For large aircraft engines, fan blade failure is one of the most dangerous scenarios. A fragment with high kinetic energy can penetrate the casing and damage other components. A solution to this problem was devised by the Kirov-based company "Kirasa".
According to the engineers' concept, the fan casing can be covered with a multi-layered aramid shell. The design includes 10 "destruction" layers and 20 additional containment layers.
The material is secured with elastic epoxy-rubber adhesive. On the outside, the shell is additionally protected by three layers of fluoroplastic coating.
For prospective large-class engines, such as the PD-35, the problem is particularly relevant due to the fan's size and the high energy of rotating parts.
Power plants are protected not only externally but also internally. For example, the composite nacelle of the PD-14 required an additional lightning protection system, which increased the weight of the engine's external elements.
To protect the carbon fiber, UEC engineers used a conductive copper mesh and several metallization jumpers.