Circumferential Skin Joints for Aerospace Fuselage Structures

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Solution Overview

Problem

Conventional skin joints in aerospace structures require numerous fasteners and components, leading to increased cost, manufacturing time, and weight, and are complex due to the use of cylindrical or semi-cylindrical components.

Innovation Solution

A circumferential skin joint is developed using a first composite fuselage member with a chamfered distal end and a second composite fuselage member with a complementary chamfered distal end, forming a tapered lap joint that reduces the need for fasteners and shimming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional butt joints with splice straps are used to join skin components, then the joint can connect cylindrical or semi-cylindrical components, but the number of fasteners and components increases, leading to increased weight, cost, and manufacturing time

Engineering Contradiction:

Improvejoint assembly processVSAvoidweight of aerospace structure

Core Design Contradiction:

Ease of manufactureVSWeight of stationary object

Solution Approach 1:

The invention extracts and eliminates the splice strap component from the conventional butt joint design. By using a tapered lap joint configuration where the first skin component overlaps and tapers into the second skin component, the intermediate splice strap is removed entirely, reducing the number of parts and overall weight while maintaining structural integrity

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the functions of the splice strap and the joint configuration into a single integrated tapered lap joint design. The overlapping tapered surfaces of the skin components themselves perform the joining function that previously required a separate splice strap, combining multiple functions into a unified structure

Inventive Principle:

Principle #5Merging (Combining)

2Manufacturing precision

If conventional butt joints are used to join skin components, then the components can be connected, but numerous fasteners are required to obtain a tight fit, increasing manufacturing time and cost

Engineering Contradiction:

Improvetight fit between skin componentsVSAvoidmanufacturing time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The invention applies preliminary action by pre-forming the tapered surfaces on the skin components during manufacturing. The tapered mating surfaces are created in advance with precise angles and dimensions, so that during assembly, the components naturally align and fit together tightly without requiring extensive adjustment or multiple fasteners to achieve the tight fit

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If conventional butt joints are used to join skin components, then the components can be connected, but shimming is required to manage gaps between components, increasing complexity

Engineering Contradiction:

Improvegap management between componentsVSAvoidjoint design complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention applies preliminary action by pre-forming the tapered surfaces with precise dimensions and angles during manufacturing. This preliminary precision work ensures that when the components are assembled, the tapered surfaces mate perfectly without creating gaps, eliminating the need for shimming and reducing joint design complexity

Inventive Principle:

Principle #10Preliminary action

4Weight of stationary object

If tapered lap joints are used to join composite fuselage members, then the number of fasteners and components is reduced, but the manufacturing precision of the tapered surfaces must be high

Engineering Contradiction:

Improveweight of aerospace structureVSAvoidprecision of tapered mating surfaces

Core Design Contradiction:

Weight of stationary objectVSManufacturing precision

Solution Approach 1:

The invention applies preliminary action by incorporating the tapered surface formation into the initial composite manufacturing process. The tapered surfaces are created during the layup and curing process using precision molds or mandrels, ensuring high manufacturing precision is achieved during production rather than requiring post-manufacturing machining or adjustment

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20250083792A1Circumferential skin joints for aerospace structures, methods of assembling the joints, and methods of manufacturing fuselage members that define the joints

Publication Date: 2025.03.13 THE BOEING CO

AI summary

A circumferential skin joint according to the present disclosure may comprise a first composite fuselage member having a first composite skin comprising a first chamfer at least partially defining a first distal end of the first composite fuselage member, the first chamfer defining a first tapered mating surface extending circumferentially around an outer surface of the first composite fuselage member. In some examples, the circumferential skin joint further comprises a second composite fuselage member having a second composite skin, the second composite skin comprising a second chamfer at least partially defining a second distal end of the second composite fuselage member and defining a second tapered mating surface extending circumferentially around an inner surface of the second composite fuselage member. The first tapered mating surface contacts the second tapered mating surface to form a tapered lap joint between the first composite fuselage member and the second composite fuselage member.