in Stiffened Panels under Pressure Loading

2009 ◽  
pp. 345-345-28 ◽  
Author(s):  
HP Chu ◽  
JA Hauser ◽  
JP Sikora
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Pressure Loading ◽  
Stiffened Panels

Fatigue Crack Growth Model for Part-Through Flaws in Plates and Pipes

1979 ◽  
Vol 101 (1) ◽  
pp. 53-58 ◽  
Author(s):  
P. K. Nair
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Aspect Ratio ◽  
Crack Growth ◽  
Growth Model ◽  
Tensile Load ◽  
Structural Components ◽  
Pressure Loading ◽  
Axial Part ◽  
Crack Growth Model

A fatigue crack growth model is developed to evaluate the behavior of planar elliptic flaws in structural components under cyclic loadings. The model is applied to plates with cyclic tensile load and nuclear piping under cyclic pressure loading. It is found that small flaws in plates tend to grow to a fixed aspect ratio, b/a≃0.9 (b is the through thickness direction). The trend checks well with available experimental data. For an axial part-through flaw in piping there is no fixed aspect ratio for growth. However, the flaws in piping are found to grow to a definite axial length. An evaluation is made of the applicability of the model to nuclear primary piping.

Fatigue Crack Growth in Integrally Stiffened Panels Joined Using Friction Stir Welding and Swept Friction Stir Spot Welding

2008 ◽  
Vol 5 (4) ◽  
pp. 101568 ◽  
Author(s):  
Dwight A. Burford ◽  
Bryan M. Tweedy ◽  
Christian A. Widener ◽  
R. W. Neu ◽  
K. R. W. Wallin ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Friction Stir Welding ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Spot Welding ◽  
Friction Stir Spot Welding ◽  
Stiffened Panels ◽  
Friction Stir ◽  
Integrally Stiffened Panels

Composite Repair of Curved Stiffened Aluminum Panels under Combined Tension and Shear Cyclic Loadings

2012 ◽  
Vol 225 ◽  
pp. 219-224
Author(s):  
Hossein Hosseini-Toudeshky ◽  
Mir Ali Ghaffari ◽  
Bijan Mohammadi
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Initial Crack ◽  
Stiffened Panels ◽  
Crack Trajectory ◽  
Aluminum Panels ◽  
Crack Growth Modeling ◽  
Tension Loading

In this study, finite element method is used to investigate the fracture analyses, crack growth trajectory and fatigue life of curved stiffened panels repaired with composite patches subjected to combined tension and shear cyclic loadings. For this purpose, 3-D finite element modeling are performed for consideration of real 3-D crack-front in general mixed-mode conditions. Contact elements are used between the crack surfaces on two crack sides to prevent interferences of crack surfaces and a complementary program was developed to handle the automatic fatigue crack growth modeling. The effects of various patch layups and shear-tension loading ratios on fracture parameters of the aluminum panel are investigated. It is shown that in low shear to tension ratios like 0.4, the patch layup of [90]4 (perpendicular to the initial crack) is more efficient than the patch with layups angle along the tension loading. As the shear to tension ratio increases, effect of patch layups with orientations of almost perpendicular to the crack trajectory on fatigue crack growth life is increased comparing with the patch layups parallel to the tension orientation like [90]4.

scholarly journals Simulation of Fatigue Crack Growth in Integrally Stiffened Panels Under the Constant Amplitude and Spectrum Loadin

2009 ◽  
Vol 2009 (1) ◽  
pp. 5-19 ◽  
Author(s):  
Petr Augustin
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Experimental Program ◽  
Constant Amplitude ◽  
Load Spectrum ◽  
Stiffened Panels ◽  
Load Sequence ◽  
Integrally Stiffened Panels ◽  
Spectrum Loading

Simulation of Fatigue Crack Growth in Integrally Stiffened Panels Under the Constant Amplitude and Spectrum LoadinThe paper describes methodology of numerical simulation of fatigue crack growth and its application on integrally stiffened panels made of 2024-T351 aluminium alloy using high speed cutting technique. Presented approach for crack growth simulation starts by the calculation of stress intensity factor function from finite element results obtained using MSC. Patran/Nastran. Subsequent crack growth analysis is done in NASGRO and uses description of crack growth rates either by the Forman-Newman-de Koning relationship or by the table lookup form. Three crack growth models were applied for spectrum loading: non-interaction, Willenborg and Strip Yield model. Relatively large experimental program comprising both the constant amplitude and spectrum tests on integral panels and CCT specimens was undertaken at the Institute of Aerospace Engineering laboratory in order to acquire crack growth rate data and enable verification of simulations. First analyses and verification tests of panels were performed under the constant amplitude loading. For predictions of crack growth using the spectrum loading a load sequence representing service loading of the transport airplane wing was prepared. Applied load spectrum was measured on B737 airplane within the joint FAA/NASA collection program. The load sequence is composed of 10 flight types with different severity analogous to the standardized load sequence TWIST. Before application on the stiffened panels a calculation of crack growth under the spectrum loading was performed for simple CCT specimen geometry. The paper finally presents comparison of simulations of fatigue crack propagation in two-stringer stiffened panel under the spectrum loading with verification test carried out in the IAE lab. The work was performed within the scope of the 6th Framework Programme project DaToN - Innovative Fatigue and Damage Tolerance Methods for the Application of New Structural Concepts.

scholarly journals Multiscale fatigue crack growth modelling for welded stiffened panels

2014 ◽  
Vol 37 (9) ◽  
pp. 1043-1054 ◽  
Author(s):  
Ž. Božić ◽  
S. Schmauder ◽  
M. Mlikota ◽  
M. Hummel
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Modelling ◽  
Stiffened Panels

Fractographic analysis of fatigue crack growth in lightweight integral stiffened panels

2010 ◽  
Vol 1 (3) ◽  
pp. 233-258 ◽  
Author(s):  
Pedro M.G.P. Moreira ◽  
Paulo M.S.T. de Castro
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Testing ◽  
Content Type ◽  
Stiffened Panels ◽  
Friction Stir ◽  
Final Fracture ◽  
Striation Spacing ◽  
Macroscopic Crack

PurposeThe purpose of this paper is to complement available macroscopic fatigue crack growth measurements in flat stiffened panels with scanning electron microscopy (SEM) measurements of striation spacing.Design/methodology/approachThe paper's approach is fatigue testing of two‐stiffener flat panels manufactured using three different processes, with a central initial crack perpendicular to the stiffeners and load, in order to identify striation spacing during crack growth up to final fracture, using SEM.FindingsAn increase of striation spacing as cracks grow was quantified. Although when cracks approach the stiffeners the stress intensity factor decreases, there is no clear decrease of striation spacing in that region. Striation spacing is roughly similar to macroscopic crack‐propagation rate da/dN measured in the panels testing. This observation is no longer valid once the stiffeners are reached; this stage is characterized by fast acceleration of the cracking process until final complete rupture is verified, and macroscopic crack growth measurements are made difficult because of the “T” geometry in that region.Originality/valueA complete picture of the striation spacing during the fatigue crack growth up to final fracture of a two‐stiffener flat panel is provided for three different manufacturing processes: high‐speed machining, laser beam welding and friction stir welding.

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