Marino Quaresimin, University of Padova: “Sustainable mobility and sustainable energy production will drive the development of future composite applications”

JEC Composites: You have been organising the Summer School on Fatigue and damage mechanics of composites for 9 years at the Department of Management and Engineering in the Vicenza campus of the University of Padova. Since the first edition in 2015, how did composite materials evolve?

In terms of materials, I would say that “conventional” thermosetting fibre-reinforced composites are still playing a very important role. We have seen, however, a significant growth of thermoplastic composites for structural applications. Composites based on recycled fibres also have very interesting properties. Smart, multifunctional composites, for which nanotechnologies provide a synergic help, are becoming more and more popular. With reference to processes, additive manufacturing is certainly the technology that has received most of the attention even though its full exploitation is rather far from assured due to the extremely high costs of the materials and the still limited production rate.

JEC Composites: Sustainability in composites became a very important topic these past few years. Do you believe that “green” resins, reinforcements and production technologies will really be able to play an important role in the industry of the future?  

Sustainability is indeed the path to follow, and the research community and industries have to work together to develop new solutions. Fully or partially bioderived thermosetting resins have reached a high level of maturity.  Natural fibres, on the other hand, are less convincing because of their limited properties (compared to conventional ones) and the typical fibre-matrix compatibility issues. Thermoplastic resins, thanks to their recyclability, are intrinsically sustainable but the high processing temperatures remain a challenging problem. Far at the horizon, vitrimers, which should combine the advantages of thermosets and thermoplastics, look very promising for future applications.

JEC Composites: Can you share your thoughts about the future of the composite materials industry: which top sectors should we watch? Construction, hydrogen tanks, aeronautics…?

Looking at the composites industry from a scientific and academic perspective, I would say that sustainable mobility and sustainable energy production will drive the development of future composite applications. Urban aerial mobility is starting a revolution in the transportation sector, and this will bring a massive increase in the use of composites, together with significant issues in terms of safety and design reliability. The scenario will be more or less the same in the field of hydrogen storage: a huge development potential for very demanding composite structures undergoing extremely high cyclic pressure loads. The design and manufacturing of composite blades for wind turbines will maintain a significant share of the market, even as the size of wind turbines continues to increase.

JEC Composites: You mentioned new applications and new design needs. In your opinion, where is the frontier, and what are the main challenges in the design of composite parts at the moment?

The structural design of composite parts is a complex task and the scenario is even more complex because of the absence, in several fields, of standards and design codes to support and guide the designers in their activity and the certification of the products. Reliability and safety are the keywords we always have to keep in mind. To reach this goal, the possibility of simulating actual working conditions during the design phase of the parts is essential.

Composite damage mechanics is probably the most suitable discipline for these simulations. I see that, after being popular in the scientific community in the last decades, it is now starting to be used by the most advanced industries. The use of damage mechanics allows for the description of damage evolution into the material while subjected to the in-service loadings and consequently the simulation of the performance degradation during its service life. In the last years, our research group has dedicated significant efforts to this subject and to the development of a unique, comprehensive design procedure, which is now ready to enter the market.

JEC Composites: How can the safety of composite structures be further improved (not necessarily on an aeroplane wing but also on the rim of a car, or the handlebar of a bike)?

The best way to improve safety in the use of a composite structure is definitely the continuous monitoring of its damage state, allowing critical conditions to be detected and managed in real-time. This approach, known as Structural Health Monitoring (SHM), can be implemented through various conventional techniques with the common – limiting – feature of requiring several distributed sensors and extensive wiring. Recently, starting from electrical methods and taking advantage of smart self-sensing materials, we have developed a sensor-free strategy which is already providing very promising results in several industrial applications.

Cover photo: Marino Quaresimin, University of Padova.