Abstract: An auxetic bi-stable structure that comprises an auxetic curved shell movable between a first and a second stable position, and a rigid element. At least part of the surface of the auxetic curved shell is joined to the rigid element such that the curved shell is movable with respect to the rigid element between the first and second stable positions.

Abstract: An internal shield inside the rear fuselage of an aircraft having a propulsion system formed by two engines mounted on each side of it. The internal shield is located in a suitable place inside the rear fuselage for covering the possible trajectories of fragments detached from one of the engines in a failure event that would impact critical elements of the opposite engine. The internal shield comprises an ensemble of fluid containers belonging to aircraft sub-systems, such as, particularly, the potable water and waste water sub-systems, with enough fluid for providing the energy absorption capability required for stopping the fragments. An aircraft having the internal shield is also disclosed.

Abstract: An auxetic bi-stable structure that comprises an auxetic curved shell movable between a first and a second stable position, and a rigid element. At least part of the surface of the auxetic curved shell is joined to the rigid element such that the curved shell is movable with respect to the rigid element between the first and second stable positions.

Abstract: The disclosure refers to a propeller blade for an aircraft engine that includes an airbag system contained inside the blade and comprising at least one bag and at least one gas generator, the at least one gas generator in fluid communication with at least one bag for inflating the bag, a detecting system for detecting a rupture of a part of the blade, a trigger for activating the at least one gas generator when the rupture is detected by the detecting system, and the blade skin being configured for allowing the at least one bag to pass through the blade skin for being expanded outside the blade upon the bag inflation by the gas generator.

Abstract: A deformable structure, such as a panel or a shock absorber, for absorbing energy from a mechanical and/or acoustic impact. The structure comprises an inner core and one or more external layers covering the inner core. The inner core comprises a set of first segments having a positive Poison's ratio and second segments having a negative Poisson's ratio. The first and second segments are arranged alternately and joined to one another so that the deformation received by one first segment is transmitted to an adjacent second segment and vice versa.

Abstract: A deformable structure, such as a panel or a shock absorber, for absorbing energy from a mechanical and/or acoustic impact. The structure comprises an inner core and one or more external layers covering the inner core. The inner core comprises a set of first segments having a positive Poison's ratio and second segments having a negative Poisson's ratio. The first and second segments are arranged alternately and joined to one another so that the deformation received by one first segment is transmitted to an adjacent second segment and vice versa.

Abstract: An internal shield inside the rear fuselage of an aircraft having a propulsion system formed by two engines mounted on each side of it. The internal shield is located in a suitable place inside the rear fuselage for covering the possible trajectories of fragments detached from one of the engines in a failure event that would impact critical elements of the opposite engine. The internal shield comprises an ensemble of fluid containers belonging to aircraft sub-systems, such as, particularly, the potable water and waste water sub-systems, with enough fluid for providing the energy absorption capability required for stopping the fragments. An aircraft having the internal shield is also disclosed.

Abstract: The disclosure refers to a propeller blade for an aircraft engine that includes an airbag system contained inside the blade and comprising at least one bag and at least one gas generator, the at least one gas generator in fluid communication with at least one bag for inflating the bag, a detecting system for detecting a rupture of a part of the blade, a trigger for activating the at least one gas generator when the rupture is detected by the detecting system, and the blade skin being configured for allowing the at least one bag to pass through the blade skin for being expanded outside the blade upon the bag inflation by the gas generator.

Abstract: The disclosure refers to an impact protective multi-layered fabric comprising a pile of layers of a dry-fabric material, wherein at least one of the layers is conformed to have least one closed fold extending longitudinally across the layer, the closed fold having first and second walls substantially facing each other, and wherein the first and second walls are stitched to each other by means of at least one yarn of a dry-fabric material. According to an aspect, the first and second walls of the closed fold, are stitched to each other by means of two or more stitching lines are arranged one above the other within the closed fold, such as when an object impact on the fabric layer, the stitches of the stitching lines break sequentially one after the other, such the energy absorption capability of the layer is increased in a simple manner and without increasing its weight.