In-situ Pressure Enhanced Composite Processing
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Solution Overview
Problem
Existing composite material production processes, such as Vacuum-assisted Resin Transfer Molding (VaRTM), struggle to consistently achieve high fiber volume and low porosity required for aerospace applications, while pre-impregnated materials face storage, handling, and cost issues.
Innovation Solution
A method involving securing dry reinforcement plies over a form, infusing resin under vacuum, consolidating and curing under pressure to increase fiber volume and reduce porosity, allowing for a broader material selection and lower costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Vacuum-assisted Resin Transfer Molding (VaRTM) is used to produce composite articles, then the process control complexity increases, but the fiber volume and porosity consistency improves
Solution Approach 1:
The process is divided into distinct stages: initial vacuum infusion followed by pressure enhancement stage. This segmentation allows each stage to be optimized independently, achieving high fiber volume without requiring complex continuous control throughout the entire process.
Solution Approach 2:
The method changes the pressure parameter from constant vacuum to variable pressure (switching from vacuum to positive pressure). This parameter change enables achieving high fiber volume and low porosity without requiring extraordinary process control, as the pressure enhancement automatically drives resin redistribution.
2Manufacturing precision
If pre-impregnated materials are used, then fiber volume can be maintained, but storage, handling, and cost issues arise
Solution Approach 1:
The reinforcement plies are prepared in advance as dry stacks without requiring pre-impregnation. This preliminary preparation eliminates the need for costly and complex pre-impregnated materials while still achieving high fiber volume through the subsequent pressure enhancement process.
Solution Approach 2:
The method uses simple, inexpensive dry reinforcement plies and resin instead of expensive pre-impregnated materials. The process achieves comparable or superior results without the storage and handling constraints of prepregs, effectively replacing expensive materials with cheaper alternatives.
3Manufacturing precision
If pressure enhancement is applied during curing, then fiber volume increases to at least 60%, but additional equipment is required
Solution Approach 1:
The pressure enhancement system can serve multiple functions: it consolidates the composite during curing, removes voids, and achieves high fiber volume. This multi-functionality reduces the need for separate equipment for each operation, making the additional equipment investment more justifiable.
Solution Approach 2:
The pressure enhancement stage is combined with the curing process, allowing both consolidation and thermal curing to occur simultaneously. This merging of operations reduces total process time and eliminates the need for separate consolidation and curing equipment.
4Manufacturing precision
If traditional VaRTM is used, then equipment simplicity is maintained, but porosity reduction below 2% is difficult to achieve
Solution Approach 1:
The process uses periodic pressure changes (vacuum phase followed by pressure enhancement phase) to achieve superior porosity reduction. This periodic action allows resin to be drawn into the plies during vacuum and then redistributed to eliminate voids during pressure enhancement, achieving porosity below 2%.
Solution Approach 2:
The method changes the pressure parameter from constant vacuum to variable pressure cycling. This parameter change enables automatic void elimination through pressure-driven resin redistribution, achieving low porosity without requiring extraordinary continuous process control.
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 effectively increases fiber volume to at least 60% and reduces porosity to less than 2%, addressing the limitations of traditional VaRTM and pre-impregnated materials, while enabling flexibility and cost-effectiveness in composite production.
Implementation Method 1
infusing resin under vacuum
Implementation Method 2
consolidating and curing under pressure
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
A method for making a composite article comprises securing a layup over a form. The layup including a plurality of dry intermediate reinforcement plies wrapped around an inner reinforcement ply. Resin is infused into the layup under vacuum. The resin-infused layup is consolidated under pressure and cured.