Hexagonal Belt Stiffener for Orifice Stability

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Solution Overview

Problem

Existing stiffened structures, particularly 'Isogrid' types, face mechanical characteristic degradation when large openings or conduits are integrated, leading to reduced stability and buckling resistance.

Innovation Solution

A stiffened structure with a hexagonal belt of peripheral stiffeners surrounding an orifice, which includes secondary stiffeners connected to adjacent nodes, maintains structural integrity by distributing loads and enhancing integration with conduits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a large opening or conduit is integrated into the stiffened structure, then the structure can accommodate conduits or access requirements, but the mechanical characteristics such as stability and buckling resistance are degraded

Engineering Contradiction:

Improveability to accommodate conduits or openingsVSAvoidmechanical characteristics including stability and buckling resistance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The opening is surrounded by a hexagonal belt that segments the structure into distinct zones: the opening area and the surrounding stiffened structure. This segmentation allows the opening to be accommodated while maintaining the structural integrity of the surrounding areas through the hexagonal configuration that distributes stresses effectively.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The hexagonal belt provides localized reinforcement around the opening without requiring strengthening of the entire structure. This local quality enhancement focuses the structural support exactly where needed - at the periphery of the opening - thereby accommodating the conduit while preserving the mechanical characteristics of the overall structure.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If a rectangular opening with peripheral stiffener is used, then the opening can be created in the stiffened structure, but the mechanical characteristics are strongly impacted

Engineering Contradiction:

Improveability to create openingVSAvoidmechanical characteristics

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The invention replaces the conventional rectangular opening shape with a hexagonal configuration. This asymmetric shape (relative to the rectangular form) better conforms to the natural stress distribution patterns in the stiffened structure, allowing the opening to be created while minimizing the impact on mechanical characteristics through optimized geometric form.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The hexagonal belt provides a curved or rounded configuration compared to sharp rectangular corners. This curvature distributes stresses more evenly around the opening perimeter, reducing stress concentration points and thereby maintaining stronger mechanical characteristics while still creating the necessary opening.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Ease of operation

If a circular peripheral ring stiffener is used for conduit integration, then better integration is achieved compared to rectangular forms, but the hexagonal belt configuration further minimizes impact on mechanical characteristics

Engineering Contradiction:

Improveintegration with conduitsVSAvoidstability and resistance to buckling

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The hexagonal belt serves multiple functions simultaneously: it provides conduit integration capability like the circular ring, while also acting as structural reinforcement that maintains stability and buckling resistance. The hexagonal configuration universally addresses both the operational need for conduit access and the structural need for mechanical integrity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention changes the geometric parameter of the peripheral stiffener from circular to hexagonal. This parameter change optimizes the balance between conduit integration capability and mechanical performance, as the hexagonal shape with its flat sides and corners provides both ease of conduit mounting and superior structural characteristics including enhanced buckling resistance.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP2481667B1Stiffened structure including an opening

Publication Date: 2015.03.04 AIRBUS OPERATIONS (SAS)

Figure 1~2B
Figure 3A~3B
Figure 4~5

AI summary

The object of the invention is a stiffened structure comprising stiffeners (14.1, 14.2, 14.3) and nodes (12) at which three stiffeners (14.1, 14.2, 14.3) of different directions intersect, the faces of the stiffeners (14.1, 14.2, 14.3) being arranged in planes perpendicular to the same plane, said stiffened structure comprising at least one orifice (26) and being characterized in that said orifice (26) is surrounded by a hexagonal belt formed by peripheral stiffeners (40).