Contoured Composite Stiffener Wrinkle Mitigation via Diffuser Tooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in producing contoured composite laminate stiffeners is the tendency of plies to wrinkle during contouring, which affects performance and limits the degree of contouring without unacceptable wrinkling.
Innovation Solution
The use of compression mold tooling with diffusers positioned between dies to diffuse wrinkles, controlling wrinkling by allowing the composite charge to strain into depressions on the diffusers, thereby reducing or eliminating undesired wrinkling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If composite laminate stiffeners are contoured to conform to structures, then the stiffeners can be attached to contoured surfaces, but the plies wrinkle during contouring which affects performance and limits the degree of contouring
Solution Approach 1:
A wrinkle diffuser is introduced as an intermediary component between the composite charge and the die surface. The diffuser has a contoured surface with variable radius of curvature that matches the desired stiffener contour, allowing it to mediate the forming process by distributing compressive forces and preventing ply wrinkling while achieving the required contour shape
Solution Approach 2:
The invention changes the geometric parameters of the forming surface by using a diffuser with variable radius of curvature. This parameter change allows the forming surface to adapt to different contour requirements and control the stress distribution during forming, thereby preventing wrinkles while achieving various contour shapes
2Shape
If the stiffener is contoured to a desired shape, then it conforms to the structure, but scrap and rework increase due to unacceptable ply wrinkling
Solution Approach 1:
The wrinkle diffuser is prepared in advance with the appropriate contour shape and radius of curvature characteristics. This preliminary preparation allows the diffuser to prevent wrinkles during the forming process itself, eliminating the need for subsequent rework or scrapping of wrinkled parts
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A composite charge (64) is formed between two compression dies (70, 74) into a composite laminate stiffener (50). The stiffener (50) is contoured along its length by contouring the dies (70, 74). Wrinkle diffusers (114, 178, 116, 180) attached to, or embedded or incorporated into the tool surfaces of the dies, diffuse wrinkles formed on the inside radius of the stiffener during the contouring.