A cool twist: "repair suitcases" will return damaged aircraft to service faster

Russian engineers have created "repair cases" that are designed for the rapid restoration of composite aircraft parts. The equipment is a portable complex weighing about 10 kg, which is powered by a conventional power grid. The device creates controlled conditions for the hardening of the composite bookmark applied to the damaged part. The technology eliminates drilling holes that lead to stress concentration and accelerated structural failure. The implementation of the development will accelerate the return of aircraft to service after repairs. For more information, see the Izvestia article.

How a portable device will replace an aircraft repair shop

Scientists from the Moscow Aviation Institute (MAI) have developed a new Russian portable complex for the restoration of composite aircraft parts. Such devices in the form of "repair suitcases" make it possible to quickly eliminate fatigue cracks in the aircraft structure, as well as damage from small impacts, stones or large hail.

— The proposed device is designed to create a vacuum environment and controlled heating. First, when a defect is detected, specialists determine its boundaries. For this purpose, non—destructive testing technologies are used - ultrasonic flaw detection, X-ray, and others. Then the damaged area is sanded, creating either a through hole or a local cavity. After that, a patch made of composite material similar to the material of the part is manually laid in layers. At the next stage, the repair area is covered with a vacuum bag. And the portable station, which acts as the "brain" of the process, starts the curing cycle," Sergey Kovtunov, one of the developers and head of the fatigue strength and repairs group at the MAI Composite Structures Center, told Izvestia.

As the engineer explained, the equipment automatically creates the necessary pressure and maintains the necessary temperature and time regime, sintering the stacked layers into a durable monolith.

According to Sergey Kovtunov, the advantage of the technology is that it eliminates the need to drill holes in the material that concentrate stresses and weaken the entire structure.

Introduction of a new aircraft repair method

As the scientist noted, the weight of the "suitcase" is about 10 kg. At the same time, it operates on a regular power grid. This makes the device optimal for field work. In particular, the proposed equipment allows repairs to be carried out directly at the site of operation of the aircraft structure.

For example, on the wing of an airplane, in the assembly compartment or on the fuselage. To do this, it is enough to raise the equipment to the level of the damaged area and make repairs. This technology significantly speeds up the process of aircraft return to service.

— Now MAI is testing the technique, conducting test repairs of more than 100 panels made of composite materials with subsequent strength studies. For quality control, X-ray tomography is used, which allows you to identify irregularities or delaminations. This is painstaking work, which makes it possible to create proven technological maps and certify the method for wide application in the aviation industry," said Sergey Kovtunov.

According to him, the implementation of the development will ensure the independence of the domestic aviation industry from foreign solutions and reduce the cost of aircraft maintenance.

— The use of polymer composite materials is a trend in the modern aircraft industry. The Russian industry cannot stand aside. The active construction of aircraft using composite materials obliges our engineers to develop this area. At the same time, normal operation of aircraft is impossible without methods and means for repairing composite aggregates," Viktor Vilents, a leading engineer at Aerocomposite JSC, told Izvestia.

According to the experience of domestic and foreign performers, he noted, it is known that the resource of properly performed repairs fully corresponds to the service life of the aircraft. At the same time, developments for the needs of aviation can also be used in shipbuilding, where the use of composite materials is also increasing.

— Technologies for repairing composite structures have been known for a long time. There is a whole range of foreign equipment that allows you to quickly repair any damage or defects in the field. In Russia, several research teams are developing such devices," explained Leonid Shabalin, director of the advanced engineering school of Kazan National Research Technical University named after A.N. Tupolev — KAI.

However, the equipment alone is not enough to understand how serviceable the repaired product is, he stressed. A set of measures is needed to create digital models, conduct virtual tests, analyze the residual strength of the repaired area, and predict its operation and resources.

It should definitely be said that the repaired area will have lower characteristics in both rigidity and strength. But the main issue remains regarding the long-term durability, operation and resource of the repaired site, the expert added.