Composite Panel Molding with Segmented Thermal Zones
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Solution Overview
Problem
Conventional methods for producing composite panel members with sandwich structures in aircraft and spacecraft often result in high residual stresses due to thermal expansion mismatches between components, and they are not energy efficient or economical.
Innovation Solution
A method involving a series of temperature-controlled stations for infusion, curing, and cooling of fiber-reinforced polymer layers, with pressure applied to maintain the foam core's volume constant, using a molding tool that transitions through an infusion station at 90-150°C, a curing station at 150-300°C, and a cooling station at 20-80°C, to minimize thermal expansion and reduce production time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional molding techniques (MVI, VARTM, VAP) with high-temperature resin infusion are used, then the panel member achieves composite material properties, but high residual stresses occur in the foam core due to thermal expansion mismatch
Solution Approach 1:
The process is divided into separate stations (infusion station, curing station, cooling station) with distinct temperature control zones, allowing different parts of the panel to experience appropriate temperatures at different times to minimize thermal stress
Solution Approach 2:
The patent implements controlled temperature parameters at each station, maintaining the foam core within a specific temperature range (100-200°C) during infusion and curing, and controlling the cooling rate to prevent excessive thermal expansion mismatch and residual stress accumulation
2Temperature
If the foam core is allowed to expand freely during heating, then the core accommodates thermal expansion, but volume change occurs leading to dimensional instability
Solution Approach 1:
The molding tool applies preliminary counteracting force to the foam core's thermal expansion tendency during heating, maintaining volume stability while allowing controlled thermal accommodation through the structured heating process at defined temperature ranges
Solution Approach 2:
The system dynamically adjusts the balance between allowing thermal expansion and maintaining volume stability by controlling the heating rate and temperature distribution across different stations, enabling the foam core to adapt to temperature changes while maintaining dimensional precision
3Productivity
If the molding tool is moved between multiple stations for infusion, curing, and cooling, then production efficiency is improved, but process complexity increases
Solution Approach 1:
The production process is segmented into distinct functional stations (infusion, curing, cooling) that can operate independently, allowing parallel processing and optimized workflow while maintaining overall process coordination through the molding tool's sequential movement
Solution Approach 2:
The molding tool is designed as a universal carrier that performs multiple functions across different stations, serving as both the infusion medium container, the curing substrate holder, and the cooling product support, thereby integrating multiple operations into a single versatile device
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
This approach significantly reduces residual stresses and enhances production efficiency by maintaining the foam core's volume, leading to a more energy-efficient and cost-effective method for producing composite panel members with reduced thermal expansion issues.
Implementation Method 1
the infusion station is heated to an infusion temperature, and infusing the one or more fiber reinforcement layer in the molding tool with a polymer resin
Implementation Method 2
the curing station is heated to a curing temperature, and curing the resin-infused fiber reinforcement layer(s) in the molding tool
Implementation Method 3
the cooling station is heated to or provided at a cooling temperature, and cooling the composite panel member in the molding tool, or in at least a part thereof, towards the cooling temperature
Implementation Method 4
with pressure applied to maintain the foam core's volume constant
Data Source
AI summary
A method of producing a composite panel member, especially a composite panel member having a foam core sandwich structure for an airframe of an aircraft or spacecraft, including: providing at least one fiber reinforcement layer in a panel molding tool; moving or transferring the molding tool to an infusion station that is pre-heated to an infusion temperature and infusing the fiber reinforcement layer in the molding tool with a polymer resin; moving or transferring the molding tool to a curing station that is pre-heated to a curing temperature and curing the at least one resin-infused fiber reinforcement layer in the molding tool to form a composite panel member; and moving or transferring the molding tool to a cooling station that is provided at a cooling temperature and cooling the composite panel member in the molding tool.