Composite Truss Structure Fabrication via Dry Fabric Mandrel Infusion
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Solution Overview
Problem
Existing methods for manufacturing composite truss structures with stiffening capabilities are inefficient and require complex manufacturing steps, making it challenging to integrate truss elements into composite sandwich architectures without additional support structures.
Innovation Solution
A method involving the preparation of a dry fabric mold with fabric-loaded mandrels, infusion with resin, and curing to create a composite truss structure with a reinforcing core of truss elements between two facesheets, allowing for a single resin infusion and curing step, thereby simplifying the manufacturing process and eliminating the need for multiple curing cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If prepreg architecture with honeycomb core is used, then composite sandwich construction achieves rigid core between facesheets, but manufacturing requires complex series of steps involving multiple curing cycles and debulking steps
Solution Approach 1:
The patent merges the core structure and facesheets into a single integrated composite component manufactured through one resin infusion and curing cycle. The mandrel assembly with fabric layers is infused with resin and cured together as one unit, eliminating the need for separate manufacturing and assembly steps for the core and facesheets that characterize traditional prepreg honeycomb constructions.
Solution Approach 2:
The patent uses pre-positioned mandrels shaped to create the desired core geometry before resin infusion. The fabric layers are draped over the mandrels in advance, and the entire assembly is prepared for single-step curing. This preliminary structuring of the mold assembly eliminates the need for post-manufacturing assembly operations.
2Productivity
If honeycomb-stiffened composite sandwich structures are cut into components, then individual parts are obtained, but exposed cut edges reduce product durability or require additional processing
Solution Approach 1:
The patent enables the large composite panel to be manufactured as a complete unit with integrated core and facesheets, which can then be cleanly segmented into individual components through cutting. The segmentation is performed on the cured composite material, producing clean edges without exposing vulnerable honeycomb structures, as the core is fully enclosed within the solid composite matrix.
3Strength
If flexible composite truss structures with single facesheet are manufactured, then truss elements provide stiffening, but additional rigid support surface such as airframe is required to provide stiffened structure
Solution Approach 1:
The patent combines the truss element core with two facesheets and rigid backing material into a single integrated composite structure. This merging creates a self-stiffening component that does not require attachment to external rigid surfaces, as the rigid support function is built into the composite structure itself through the integration of core and facesheets.
4Ease of manufacture
If dry fabric with mandrels is used instead of carbon prepregs, then manufacturing cost is reduced, but structure must be nonflexible and stiffened
Solution Approach 1:
The patent changes the material state from flexible prepreg to rigid dry fabric, and uses the resin infusion and curing process to transform the entire assembly into a rigid composite structure. The parameter change in material form (dry fabric vs. prepreg) enables cost reduction, while the curing process ensures the final structure achieves the required rigidity and stiffness without requiring flexibility during manufacturing.
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 results in a nonflexible, stiffened composite truss structure that can be manufactured in fewer steps, providing a rigid framework without additional support, and is cost-effective compared to using carbon prepregs, with improved accessibility and efficiency for various industrial applications.
Implementation Method 1
infusing the dry fabric mold with a resin, and curing the resin to provide the composite truss structure
Data Source
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AI summary
A method for fabricating a composite truss structure (10) having a core (16) with a plurality of truss elements (18), comprising: preparing a dry fabric mold (36) by a method comprising: placing a first dry fabric layer (38) on a tool (40) having a non-corrugated surface, and placing a first layer of fabric-loaded mandrels (28) on the first dry fabric layer to create a corrugated surface (44), each of the fabric-loaded mandrels including a dry fabric tube (26) wrapped around a mandrel (24); infusing the dry fabric mold (36) with a resin; and curing (56) the resin to provide the composite truss structure; wherein preparing the dry fabric mold (36) further comprises placing a second layer of fabric-loaded mandrels (28) on the first layer of fabric-loaded mandrels (28) by positioning each of the fabric-loaded mandrels (28) of the second layer in a respective one of grooves (46) formed on the corrugated surface (44); and the method further comprises: preparing each of the fabric-loaded mandrels (28) by pulling the dry fabric tube (26) over the mandrel (24) or by braiding the dry fabric tube over the mandrel; and removing the mandrels (24) from the composite truss structure (10) after curing the resin to provide the composite truss structure.