Composite Quadrangular Shell Trihedral Corner Manufacturing
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Solution Overview
Problem
The production of quadrangular hulls with composite materials reinforced by continuous fibers faces challenges in forming trihedral connections, particularly due to non-developable areas that are difficult to shape without wrinkling, achieving uniform heating, and preventing polymer drying, leading to defects and high costs in deeper drawing applications like luggage.
Innovation Solution
A method involving cutting plies with cutouts to avoid trihedral connection zones, creating consolidated connecting pieces for integration, and subjecting them to a pressure-temperature cycle in a tool with induction heating and cooling, ensuring the fibers extend from one edge to another for rigidity and solidity, while using thermoplastic polymer connecting parts with short fibers for improved mechanical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If continuous fiber plies are used to reinforce the shell, then the rigidity and strength of the shell are improved, but the trihedral connection zones become difficult to form without creating creases and wrinkles
Solution Approach 1:
The shell is divided into two distinct parts: developable surfaces covered by continuous fiber plies and non-developable trihedral connection zones filled with consolidated connecting pieces. This segmentation allows each part to be optimized independently - the plies maintain fiber continuity and rigidity on flat surfaces, while the connecting pieces provide the necessary formability for complex corners without fiber wrinkling.
Solution Approach 2:
The trihedral connection zones are extracted from the continuous fiber ply coverage area. By removing plies from these specific zones and replacing them with separately consolidated connecting pieces, the patent eliminates the problem of fiber wrinkling in non-developable areas while preserving continuous fiber reinforcement in the developable regions.
2Shape
If pressure is applied to consolidate the trihedral connection zones, then the forming of corners is improved, but complex tools with mobility punches or inflatable parts are required
Solution Approach 1:
The connecting pieces are pre-consolidated into the complex trihedral shape before being integrated into the shell assembly. This preliminary consolidation action transforms the difficult forming operation into a simpler assembly step, eliminating the need for complex mobility punches or inflatable parts during the main consolidation process.
3Productivity
If rapid heating and cooling tooling is used for consolidation, then the consolidation speed is improved, but uniform heating temperature in trihedral connection zones cannot be ensured
Solution Approach 1:
The connecting pieces undergo preliminary consolidation and heating before being integrated into the final shell assembly. This preliminary action allows for controlled, uniform heating of the trihedral zones without the thermal gradients that occur in rapid heating tooling, ensuring quality while maintaining productivity through subsequent efficient consolidation of the complete assembly.
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 production of quadrangular shells with integrated trihedral corners without defects, using a cost-effective process suitable for deeper drawing applications, ensuring uniform consolidation and improved mechanical properties.
Implementation Method 1
The tool and the preform are heated by induction in a uniform manner
Implementation Method 2
a rapid cooling of the tool and of the preform
Data Source
Figure 1~2B
Figure 3~4
Figure 5~6
AI summary
The invention concerns a method for manufacturing a quadrangular shell comprising five faces and non-developable trihedral connectors between the faces, comprising the steps consisting of: i. cutting plies (210, 220) comprising continuous fibres, covering the five faces of the shell outside of the trihedral connector zones; ii. obtaining four connector components (320) consolidated in the shape of the trihedral connectors, each of the components comprising an integration zone (321) between the plies; iii. positioning and stacking the plies obtained in step i); iv. inserting the four consolidated components (320) in the trihedral connection zones by inserting the integration zones between two plies in order to obtain a preform; v. placing the preform in a tool (502, 602) and performing the consolidation of the stack of fibrous plies by subjecting the assembly obtained in step iv) to a predetermined pressure/temperature cycle.