Composite Preform Tensioning Mandrel with Segmented Anchoring
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Solution Overview
Problem
Existing methods for anchoring and tensioning composite materials during fabrication often result in dimensional inaccuracies, resin bleed, and increased tool maintenance due to pressure inconsistencies and misalignments, particularly when using braided or woven materials, leading to aberrations like warping and wrinkling.
Innovation Solution
A tensioning device and method that includes a mandrel with anchoring and tensioning grooves, along with a tensioning mechanism, to securely anchor and apply tension throughout the layers of the composite preform, ensuring even compression and removal of aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multi-part tools with caul plates are used to compress the preform, then the preform can be secured to the mandrel, but pressure inconsistencies and misalignments occur near the edges, resulting in dimensional inaccuracies and defects
Solution Approach 1:
The tool is divided into multiple segments: a mandrel, removable caul plates, and a base plate. The caul plates can be separately positioned and secured to the mandrel, allowing for precise alignment and even pressure distribution across the preform surface, eliminating the misalignment issues of integrated multi-part tools.
Solution Approach 2:
The caul plates are positioned and secured to the mandrel before the preform is placed. This preliminary positioning ensures proper alignment and even pressure distribution are established in advance, preventing dimensional inaccuracies during the compression process.
2Manufacturing precision
If only the outermost layers are extended and gripped by the anchor, then the anchoring mechanism is simple, but tensioning is not applied throughout the layers, leading to unresolved aberrations
Solution Approach 1:
The anchoring mechanism is segmented into multiple independent anchors positioned at different locations along the preform. Each anchor can independently extend and grip its corresponding layer, ensuring uniform tensioning throughout all layers rather than concentrating force only at the outermost layers.
Solution Approach 2:
The anchoring mechanism transitions from a single-point outer-layer anchoring to a distributed multi-point system that spans the entire preform surface. This dimensional expansion of the anchoring system enables tensioning to be applied uniformly across all layers, eliminating unresolved aberrations.
3Reliability
If the clamping mechanism remains with the tool during the cure cycle, then the preform is continuously constrained, but the tool becomes more complex and requires additional maintenance
Solution Approach 1:
The clamping mechanism transitions from a static permanent attachment to a dynamic removable system. The caul plates can be attached during the layup and tensioning phases, then removed after curing. This dynamic approach maintains constraint stability during the critical fabrication phases while simplifying tool maintenance by allowing components to be removed and cleaned separately.
Data Source
AI summary
An apparatus for tensioning a preform may include a mandrel to receive a preform. The mandrel may have a first mandrel end and a second mandrel end. The preform may have a first preform end and a second preform end. The apparatus may include an anchoring groove disposed at the first mandrel end, and an anchoring device being configured and located to urge the first preform end towards the anchoring groove to secure the first preform end therebetween. The apparatus may include a tensioning groove disposed between the first mandrel end and the second mandrel end, and a tensioning device being configured and located to urge at least a portion of the preform into the tensioning groove.