Selective Needling of Fibrous Preforms for Stress-Controlled Shaping
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Solution Overview
Problem
Existing methods for producing fiber-reinforced composites struggle to effectively manage in-plane and interlaminar stresses, which vary across the composite structure, leading to issues like fiber sliding, wrinkling, and breakage during shaping processes.
Innovation Solution
A method for selective needling of fibrous preforms is introduced, where regions of high interlaminar stress are identified and needled at varying densities and angles to enhance interlaminar strength, while leaving other regions unneedled to allow flexibility and reduce fiber sliding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If through thickness reinforcement needling is performed uniformly across the entire fibrous preform, then interlaminar strength is improved, but fiber sliding and wrinkling occur in regions where it is not needed
Solution Approach 1:
The patent applies selective needling where only specific zones of the fibrous preform undergo through thickness reinforcement. The system identifies regions requiring enhanced interlaminar strength and applies needling locally to those areas, while leaving other regions unneedled to maintain flexibility and prevent fiber sliding and wrinkling during shaping.
Solution Approach 2:
The fibrous preform is divided into multiple zones based on their structural requirements. The needling process is segmented to apply different treatments to different zones - some zones receive through thickness reinforcement while others remain unneedled, allowing each region to be optimized for its specific functional requirements.
2Ease of manufacture
If needle angle is kept constant during needling, then process simplicity is maintained, but formability and damage reduction during shaping are not optimized
Solution Approach 1:
The patent implements variable needle angle needling where the needle angle is dynamically adjusted based on the specific zone being treated and the desired shaping requirements. The system modifies needle orientation in different regions to optimize fiber alignment and minimize damage during subsequent shaping operations, rather than using a fixed constant angle throughout.
Solution Approach 2:
The needling parameters, specifically needle angle, are changed according to the spatial location and structural requirements of different zones. By varying the needle angle parameter across different regions of the preform, the process optimizes both formability and damage reduction while maintaining controlled manufacturing complexity through systematic parameter adjustment.
Data Source
Figure 1A~1B
Figure 2A~3A
Figure 2B~3B
AI summary
A method for selective needling on a fibrous preform (110) includes performing a through thickness reinforcement process on the fibrous preform and varying a needle density, a needle angle, and/or a needle penetrating depth during the through thickness reinforcement process such that a first needle density, a first needle angle, and/or a first needle penetrating depth of a first zone of the fibrous preform is greater than a second needle density, a second needle angle, and/or a second needle penetrating depth of a second zone of the fibrous preform. The method can further include identifying expected interlaminar stress (250) throughout the fibrous preform and varying the needle density, needle angle, and/or needle penetrating depth in accordance with a magnitude of the expected interlaminar stress.