BEASY Software & Services 
     
December 2015

 

SEASONS GREETINGS FROM THE BEASY TEAM
 
As we approach the end of 2015 in this issue of the newsletter we recap on some of the BEASY news stories we think you will find of interest.
 
In early 2015 the AA&S Conference in Baltimore provided an opportunity to present recent developments and applications of BEASY technology and services. It was great to meet many friends at the conference and discuss how modelling can be used in the areas of fatigue crack growth in residual stress fields, fracture behaviour of composite plates as well as the modelling of corrosion related damage. There was also considerable interest in the BEASY Corrosion Manager software which is used to predict and simulate galvanic corrosion in structures such as aircraft.

Cold worked hole - BEASY crack path

Of particular interest at this year's AA&S conference was the impact of residual stresses on the crack path and the rate of growth of cracks. The effect on the crack path can be clearly seen in the above figure where the lines show the predicted crack fronts as the crack grows from a hole with, and without, cold working. The red lines show the predicted crack fronts without cold working and the green dotted lines show the predicted crack fronts with cold working. The study clearly indicates the need to include residual stresses in crack growth calculations as otherwise unexpected failure modes can occur, and excessively conservative designs can result.
  
Please contact us for background papers on some of the topics presented at AA&S 2015.
BEASY Corrosion Manager
 
Another area of considerable interest at the AA&S conference was the use of computer simulation to assess the risks associated with corrosion. During the product development process, various design configurations are often exposed to actual environmental conditions for an extended period of time to evaluate corrosion damage in the structural assembly. However, these testing methods require anywhere from several months to several years of exposure time in order to complete. Computer modelling has the potential to significantly shorten, and reduce, the cost of testing by providing a corrosion simulation option that can be used to supplement these long term experimental tests.

BEASY Galvanic Stack-up Model
In the model shown a computer simulation is used to predict the risk and extent of corrosion damage on a test structure.

For further information, or if you wish to make arrangements to meet with BEASY at the 2016 conference, please contact us.
BEASY attend ICAF 2015
 
International Committee on Aeronautical Fatigue and Structural Integrity (ICAF) Conference in Helsinki, Finland
 
Dr Sharon Mellings from BEASY attended the ICAF conference in Helsinki and presented a paper describing some recent work on the simulation of corrosion and fracture damage.
 
Airframe structures regularly operate in environments that allow high levels of corrosion damage, and this damage leads to stress concentrations within the structure and potential development of cracks. Even when only a thin film of electrolyte is present on the structure, this can still lead to an electrical field that causes surface damage.
 
Computation of this electrical field can be used to identify areas in the airframe structure that are most susceptible to corrosion damage and which, after possible fatigue crack initiation, may lead to structural failure. Corrosion simulation can be used to take account of the properties of the electrolyte as well as the structural materials, to Corrosion simulationdetermine the rate of material loss from the structure.
 
Having removed material from the surface (corresponding to corrosion occurring over a given exposure time) the stress concentrations can be evaluated and, if required, cracks can be initiated in each potential problem area, to identify vulnerability to fatigue failure.
 
 
 
 

 
 
 
   
The geometry change caused by corrosion mass loss can be used to perform stress analysis of the structure, to determine the stress concentration in the component at the corresponding time in the life of the aircraft. It can then be assumed that cracks initiate at the peak stress locations, and the subsequent crack growth simulated. This crack growth takes into account the corrosion damage and will inherently include local stress concentration due to the damaged surface. In the crack growth simulation, the full crack path and direction is determined along with the fatigue life.
 
 
 
For a copy of the paper, or for more information about corrosion and fracture simulation, please , please contact us 
Published Papers
 
There were also a number of papers published by BEASY users in 2015, some of which are listed below:
 
Analysis of Fatigue Crack Growth for CFRP-Strengthened Steel Plates with Longitudinal Weld Attachments
Analysis of Fatigue Crack Growth for CFRP-Strengthened Steel Plates with Longitudinal Weld Attachments
Analysis of CFRP reinforced steel plates
Analysis of CFRP reinforced steel plates
Analysis of fatigue crack growth for welded connections under bending
Analysis of fatigue crack growth for welded connections under bending

Calculation of bending fatigue life of thin-rim spur gears

Calculation of bending fatigue life of thin-rim spur gears
Analysis of fretting fatigue life of dovetail assemblies based on fracture mechanics method
Analysis of fretting fatigue life of dovetail assemblies based on fracture mechanics method

For a copy of any of the papers, or for more information about fracture simulation, please contact us
Related Research
 
In 2015 BEASY also presented some its latest research at the Boundary Elements and Other Mesh Reduction Methods Conference held in the New Forest UK in September.
 
Boundary Elements and Other Mesh Reduction Methods Conference 2015 The BEM/MRM conference has long been recognized as THE international forum on the technique. The proceedings of the conference therefore constitute a record of the development of the method, running from the initial successful development of boundary integral techniques. The conference proceedings edited by A.H-D. Cheng, University of Mississippi, USA and C.A. Brebbia, Wessex Institute of Technology, UK, are available from WITPress
 
Further information can be found here
 

39th International Conference on Boundary Elements and other Mesh Reduction Methods 2016
BEM/MRM 39
39th International Conference on Boundary Elements and other Mesh Reduction Methods. 20-22 September 2016, Siena, Italy.
 
The next conference in the series takes place in 2016 and further information can be found here  
Christmas & New Year Holidays
 
The BEASY offices in the UK and USA will close after business on Thursday 24th December 2015 and re-open on Monday 4th January 2016, but if you would like to learn about any of the items above, or if you have a project which you would like to discuss, please contact us

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