Corrugated Sandwich Panel Core for Thermal Gradient Relief
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Solution Overview
Problem
Existing sandwich panels for aircraft turbojet nacelles face mechanical stress issues due to thermal gradients, which can lead to material failure, particularly when using lighter materials like ceramics, and existing solutions either increase mass or compromise acoustic performance.
Innovation Solution
Incorporating an inner skin with undulations, such as curvatures and shears, to allow for deformation during thermal variations, reducing mechanical stresses without increasing mass or compromising acoustic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional foam core materials are used in sandwich panels, then the panels achieve lightweight construction, but the core materials lack structural strength and dimensional stability
Solution Approach 1:
The foam core material undergoes parameter changes by incorporating expandable microcapsules that transform from a compact state to an expanded state, changing the density, volume, and mechanical properties of the core material to simultaneously achieve lightweight construction and enhanced structural strength
Solution Approach 2:
The invention creates a composite core material by combining conventional foam with expandable microcapsules, achieving a synergistic effect where the foam provides lightweight construction and the microcapsules provide structural reinforcement and dimensional stability when activated
2Weight of moving object
If conventional foam core materials are used in sandwich panels, then the panels achieve lightweight construction, but the core materials exhibit poor dimensional stability
Solution Approach 1:
The foam core material undergoes parameter changes by incorporating expandable microcapsules that transform from a compact state to an expanded state, changing the density, volume, and mechanical properties of the core material to simultaneously achieve lightweight construction and enhanced structural strength
Solution Approach 2:
The invention creates a composite core material by combining conventional foam with expandable microcapsules, achieving a synergistic effect where the foam provides lightweight construction and the microcapsules provide structural reinforcement and dimensional stability when activated
3Strength
If traditional core materials are used in sandwich panels, then the panels achieve structural integrity, but the overall weight increases
Solution Approach 1:
The core material is segmented into a composite structure consisting of a foam matrix and dispersed expandable microcapsules, allowing the lightweight foam to provide the primary structure while the microcapsules provide localized reinforcement without significant weight penalty
Solution Approach 2:
The invention creates a composite core material by combining conventional foam with expandable microcapsules, achieving a synergistic effect where the foam provides lightweight construction and the microcapsules provide structural reinforcement and dimensional stability when activated
4Ease of manufacture
If sandwich panels use standard core materials, then manufacturing is straightforward, but the panels lack adaptability to different performance requirements
Solution Approach 1:
The core material incorporates dynamically activatable expandable microcapsules that can transform from an inactive compact state to an active expanded state, allowing the panel properties to be changed on-demand to adapt to different performance requirements while maintaining ease of manufacture
Solution Approach 2:
The foam core material undergoes parameter changes by incorporating expandable microcapsules that transform from a compact state to an expanded state, changing the density, volume, and mechanical properties of the core material to simultaneously achieve lightweight construction and enhanced structural strength
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The undulating inner skin design effectively mitigates mechanical stresses caused by thermal gradients, enabling the use of lighter materials while maintaining structural integrity and acoustic functionality.
Implementation Method 1
an expandable agent is mixed with a foam core material to form a mixed core material, and the mixed core material is placed in a sandwich panel
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a sandwich panel (10) for an aircraft turbojet nacelle (100), comprising: - a skin, termed outer skin (14, 141), intended to be contact with an air flow, - a skin, termed inner skin (12, 120, 121, 122, 123), opposed to the outer skin (14, 141), - an intermediate system (15) comprising partitions (16, 161) connecting the inner (12, 120, 121, 122, 123) and outer (14, 141) skins so as to form cells (18, 180, 181, 182, 183), the inner skin (12, 120, 121, 122, 123) of at least one cell (18, 180, 181, 182, 183) having at least one corrugation intended to allow the materials making up the sandwich panel to deform in the event of thermal variation.