Fibrous Preform Shaping with Segmented Tension Rods
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Solution Overview
Problem
The shaping of fibrous preforms with evolving profiles in composite material reinforcement is hindered by tension imbalances and defects such as waviness, fiber buckling, and uneven thickness due to differences between the woven profile and the actual mold profile, leading to increased complexity and time in the shaping process.
Innovation Solution
An installation with a tension adjustment device featuring movable rods equipped with tension sensors, allowing for real-time tension adjustments to maintain uniformity and prevent defects, is used in conjunction with follower rollers having variable radii to match the mold profile, ensuring consistent tension across the fibrous texture during winding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If follower rollers with variable radii are used to match the mold profile, then the profile accuracy is improved, but tension imbalances still occur due to evolving radius ratios during winding
Solution Approach 1:
The follower roller is segmented into multiple independent rods that can move individually along their axes. Each rod can be adjusted independently to maintain uniform tension in different zones of the fibrous texture, resolving the tension imbalance problem while preserving the profile accuracy achieved by the variable radius design.
Solution Approach 2:
The rods are made movable along the axial direction rather than being fixed. This dynamic adjustment capability allows the system to adapt to changing tension requirements during the winding process, particularly when the radius ratios evolve significantly, thereby maintaining tension uniformity without compromising profile accuracy.
2Manufacturing precision
If the fibrous texture is wound under tension on a mold with evolving profile, then the shaping accuracy is improved, but defects such as waviness, fiber buckling, and uneven thickness occur due to tension losses
Solution Approach 1:
Different zones of the fibrous texture receive different tension forces through the independently adjustable rods. This local quality adjustment prevents tension losses in specific zones that would otherwise lead to defects such as waviness, fiber buckling, and uneven thickness, while maintaining the overall shaping accuracy of the evolving profile.
Solution Approach 2:
The system incorporates tension sensors that provide feedback on the actual tension in the fibrous texture. This feedback enables real-time adjustment of the rod positions to maintain optimal tension levels, preventing the occurrence of defects while preserving the shaping accuracy required for evolving profiles.
3Manufacturing precision
If shaped weaving with different warp thread lengths is used to adapt to the evolving profile, then the profile matching is improved, but the complexity of the weaving process increases
Solution Approach 1:
The movable rods act as an intermediary mechanism between the woven fibrous texture and the mold. Instead of requiring complex shaped weaving to achieve profile matching, the rods mediate the tension distribution to accommodate the evolving profile, thereby reducing weaving process complexity while maintaining profile matching accuracy.
4Reliability
If follower rollers with variable radii are used to maintain yarn length ratios, then the tension uniformity is improved, but the device complexity increases
Solution Approach 1:
The follower roller is segmented into multiple simple, movable rods rather than a single complex variable radius structure. This segmentation simplifies the overall device structure while achieving tension uniformity through the collective action of multiple independently adjustable rods, reducing the complexity compared to a fully variable radius follower roller.
Data Source
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AI summary
The invention relates to a facility (10) for shaping a rotating fibrous preform having an evolving profile in the radial cross-section, comprising a storage mandrel (300) designed to store a fibrous web (210) in the form of a rolled-up strip, at least one follower roller (400, 500) and a rotating mould (600) on which the fibrous web is to be shaped by rolling, the at least one follower roller being placed between the storage mandrel and the rotating mould, the facility comprising at least one device (700) for adjusting the tension applied to the fibrous web, and the device comprising a row of rods (70) aligned in a first direction parallel to an axis of rotation of the at least one follower roller, each rod having an end fitting (72) on a free end, which is designed to come into contact with the fibrous web.