Helical Reinforcing Pin for Composite Delamination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional z-pinning techniques using smooth-surface fibrous composite pins are prone to delamination under high loads due to the pins pulling through the composite laminate structures, despite improving through-thickness strength and resistance to delamination.
Innovation Solution
The development of reinforcing pins with a helical configuration and a corrugated outer surface, formed by twisting fibres within a polymeric matrix, which are inserted into channels within the composite structure to anchor securely through a curing process that allows the matrix to flow into the corrugations, enhancing grip and resistance to delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If smooth-surface fibrous composite pins are used for z-pinning, then the pins can be easily manufactured using conventional pultrusion processes, but the pins pull through the composite laminate under high loads, allowing delamination to occur
Solution Approach 1:
The patent applies curvature by forming the fibres into a helical configuration around the longitudinal axis of the pin. This helical shape creates a corrugated outer surface that mechanically interlocks with the composite laminate, preventing pull-through under high loads while maintaining ease of manufacture through a modified pultrusion process with a rotating die.
Solution Approach 2:
The patent transitions from a two-dimensional smooth surface to a three-dimensional corrugated surface by helically winding the fibres. This adds dimensional complexity to the pin's outer surface, creating anchoring features that significantly improve resistance to delamination without complicating the manufacturing process.
2Reliability
If fibres are twisted into a helical configuration to create a corrugated surface, then grip and resistance to delamination are enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent replaces complex post-manufacturing fibre twisting operations with an integrated helical fibre formation process during pultrusion. The rotating die automatically imparts the helical configuration to the fibres as they are pulled through, eliminating the need for separate twisting equipment and reducing overall device complexity.
Solution Approach 2:
The patent merges the fibre winding operation with the pultrusion manufacturing process. By integrating the helical fibre formation into the single-step pultrusion process using a rotating die, the invention combines what would otherwise be separate manufacturing operations, thereby reducing device complexity while achieving the desired corrugated surface.
3Reliability
If fibres are twisted helically during pultrusion, then the outer surface becomes corrugated providing better anchoring, but the cross-sectional shape of the pin becomes irregular
Solution Approach 1:
The patent applies local quality by creating helical corrugations only on the outer surface of the pin while maintaining a uniform cross-sectional shape in the core. The fibres are twisted into a helical configuration that provides surface anchoring features without compromising the overall geometric regularity of the pin's cross-section, ensuring consistent mechanical properties.
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 helical reinforcing pins significantly increase grip within the composite structure, effectively locking into place and reducing delamination propagation under severe out-of-plane loads, providing enhanced reinforcement compared to conventional smooth-surface pins.
Implementation Method 1
The fibres may define a corrugated outer surface to the reinforcing pin... The helical reinforcing pins significantly increase grip within the composite structure
Implementation Method 2
subsequently curing the matrix material to fix the helical configuration of the fibres... a curing process that allows the matrix to flow into the corrugations, enhancing grip
Data Source
Figure 1~3
Figure 4~5
Figure 6~8
AI summary
There is proposed a reinforcing pin (19) for reinforcing a laminated composite structure (22), the reinforcing pin (19) being formed from a plurality of fibres (5) in a polymeric matrix (9), each of the fibres (5) having the form of a helix extending along the length of the reinforcing pin (19). A related reinforced composite structure and a related method for producing the pin are also proposed.