Abstract: Internal shield in the rear fuselage of an aircraft having a propulsion system formed by two engines mounted on each side of it; the rear fuselage having at least a vertical symmetry plane; the rear fuselage being made of a composite material; the internal shield being located in said vertical symmetry plane and extended in an area that covers the possible trajectories of a set of pre-defined fragments detached from one of said engines in a failure event that would impact on critical elements of the opposite engine; the internal shield having a flat shape and an energy absorption capability that allows stopping said fragments. The invention also refers to a method for determining the area of an internal shield and to an aircraft having said internal shield.

Abstract: An aircraft fuselage part (31) located in a section of an aircraft (11) having a propulsion system (13) attached by upstream pylons (17), the fuselage part includes a skin (35); a plurality of frames (37) arranged perpendicularly to a longitudinal axis (33); a single or internally divided upper longitudinal box (41) and a single or internally divided lower longitudinal box (51) which are configured to form with the skin (35) a multi-cell structure, belonging in each cell the external side to the skin (35) and the internal sides to the longitudinal boxes (41, 51); a plurality of lateral beams (61) that are interconnected with the frames (37) to form together with the skin (35) a structural unity. The fuselage components (35, 37, 41, 51, 61) are dimensioned so that the aircraft can withstand the effect of pre-defined failure events keeping a sufficient number of closed cells.

Abstract: A fuselage section of an aircraft includes a skin, a plurality of frames positioned transversely to a longitudinal axis of a fuselage of the aircraft, and a plurality of longitudinal stringers at least one of which is configured with a closed transversal section including a stringer hat, two stringer webs, and two stringer feet joined to the skin. At least one of the frames is configured in at least one sector with a frame foot joined to the skin, a frame web having holes at crossing zones with the stringers, a frame cap, and a frame cap extension which does not interfere with the stringers. The frames are joined to, at least, the stringer hats at crossing zones of the frames and the stringer hats.

Abstract: Aircraft fuselage section (32) subjected to impacts of external bodies, the aircraft fuselage having a curved shape with at least a vertical symmetry plane (A-A) and a central longitudinal axis and comprising a skin (35) and a plurality of frames (37) arranged perpendicularly to said longitudinal axis (33), the aircraft fuselage section also comprising at least an inner reticular structure (51, 53) mounted on a supporting structure (41, 43) comprising longitudinal beams (39) attached to the skin (35) and interconnected with said frames (37), said inner reticular structure (51, 53) being arranged for creating at least one closed cell (75) with the skin (35) for improving its resistance and its damage tolerance to said impacts. Said inner reticular structure (51, 53) can be formed by panels (61), rods (65, 65?), cables (67, 67?) or belts (69, 69?).

Abstract: A computer-aided method for carrying out the structural design of a part subjected to damages having significant effects on its structural integrity, such as an aircraft fuselage section subjected to a propeller blade release event, is provided. The method includes: obtaining finite element models that include all the relevant information for an optimization analysis for the un-damaged part and for at least one possible damaged part; defining at least one design variable of the part and at least one design constraint and one load case for the un-damaged part and for the damaged part; providing at least one simulation module for analyzing one or more failure modes of the part; iteratively modifying the design variables of the part for the purpose of optimizing a target function by analyzing simultaneously the un-damaged part and the at least one damaged part using the at least one simulation module.

Abstract: Protective shield against ice impacts on aircraft, wherein the shield comprises plies of composite material (1) having microcapsules (2), each microcapsule containing a healing agent (5). When a crack (4) produced on the shield reaches at least a microcapsule (2), the healing agent is spilled in the delaminated area. Some catalyst particles (3) can be included in the material and in that case, the healing agent (5) is polymerized reacting with the catalyst particles (3). If no catalyst particles (3) are included in the material, the healing agent (5) may also actuate when manually heated. Such kinds of materials allow recovering at least partially the impact strength of the shields after impact, which is particularly important in case of ice impacts that can be repetitive during operations in icing conditions.

