Isogrid Stiffener Integration for Pipe Clearance and Assembly

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Solution Overview

Problem

The existing isogrid structures in aircraft and aerospace applications face challenges due to stiffeners being attached to the back of the panel, which restricts space for pipes and complicates assembly, leading to manufacturing constraints and undesirable bending moments.

Innovation Solution

A modified isogrid structure with pad-ups along the edges of triangular pockets and added stiffeners that pass through mouse holes, allowing for the integration of additional stiffeners on the isogrid face without duplicating ribs, maintaining load distribution and reducing weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If stiffeners are attached to the back of the isogrid panel, then structural strength is improved, but space for pipes and assembly accessibility deteriorates

Engineering Contradiction:

Improvestructural strengthVSAvoidassembly accessibility

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The stiffener is repositioned from the back surface to the front surface of the isogrid panel, fundamentally changing its spatial dimension and location. This allows the stiffener to provide structural support while eliminating interference with pipe routing and assembly operations on the back side.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Instead of attaching the stiffener to the conventional location (back of the panel), the invention inverts the approach by attaching it to the opposite side (front of the panel). This inversion resolves the conflict between structural reinforcement and assembly accessibility.

Inventive Principle:

Principle #13The other way round (Inversion)

2Strength

If stiffeners are attached to the back of the panel, then structural support is improved, but manufacturing complexity increases due to tooling constraints

Engineering Contradiction:

Improvestructural supportVSAvoidmanufacturing complexity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

By moving the stiffener attachment location to the front surface, the invention eliminates the need for complex back-side tooling and alignment fixtures, simplifying the manufacturing process while maintaining structural support functionality.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Strength

If stiffeners are attached to the back of the panel, then structural reinforcement is achieved, but bending moments increase due to misalignment with frames

Engineering Contradiction:

Improvestructural reinforcementVSAvoidbending moments

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

Inverting the stiffener location to the front surface enables precise alignment with the longitudinal axis of the isogrid panel and the aircraft frames, eliminating the misalignment-induced bending moments that occur with back-attachment.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS20230382511A1Stiffener integration in an isogrid structure

Publication Date: 2023.11.30 AIRBUS CANADA LLP

AI summary

A system for stiffener integration in an isogrid structure. The modified isogrid structure comprises an isogrid panel; and at least one added stiffener attached to the isogrid panel. The added stiffener can be attached by welding, gluing, or bolting the stiffener to the isogrid panel. The modified isogrid panel has a pad-up in place of one of the ribs of the triangular pockets, wherein the added stiffener is affixed to the pad-up.