Stream Function Design for Curved Composite Fiber Paths
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Solution Overview
Problem
Current methods for designing composite laminates with steered fibers face challenges in managing large design spaces while ensuring manufacturability, often resulting in unmanufacturable designs or computationally expensive processes, which limits the efficiency and weight reduction potential of variable-stiffness composites.
Innovation Solution
A computational optimization process that uses finite element-based analysis and geometry optimization to determine steered fiber angles and stream functions, guiding the design to meet performance targets and manufacturing constraints, thereby expanding the design space and facilitating weight reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fiber angle distributions are represented directly (e.g., as Bezier surfaces), then the design space is simple and easy to define, but computing the thickness build-up becomes expensive and may result in unmanufacturable designs
Solution Approach 1:
The patent introduces stream functions as an intermediary mathematical tool to represent fiber angle distributions. Instead of directly representing complex angle distributions with Bezier surfaces, the stream function serves as a mediator that simplifies the representation while enabling efficient computation of thickness build-up and curvature constraints. This intermediary approach resolves the contradiction by providing both design flexibility and computational efficiency.
Solution Approach 2:
The patent changes the parameterization approach from direct fiber angle distribution representation to stream function-based representation. By transforming the design parameters into stream function form, the methodology achieves simpler design space exploration while maintaining the ability to compute thickness build-up and enforce manufacturing constraints efficiently.
2Strength
If multiple plies with different fiber angle distributions are designed to meet performance requirements, then structural performance is optimized, but the computational cost and design complexity increase significantly
Solution Approach 1:
The patent segments the laminate structure into multiple plies, each with optimized fiber angle distributions designed independently using stream functions. This segmentation allows each ply to be optimized for specific loading conditions while maintaining overall structural performance, reducing the complexity of designing the entire multi-ply structure as a single integrated system.
Solution Approach 2:
The patent applies local quality optimization by designing each ply with fiber angle distributions tailored to specific regional requirements and loading conditions. Instead of using uniform fiber orientations throughout the laminate, the methodology optimizes local fiber angles in each ply to meet specific performance requirements, achieving overall structural optimization through localized design decisions.
3Ease of manufacture
If conventional straight fiber designs are used, then manufacturing is simple and constraints are easily met, but weight reduction and structural efficiency are limited
Solution Approach 1:
The patent introduces curved fiber paths through stream function-based design, allowing fibers to follow curved trajectories rather than straight lines. This curvature enables optimized load paths and stress distribution that reduce structural weight while maintaining manufacturability through controlled curvature constraints. The stream function approach provides a systematic way to design these curved paths without compromising manufacturing feasibility.
Data Source
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AI summary
A computational optimization process uses the variable stiffness performance of composite laminates attributed to steered fiber to guide the design of stream functions describing the fibers to build it. This design process combines a finite element-based analysis tool, failure criteria and geometry optimization to determine steered angles associated with stream functions by an optimization program to meet target performance requirements, e.g., load condition(s), and failure criteria for quasi-static or dynamic events. The fiber angle distribution and thickness buildup are computed based on the stream function. The simulated structure is analyzed using finite element analysis. The disclosed process allows the designer to impose manufacturing constraints such as fiber steering radius.