Asymmetric Composite Laminates for Tapering and Crack Resistance
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Solution Overview
Problem
Conventional composite laminated structures are constrained by symmetry and balance requirements, leading to inefficiencies such as excessive material usage, complexity in tapering, and micro-cracking, which limits their suitability for applications requiring minimal stress differential between first and last ply failure.
Innovation Solution
The development of asymmetric and unbalanced laminated structures using sub-laminate modules with acute angles less than 90°, allowing for non-crimped configurations and reduced ply orientations, which facilitates easier manufacturing and improved homogenization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If symmetric and balanced laminate structures are used, then structural stability and resistance to warping are improved, but material usage increases and manufacturing complexity increases
Solution Approach 1:
The patent applies asymmetry by using unbalanced laminate structures with non-mirror-image ply orientations. Specifically, the laminate includes plies with different orientations (e.g., 0°, ±45°, 90°) that are not symmetrically arranged about the mid-plane, eliminating the need for excessive material while maintaining structural integrity through optimized fiber distribution.
2Stability of the object's composition
If symmetric and balanced laminate structures are used, then structural stability is improved, but device complexity increases
Solution Approach 1:
The patent eliminates symmetry requirements by designing unbalanced laminates where plies are arranged according to performance needs rather than mirror-image constraints. This reduces manufacturing complexity by removing the need for precise symmetric stacking sequences while maintaining structural stability through optimized ply orientations.
Solution Approach 2:
The patent applies local quality by varying ply orientations and thicknesses at different locations within the laminate to optimize local stress distribution and structural performance. This allows tailored fiber reinforcement in high-stress areas without requiring symmetric arrangements throughout the entire structure.
3Ease of manufacture
If conventional laminate structures are used, then manufacturing process is standardized, but micro-cracking occurs reducing reliability
Solution Approach 1:
The patent changes the structural parameters by using unbalanced ply orientations and non-traditional stacking sequences. This alters the stress distribution pattern within the laminate, reducing stress concentrations that lead to micro-cracking while maintaining manufacturability through adapted curing processes.
4Strength
If symmetric laminate structures are used, then structural integrity is maintained, but tapering capability is reduced
Solution Approach 1:
The patent enables tapering by using asymmetric laminate structures where plies can be selectively dropped or varied in thickness at different locations without compromising overall structural integrity. The unbalanced design allows gradual transitions in cross-section while maintaining optimized fiber reinforcement patterns.
Solution Approach 2:
The patent applies local quality by varying ply orientations and thicknesses at different locations within the laminate to optimize local stress distribution and structural performance. This allows tailored fiber reinforcement in high-stress areas without requiring symmetric arrangements throughout the entire structure.
Data Source
AI summary
Variously configured sub-laminate modules are provided, which comprise at least a first ply and a second ply, the first ply comprising fibers extending in a first orientation, the second ply comprising fibers extending in a second orientation. The second orientation is offset relative to the first orientation, which offset defines an acute angle between the two orientations. The acute angle is less than 90 degrees and in at least one embodiment, the acute angle is approximately 25°. In certain embodiments, the acute angle further defines an unbalanced structure of the sub-laminate module. In certain embodiments, the first and second plies may be further secured relative to one another in a non-crimped configuration. Composite laminated structures formed from various embodiments of the sub-laminate modules are also provided, at least some of which may be homogenized. Various methods of manufacturing the sub-laminate modules and the composite laminated structures are also provided.