Tape-shaped prepreg uniform fiber dispersion
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Solution Overview
Problem
Existing tape-shaped prepregs face challenges in achieving a balance between formability, mechanical properties, and uniformity of fiber-reinforced molded objects, as reducing average thickness to improve formability leads to decreased fiber content and orientation quality, while increasing fiber content can result in aggregation and decreased dispersion.
Innovation Solution
A tape-shaped prepreg with an average thickness of 50 µm to 150 µm and a fiber content percentage of 30 vol% to 60 vol%, characterized by a fractal dimension of 0.4 to 1.5 and a degree of orientation of 0.8 to 1.0, ensuring uniform fiber dispersion and orientation, thereby enhancing both formability and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the average thickness of the tape-shaped prepreg is reduced to improve formability, then the formability is improved, but the fiber content decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the average thickness within 50-150 μm and fiber content within 30-60 vol%, along with controlling the fractal dimension and degree of orientation parameters, to achieve optimal balance between formability and mechanical properties without fiber aggregation
Solution Approach 2:
The patent introduces the fractal dimension D as a new dimensional parameter to characterize fiber dispersion, moving beyond traditional single-parameter control. By controlling the fractal dimension of the coefficient of variation, the patent achieves uniform fiber distribution in three-dimensional space while maintaining high fiber content
2Strength
If the content percentage of fibers is increased to improve mechanical properties, then the mechanical properties are improved, but the degree of dispersion and orientation of fibers decrease due to aggregation
Solution Approach 1:
The patent simultaneously controls multiple parameters including fiber content (30-60 vol%), average thickness (50-150 μm), fractal dimension D (0.4-1.5), and degree of orientation P (0.8-1.0) to achieve uniform fiber dispersion without aggregation, resolving the contradiction between high fiber content and good dispersion
Solution Approach 2:
The patent creates a composite structure with optimized fiber-resin distribution by controlling the fractal dimension parameter, achieving uniform dispersion of high fiber content throughout the matrix material, preventing aggregation while maintaining mechanical properties
3Strength
If the content percentage of fibers is increased to improve mechanical properties, then the mechanical properties are improved, but the uniformity of product quality decreases
Solution Approach 1:
The patent controls the fractal dimension D of the coefficient of variation within 0.4-1.5 to ensure uniform fiber distribution, which directly improves product quality uniformity while maintaining high fiber content for mechanical properties
Solution Approach 2:
The patent uses the fractal dimension and degree of orientation as feedback parameters to monitor and control fiber dispersion quality, enabling consistent production of uniform product quality across batches
Data Source
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AI summary
An aspect of the present invention is a tape-shaped prepreg which includes a plurality of unidirectionally oriented fibers and a binder infiltrated into these fibers. The tape-shaped prepreg is characterized by having an average thickness of 50 µm to 150 µm and a content percentage of these fibers of 30 vol% to 60 vol%. The prepreg is further characterized in that: when a cross-sectional image perpendicular to the orientation direction of these fibers is equally divided into n sections (n is an integer of 2 or larger) along each of the lengthwise and crosswise directions and a coefficient of variation Cv(n) is determined from the areal proportion a of fibers in each of the regions formed by the division, then the coefficient of variation Cv(n) has a fractal dimension D of 0.4 to 1.5; and a degree of orientation P, expressed by the following equation (1) determined from an approximate ellipse of a power-spectrum image obtained by the Fourier transform of a cross-sectional image parallel to the orientation direction of these fibers, is 0.8 or greater and less than 1.0. Degree of orientation P = 1 - ((minor-axis length of approximate ellipse)/(major-axis length thereof)) ····(1).