Can virtual simulation replace real-scale fatigue testing of materials?

14-04-2020 | Posted by Principia

In the aeronautical industry safety and durability come first, hence, to certify the design and materials used in making airplanes, there is no alternative to fatigue testing of materials at the real scale.

However, the increasing complexity of ever more sophisticated materials and designs employed in new prototypes, particularly due to using composites, creates doubts about the feasibility of this type of tests, in terms of both duration and cost. Indeed, it has been some time since NATO concluded that “the time and cost associated with the design, development and validation of new aerial military vehicles is simply prohibitive”.

Thus, virtual simulation appears as an interesting alternative to replace, at least partially, some physical tests during the design and certification phases. Few would dare predict a complete replacement one day, but there is a general consensus that virtual simulation and computer-aided analysis must play a key role in reducing development cycles and associated costs.

The possibility is not very developed yet at the industrial scale, but a number of tests have demonstrated its capabilities and the real possibility of going further through the multi-scale simulation of composite materials and their performance.

As an example, Cobham Life Support collaborated with NASA to design, using virtual simulation, the first aerospace fuel tank that had to disintegrate on re-entry. Made of carbon fibre, the intensive use of computer-aided design tools and virtual testing allowed halving the number of destructive tests, saving about US$500,000 in the 38-month project.

Also, the Advanced Composite Structures Laboratory of the University of Washington in Seattle made use of finite-element methods to develop the monocoque of the Lamborghini Aventador. The vehicle survived the crash test at the first try, at a cost of US$1m. Considering that previous models required up to three prototypes to succeed, the savings are evident.

Companies like Boeing and Airbus are already beginning to employ these tools in some phases of the design and certification processes, but only an easy access to the simulation software and its widespread use will make it an alternative to the physical tests at the real scale.

In Principia we have a long experience in material fatigue and Simulia’s fe-safe is an advanced tool for fatigue analysis, based on the results of finite-element programs like Abaqus.