Integrated Mounting Lug Structure for Composite Laminate Load Transfer

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Solution Overview

Problem

Existing methods for load introduction in fiber composite laminate parts for aircrafts are inefficient and require multiple components, leading to complex assembly and increased weight.

Innovation Solution

A method involving the integration of a longitudinal fiber structure to form an integral load introduction feature by pulling it through a laminate structure, forming an opening, and curing it with the laminate to create a single unitary member, reducing the need for external brackets and simplifying assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal bracket inserts and external brackets are used for load introduction, then the load carrying capacity is sufficient, but the device complexity and assembly complexity increase

Engineering Contradiction:
Improveload carrying capacityVSAvoidassembly complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the load introduction feature directly into the fiber composite laminate part by integrating longitudinal fiber structures (cords) that extend through the laminate thickness. This eliminates the need for separate metal bracket inserts and external brackets, combining multiple components into a single integrated structure that maintains load carrying capacity while reducing assembly complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses composite material structures by incorporating longitudinal fiber cords (such as carbon fiber or glass fiber) within the fiber composite laminate. These cords are embedded in the matrix material and oriented to carry loads in the thickness direction, creating a composite reinforcement system that provides structural strength without requiring separate metal fastening components

Inventive Principle:
Principle #40Composite materials

2Strength

If metal bracket inserts and external brackets are used for load introduction, then the load carrying capacity is sufficient, but the weight increases

Engineering Contradiction:
Improveload carrying capacityVSAvoidpart weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent replaces heavy metal bracket inserts and external brackets with lightweight fiber composite cords embedded in the laminate. The longitudinal fiber structures (typically carbon fiber or glass fiber cords) provide the necessary load carrying capacity while being significantly lighter than metal alternatives, thus reducing the overall part weight while maintaining structural strength

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

By integrating the load introduction feature directly into the laminate structure through embedded fiber cords, the patent eliminates the need for separate metal fastening components. This integration removes the additional weight that would be required for metal brackets, inserts, and associated fasteners, achieving weight reduction while maintaining load carrying capacity

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If multiple components are used for load introduction, then the load carrying capacity is sufficient, but the number of parts increases

Engineering Contradiction:
Improveload carrying capacityVSAvoidnumber of parts
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent combines multiple separate components (metal bracket inserts, external brackets, fasteners) into a single integrated fiber composite laminate structure. The longitudinal fiber cords are embedded within the laminate during manufacturing, creating an integrated load introduction feature that eliminates the need for multiple separate parts and reduces the total number of components required

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4112283B1Method for manufacturing a load introduction feature for a fiber composite laminate part
Publication Date: 2026.04.22 AIRBUS OPERATIONS GMBH
  • EP4112283B1 patent drawingFigure 1
  • EP4112283B1 patent drawingFigure 2
  • EP4112283B1 patent drawingFigure 3

AI summary

In order to improve load introduction into a fiber composite laminate part (52), the invention proposes to integrate a mounting lug (54) by pulling a cord (18) through an initial laminate structure (10) such that an opening (30) is formed. The ends (20, 22) of the cord (18) are split and pressed onto the laminate structure (10) thereby forming fixing members (36) that are subsequently covered by another laminate structure (38). Laminate patches (42) may be arranged next to the fixing members (36) so as to improve smoothness of the surface. The mounting lug (54) may be clamped between two plates (58) for mounting to another structure.