CN-121990152-A - Abnormal end cooperative energy-absorbing upright post combined structure at lower part of aircraft fuselage floor

CN121990152ACN 121990152 ACN121990152 ACN 121990152ACN-121990152-A

Abstract

The invention discloses a special-end cooperative energy-absorbing upright post combined structure of the lower part of an aircraft fuselage floor, wherein a floor beam connecting area of the lower part of the fuselage floor is fixedly connected with the lower side wall of a beam of the lower part of the floor, a connecting area of the upper end of a C-shaped upright post element is fixedly connected with the upper end of the C-shaped upright post element, the lower end of the C-shaped upright post element is sleeved into the connecting area of the lower end of the C-shaped upright post element and is fixedly connected through a shearing pin, a shearing device is arranged on the inner wall of a frame cap-shaped connecting structure of the fuselage, the structural strength of the cap-shaped connecting structure of the lower part of the floor and the frame cap-shaped connecting structure of the fuselage are both greater than that of the C-shaped upright post element, the C-shaped upright post element is of a thin-wall hollow structure, an inner chamfer is arranged at the upper end of the floor beam connecting area of the lower part of the fuselage floor and a contact area of the upper end connecting area of the C-shaped upright post element is provided with a round corner guiding arrangement. According to the invention, through the shear pin triggering and the abnormal end cooperative energy absorbing mechanism, the C-shaped upright post is enabled to be in progressive shear failure, fragments are prevented from overflowing, and the energy absorbing and anti-falling collision performance is enhanced.

Inventors

Mou Haolei
CHEN YINGSHI
XIE JIANG
FENG ZHENYU

Assignees

中国民航大学

Dates

Publication Date: 20260508
Application Date: 20230407

Claims (9)

1. The utility model provides an aircraft fuselage floor lower special-end collaborative energy-absorbing upright post composite structure which is characterized in that the composite structure comprises a floor lower cross beam (1), a floor lower cap-shaped connecting structure (2), a C-shaped upright post element (3), a fuselage frame cap-shaped connecting structure (4) and a fuselage frame (5), wherein the floor lower cap-shaped connecting structure (2) comprises a fuselage floor lower floor beam connecting area (201) and a C-shaped upright post element upper end connecting area (202), the fuselage floor lower floor beam connecting area (201) is fixedly connected with the lower side wall of the floor lower cross beam (1), the C-shaped upright post element upper end connecting area (202) is fixedly connected with the upper end of the C-shaped upright post element (3), the fuselage frame cap-shaped connecting structure (4) comprises a fuselage frame connecting area (401), a shearing device (404) and a C-shaped upright post element lower end connecting area (406), the lower end of the C-shaped upright post element (3) is fixedly connected with the fuselage frame (5), the lower end of the C-shaped upright post element (3) is sleeved into the lower end of the C-shaped upright post element (406) and is fixedly connected with the lower end of the fuselage frame (4) through a shearing device (402), the structure strength of the cap-shaped connecting structure (2) at the lower part of the floor and the structure strength of the cap-shaped connecting structure (4) of the frame body are both larger than that of the C-shaped upright post element (3), the C-shaped upright post element (3) is of a thin-wall hollow structure, an inner chamfer (8) is arranged at the upper end of the C-shaped upright post element, a contact area of the floor beam connecting area (201) at the lower part of the floor and the connecting area (202) at the upper end of the C-shaped upright post element is provided with a round angle guiding arrangement, when the floor is subjected to impact load, the shearing pin (402) is broken, the C-shaped upright post element (3) is contacted with the shearing device (404), the lower end of the C-shaped upright post element (3) is cut into fragments, and the fragments move upwards along the inner cavity of the C-shaped upright post element (3) and are filled into the inner cavity of the C-shaped upright post element (3) under the guiding arrangement of the round angle guiding arrangement and the inner chamfer (8).
2. The structure of an aircraft fuselage lower, heteroend cooperative energy-absorbing column assembly of claim 1, wherein the shearing device (404) employs a pointed cutting structure near one end edge of the C-column element (3).
3. The structure of an aircraft fuselage lower, heteroend cooperative energy-absorbing column assembly according to claim 1, characterized in that the fuselage frame hat-shaped connection structure (4) further comprises a chip release zone (403) and a chip guiding groove (405), the chip guiding groove (405) being adapted to guide the axial movement of the cut chips along the C-shaped column element (3), the chip release zone (403) being adapted to temporarily accommodate chips during movement.
4. The composite structure of the special-end cooperative energy-absorbing upright column at the lower part of the aircraft fuselage floor according to claim 1, wherein the floor beam connecting area (201) at the lower part of the fuselage floor is of a solid structure, and the connecting area (202) at the upper end of the C-shaped upright column element is of a thin-wall hollow structure sleeved and matched with the upper end of the C-shaped upright column element (3).
5. The composite structure of the different-end cooperative energy-absorbing upright at the lower part of the aircraft fuselage floor according to claim 1, wherein the fuselage frame connecting region (401) is of a solid structure, and the lower-end connecting region (406) of the C-shaped upright element is of a thin-wall hollow structure sleeved and matched with the lower end of the C-shaped upright element (3).
6. An aircraft fuselage lower, heteroend cooperative energy-absorbing column assembly according to claim 1, characterized in that two of the C-shaped column elements (3) are symmetrically arranged and that the angle of placement of the two C-shaped column elements (3) is in the range of 0-120 °.
7. An aircraft fuselage lower, heteroend cooperative energy-absorbing column composite structure in accordance with claim 1, characterized in that the C-column element (3) is of a fibre-reinforced composite structure.
8. The structure of an aircraft fuselage lower, heteroend cooperative energy absorbing column assembly of claim 1, wherein the lower floor cross member (1) is fixedly connected to the lower fuselage floor beam connection region (201) by bolts, and the fuselage frame connection region (401) is fixedly connected to the fuselage frame (5) by bolts.
9. -A composite structure of an energy absorbing column with cooperative at the opposite ends of the lower part of the fuselage floor of an aircraft according to any of claims 1 to 8, characterized in that the lower part of the fuselage frame (5) and the stringers (6) are both fixedly connected to the fuselage skin (7).

