BEASY Attends ICAF 2015, June 1-5 2015, Helsinki, Finland 

Dr Sharon Mellings will be attending the ICAF conference again this year. She will be presenting a paper on the topic of simulation of corrosion damage, stress concentrations, and fatigue crack growth, and describing technology that can be used to improve the design and maintenance of aircraft structures.

Airframe structures regularly operate in environments that can experience high levels of corrosion damage, and this damage leads to stress concentrations within the structure and the lowering of the threshold for the development of cracks. Even if only a thin film of electrolyte is deposited on the structure, this can still lead to an electrical field that causes surface damage. This paper provides a methodology that can be used by design engineers, to identify potential problems in an airframe structure during initial development, giving scope to change designs and so reduce potential failures and in-service repair costs. This methodology identifies areas of the structure that have the greatest risk of damage - which may not be obvious without combined corrosion and fracture simulation; and so provides more informed targeting of locations where "what if" fracture mechanics should be applied.

The figure below shows the predicted geometry changes due to corrosion damage.

If you would like more information about corrosion and fracture simulation, or if you would like to make an appointment to meet Sharon in Helsinki, please contact us 

Aircraft Airworthiness & Sustainment (AA&S) Conference

BEASY staff attended the 2015 AA&S Conference in Baltimore in April and met with many customers to discuss their applications and update them about projects underway at BEASY.  

We had a lot of new interest at our booth this year 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.

We look forward to seeing everyone again next year in Grapevine, Texas. 

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.

Background papers are available here on some of the topics presented at AA&S 2015:

Analysis of Fatigue Crack Growth for CFRP-Strengthened Steel Plates with Longitudinal Weld Attachments

Analysis of CFRP reinforced steel plates

Analysis of fatigue crack growth for welded connections under bending

Calculation of bending fatigue life of thin-rim spur gears

Analysis of fretting fatigue life of dovetail assemblies based on fracture mechanics method