Rescue Bladder Sealing for Composite Part Curing Leaks
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Solution Overview
Problem
Leaks in internal bladders of composite parts during the curing process, particularly in the aircraft industry, can go undetected until it's too late, leading to defects in the composite material due to high pressure and heat, and are difficult to repair once the composite material reaches a critical cure stage.
Innovation Solution
A rescue bladder is placed within the internal bladder, sealed with an impermeable membrane and rigid forming tool, allowing it to inflate and press against the composite part to seal any leaks, with optional additional support from a stiffener and vent openings for pressure differential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cure cycle continues under high pressure and heat, then the composite material cures properly, but leaks in the bladder develop and cause defects
Solution Approach 1:
The patent applies preliminary action by implementing a leak detection and repair system before the cure cycle reaches critical temperatures. The process includes pre-cure leak detection using pressure testing, and if leaks are detected, the system automatically initiates repair procedures by injecting sealant or replacing the bladder before the composite material cures, thereby preventing leaks from developing into defects during curing.
Solution Approach 2:
The patent applies beforehand cushioning by incorporating a backup bladder system and emergency repair mechanisms. If a leak is detected during the cure cycle, the system can inject additional pressure to temporarily seal the leak or deploy a backup bladder to maintain the necessary pressure differential, cushioning against the harmful effects of leaks until the cure cycle can be safely aborted or repaired.
2Ease of repair
If the cure cycle is aborted to repair leaks, then leaks can be fixed, but the curing process is interrupted and productivity decreases
Solution Approach 1:
The patent applies preliminary action by performing comprehensive leak detection before the cure cycle begins and during early stages before critical temperatures are reached. This allows leaks to be identified and repaired during planned maintenance windows rather than requiring emergency interruptions, thereby maintaining productivity while ensuring repair capability.
Solution Approach 2:
The patent applies mechanics substitution by replacing manual leak detection and repair operations with automated sensing and actuation systems. Sensors continuously monitor for leaks, and automated systems can inject sealant or adjust pressure without requiring operators to open the autoclave and manually inspect or repair the bladder, thus maintaining ease of repair while minimizing interruptions to the cure cycle and preserving productivity.
3Manufacturing precision
If composite material reaches critical cure stage, then proper curing is achieved, but leak detection and repair become difficult or impossible
Solution Approach 1:
The patent applies preliminary action by implementing a staged cure process with multiple detection points. Before the composite material reaches the critical cure stage, the system performs intermediate leak detections at lower temperatures when the material is still pliable and accessible. This allows leaks to be detected and repaired while the material remains workable, avoiding the impossibility of repair that occurs after critical curing is achieved.
Solution Approach 2:
The patent applies feedback by implementing continuous monitoring systems that track both the cure progress and potential leaks throughout the entire process. Sensors provide real-time feedback on pressure differentials, temperature profiles, and potential leak locations, allowing the system to adjust the cure cycle dynamically. This feedback mechanism enables early warning of leaks before they become undetectable after critical curing, maintaining both manufacturing precision and leak detectability.
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 seals leaks in internal bladders during the curing process, preventing defects in composite parts by allowing for leak detection and repair before reaching critical cure temperatures, ensuring the composite material is properly formed and cured.
Implementation Method 1
A pressure differential between atmosphere within the chamber and atmosphere outward of the chamber during the curing step may cause the rescue bladder to inflate and press the internal bladder against an inner surface of the hollow uncured composite part
Data Source
AI summary
A system and method of a method of sealing a leak in an internal bladder within a hollow uncured composite part during cure thereof. The method may include placing a rescue bladder within the internal bladder and sealing an impermeable membrane and/or rigid forming tool to the rescue bladder, such that the uncured composite part is sealed within a chamber cooperatively formed by the impermeable membrane, the rigid forming tool, and the outer surface of the rescue bladder. A vent opening of the rescue bladder and/or a vent opening of the end fitting may remain located outward of the chamber. The method may also include curing the hollow uncured composite part, introducing a pressure differential causing the rescue bladder to inflate and press the internal bladder against an inner surface of the hollow uncured composite part.