Integrated Composite Spar for Aircraft Fuselage Load Transfer
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Solution Overview
Problem
Existing aircraft structures require the use of metal fittings and accessories for joining horizontal structures to the fuselage, which increases assembly and maintenance efforts and weight.
Innovation Solution
The use of composite spars made of carbon fiber-reinforced plastic that integrate structural functions of a longitudinal member and frame member in a single piece, allowing efficient connection to the aircraft fuselage without metal fittings, utilizing preforms and vacuum assembly to form the spar.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If metal fittings and accessories are used to join horizontal structures to the fuselage, then structural connection is achieved, but assembly and maintenance efforts increase and weight increases
Solution Approach 1:
The patent merges the longitudinal member and frame member into a single integrated composite spar component. This consolidation eliminates the need for separate metal fittings and accessories, thereby reducing assembly steps, maintenance requirements, and overall weight while maintaining structural connection functionality between horizontal structures and the fuselage
Solution Approach 2:
The invention employs composite materials (carbon fiber-reinforced plastic) to create a spar that combines the structural functions of both longitudinal members and frame members. This composite construction replaces traditional metal fittings and accessories, achieving weight reduction and simplified assembly while providing the necessary structural connection and load transfer capabilities
2Strength
If metal accessories are used for joining central box to fuselage, then load transfer is achieved, but weight and assembly complexity increase
Solution Approach 1:
The patent integrates the load transfer function directly into the composite spar structure by combining longitudinal and frame member functions in one component. This eliminates the need for separate metal accessories and fittings, maintaining load transfer capability while reducing overall structure weight and assembly complexity
Solution Approach 2:
The invention uses composite materials to create a spar that inherently provides the necessary load transfer capability between the central box and fuselage. The composite construction delivers equivalent or superior strength-to-weight ratio compared to traditional metal accessories, achieving both load transfer and weight reduction simultaneously
Data Source
AI summary
A composite spar (100) for horizontal structures external to the fuselage of an aircraft, the composite spar (100) including a web (110) configured as a longitudinal element, upper and lower flanges (110a) and two distal ends, wherein for each end, the composite spar (100) includes an end portion (105) established in the longitudinal direction of the web (110), and a curved-edged end portion (120) with curved flanges (120a) and a truncated section (125) established in the transverse direction of the web (110), wherein the truncated section (125) is connectable to a frame of the fuselage of the aircraft and configured as a load transfer element between the web (110) and the frame, and wherein one or more of the lower flanges (110a) are connected to the curved flanges (120a).