Abstract: Commercial aircraft (11) having a black box (41) comprising a flight data recorder (49) connected to suitable acquisition units (13, 14, 15) for recording information required for crash investigation purposes inside a container (43), wherein the aircraft (11) comprises a crash detection device (17); the black box (41) is installed in a suitable location for being ejected outside the aircraft in a crash event through a duct (21, 31) having its exit in a fuselage area where the ejected black box (41) would not impact on the aircraft; the aircraft (11) also comprises ejection means (23, 33), controlled by a black box ejection control unit (19) connected to said crash detection device (17), for ejecting the black box (41) through said duct (21, 31), when an impending crash is detected by said crash detection device (17).

Abstract: Aircraft fuselage section (32) subjected to impacts of external bodies, the aircraft fuselage having a curved shape with at least a vertical symmetry plane (A-A) and a central longitudinal axis and comprising a skin (35) and a plurality of frames (37) arranged perpendicularly to said longitudinal axis (33), the aircraft fuselage section also comprising at least an inner reticular structure (51, 53) mounted on a supporting structure (41, 43) comprising longitudinal beams (39) attached to the skin (35) and interconnected with said frames (37), said inner reticular structure (51, 53) being arranged for creating at least one closed cell (75) with the skin (35) for improving its resistance and its damage tolerance to said impacts. Said inner reticular structure (51, 53) can be formed by panels (61), rods (65, 65?), cables (67, 67?) or belts (69, 69?).

Abstract: Fuselage section of an aircraft whose structure comprises a skin (10), a plurality of frames (30) positioned transversely to the longitudinal axis of the fuselage and a plurality of longitudinal stringers (20); the stringers being configured with a closed transversal section comprising a hat (21), two webs (23, 25) and two feet (27, 29) joined to the skin (10); the frames (30) being configured in at least one its sectors with a foot (31) joined to the skin (10), a web (33) having holes at the crossing zones with said stringers (20), a cap (35) and a cap extension (37) which does not interfere with the stringers (20); the frames (30) being joined to, at least, the stringer hats (21) at their crossing zones.

Abstract: Commercial aircraft (11) having a black box (41) comprising a flight data recorder (49) connected to suitable acquisition units (13, 14, 15) for recording information required for crash investigation purposes inside a container (43), wherein the aircraft (11) comprises a crash detection device (17); the black box (41) is installed in a suitable location for being ejected outside the aircraft in a crash event through a duct (21, 31) having its exit in a fuselage area where the ejected black box (41) would not impact on the aircraft; the aircraft (11) also comprises ejection means (23, 33), controlled by a black box ejection control unit (19) connected to said crash detection device (17), for ejecting the black box (41) through said duct (21, 31), when an impending crash is detected by said crash detection device (17).

Abstract: The aircraft fuselage part (31) located in a section of an aircraft (11) having attached a propulsion system (13) by means of upstream pylons (17) that comprises: a skin (35); a plurality of frames (37) arranged perpendicularly to the longitudinal axis (33), a single or internally divided upper longitudinal box (41) and a single or internally divided lower longitudinal box (51) which are configured to form with the skin (35) a multi-cell structure, belonging in each cell the external side to the skin (35) and the internal sides to said longitudinal boxes (41, 51); a plurality of lateral beams (61) that are interconnected with said frames (37) to form together with the skin (35) a structural unity. Said fuselage components (35, 37, 41, 51, 61) are dimensioned so that the aircraft can withstand the effect of pre-defined failure events keeping a sufficient number of closed cells.

Abstract: A computer-aided method for carrying out the structural design of a part subjected to damages having significant effects on its structural integrity, such as an aircraft fuselage section subjected to a PBR event, comprising steps of: Obtaining FE models that include all the relevant information for an optimization analysis for the un-damaged part and for at least one possible damaged part; Defining at least one design variable of said part and at least one design constraint and one load case for said un-damaged part and for said damaged part; Providing at least one simulation module for analyzing one or more failure modes of said part; Iteratively modifying the design variables of said part for the purpose of optimizing said target function by analyzing simultaneously said un-damaged part and said at least one damaged part using said at least one simulation module.