Composite Skin Butt Strap Friction Stir Welding

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Solution Overview

Problem

The use of a large number of rivets to connect fuselage sections in aircraft construction increases the weight and production costs of commercial aircraft, as existing methods require extensive drilling and riveting.

Innovation Solution

A method involving the removal of excess material to form a butt strap on a butt plate, with one end connected to a skin plate via a substance-to-substance bond, such as friction stir welding, and the further skin plate fastened to the butt strap, reducing the need for rivets and allowing for weight reduction and cost savings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rivets are used to connect fuselage sections, then structural integrity is ensured, but the weight of the aircraft increases and production costs rise

Engineering Contradiction:

Improvestructural integrityVSAvoidaircraft weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent replaces the mechanical riveting system with a friction stir welding process. Instead of using multiple rivets to mechanically fasten the butt strap to the skin, the invention uses friction stir welding to create a metallurgical bond between the butt plate and the skin plate, thereby eliminating the need for numerous rivets and reducing aircraft weight while maintaining structural integrity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the connection parameter from discrete mechanical fastening (rivets) to continuous metallurgical bonding (friction stir weld). This parameter change transforms the connection method from a mechanical assembly process to a thermal-mechanical welding process, achieving both weight reduction and structural strength

Inventive Principle:

Principle #35Parameter changes

2Strength

If rivets are used to connect fuselage sections, then structural integrity is ensured, but production costs increase due to extensive drilling and riveting

Engineering Contradiction:

Improvestructural integrityVSAvoidproduction cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention extracts and removes the riveting operation from the manufacturing process. By eliminating the rivets, the patent removes the associated drilling operations, rivet installation steps, and quality inspection requirements, thereby simplifying the manufacturing process and reducing production costs

Inventive Principle:

Principle #2Taking out (Extraction)

3Weight of moving object

If excess material is removed from the butt plate to form a butt strap, then weight is reduced, but manufacturing complexity increases

Engineering Contradiction:

Improveaircraft weightVSAvoidmanufacturing complexity

Core Design Contradiction:

Weight of moving objectVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-forming the butt strap with the required Z-shaped cross-section before the friction stir welding operation. The excess material is removed in advance to create the optimized geometry, allowing the subsequent welding process to proceed efficiently without additional complex operations during assembly

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly reduces the weight of the aircraft and lowers production costs by eliminating the need for numerous rivets while maintaining structural integrity through efficient bonding methods like friction stir welding.

Implementation Method 1

connecting the other end of the butt plate to a skin plate with a substance-to-substance bond is achieved by friction stir welding

Methodology Applied

Scientific EffectFriction stir welding: Friction Welding

Implementation Method 2

the structure of the weld produced by this method is changed only slightly, since the metal is not melted on in friction stir welding

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 3

connecting the other end of the butt plate to a skin plate with a substance-to-substance bond is achieved by friction stir welding, laser welding and/or electron beam welding

Methodology Applied

Scientific EffectLaser welding: Laser Beam Welding

Implementation Method 4

connecting the other end of the butt plate to a skin plate with a substance-to-substance bond is achieved by friction stir welding, laser welding and/or electron beam welding

Methodology Applied

Scientific EffectElectron beam welding: Electron Beam

Data Source

PatentUS9314875B2Method for producing a composite skin in the field of aeronautics and astronautics

Publication Date: 2016.04.19 AIRBUS OPERATIONS GMBH

AI summary

A composite skin for the aeronautics and astronautics industries, and also a method for producing a composite skin of this type is provided. The method comprises the following method steps: removing excess material from a butt plate to form a butt strap at one end thereof, subsequently connecting the other end of the butt plate to a skin plate with a substance-to-substance bond, and then fastening a further skin plate to the butt strap to form the composite skin. The idea behind the invention involves replacing a rivet connection with a substance-to-substance bond. This provides the advantage that the weight of the composite skin and the production costs for the composite skin are reduced.