Compliant Layer for Conformal Electronic Device Adhesion
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Solution Overview
Problem
Existing methods for measuring operating conditions in gas turbine engines using external sensors are obstructive and fail to adhere properly to ceramic-based or high-temperature materials, leading to premature detachment and skewed measurements due to thermal and mechanical stresses.
Innovation Solution
An instrumented article with a conformal electronic device deposited on a ceramic-based substrate, featuring a compliant layer that mitigates thermo-mechanical forces and enhances adherence by matching thermal expansion and providing a chemical/reactivity barrier, along with conformal lead wires extending to a cold surface zone for reliable data collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external sensors are attached to the article, then measurements of operating conditions can be obtained, but the sensors are obtrusive and influence the performance of the article
Solution Approach 1:
The sensor is merged with the substrate to form an integrated structure where the sensor becomes part of the article itself. This is achieved by depositing the sensor directly onto the substrate surface, eliminating the need for separate external sensor attachments and thereby avoiding performance interference while maintaining measurement capability.
Solution Approach 2:
The sensor is nested within the overall article structure by being deposited on the substrate surface, making the sensor an integral component rather than an external attachment. This nesting approach allows the sensor to be embedded in the article's architecture, reducing its obtrusiveness while preserving measurement function.
2Measurement precision
If external sensors are attached to the article, then measurements can be obtained, but the sensors are difficult to affix at the desired location
Solution Approach 1:
The sensor is deposited onto the substrate surface during the manufacturing process itself, before the article is completed. This preliminary action integrates sensor attachment into the base manufacturing workflow, eliminating separate attachment steps and making the process easier to execute at desired locations.
Solution Approach 2:
The mechanical attachment process is replaced by a deposition process where the sensor is directly deposited onto the substrate surface. This substitution eliminates the need for mechanical fastening, bonding, or other complex attachment methods, thereby simplifying the manufacturing process.
3Reliability
If conformal electronic device is deposited directly on ceramic-based substrate, then adherence is achieved, but thermal and mechanical stresses cause premature detachment
Solution Approach 1:
An intermediary layer is introduced between the conformal electronic device and the ceramic-based substrate. This intermediate layer acts as a buffer that accommodates thermal and mechanical stresses, preventing direct stress transmission that would cause detachment while maintaining the adhesive bond between the device and substrate.
Solution Approach 2:
The structure is designed as a composite system with multiple layers having different material properties. The combination of the conformal electronic device, intermediary layer, and ceramic substrate creates a composite structure that leverages the advantageous properties of each material to resist thermal and mechanical stresses while maintaining adherence.
4Adaptability or versatility
If conformal electronic device is deposited on ceramic-based substrate, then integration is achieved, but thermal expansion differences cause stress and detachment
Solution Approach 1:
An intermediary layer is positioned between the conformal electronic device and the ceramic substrate to mediate the thermal expansion mismatch. This intermediate layer has thermal expansion properties that are intermediate between the device and substrate, thereby reducing the differential stress caused by thermal expansion differences and preventing detachment.
Solution Approach 2:
The thermal expansion parameters of the layered structure are optimized to reduce stress. By selecting materials with appropriate thermal expansion coefficients for each layer, particularly the intermediary layer, the overall thermal expansion stress in the integrated structure is minimized, allowing the device to remain attached under thermal cycling conditions.
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
The solution ensures stable and accurate measurement of operating conditions by preventing premature detachment and maintaining the integrity of the ceramic-based materials, while reducing the influence of thermal and mechanical stresses on the sensor adherence.
Implementation Method 1
a compliant layer that mitigates thermo-mechanical forces and enhances adherence by matching thermal expansion
Implementation Method 2
the conformal electronic device includes a piezoresistive sensor
Data Source
Figure 1~5
Figure 6A~6B
AI summary
An instrumented article (20; 120; 220; 320; 420; 520) includes a ceramic-based substrate (22) and at least one conformal electronic device (24; 524a, 524b) deposited on a surface of the ceramic-based substrate (22). A compliant layer (26) is located between the ceramic-based substrate (22) and the one or more conformal electronic devices (24; 524a, 524b). The compliant layer (26) has a thermal expansion that is intermediate of the thermal expansions of, respectively, the ceramic-based substrate (22) and the one or more conformal electronic devices (24; 524a, 524b).