Composite Sandwich Panel With Heterogeneous Core For Weight Reduction
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Solution Overview
Problem
Conventional composite sandwich panels for rotary wing aircrafts are overweight due to excessive material margins for global buckling, leading to inefficiencies in mass and weight, and are not optimized for actual load conditions, resulting in suboptimal weight efficiency.
Innovation Solution
A composite sandwich panel design featuring a heterogeneous sandwich area with a nonuniform pattern, including a plateau and composite core-free interstices, which reduces the overall dimensions and weight by optimizing bending stiffness and distribution, allowing for tailored mechanical performance and reduced weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional composite sandwich panels are designed with minimum sandwich configuration to ensure robustness and buckling resistance, then structural stability is improved, but weight increases due to excessive material margins
Solution Approach 1:
The patent applies local quality by transitioning from a uniform sandwich structure to a non-uniform pattern with varying core thickness. The sandwich core thickness t_sandwich(z) is optimized locally across different zones, allowing thinner cores in low-stress areas while maintaining adequate thickness in high-stress regions, thereby reducing overall weight while preserving buckling resistance where needed.
Solution Approach 2:
The patent employs parameter changes by optimizing the sandwich core thickness distribution as a continuous function t_sandwich(z) rather than using a constant minimum thickness. This allows the structural parameters to be tailored to the actual stress distribution, eliminating excessive material margins and achieving weight reduction of approximately 17% while maintaining stability.
2Ease of manufacture
If uniform sandwich configuration is used across the entire panel, then manufacturing simplicity is improved, but weight efficiency deteriorates due to over-engineering in low-stress areas
Solution Approach 1:
The patent implements local quality by defining different sandwich core thickness zones based on local stress requirements. The non-uniform thickness distribution t_sandwich(z) allows the structure to have varying properties across different locations, optimizing weight efficiency while maintaining manufacturability through a systematic zonal approach.
3Stability of the object's composition
If monolithic sandwich structure is used, then structural continuity is improved, but weight increases and debonding failure impact is amplified
Solution Approach 1:
The patent applies segmentation by dividing the monolithic sandwich structure into multiple zones with different core thicknesses. This zonal segmentation allows independent optimization of each region's weight and stiffness characteristics, reducing overall weight while maintaining structural continuity through the controlled thickness transitions.
4Reliability
If minimum sandwich configuration is used to meet robustness requirements, then structural safety is improved, but mass efficiency deteriorates
Solution Approach 1:
The patent uses parameter changes by optimizing the sandwich core thickness as a spatially varying function t_sandwich(z) rather than using a uniform minimum thickness. This allows the material quantity to be precisely matched to the actual structural requirements at each location, improving mass efficiency while maintaining structural safety through adequate thickness in critical zones.
Data Source
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AI summary
The invention is related to a composite sandwich panel 6 with a sandwich area 14 which is heterogenous and comprises: a plateau 15 that merges via a predetermined number of ramps 16 into a predefined number of composite core-free interstices 17, wherein the plateau 15 and the predefined number of composite core-free interstices 17 define a nonuniform pattern 24 in which the predefined number of composite core-free interstices 17 comprises a first bending stiffness, and at least one brace 20 that is provided adjacent to at least one of the predefined number of composite core-free interstices 17 by means of the plateau 15, the at least one brace 20 comprising a second bending stiffness, wherein the first bending stiffness is smaller than the second bending stiffness.