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December 2011
BEASY FRACTURE NEWSLETTER |
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In this final Fracture Newsletter of 2011, we review some of the recent applications using BEASY Fatigue & Crack Growth Software, and we would like to acknowledge the help of Professor Roberto Citarella of the University Of Salerno in putting together this section.
Seasons greetings from the BEASY team |
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Experimental Test and Crack Growth Simulation of FML Full Scale Aeronautic Panel under Multiaxial Fatigue
This study concerns the numerical and experimental characterization of the static and fatigue strength of a flat stiffened panel, designed as a Fibre Metal Laminate (FML) and made of aluminium alloy and Fibre Glass FRP. The full scale panel was tested under both static and fatigue bi-axial loads, applied by means of an in-house designed and built multiaxial fatigue machine. The strain gauge outcomes from a preliminary static test are compared with the corresponding numerical results, getting a satisfactory correlation. A crack propagation in the FML was simulated by a two dimensional approach.
This approach aims at providing a general purpose evaluation tool for a better  understanding of the fatigue resistance of FML panels, providing a deeper insight into the role of fibre stiffness and of delamination extension on the Stress Intensity Factors. The experimental test was realized in the context of a European research project (DIALFAST).
For a copy of the paper, please click here |
Analysis of an Extrusion Press Fatigue Failure
This study describes the simulation of a fatigue crack propagation phenomenon affecting the main cylinder of an extrusion press for aluminium sections. Such methodology is particularly effective for simulation of three-dimensional single/multiple crack propagation under the hypothesis of isotropic and linear elastic material properties. The crack propagates through the thickness, causing a leakage of the pressurized oil and consequent production stop after 1,310,400 cycles (the extrusion press had been working for 11 years, 240 working days per year, 5 days per week, 24 hours per day, with basic cycles lasting 3 min each).
 | | Internal view of damaged cylinder (left) during welding repair operations and close-up of the crack under repair (right) |
The main aim of the simulation was to assess the most probable initial crack dimensions
 | | Cracked model in the final configuration (at crack instability), showing highlight of von Mises stresses (N/m2), and close-up of the final crack internal view |
that, after the recorded in service fatigue cycles, led to the final crack scenario; therefore determining if it was possible to detect such cracks by using non destructive detection techniques.
For a copy of the paper, please click
here
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3D Non-linear Multiple Site Damage (MSD) Crack Growth For A Riveted Aeronautic Reinforcement
 | | Experimental test arrangement for the door |
In this study mechanically fastened joints in an aircraft structure are analysed to
evaluate their fatigue behaviour and to identify the most fatigue critical locations.
The model simulated the complex stress fields created by the doublers as well as the resulting reduction in the stress intensity factors (SIFs) of cracks in the skin.
An example crack growth simulation is presented for the case of an upper door corner of a commercial aircraft.
 | | Comparison between model predictions and experimental test |
For a copy of the paper, please click here
Some other studies of interest:
Comparison of crack growth simulation by DBEM and FEM for SEN-specimens undergoing torsion or bending loading. R. Citarella, F.G. Buchholz. Engineering Fracture Mechanics 75 (2008) 489-509
http://www.sciencedirect.com/science/article/pii/S0013794407001713
A two-parameter model for crack growth simulation by combined FEM-DBEM approach. R. Citarella, G. Cricrì. Advances in Engineering Software 40 (2009) 363-377 http://www.sciencedirect.com/science/article/pii/S0965997808000999
Comparison of DBEM and FEM crack path predictions in a notched shaft under torsion. R. Citarella, G. Cricrì. Engineering Fracture Mechanics 77 (2010) 1730-1749
http://www.sciencedirect.com/science/article/pii/S0013794410001396
Behaviour of a riveted joint. Progettare 346 LUGLIO/AGOSTO 2010. (in Italian)
Please click here
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Training
Hands-on courses which provide training to maximize the benefits from BEASY's fracture software, will be held in the UK and US as follows:
* UK Fracture & Crack Growth Simulation - March 6-8 2012
* US Fracture & Crack Growth Simulation - April 24-26 2012
Related conferences
HPSM 2012 6th International Conference on High Performance Structures and Materials. 19 - 21 June, 2012, New Forest, UK
BEM/MRM 2012 34th International Conference on Boundary Elements and other Mesh Reduction Methods. 25 - 27 June, 2012, Split, Croatia
For further information about BEASY, please visit our website: www.beasy.com or email us at info@beasy.com |
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In case you missed it in our previous newsletter:
Predicting the impact of Residual Stresses on Crack Growth
There has been a significant increase in the interest in simulating crack growth in the presence of residual stress fields. Residual stresses can occur due to the manufacturing or fabrication process such as welding where the stresses in the Heat Affected Zone (HAZ) can significantly impact the crack behaviour.
In this extract from a BEASY tutorial a crack is initiated in a hole and crack growth is simulated through the residual stress field under a loading spectrum.
To review an extract from the tutorial, please click here
For more details, please contact info@beasy.com
For further information, please select one of the links:
Fracture Assessment Datasheet
BEASY ABAQUS Datasheet |
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Aircraft Corrosion Risk Assessment
BEASY Corrosion Manager Software enables engineers to quickly assess the risk to components and structures of corrosion and the effectiveness of surface protection systems. Galvanic Corrosion is important as it occurs whenever dissimilar metals or certain types of composites (e.g. carbon based) are located close to each other. The modelling technology can be applied to a wide range of structures and components such as those found in Aircraft, Automobiles, Ground Vehicles, Ships and similar structures.
For further information, please click here |
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