Sacrificial Mold Co-Curing for Lightweight Sandwich Structures

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for manufacturing sandwich structures with lightweight cores cannot co-cure facesheets due to pressure exceeding the compressive strength of the core, leading to increased mass and cost, or sub-optimal performance with reduced compaction pressure.

Innovation Solution

A method involving partial filling of an open cellular core with a sacrificial mold material, consolidating it, and co-curing composite facesheets with controlled pressure and temperature to form the sandwich structure, while removing the sacrificial mold, ensuring the pressure exceeds the core's strength but not the combined core-mold strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If co-curing is used to consolidate facesheets, then facesheet stiffness and strength increase, but the lightweight core is damaged due to excessive compaction pressure

Engineering Contradiction:

Improvefacesheet stiffness and strengthVSAvoidcore damage from excessive pressure

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

A sacrificial mold material is introduced as an intermediary between the facesheets and the lightweight core. This mediator absorbs the excess compaction pressure during co-curing, protecting the core from damage while still allowing the facesheets to be properly consolidated. The sacrificial material is removed after co-curing, leaving the core intact.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sacrificial mold material is placed in the core cavity before assembling the facesheets. This preliminary action creates a protective barrier that prevents direct contact between high compaction pressure and the fragile lightweight core during the co-curing process.

Inventive Principle:

Principle #10Preliminary action

2Object-affected harmful factors

If separate formation and attachment of facesheets is used, then core integrity is maintained, but manufacturing mass and cost increase

Engineering Contradiction:

Improvecore integrityVSAvoidmanufacturing mass

Core Design Contradiction:

Object-affected harmful factorsVSWeight of stationary object

Solution Approach 1:

The process merges the formation of facesheets and attachment to the core into a single co-curing operation. By combining these steps, the manufacturing process eliminates the need for separate attachment operations, reducing overall manufacturing mass and cost while maintaining core integrity through the use of sacrificial mold material.

Inventive Principle:

Principle #5Merging (Combining)

3Object-affected harmful factors

If reduced compaction pressure is used during co-curing, then core integrity is maintained, but facesheet performance is limited

Engineering Contradiction:

Improvecore integrityVSAvoidfacesheet performance

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The sacrificial mold material serves as a pressure-absorbing intermediary that allows high compaction pressure to be applied during co-curing without transmitting excessive force to the lightweight core. This enables optimal facesheet consolidation and performance while protecting the core integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This method allows for the formation of sandwich structures with increased facesheet stiffness and reduced parasitic adhesive mass, maintaining core integrity and reducing manufacturing costs by enabling co-curing without damaging the lightweight core.

Implementation Method 1

consolidating the sacrificial mold material to form a sacrificial mold

Methodology Applied

Scientific EffectConsolidation:

Implementation Method 2

co-curing the composite facesheets by applying a consolidation temperature and a compaction pressure to the composite facesheets

Methodology Applied

Scientific EffectCo-curing:

Implementation Method 3

consolidating the composite facesheets by applying a consolidation temperature and a compaction pressure

Methodology Applied

Scientific EffectThermal consolidation:

Implementation Method 4

removing the sacrificial mold

Methodology Applied

Scientific EffectMaterial removal:

Data Source

PatentUS11358350B1Lightweight sandwich structures and methods of manufacturing the same

Publication Date: 2022.06.14 HRL LAB

AI summary

A method of forming a sandwich structure including at least partially filling an open volume of an open cellular core with a sacrificial mold material, consolidating the sacrificial mold material to form a sacrificial mold, laying up a composite facesheet on each of at least two surfaces of the open cellular core, co-curing the composite facesheets by applying a consolidation temperature and a compaction pressure to the composite facesheets to form the sandwich structure, and removing the sacrificial mold. The compaction pressure is greater than a compressive strength of the open cellular core and less than a combined compressive strength of the open cellular core and the sacrificial mold.