Description

Abnormal end cooperative energy-absorbing upright post combined structure at lower part of aircraft fuselage floor Technical Field The invention relates to the technical field of aircraft energy absorption structures, in particular to a different-end cooperative energy absorption upright post combined structure at the lower part of an aircraft fuselage floor. Background Safety is a perpetual theme, aviation safety is an important component of national strategy and national safety, and crash safety is an important component of aviation safety. Aircraft flight accidents are always difficult to completely avoid, and seriously threaten the life safety of personnel on the aircraft. In order to improve the survivability of the onboard passengers in the event of an emergency landing, to avoid the passengers from being subjected to fatal injury, reasonable design must be adopted so that the impact overload transmitted to the passengers during the aircraft crash is reduced to within the tolerance limit of the human body. The lower upright post structure of the aircraft floor contacts the ground first, a large amount of falling impact energy is absorbed through progressive damage of the lower upright post structure of the floor, and the amount of the absorbed energy directly influences the falling impact safety of the integral structure of the aircraft body. With the wide variety of applications of composite materials in aircraft fuselage structures, composite materials are also commonly used for underfloor open-section stud structures, with C-stud elements being typical open-section stud structures for underfloor. Compared with the closed composite material upright post structure, the energy absorption capability of the open section composite material upright post structure is reduced, and the initial peak load is too high and the integral buckling instability is easy to occur in the falling collision impact process. Meanwhile, the open-section composite upright post structure is mainly connected through bolts at two ends and transmits load, and stress concentration is serious at the connecting position. The existing fuselage frame section crash test and numerical simulation show that unstable failure conditions such as local buckling and the like are easy to occur to the C-shaped upright post element of the open-section composite material at the lower part of the fuselage floor, the overall energy absorption of the C-shaped upright post element of the open-section composite material is less, the energy absorption effect is not exerted to the maximum extent, the C-shaped upright post element of the open-section composite material is guided to produce progressive damage and failure through reasonable design, and the energy absorption capability of the C-shaped upright post element of the open-section composite material is further improved. Disclosure of Invention The invention aims to provide a different-end cooperative type energy-absorbing upright post combined structure at the lower part of an aircraft fuselage floor, which solves the problem that a bolt-connected composite upright post structure can generate larger stress concentration at a bolt hole and the problem that the open-section composite upright post structure is easy to generate an undesirable energy-absorbing mode such as local buckling, brittle fracture, integral instability and the like in the impact process. The shearing device arranged in the cap-shaped connecting structure can enable the open-section composite material upright post structure to fail in a stable progressive shearing mode, and the energy absorption capacity of the open-section composite material upright post structure in the falling collision process is increased. The improved connecting structure not only improves the traditional force transmission path, but also increases the connecting action range compared with the traditional bolt connection, and strengthens the axial stability of the open-section composite material upright post structure, so that the open-section composite material upright post structure is less prone to instability in the falling impact process. In order to solve the technical problems, the invention adopts the following technical scheme: The invention relates to a special-end cooperative energy-absorbing upright post combined structure of the lower part of an aircraft fuselage floor, which comprises a floor lower cross beam, a floor lower cap-shaped connecting structure, a C-shaped upright post element, a fuselage frame cap-shaped connecting structure and a fuselage frame, wherein the floor lower cap-shaped connecting structure comprises a fuselage floor lower floor beam connecting area and a C-shaped upright post element upper end connecting area, the fuselage floor lower floor beam connecting area is fixedly connected with the lower side wall of the floor lower cross beam, the C-shaped upright post element upper end connecting area is fixedly connected wi