CMC Panel Attachment Assembly With Spring-Loaded Pin
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Solution Overview
Problem
Gas turbine engine components, such as combustor liners and exhaust nozzles, face challenges in withstanding high-pressure exhaust gas streams, and existing attachment methods may compromise the structural integrity of ceramic matrix composite (CMC) panels.
Innovation Solution
A novel attachment assembly featuring a pin with a spring mechanism that preloads the CMC panel into contact with a liner, utilizing a row of aligned loops and fasteners to secure the panel without compromising its structural integrity, allowing for reliable attachment and reduced force concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a CMC panel is directly fastened to a metal plate by way of a fastener, then the attachment is simple and direct, but the structural integrity of the CMC panel may be compromised due to force concentrations
Solution Approach 1:
A compliant attachment member is introduced as an intermediary between the CMC panel and the metal plate. This compliant member distributes the attachment forces across a larger area of the CMC panel, preventing stress concentrations that would occur with direct fastening, while still achieving secure attachment.
Solution Approach 2:
The attachment system changes the mechanical parameters of the connection by using a compliant member with specific elasticity characteristics. This allows the system to accommodate thermal expansion and contraction differences between the CMC panel and metal plate, reducing stress on the CMC panel while maintaining attachment integrity.
2Force
If rigid fastening methods are used to secure the CMC panel, then the attachment is strong and secure, but the CMC panel is susceptible to damage from thermal stress and pressure fluctuations
Solution Approach 1:
The compliant attachment member is designed with specific elastic properties that allow it to flex and absorb thermal stresses and pressure fluctuations. This maintains a secure attachment while protecting the CMC panel from damage that would occur with rigid fastening methods.
Solution Approach 2:
The compliant member acts as a cushioning element that anticipates and absorbs thermal and pressure stresses before they can damage the CMC panel. This pre-cushioning effect protects the panel during normal operation and transient conditions.
3Area of stationary object
If the CMC panel is tightly constrained to the metal plate, then the protective coverage is maximized, but the panel cannot accommodate thermal expansion and contraction
Solution Approach 1:
The compliant attachment member's elastic properties allow the CMC panel to maintain full contact with the metal plate for maximum protective coverage while simultaneously accommodating thermal expansion and contraction. The compliant member deforms elastically to permit movement without creating gaps in the protective coverage.
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 provides a reliable and structurally sound attachment method for CMC panels, reducing the risk of structural compromise and ensuring effective protection against high-pressure exhaust gases in gas turbine engines.
Implementation Method 1
a spring is provided between the pin and the liner, the spring urging the pin into contact with the loop
Data Source
AI summary
One exemplary embodiment of this disclosure relates to a gas turbine engine. The engine includes a first attachment member including an opening, a second attachment member including a loop at least partially extending through the opening, and a pin between the first attachment member and the loop.