Numerical Calculation of the Aircraft Skin with Multi-Site Damage

2009 ◽  
Vol 25 (1) ◽  
pp. 37-47
Author(s):  
Andrzej Leski
Keyword(s):  
Numerical Simulation ◽  
Numerical Calculation ◽  
Residual Strength ◽  
Crack Size ◽  
Opening Angle ◽  
Aircraft Structure ◽  
Crack Tip Opening Angle ◽  
Aircraft Skin ◽  
Crack Tip Opening ◽  
Stable Tearing

Numerical Calculation of the Aircraft Skin with Multi-Site DamageThe presence of the multi-site damage (MSD) in an aircraft structure can result in catastrophic damage when the residual strength is not sufficient to sustain operational loads. In this paper the influence of the MSD crack size on the residual strength was examined. As a crack criterion the crack tip opening angle (CTOA) was applied in the numerical simulation of the stable tearing. The CTOA criterion was implemented in the commercial software, the MSC.Marc, by means of additional user subroutines. The verification of this implementation was carried out and the obtained results are consistent with those presented in literature. The influence of the MSD crack size was determined for two crack scenarios: with a leading crack and without one.

Residual Strength Prediction of Aircraft Fuselages Using Crack-Tip Opening Angle Criterion

AIAA Journal ◽  
2002 ◽  
Vol 40 (3) ◽  
pp. 566-575 ◽  
Author(s):  
Chuin-Shan Chen ◽  
Anthony R. Ingraffea ◽  
Paul A. Wawrzynek
Keyword(s):  
Residual Strength ◽  
Crack Tip ◽  
Strength Prediction ◽  
Opening Angle ◽  
Crack Tip Opening Angle ◽  
Angle Criterion ◽  
Crack Tip Opening

Crack Tip Opening Angle: Measurement and Modeling of Fracture Resistance in Low and High Strength Pipeline Steels

2006 ◽  
Author(s):  
Ph. P. Darcis ◽  
G. Kohn ◽  
A. Bussiba ◽  
J. D. McColskey ◽  
C. N. McCowan ◽  
...  
Keyword(s):  
Steady State ◽  
Fracture Resistance ◽  
Fracture Process ◽  
Pipeline Steel ◽  
Crack Tip ◽  
High Strength ◽  
Opening Angle ◽  
Test Technique ◽  
Crack Tip Opening Angle ◽  
Crack Tip Opening

Crack tip opening angle (CTOA) is becoming one of the more widely accepted properties for characterizing fully plastic fracture. In fact, it has been recognized as a measure of the resistance of a material to fracture, in cases where there is a large degree of stable-tearing crack extension during the fracture process. This type of steady-state fracture resistance takes place when the CTOA in a material reaches a critical value, as typically occurs in low-constraint configurations. Our current research has applied the CTOA concept as an alternative or an addition to the Charpy V-notch and the drop weight tear test (DWTT) fracture energy in pipeline characterization. A test technique for direct measurement of CTOA was developed, using a modified double cantilever beam (MDCB) specimen. A digital camera and image analysis software are used to record the progression of the crack tip and to estimate CTOA using the crack edges adjacent to the crack tip. A steady-state CTOA has been successfully measured on five different strength grades of gas pipeline steel (four low strength grades and one high strength grade: X100). In addition, two-dimensional finite element models (2D FEMs) are used to demonstrate the sequence of the fracture process and the deformation mechanisms involved. The CTOA measurements and models are correlated and agree well.

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