Collapsible Mandrel for Composite Part Curing and Repair

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Solution Overview

Problem

Existing mandrel systems for composite parts are not suitable for out-of-autoclave curing processes, as inflatable bladders used in autoclave curing may not perform effectively under different temperature and pressure conditions, potentially impacting the final part characteristics during repairs.

Innovation Solution

A mandrel system with an actuator that moves between expanded and contracted states, allowing it to fit into composite part cavities for support during curing and subsequent easy removal, featuring a housing with upper, lower, and mid-mandrel portions and an actuator that changes the mandrel's perimeter length to accommodate various states, facilitating both formation and repair of composite parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an inflatable bladder is used to support composite parts during autoclave curing, then the part geometry is properly maintained during autoclave pressure, but the bladder may not perform properly under out-of-autoclave curing conditions and could negatively impact final part characteristics

Engineering Contradiction:
Improvesupport performance during curingVSAvoidadaptability to different curing conditions
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The mandrel employs a dynamic structure with collapsible support elements that can transition between expanded and collapsed states. The support elements include segments capable of relative movement, allowing the mandrel to adapt its configuration based on curing conditions and facilitate easy removal after curing completes

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mandrel utilizes collapsible support elements that can change their physical state from expanded to collapsed. This parameter change allows the same mandrel structure to function effectively under different curing conditions (autoclave and out-of-autoclave) and enables easy removal by collapsing to a reduced size

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If a rigid mandrel is used to support composite parts during curing, then the part geometry is maintained, but the mandrel cannot be easily removed from the part after cure

Engineering Contradiction:
Improvegeometry maintenance during curingVSAvoidease of removal after curing
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The mandrel employs a dynamic structure with collapsible support elements that can transition between expanded and collapsed states. The support elements include segments capable of relative movement, allowing the mandrel to adapt its configuration based on curing conditions and facilitate easy removal after curing completes

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mandrel is divided into multiple support elements that can move relative to each other. These segmented components allow the mandrel to collapse into a compact configuration for removal while maintaining structural integrity during the curing process

Inventive Principle:
Principle #1Segmentation

3Reliability

If an inflatable bladder is used for autoclave curing, then the bladder can be inflated to support the part, but the bladder cannot be easily deflated and removed from the part after cure

Engineering Contradiction:
Improvesupport function during curingVSAvoidease of removal after curing
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The mandrel employs a dynamic structure with collapsible support elements that can transition between expanded and collapsed states. The support elements include segments capable of relative movement, allowing the mandrel to adapt its configuration based on curing conditions and facilitate easy removal after curing completes

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mandrel is divided into multiple support elements that can move relative to each other. These segmented components allow the mandrel to collapse into a compact configuration for removal while maintaining structural integrity during the curing process

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3354448B1Mandrel for composite part fabrication and repair
Publication Date: 2024.06.26 THE BOEING CO
  • EP3354448B1 patent drawingFigure 1~2
  • EP3354448B1 patent drawingFigure 3A
  • EP3354448B1 patent drawingFigure 3B

AI summary

A mandrel (100) for a composite part includes an upper-mandrel portion (310), a lower-mandrel portion (312), and a mid-mandrel portion (314,316) between the upper-mandrel portion (310) and the lower-mandrel portion (316). The mandrel (100) also includes a cavity (328) and an exterior surface (318) defined by the upper-mandrel portion (310), the lower-mandrel portion (312), and the mid-mandrel portion (314,316). An actuator (106) is movable in the cavity (328) between a first position and a second position. The exterior surface (318) can support the composite part. A perimeter of the exterior surface (318) has a first length when the actuator (106) is in the first position and the perimeter has a second length when the actuator (106) is in the second position. The first length is greater than the second length such that the mandrel (100) is in an expanded state when the actuator (106) is in the first position and the mandrel (100) is in a contracted state when the actuator (106) is in the second position.