Laminated Structure Delamination Detection via DC Heater Current Imbalance
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Solution Overview
Problem
Delamination in laminated structures, particularly in composite materials used in vehicles like aircraft, is difficult to detect, especially with DC power systems, which can lead to catastrophic failures due to overheating from heater systems.
Innovation Solution
A method and apparatus using DC-powered heaters connected through a magnetically saturable transformer core to detect delamination by measuring current imbalances, utilizing sensors to monitor AC voltage or current changes indicative of delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If DC-powered heaters are used to heat the laminated structure, then energy efficiency and control precision are improved, but the ability to detect delamination is worsened
Solution Approach 1:
The patent introduces an AC signal as an intermediary carrier to detect delamination. The AC signal passes through the DC heater circuit, and any delamination-induced current imbalance modulates this AC signal. This intermediary AC signal enables detection capability without compromising the DC heating function, thus resolving the contradiction between energy-efficient DC heating and delamination detection.
2Power
If heaters are placed in direct contact with the laminated structure for efficient heating, then heating efficiency is improved, but the risk of overheating and delamination is worsened
Solution Approach 1:
The patent implements a feedback mechanism where the AC signal monitoring continuously detects current imbalances that indicate delamination. When delamination is detected, the system can provide feedback to reduce or shut off heater power, preventing overheating. This feedback loop enables efficient direct-contact heating while mitigating the overheating risk through real-time monitoring.
3Ease of manufacture
If the glue bonding layers is used to bond laminated layers, then manufacturing simplicity is improved, but susceptibility to delamination at low temperatures is worsened
Solution Approach 1:
The patent applies preliminary action by implementing delamination detection and warning systems before catastrophic failure occurs. The AC signal monitoring detects early-stage delamination through current imbalances, allowing preventive measures to be taken before the glue bonding fails completely. This preliminary detection compensates for the inherent vulnerability of glue-bonded structures to low-temperature delamination.
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
Enables early detection of delamination, allowing for preventive measures to avoid catastrophic failures by monitoring current imbalances and transformer core saturation.
Implementation Method 1
a magnetically saturable closed loop transformer core, the source and return wires carrying the DC current passing through the transformer core
Data Source
Figure 1~2
Figure 3
Figure 4a~4c
AI summary
We describe a way of detecting delamination of a laminated structure that is heated by DC powered heaters by passing the source and return wires that supply current to the heaters through a toroidal transformer core. Should there be a breakdown in the laminations, current flowing through the heater will flow into the structure, resulting in less current being present in the return wire than in the source wire. The current imbalance between the source and return wires causes the transformer core to saturate. Using the core saturation, caused by the DC current imbalance, the delamination (or imminent delamination) of the laminated structure can be detected.