Honeycomb Sandwich Panel Thermal Expansion Control
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Solution Overview
Problem
Honeycomb sandwich panels used in optical devices for aerospace and astronomical applications face challenges with high thermal expansion coefficients, which can cause deformation and affect precision, especially in space environments where temperature changes are significant.
Innovation Solution
A honeycomb sandwich panel design featuring a core made of carbon fiber reinforced plastic (CFRP) and skins made of a low expansion metal, such as Invar, with a hexagonal tubular cell structure to minimize thermal expansion, allowing for precise thermal management and reduced deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a honeycomb sandwich panel is made of CFRP to achieve lightweight and high stiffness, then weight is reduced and stiffness is improved, but the thermal expansion coefficient remains too high for precise optical applications in space
Solution Approach 1:
The patent uses a composite structure combining CFRP core with low expansion metal skins (Invar or Kovar). The CFRP core provides lightweight and high stiffness properties, while the low expansion metal skins reduce the overall thermal expansion coefficient. This composite approach allows simultaneous achievement of weight reduction and thermal stability for space optical applications.
2Reliability
If the thermal expansion coefficient is reduced to maintain precision in space, then reliability is improved, but manufacturing complexity increases due to material selection and bonding requirements
Solution Approach 1:
The patent applies different materials to different parts of the sandwich panel structure. The core uses CFRP for lightweight and stiffness, while the skins use low expansion metals for thermal stability. This local differentiation of material properties allows optimization of each component's function while managing overall manufacturing complexity through specialized skin-core bonding processes.
3Reliability
If low expansion metal skins are used to reduce thermal expansion, then thermal stability is improved, but weight increases compared to all-CFRP panels
Solution Approach 1:
The patent creates a weight-optimized composite structure where thin low expansion metal skins are bonded to a CFRP core. The skin thickness is minimized while maintaining thermal stability, allowing the lightweight CFRP core to contribute to overall weight reduction. This composite configuration achieves thermal stability with minimal weight penalty compared to using low expansion metal throughout.
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 solution achieves a lower thermal expansion coefficient than traditional CFRP panels, reducing deformation and maintaining precision in optical devices, especially in space environments, while also simplifying the manufacturing process and reducing costs.
Implementation Method 1
a first skin (21) being a plate material made of a low expansion metal, the low expansion metal being a metal having an absolute value of thermal expansion coefficient smaller than an absolute value of thermal expansion coefficient of carbon fiber reinforced plastic
Data Source
AI summary
A honeycomb sandwich panel having an absolute value of thermal expansion coefficient smaller than an absolute value of thermal expansion coefficient obtained by using carbon fiber reinforced plastic (CFRP) is provided. The honeycomb sandwich panel includes: a first skin being a plate material made of a low expansion metal being a metal having an absolute value of thermal expansion coefficient smaller than an absolute value of thermal expansion coefficient of CFRP; a second skin being a plate material made of the low expansion metal and arranged to face the first skin; and a core made of CFRP or the low expansion metal, being bonded to the first skin and the second skin and including a plurality of tubular cells each having a hexagonal cross section, the tubular cells being formed adjacently to each other.