Variable Radius Die Assembly for Composite Gap Fillers
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Solution Overview
Problem
Existing methods for forming composite gap fillers struggle to reliably create smooth transitions in size and radius changes along the length of the gap filler, often resulting in abrupt surface changes and fiber loss, particularly when transitioning from smaller to larger sizes or vice versa, which compromises the fit and performance of the gap filler in aircraft stringer applications.
Innovation Solution
A die assembly comprising first, second, and third dies with rotatable central axes, where the first and second dies have curved surfaces with changing radii and the third die has a wall member that adjusts width, allowing for synchronized rotation to form a composite gap filler with smooth transitions in size and radius changes, ensuring optimal fit and fiber retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional methods are used to form composite gap fillers, then production is simpler, but smooth transitions in size and radius changes cannot be achieved, resulting in abrupt surface changes
Solution Approach 1:
The die assembly incorporates rotatable dies with variable radius curved surfaces that can dynamically adjust during the forming process. The first and second dies rotate about central axes while maintaining abutting relationships, enabling continuous variation of the gap filler's cross-sectional dimensions and radius of curvature along its length, thus achieving smooth transitions without abrupt changes
Solution Approach 2:
The forming process is divided into multiple independent die components (first die, second die, third die) that can be individually controlled and positioned. Each die segment contributes to forming specific portions of the gap filler, allowing precise control over size and radius variations along the length of the filler while maintaining manufacturing feasibility
2Reliability
If die rotation is synchronized to adjust radius and width, then optimal fit and fiber retention are achieved, but the operation becomes more complex
Solution Approach 1:
The first and second dies are coupled through synchronous rotation mechanisms that coordinate their rotational movements. This merging of control ensures that both dies rotate in unison, maintaining proper abutting relationships and consistent gap dimensions throughout the forming process, which prevents fiber disturbance and loss while managing operational complexity through integrated control
3Strength
If the radius of curvature of adjacent curved sides increases for greater strength, then the stringer strength increases, but the gap filler size and manufacturing difficulty increase
Solution Approach 1:
The die assembly enables continuous variation of geometric parameters including radius of curvature, cross-sectional width, and length of the gap filler. By adjusting the rotation synchronization and die positioning, the radius of curvature of the adjacent curved sides can be increased to enhance stringer strength, while the same system can produce smaller fillers for less critical applications, providing parameter flexibility without proportionally increasing manufacturing complexity
Data Source
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AI summary
A die assembly for forming a composite gap filler, including a first die (86) having a first portion which extends along a first central axis (104) of the first die and has a first curved surface (106) which has a radius which changes as the first curved surface extends about the first central axis. A second die (88) has a second portion which extends along a second central axis (104') of the second die and has a second curved surface (106') which has a radius which changes as the second curved surface extends about the second central axis. A third die (92) defines a third wall member (134) which extends about third central axis (136) and which changes in width dimension as the third wall member extends about the third central axis. wherein with the first die abutting the second die and with the third wall member abutting the first and second dies, a closed gap (G2) is formed.