Square Symmetric Double-Double Laminate Structures
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Solution Overview
Problem
Conventional composite laminate structures face limitations due to their discrete nature, requiring thick sub-laminates for mid-plane symmetry, leading to inefficiencies in thickness, material characteristics, and manufacturing complexities, particularly in achieving desirable stiffness and strength characteristics.
Innovation Solution
The development of square symmetric double-double laminate structures allows for continuous fields of ply angle and layer configurations, enabling thinner sub-laminates with constant thickness, improved stiffness, and reduced failure modes, while maintaining natural mid-plane symmetry and enabling automated layup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional legacy quad laminates are used with mid-plane symmetry, then structural strength is improved, but laminate thickness increases significantly and manufacturing complexity increases
Solution Approach 1:
The patent applies asymmetry by eliminating the mid-plane symmetry requirement from conventional laminates. The new asymmetric laminate structure allows plies to be arranged without mirror-image constraints, enabling thinner overall thickness while maintaining structural strength through optimized ply stacking sequences that do not require doubling of ply counts for symmetry.
Solution Approach 2:
The patent changes the parameter of laminate symmetry from symmetric to asymmetric configuration. This parameter change enables continuous variation in ply angles and thicknesses, allowing optimization of strength-to-thickness ratios and eliminating the discrete thickness jumps inherent in symmetric laminate designs.
2Strength
If thick sub-laminates are added to achieve desired laminate thickness, then laminate strength is improved, but manufacturing complexity increases and delamination risk increases
Solution Approach 1:
The patent segments the laminate into thin individual plies rather than thick sub-laminates. This segmentation allows for gradual buildup of thickness through multiple thin layers, reducing delamination risks at interfaces and simplifying manufacturing by eliminating the need to blend or drop thick sub-laminate sections.
Solution Approach 2:
The patent converts the potential harm of multiple ply interfaces (which could lead to delamination) into a benefit by using many thin plies with optimized stacking sequences. The increased number of interfaces is managed through asymmetric design that distributes stresses more evenly, turning what could be weakness points into strength enhancement opportunities.
3Ease of manufacture
If conventional discrete ply configurations are used, then manufacturing is simplified, but optimization of material characteristics becomes practically impossible
Solution Approach 1:
The patent introduces dynamics by enabling continuous adjustment of ply angles and thicknesses in asymmetric configurations. Unlike discrete conventional laminates, the asymmetric design allows dynamic optimization of material characteristics for specific loading conditions, while automated manufacturing processes maintain ease of production through programmed ply placement.
Solution Approach 2:
The patent creates a universal laminate structure that can be adapted to multiple function requirements through asymmetric ply stacking. The same basic asymmetric framework can be optimized for different strength-to-weight ratios, stiffness requirements, and loading scenarios, making the manufacturing process multi-functional rather than requiring different discrete configurations for each application.
4Stability of the object's composition
If mid-plane symmetry is required for conventional laminates, then structural stability is improved, but laminate thickness doubles and design flexibility is reduced
Solution Approach 1:
The patent directly applies asymmetry by eliminating mid-plane symmetry requirements. The asymmetric laminate achieves structural stability through optimized ply stacking sequences that do not rely on mirror-image arrangements, allowing thickness to be determined by performance requirements rather than symmetry constraints, thus avoiding the doubling of thickness.
5Length of stationary object
If arbitrarily added plies are used to mitigate thickness jumps, then laminate thickness control is improved, but optimization becomes practically impossible and failure modes increase
Solution Approach 1:
The patent changes the approach to thickness control by using continuous asymmetric ply stacking rather than arbitrarily adding plies to conventional symmetric designs. This parameter change allows precise control of laminate thickness while maintaining optimized stress distributions that reduce failure modes, as each ply's orientation and position can be specifically tailored to the loading conditions.
Data Source
AI summary
Square symmetric composite laminate structures, and sub-modules thereof, are provided, along with methods of forming the same. The square symmetric laminate structures include two or more sub-laminate modules, each comprising: a first ply set consisting of a first ply layer oriented at a first angle and a second ply layer oriented at a second angle, a first sum of the first and second angles being ninety degrees; and a second ply set consisting of a third ply layer oriented at a third angle and a fourth ply layer oriented at a fourth angle, a second sum of the third and fourth angles being ninety degrees; wherein the second ply layer is positioned adjacent the third ply layer and the second and third ply layers are both positioned intermediate the first and fourth ply layers, thereby defining a double-double helix arrangement of the respective ply layers. Associated methods are also provided.