Tensioning Fork for Composite Wrinkle Elimination
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Solution Overview
Problem
Composite materials undergoing forming and curing processes in curved C-channel molds often develop undesirable wrinkles and aberrations due to differences in path lengths between the inner and outer radii, which are not effectively addressed by existing methods.
Innovation Solution
A tensioning fork apparatus with tapered legs and a joining arm is used to apply precise tension to the material over a mold, featuring a first tapered leg positioned between the mold and the material, a second tapered leg against the material's top face, and a force-exacting component to compress and pivot the second leg, ensuring even tension and preventing wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If material is pressed against inner surfaces of a curved C-channel and then tensioned and compressed, then the material conforms to the mold shape, but wrinkles and aberrations form due to path length differences between inner and outer radii
Solution Approach 1:
The tensioning fork is positioned against the material before vacuum compression is applied. The forks pre-tension the material by forcing it against the mold surface, eliminating path length differences between inner and outer radii before the compression process begins. This preliminary action prevents wrinkles from forming during subsequent compression.
Solution Approach 2:
The tensioning fork acts as an intermediary device between the material and the mold surface. It transfers force from the mold surface through the material, ensuring uniform tension distribution and preventing direct compression that would cause wrinkles. The fork's structure with legs positioned at different heights allows it to mediate the force application effectively.
2Productivity
If vacuum compression is applied to compress material and resin in a curved C-channel, then the composite part is formed, but wrinkles form along the inner wall due to path length differences
Solution Approach 1:
The tensioning forks are positioned and pre-tension the material before vacuum compression begins. This preliminary action ensures the material is already conforming to the mold surface with uniform tension, so when vacuum compression is applied to complete the forming process, no wrinkles form along the inner wall.
Solution Approach 2:
The tensioning forks apply localized tension at specific positions within the C-channel, particularly addressing the inner radius area where wrinkles typically form. The forks can be positioned to provide enhanced tension where path length differences are most pronounced, ensuring local quality control during the forming process.
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
The solution effectively eliminates wrinkles and aberrations by applying uniform tension across the material, ensuring a smooth, flat surface post-curing, even in curved C-channel molds, enhancing the quality of composite parts.
Implementation Method 1
creating a vacuum between the airtight lining and the mold surface to compress the material and resin
Implementation Method 2
applying heat to the material, resin, and airtight lining
Data Source
AI summary
An apparatus and method for tensioning material (12) over a mold (14), such as a cure tool, comprises a tensioning fork (10) consisting of two substantially parallel tapered legs (18,20) between which material (12) is disposed. A tensioning fork (10) is positioned at a first side edge (42) and proximate a first end edge (38) of the material (12). A first leg (18) of the tensioning fork (10) is disposed under the material (12), and a second leg (20) of the tensioning fork (10) is disposed over the material (12). When force is applied to the second leg (20), it pivots about the first leg (18) along the length of the legs, remaining parallel to the first leg (18), thereby pressing a portion of the material (12) against the mold (14).