Composite Spar and Skin Co-Curing for Precise Blade Assembly
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Solution Overview
Problem
The existing process for constructing composite assemblies, such as helicopter rotor blades, is costly and time-consuming, requiring separate curing and assembly steps for composite components, which demands high precision to avoid defects and ensure proper performance over the operational life.
Innovation Solution
A method that simultaneously cures the uncured composite spar and bonds the skin to it within a bonding tool, using an inflatable bladder to compact layers and reduce voids, while integrating spar keys and cores for structural support, allowing for a single curing cycle to achieve both curing and bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate curing and assembly steps are used for composite components, then manufacturing precision can be maintained, but the assembly process becomes costly and time-consuming
Solution Approach 1:
The patent combines the curing of the composite spar and the bonding of skin assemblies into a single integrated curing cycle. The bonding tool is configured to hold all components (uncured spar, skin assemblies, and bonding surfaces) in their final positions before a single curing operation, eliminating the need for separate curing and assembly steps while maintaining precision through fixed positioning fixtures and alignment features built into the bonding tool.
2Reliability
If high precision is demanded in assembly process, then defects can be minimized, but the process complexity increases
Solution Approach 1:
The patent implements preliminary positioning and alignment of all composite components within the bonding tool before the curing cycle begins. Fixtures, alignment features, and pre-positioning mechanisms are used to ensure that skin assemblies, spar, and bonding surfaces are correctly aligned and secured in their final positions. This preliminary action ensures proper placement and minimizes defects while simplifying the overall process by eliminating the need for complex post-assembly adjustments.
3Strength
If components are assembled before curing, then structural integrity can be ensured, but the curing process becomes more complex
Solution Approach 1:
The patent merges the assembly and curing operations into a single integrated process. All components are assembled within the bonding tool in their final configurations, and then the entire assembly undergoes one unified curing cycle. The bonding tool is designed to maintain precise component positions throughout the curing process, ensuring structural integrity is achieved without requiring complex multi-stage curing procedures.
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 method reduces the complexity and cost of the assembly process by integrating curing and bonding in a single step, enhancing precision and structural integrity of composite assemblies, thereby improving the efficiency and performance of composite blade construction.
Implementation Method 1
an inflatable bladder may be disposed within the uncured spar and expanded to help compact the layers of preformed composite material and remove any excess air bubbles or other voids
Implementation Method 2
performing a curing cycle on the composite assembly to simultaneously cure the uncured composite spar and bond the skin to the cured composite spar
Data Source
AI summary
A method of constructing a cured composite assembly includes positioning a composite assembly within a bonding tool, wherein the composite assembly comprises an uncured composite spar and a skin and performing a curing cycle on the composite assembly to simultaneously cure the uncured composite spar and bond the skin to the cured composite spar.