The evaluation of the structural integrity is always an open problem that should not be underestimated, especially when dealing with new materials and projects. Dedicating resources to this aspect of designing and to systems for monitoring the condition of a system, can be fundamental for the success of the project
In Italian the word “cricca” (crack) has several different meanings. In this context I refer to the word “cricca” as a synonymous of crack, small fissure, that can become an important problem for the integrity of structures with consequent potential serious fall backs for the security of operators or for who, in whatever way, uses a structure. Dealing with “cricche” (cracks) can seem a bit out of fashion: by just taking a glance at the announcements for rich European funds, it is possible to see that the most popular subjects are environmental sustainability, green design, energy saving, search for efficiency and performance. Of course, all these are extremely important subjects.
Practically, there is no or very little trace of structural safety and of the numerous aspects that the latter involves; as if it is taken for granted that the results of technological innovation able to satisfy the above mentioned needs, should be able to sustain more and more severe performance conditions. But, it is recent news, the discovery of unexpected cracks on the wings of an A380 of Quantas airlines after a flight with numerous and strong turbulences which caused the interruption of the service of the 77 A380 airplanes flying in Europe. The inspections performed have highlighted the presence of cracks on the wings of 20 models of this airplane not due to turbulences or conditions of excessive use, but (it seems) to technological problems of the manufacturing process of the wings.
It seems impossible that after years of studies on the structural integrity and (unfortunately) many study-cases connected to past breakdowns (starting from the lesson-learnt of the Comet), an airplane of the importance of the A380 can be produced and have problems of this kind. How is it possible that with the calculation means that are now available and the experimental instruments that were certainly available to Airbus during designing, cracks potentially dangerous for safety can be created on a new airplane?
And, as if it was not enough, not very different news is arriving from America regarding the Boeing 787, with more than 50 airplanes grounded and inspected.
Actually, any project with an innovative content has an intrinsic potential failure and breakdown risk connected to it, because new materials are used or also because new functions are developed,(and this limiting to structural and mechanical components). And so, even those with a high innovation rate, surely the A380, that has a wide use of composed materials and which has a capacity never used before. The above mentioned Comet is, still today a prime example: with too many innovations, it ended up becoming g by Mario Guagliano Politecnico di Milanoa big commercial failure and was an important factor in determining the hegemony of Boeing (competitor of De Havilland, builder of the Comet) in the sector of civil aviation due to the systematical structural breakdowns which affected several models and which derived from an inappropriate geometrical configuration of the windows located on the fuselage and which could have probably been avoided by having a plan of periodic inspections.
So, going back to the A380, cracks were discovered during some necessary checks after the damage to one of the engines during a flight with many turbulences which had nothing to do with the cracks found on the wings. Although the official report excluded the possibility of a spread of those cracks and that their possible spread could lead to a problem of structural integrity, there is still a doubt: what could have happened if the cracks were not discovered? Maybe some breakdown that could have compromised the whole European aviation industry.
