Inflatable Compaction Tool for Composite Corner Consolidation

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Solution Overview

Problem

Manufacturing composite parts in hollow, faceted molds often results in poor consolidation and resin richness at corner regions due to bridging or wrinkling, leading to inferior material properties like excess thickness and porosity, especially when using traditional mandrels that are fragile and environmentally hazardous.

Innovation Solution

An inflatable compaction tool with corner and wall segments that expand to compress the composite material evenly into internal corner regions and against flat wall surfaces, allowing for even consolidation and easy removal from molds with curved or angled surfaces, and can be reused without generating hazardous waste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional solid mandrels are used to prevent corner bridging, then corner consolidation improves, but mandrel removal becomes difficult from molds with curved or angled surfaces

Engineering Contradiction:

Improvecorner consolidationVSAvoidmandrel removal

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The mandrel is divided into multiple inflatable segments or zones that can be independently controlled. This segmentation allows the mandrel to be deflated in sections during removal, reducing friction and enabling easy extraction from molds with curved or angled surfaces while maintaining effective corner consolidation during manufacturing

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mandrel transitions from a static solid structure to a dynamic inflatable structure. By controlling inflation and deflation, the mandrel can adapt its shape and size - inflated during manufacturing to prevent corner bridging, and deflated during removal to facilitate extraction from complex mold geometries

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If soluble or washable mandrel materials are used to enable removal, then mandrel extraction improves, but mandrel strength decreases and handling becomes difficult

Engineering Contradiction:

Improvemandrel removalVSAvoidmandrel tensile strength

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The mechanical strength of solid mandrel materials is replaced by pneumatic pressure. The inflatable mandrel derives its structural integrity and strength from internal air pressure rather than material properties, allowing for easy removal without sacrificing strength during handling and operation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The mandrel's physical state changes between inflated and deflated conditions. When inflated, the mandrel gains sufficient strength and rigidity to prevent corner bridging; when deflated, it becomes flexible and easy to remove. This parameter change eliminates the need for weak soluble or washable materials

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If uniform compression is applied to the composite material, then consolidation quality improves, but corner regions still experience bridging and wrinkling due to mold geometry

Engineering Contradiction:

Improveconsolidation qualityVSAvoidcorner region uniformity

Core Design Contradiction:

Manufacturing precisionVSShape

Solution Approach 1:

The inflatable mandrel provides different compression characteristics to different regions of the mold. By strategically positioning and independently controlling inflation of various segments, the mandrel delivers enhanced compression force to corner regions that are prone to bridging, while maintaining appropriate compression on flat surfaces, thus achieving uniform consolidation across the entire composite part

Inventive Principle:

Principle #3Local quality

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

The inflatable compaction tool effectively prevents bridging and wrinkling, ensuring uniform fiber density and improved material properties, while being reusable and environmentally friendly.

Implementation Method 1

An inflatable compaction tool with corner and wall segments that expand to compress the composite material evenly

Methodology Applied

Scientific EffectPneumatic pressure: Pressurisation

Data Source

PatentUS7824171B2Corner-consolidating inflatable apparatus and method for manufacturing composite structures

Publication Date: 2010.11.02 THE BOEING CO

AI summary

An inflatable compaction tool for consolidating a composite material inside a faceted hollow or tubular mold for a composite part is made from an elastic material. The compaction tool includes relatively flat wall segments conjoined by corner segments that define a sealed chamber. The wall segments curve away from the mold surface toward the midpoint of each wall segment, so that as a pressurized fluid is introduced into the compaction tool, a component of the force exerted on the tool interior surface is transmitted through the wall segments toward the corner segments. Thus, during initial inflation, the corner segments are forced toward the corner regions of the mold before the wall segments contact the composite material, firmly compressing the composite material into the corner regions of the mold before the friction of the wall segments against the composite material inhibits expansion of the corner segments into the mold corner regions.