Hatigue crack propagation in stiffened panels

2010 ◽  
pp. 155-162
Author(s):  
_ Bo_i_ ◽  
J Parunov ◽  
M Fadljevi_
Keyword(s):  
Crack Propagation ◽  
Stiffened Panels

Crack propagation in welded stiffened panels

2002 ◽  
Vol 58 (5-8) ◽  
pp. 1081-1102 ◽  
Author(s):  
R.J. Dexter ◽  
P.J. Pilarski
Keyword(s):  
Crack Propagation ◽  
Stiffened Panels

Optimization of Integrally Stiffened Panels Based on Crack Propagation Life

2008 ◽  
Vol 33-37 ◽  
pp. 249-254
Author(s):  
Zhi Ping Yin ◽  
Qi Qing Huang ◽  
Bing Hui Zhang
Keyword(s):  
Crack Propagation ◽  
Structural Optimization ◽  
Optimization Design ◽  
Design Method ◽  
Structural Parameters ◽  
Stiffened Panels ◽  
Structural Fatigue ◽  
Design Variables ◽  
Optimization Methodology ◽  
Integrally Stiffened Panels

Recent development in structure optimization offers the potential for significant improvements in the design of more durable structures. The present paper reveals the importance of structural optimization with crack propagation life of integrally stiffened panels. In the full paper, we explain in detail how to optimize structural fatigue life and design the structure of integrally stiffened panels which has the optimization life. The first topic is: the review of existing structural optimization design method. The second topic is: optimization methodology with crack propagation life. In our optimization methodology, the RSM (Response Surface Methodology) and GA (Genetic Algorithm) are successfully applied for structural optimization design with crack propagation life. The third topic is: damage tolerance optimization of integrally stiffened panels with crack propagation life. In this paper, structural parameters: the height and location of stringer, are the design variables. The structural weight is a fixed value. Through analyzing, the optimization structure with maximum life can not simply be chosen, and the maximum life would not increase all ways while the high of stringer increased. At last, the optimization structure, which has maximum crack propagation life, is given on the integrally stiffened panels.

Experimental Determination of the Crack Tip Stress Intensity Factor in Integrally Stiffened Panels

2016 ◽  
Vol 1135 ◽  
pp. 112-127
Author(s):  
Carlos E. Chaves ◽  
Caio Magno de Assunção
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Propagation ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Experimental Information ◽  
Image Correlation ◽  
Manufacturing Cost ◽  
Stiffened Panels

Integral structures offer large benefits in terms of manufacturing cost, but suffer from a lower degree of fail safety when compared to built-up structures. In order to achieve an improvement on the fatigue crack propagation (FCP), crack containment features (also known as crenellations) have been used on these structures. The source of the FCP improvement is the stress intensity factor (K) modification due to the geometry change. In the current study, an analysis about means of estimating K from the experimental information, and also to verify the K behavior while the crack propagates was performed. The study tested two AA 7475 panels, one with crenellations and another without. As the crack propagates, the K values were estimated in two forms, based on the crack propagation rate and by using a digital image correlation (DIC) system, coupled with strain gages. Based on DIC system, it was possible to evaluate the K estimation, the singularity dominated zone size and the K increase, as long as the crack propagated, for both test specimens. A comparison between the two methods was also made, and finally the use of a DIC system as a tool for estimating the K parameter was discussed.

Analysis of Residual Stress Effect on Fatigue Crack Propagation in Bonded Aeronautical Stiffened Panels

2011 ◽  
Vol 681 ◽  
pp. 236-242 ◽  
Author(s):  
Ivan Meneghin ◽  
Goran Ivetic ◽  
Enrico Troiani
Keyword(s):  
Residual Stress ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Stress Fields ◽  
Stiffened Panel ◽  
Stress Effect ◽  
Adhesively Bonded ◽  
Stiffened Panels ◽  
Residual Stress Effect

The application of adhesively bonded straps made of high-static strength materials on aeronautical stiffened panels to retard the fatigue skin crack growth is currently a topical research subject. The detrimental effect of the residual stress fields induced as a consequence of the dissimilar coefficients of thermal expansion of the skin and strap materials on the fatigue skin crack propagation was investigated. The residual stresses induced in a stiffened panel representative of a pressurized fuselage shell with titanium doublers in the middle of the stringer bays is numerically quantified for two likely operational temperatures. Their effect on the fatigue crack propagation is analyzed by means of a linear elastic fracture mechanics approach. The results show that adhesively bonded straps on the cracked surface can significantly retard the fatigue crack propagation but, in order to achieve reliable and conservative predictions on their performances, the effect of the residual stress fields they introduce must be taken into account.

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