Pressurizable Core for Complex Composite Structures
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Solution Overview
Problem
Existing methods for producing large, complex-shaped, three-dimensional fiber reinforced composite components face challenges in achieving high surface finish, strength, and damage tolerance, particularly when curing at elevated temperatures, as non-vented cores can lead to pressure buildup and potential distortion or explosion.
Innovation Solution
The method involves using pressurizable members with openings for internal pressurization, allowing counteracting pressures to be applied to fiber plies within a mold, enabling elevated temperature and pressure curing while maintaining geometric shape and preventing pressure-related issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If hollow cell or foam block cores are used in vacuum assisted resin transfer molding, then complex-shaped composite structures can be produced, but the cores are sealed and non-vented which prevents elevated temperature curing due to pressure buildup
Solution Approach 1:
The core is divided into multiple sealed chambers separated by internal partitions or webs. Each chamber can be independently vented or pressurized, allowing the structure to maintain its complex shape while enabling elevated temperature curing through controlled pressure release pathways.
Solution Approach 2:
A venting system or pressure equalization mechanism is introduced as an intermediary between the sealed core chambers and the external environment. This allows pressure buildup to be managed during elevated temperature curing while maintaining the structural integrity and complex geometry of the core.
2Shape
If plaster mandrels are used to form complex shapes, then hollow composite components can be produced, but the mandrels must be struck through and crumbled which is labor-intensive and limits structural strength
Solution Approach 1:
The core structure is designed to be extractable or removable from the cured composite component. The core may be designed with features that allow for easy removal through dissolution, disassembly, or controlled destruction, eliminating the labor-intensive process of striking through and crumbling plaster mandrels.
3Strength
If steel or aluminum tooling is used to create strong mold surfaces, then structural strength requirements are met, but the device complexity and cost increase significantly
Solution Approach 1:
The core structure itself is made from composite materials that provide the necessary structural strength and rigidity to support fiber plies and maintain geometric shape during curing. This eliminates or reduces the need for heavy steel or aluminum tooling, simplifying the overall device while meeting strength requirements.
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 approach enables the production of complex-shaped composite structures with improved strength, surface finish, and reduced weight, allowing for radical new designs and lower production costs, while avoiding the limitations of traditional curing methods.
Implementation Method 1
pressurizing the interior of the pressurizable members with a gas or liquid
Implementation Method 2
The mold and fiber plies are heated to elevated temperatures to cure the polymer matrix material
Data Source
AI summary
A complex- shaped, three-dimensional fiber reinforced composite structure may be formed by using counteracting pressures applied to a structural lay-up of fiber plies. The fiber plies (104) are arranged on a pressurizable member (106) that may become an integral part of the final product, or may be removed before the product is finalized. The pressurizable member may take the form of a hollow blow molded or rotomolded thermoplastic component or a superplastic formed metallic component having an opening such that the pressurizable member may be vented or pressurized and thus expanded against the fiber plies. In addition, a number of the pressurizable members may be joined in fluid communication, where they may each have different configurations, yet be arranged to form a large, complex- shaped lay-up surface for the fiber plies. The arrangement of the fiber plies onto the pressurizable members may produce integral I-Beam stiffeners, ribs, flanges, and other complex shaped structural components.