Thermoplastic Blocker Door Assembly for Gas Turbines

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Solution Overview

Problem

Conventional blocker doors in gas turbine engines, made from aluminum honeycomb cores and skins, face issues with increased weight and compromised sound attenuation due to the use of potting compounds, which are not customizable and restrict noise attenuation performance.

Innovation Solution

The development of a thermoplastic blocker door assembly with a honeycomb core and mounting structures integrally formed from a thermoplastic material, allowing for customized cell sizes and reduced weight, using processes like injection molding or compression molding to create a lightweight and cost-effective component.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If potting compound is used to fill the honeycomb core for structural support, then the blocker door can sustain higher loads, but the weight of the blocker door increases and sound attenuation characteristics are compromised

Engineering Contradiction:

Improveload bearing capacityVSAvoidblocker door weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent removes the potting compound from the honeycomb core structure. Instead of filling the core with compound to achieve structural integrity, the design uses the hollow honeycomb structure itself with strategic skin thickness variations and rib reinforcements to provide the necessary strength without the added weight and sound attenuation issues of potting material.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different skin thicknesses in different regions of the blocker door. The skin is thicker in areas requiring higher structural support and thinner in areas where weight reduction is prioritized. This localized quality variation allows the structure to sustain necessary loads while minimizing overall weight without requiring potting compound.

Inventive Principle:

Principle #3Local quality

2Strength

If potting compound is used to fill the honeycomb core for structural support, then the blocker door can sustain higher loads, but the sound attenuation characteristics of the honeycomb core are compromised

Engineering Contradiction:

Improveload bearing capacityVSAvoidsound attenuation

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent removes the potting compound that degrades sound attenuation properties. By eliminating this harmful element and relying on the hollow honeycomb structure with optimized skin thickness, the design maintains structural integrity while preserving the acoustic absorption capabilities of the honeycomb core.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses a composite structure combining the hollow aluminum honeycomb core with thermoplastic skin materials of varying thicknesses. This composite approach provides structural strength through the skin-honeycomb-skin sandwich construction while maintaining the sound attenuation properties of the untreated honeycomb cells.

Inventive Principle:

Principle #40Composite materials

3Strength

If conventional aluminum honeycomb core with skins and adhesive is used, then structural integrity is achieved, but the manufacturing process becomes complex and cost increases

Engineering Contradiction:

Improvestructural integrityVSAvoidmanufacturing complexity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent combines multiple manufacturing operations into a single injection molding process. The thermoplastic skin material is molded directly over the honeycomb core in one continuous operation, eliminating the separate steps of skin fabrication, adhesive application, and assembly. This merging of processes reduces manufacturing complexity and cost while maintaining structural integrity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the mechanical adhesive bonding system with a thermal molding process. Instead of using adhesives to bond skins to the honeycomb core, the thermoplastic material is molded directly onto the core structure, creating a permanent bond through cooling and solidification. This substitution eliminates adhesive application complexity and improves manufacturing efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11840986B2Blocker door assembly having a thermoplastic blocker door for use in a turbine engine

Publication Date: 2023.12.12 THE BOEING CO

AI summary

A blocker door assembly for use in a gas turbine includes a panel, a core integrally formed with the panel, and a plurality of mounting structures extending from at least one of the panel and the core. The plurality of mounting structures are integrally formed with the core and the panel such that the panel, the core, and the mounting structures are co-molded from a thermoplastic material.